TECHNICAL FIELD

The present invention relates to the field of postural seats and/or postural seat backrests configured to detect a user's posture, for example used for office chairs or transportation vehicle seats. The present invention also relates to a method for determining a user's posture with respect to a support system, for example with respect to a postural seat and/or with respect to a postural seat backrest.

STATE OF THE ART

In contemporary society, people are inclined to spend more than half of their day sitting, for example, in the office, in the car or on the sofa. A very important factor to consider for the health of sedentary individuals is the posture they maintain during the hours they spend sitting. It is well known, in fact, that poor sitting posture can greatly affect the real and perceived well-being of a person. Therefore, it is essential to monitor the sitting posture of sedentary subjects in order to conduct both preventive and informative screening.

Several tools are known at the state of the art to monitor the posture of a subject sitting in a chair, such as position sensors and volumetric cameras.

Paloschi et al.'s 2021 article, "Validation and Assessment of a Posture Measurement System with Magneto-Inertial Measurement Units," demonstrates the effective accuracy of inertial systems to monitor the spine posture of sedentary subjects while performing dynamic movements. Despite the excellent correlation between the data obtained from the inertial system and the motion analysis reference system, the authors of the study emphasize the importance of proper positioning of inertial sensors to obtain valid data. Therefore, it would be preferable to use simpler instrumentation to determine spine posture that avoids the placement of sensors on the subjects' bodies.

Mortazavi et al.'s 2018 article, "Stability of Kinect for range of motion analysis in static stretching exercises," highlights the effectiveness of using cameras to determine the position of a user's body joint. However, cameras have the disadvantage of not allowing detection of all poses and occlusions of the subject, as is the case with inertial sensors. In the recent past, several innovative types of seating have been developed to try to reduce issues related to excessive sitting, such as dynamic seating. A 2022 study by Farhani et al., "Implementing Machine Learning Algorithms to Classify Postures and Forecast Motions When Using a Dynamic Chair," explains, however, that dynamic seating does not generally lead to improved lower back discomfort or increased muscle activations. In fact, dynamic chairs are used to replace traditional seating, but most users are not aware of their sitting posture and therefore are unable to use dynamic seating effectively. Based on Farhani et al.'s study, it is therefore clear that one of the main problems of highly sedentary individuals is people's lack of awareness of the muscles involved during sitting and what they need to adjust and improve posture.

The use of sensors to monitor a subject's posture is also known for safety purposes. For example, patent application CN107187467A describes a system and method for measuring a train driver's vital parameters in real time, such as blood pressure and heart rate, but also facial features and joint positions through a Kinect-type camera. These parameters are then compared with reference values of the subject's normal parameters, and if they deviate from them above a threshold value, a warning signal is issued. In this way, the system makes it possible to determine whether the subject is making movements or assuming dangerous postures, so as to ensure the safety of the driver and passengers. However, this system does not integrate camera data with data collected by other sensors, such as force sensors, to determine the driver's seating condition; as a result, it detects the driver's posture in a biased way.

Based on the issues highlighted above, there is a need to develop a system and method to detect and monitor, with great accuracy, a user's posture during the hours he or she spends sitting.

SUMMARY

The present invention is based on the idea of providing a system comprising a seat and/or seat backrest equipped with sensors to detect and monitor a user's posture. The sensors are configured to detect a weight distribution of the user.

In this disclosure, it should be understood that relative terms such as "top", "bottom", "front", "back", and the like refer to the orientation shown in the figures. Specifically, in the present disclosure, the ground (or floor) on which the chair rests determines a preferred orientation of the system and defines the lower part of the system. The expression "lower limbs" is specifically used to refer to the appendages that articulate with the trunk in its lower part, namely hip, thigh, knee, leg, ankle, tarsus, metatarsus, and phalanges. The expression "upper limbs" is used to refer to the appendages that articulate with the trunk in its upper part, namely shoulder, arm, elbow, forearm, carpus, metacarpus, and phalanges.

In this disclosure, it should also be understood that the term "posture" can indicate the position a subject's body takes in space and/or the spatial relationship between various parts of the body (e.g., limbs, back, neck, head).

In this disclosure, an infotainment system shall be understood to include a system for the enjoyment of visual and/or auditory information.

According to one aspect of the present invention, a seat system is provided for a user configured to detect the user's posture, where the user has a weighted body and the seat system includes the following elements: a seat configured to support the user and transfer at least some of the weight to the ground; a data transmission unit; a control unit; characterized by the fact that the seat includes a plurality of sensors for detecting a weight distribution on the seat, and the control unit is configured to receive data from the distribution- related sensors via the data transmission unit, preferably in wireless mode, and to process it to determine the user's posture relative to the seat.

The advantage of this system is that it allows the subject's posture to be monitored, on a constant basis, with respect to sitting and, consequently, to intervene in a targeted and specific manner to correct any posture defects or problems related to excessive sedentariness. For example, this system allows intervention through ad hoc mini-training if the user sits for too long (e.g., more than half an hour at a time), or sits in the same position for too long (e.g., more than ten minutes at a time), or adopts an asymmetrical posture in sitting.

This system also has the advantage of increasing the user's awareness during sitting, in order to make him/her aware of the amount of time he/she remains immobile and/or sitting asymmetrically on the seat. The seat system is then configured to accompany the user on a path in which he/she activates all muscle groups of interest to correct posture. According to a preferred configuration, the seat sensors allow a spatial distribution of the user's weight force on the seat to be determined.

In the present disclosure, it should be understood that "determining the user's posture with respect to the seat" refers to determining at least one parameter, e.g., the center of loading and/or area of sway that allows the user's posture with respect to sitting (e.g., lower limb support conditions) to be identified. A user's load center refers to the weighted average of the pressures or forces applied to a support surface relative to a set of defined positions on that surface. The sway area indicates a set of positions of application of pressures, or forces, by the user around the load center. The sway area is approximated by an ellipse comprising 95 percent of the positions of application of pressures, or forces, by the user around the load center.

According to an embodiment of the present invention, a seat system is provided, where the seat is configured to rotate around an antero-posterior axis and/or around a mid-lateral axis and/or around an axis perpendicular to the ground.

The advantage of this configuration is that the seat is movable and thus allows the user to perform mobilizing movements of the spine and/or pelvis while sitting. Specifically, because the seat can swing around an antero-posterior axis and/or around a mid-lateral axis, the user can perform tilting and rotational movements of the spine and pelvis.

Antero-posterior axis means an axis parallel to the ground and parallel to an axis passing from the front to the back of the user when the user sits on the seat in the correct posture and position.

The mid-lateral axis indicates an axis parallel to the ground and parallel to an axis passing from the right side to the left side of the user when the user sits on the seat in the correct posture and position.

Preferably, the seat is configured to move along a frontal plane and/or along a sagittal plane of the user, where frontal plane means an ideal plane that runs parallel to the user's forehead and divides the body into a front and a back part, and sagittal plane means the ideal plane passing through the longitudinal axis of the body, which divides the body into two mirror-symmetrical left and right halves.

According to a preferred alternative configuration, the seat can be configured to swing and rotate selectively around an antero-posterior axis or around a mid-lateral axis. According to an alternative preferred configuration, the seat can be configured to swing and rotate around both antero-posterior and mid-lateral axes.

According to a further embodiment of the present invention, a seat system is provided, where sensors include force sensors, for example load cells.

The advantage of this configuration is that the force sensors allow the user to determine the weight force applied to the seat by the user and subsequently estimate the user's center of body pressure and sway in order to measure the amount of movement the subject makes in a time frame.

The advantage of load cells is that they have a high and linear full-scale. In addition, they have high accuracy and precision in measurement. For example, load cells can take advantage of strain-gauge or piezoelectric or resistive technology.

Preferably, at least three force sensors are applied to the seat.

According to a further embodiment of the present invention, a seat system is provided, where sensors include pressure sensors.

The advantage of this configuration is that the pressure sensors make it possible to determine the spatial distribution of the pressure exerted by the user on the seat and subsequently estimate the center of pressure of the user's body and its sway, in order to measure the amount of movement the subject makes in a time frame. Pressure sensors also make it possible to determine the subject's absolute position on the seat and the posture he or she is adopting in real time.

Preferably, at least three pressure sensors are applied to the seat.

According to a further embodiment of the present invention, a seat system is provided, where the seat has a center, for example, a center of symmetry, and the sensors are arranged radially with respect to the center.

The advantage of this solution is that it is possible to minimize the number of sensors applied to the seat while still obtaining a valid measure of the distribution of weight and/or pressures exerted by the subject during the seat. Preferably, eight sensors are placed on the seat radially from the center of the seat. For example, the center of the seat may be the center of symmetry of the seat if it is in the shape of a circle and/or a symmetrical polygon.

According to a further embodiment of the present invention, a seat system is provided, where sensors are arranged on the seat to form an array.

The advantage of this solution is that it is possible to obtain a homogeneous and uniform measurement of the distribution of weight and/or pressures exerted by the subject during sitting, since the sensors are evenly distributed over the seat and are organized in rows and columns of a matrix.

For example, the sensors can be distributed on the seat to form a matrix having between four and fifty rows and between four and fifty columns, depending on the size of the individual sensor and/or the area of the seat. Preferably, the number of rows can be equal to the number of columns.

According to a further embodiment of the present invention, a seat system is provided, wherein the seat system further comprises one or more vibro-tactile actuators placed on the seat and configured to transmit haptic signals to the user.

The advantage of this configuration is that it allows vibro-tactile feedback to be provided to the user's body under predefined conditions, without disturbing any nearby users and without disturbing the subject while working. For example, such feedback can be used to provide a warning to the user that a mini-workout needs to be started, without interruption on the working monitor. For example, during the performance of a sequence of lower and/or upper limb mobilization exercises, such feedback can be used to indicate the direction in which the user should move, whether in static or dynamic sitting conditions. For example, during a sequence of breathing or mindfulness exercises, vibro-tactile feedback can be used to provide the rhythm of inhalation and exhalation to the user.

It is possible to perform this exercise while continuing to work, although for mental and physical well-being it is good to use it as a break time.

Preferably, the actuator vibrates with an increasingly higher frequency until the target is reached.

Preferably, there are eight actuators inside the seat backrest that vibrate to provide vibro-tactile feedback to the user's body. According to a further embodiment of the present invention, a seat system is provided, wherein the seat system further comprises an orientation sensor configured to detect a seating orientation, for example, an orientation following rotation about an antero-posterior axis and/or a mid-lateral axis and/or an axis perpendicular to the ground. In this case, the control unit is configured to also receive data from the orientation sensor via the data transmission unit, preferably in wireless mode.

The advantage of this configuration is that it allows the user to detect the orientation of the seat and measure, for example, an angle formed between the seat and a seat support structure. In this way, the user's posture can be monitored while performing mobilization movements of the spine and/or pelvis while sitting.

For example, the orientation sensor may include an inertial sensor. For example, the orientation sensor may include a rotation sensor, such as an encoder.

According to another aspect of the present invention, a seat backrest system is provided for a user configured to detect the user's posture, where the user has a weighted body, and the seat backrest system includes the following elements: a seat backrest configured to support the user and transfer at least some of the weight to the ground; a data transmission unit; a control unit; characterized by the fact that the seat backrest includes a plurality of sensors for detecting a distribution of weight on the seat backrest, and the control unit is configured to receive data from the sensors related to the distribution via the data transmission unit, preferably in wireless mode, and to process it to determine the user's posture relative to the seat backrest.

The advantage of this system is that it allows the user's posture with respect to the seat backrest to be monitored, on a constant basis, and, consequently, to intervene in a targeted and specific manner to correct any posture defects or problems related to excessive sedentariness. For example, this system allows intervention through ad hoc mini-workouts if the user sits for too long (e.g., more than half an hour at a time), or sits in the same position for too long (e.g., more than ten minutes at a time), or adopts an asymmetrical posture with respect to the seat backrest. This system also has the advantage of increasing the user's awareness during sitting, in order to make him/her aware of the amount of time he/she remains immobile and/or sits asymmetrically to the seat backrest. The seat backrest system is then configured to accompany the user on a path in which he/she activates all muscle groups of interest to correct posture.

In this disclosure, it should be understood that "determining the user's posture with respect to the seat backrest" means determining at least one parameter, e.g., the symmetry index, to identify the user's posture on the seat backrest (e.g., the condition of the back and/or upper limbs on the seat backrest). The symmetry index is an indicator of the symmetry of the forces or pressures applied on a support surface ideally divided into two parts. The more the symmetry index tends to 0, the more symmetrical the applied forces or pressures are on the support surface.

According to a preferred configuration, seat backrest sensors allow a spatial distribution of the user's weight force on the seat backrest to be determined.

According to a further embodiment of the present invention, a seat backrest system is provided, where the seat backrest comprises a first portion and a second portion, the second portion being independent of the first portion, where the plurality of sensors is divided, preferably equally, between the first portion and the second portion.

The advantage of this configuration is that it allows independent measurement of the forces and/or pressures exerted by the user on each portion of the seat backrest, since the two portions are mechanically separated from each other.

In fact, it should be understood that the two portions are mechanically independent and thus allow for independent measurement of applied forces.

Preferably, the first and second portions include a right portion of the seat backrest and a left portion of the seat backrest, and thus the system allows for independent measurement of the forces and/or pressures exerted by the user on the right and left portions of the seat backrest.

According to a further embodiment of the present invention, a seat backrest system is provided, where the second portion is symmetrical with respect to the first portion and the plurality of sensors is equally and symmetrically divided between the first portion and the second portion.

The advantage of this configuration is that it allows for accurate measurement of the forces and pressures exerted by the user on the two portions of the seat backrest, because the two portions include an equal number of sensors and these sensors are symmetrically divided between the two portions, and thus the system has a homogeneous and uniform distribution of force and pressure data.

Preferably, the first and second portions are defined symmetrically with respect to an axis perpendicular to the ground.

According to a preferred configuration, the first portion may in turn comprise an upper half-portion and a lower half-portion, where the upper half-portion is placed at the scapular area of the user's back and the lower half-portion is placed at the lumbar area of the user's back. Preferably, the sensors of the first portion are symmetrically and evenly distributed between the upper semiportion and the lower semi-portion. In this way, the load difference between the scapular area and the lumbar area of one half of the user's back resting on the first portion of the seat backrest can be determined.

Similarly, according to a preferred configuration, the second portion may itself include an upper and a lower half-portion, and the sensors in the second portion may be symmetrically and evenly distributed between the upper half-portion and the lower half-portion.

Due to the symmetrical distribution of sensors on the seat backrest, divided between the first and second portions and between the upper and lower half-portions, it is possible to determine the load difference between the scapular and lumbar parts of the back.

According to a further embodiment of the present invention, a seat backrest system is provided, where sensors include force sensors, for example load cells.

The advantage of this configuration is that the force sensors allow the user to determine the weight force applied to the seat backrest by the user and subsequently calculate the user's center of body pressure and sway in order to measure the amount of movement the subject makes in a time frame.

According to a further embodiment of the present invention, a seat backrest system is provided, where the sensors include pressure sensors.

The advantage of this configuration is that the pressure sensors make it possible to determine the spatial distribution of the pressure applied by the user on the seat backrest and subsequently estimate the center of pressure of the user's body and its sway, in order to measure the amount of movement the subject makes in a time frame. Pressure sensors make it possible to determine the subject's absolute position on the seat backrest and the posture he or she is adopting in real time.

According to a further embodiment of the present invention, a seat backrest system is provided, where the seat backrest is configured to rotate around a mid-lateral axis.

The advantage of this configuration is that the seat backrest is movable and thus allows the user to perform mobilization movements of the hip and spine joints in the flexion-extension plane while sitting.

According to a further embodiment of the present invention, a seat backrest system is provided, further comprising one or more vibro-tactile actuators placed on the seat backrest and configured to transmit haptic signals to the user.

The advantage of this configuration is that it allows vibro-tactile feedback to be provided to the user's body under predefined alert conditions, without disturbing any nearby users and without disturbing the subject while working. For example, such feedback can be used to provide a warning to the user that a mini-workout needs to begin, without interruption on the working monitor. For example, during the performance of a sequence of lower and/or upper limb mobilization exercises, such feedback can be used to indicate the direction in which the user should move. For example, during a sequence of breathing or mindfulness exercises, vibro-tactile feedback can be used to provide the rhythm of inhalation and exhalation to the user.

It is possible to perform this exercise while continuing to work, although for mental and physical well-being it is good to use it as a break time.

Preferably, the actuator vibrates with an increasingly higher frequency until the target is reached.

Preferably, there are eight actuators inside the seat backrest that vibrate to provide vibro-tactile feedback to the user's body.

According to a further embodiment of the present invention, a seat backrest system is provided comprising, in addition, an orientation sensor configured to detect an orientation of the seat backrest, for example, an orientation following rotation about a mid-lateral axis and/or about an axis perpendicular to the ground. In this case, the control unit is configured to also receive data from the orientation sensor via the data transmission unit, preferably in wireless mode. The advantage of this configuration is that it allows the user to detect the orientation of the seat backrest and measure, for example, an angle formed between the seat backrest and a seat backrest support structure. Thus, it is possible to monitorthe user's back posture while performing hip joint and spine mobilization movements in the flexion-extension plane while sitting. In addition, it is possible to monitor the user's posture while performing rotational movements of the trunk with respect to the lower limbs.

For example, the orientation sensor may include an inertial sensor. For example, the orientation sensor may include an encoder.

According to a further embodiment of the present invention, a seat system such as those defined above or a seat backrest system such as those defined above is provided additionally comprising a camera to detect a user's position in space, where the control unit is configured to also collect data, related to position, detected by the camera and to combine it with the data detected by the sensors, so as to derive the user's posture with respect to the seat or seat backrest.

The advantage of this solution is that, thanks to the multiplicity of sensors in the seating and/or seat backrest system and the interpolation of data collected in real time by the camera, an accurate estimate of the subject's posture can be made. Constant posture detection is used to constantly monitor the quality of postures adopted by the subject, providing suggestions on how to improve them. In addition, thanks to the camera, the system is able to detect the user's upper limb support plane, estimating its correct height and tilt and providing suggestions on what adjustments to make in order to be as close as possible to ergonomic guidelines.

Preferably, the camera is installed on the computer monitor used by the user.

According to a preferred configuration, the control unit is configured to provide a set of parameters related to a user's posture, obtained through the sensors placed on the seat or seat backrest system, such as the center of pressure, area of sway, and/or symmetry index, and to additionally provide a set of parameters related to a user's posture obtained by means of the camera of the seat and/or seat backrest system, for example, the absolute position of the user in space and/or with respect to the seat and/or seat backrest system. In this way, the control unit is able to define and characterize the user's posture more accurately than a system for postural detection that include only part of the sensors (e.g., only the force and/or pressure sensors or only the camera). According to a further preferred configuration, the control unit is configured to determine a user's posture based on a first reference system defined by the sensors of the seating and/or seat backrest system, to then determine a user's posture based on a second reference system defined by the camera, and to combine the two reference systems in order to determine a user's posture in a third reference system, obtained by applying an appropriate transformation on the first reference system and an appropriate transformation on the second reference system, so that the data from the sensors and the camera can be integrated.

According to a further embodiment of the present invention, a seat system such as those defined above or a seat backrest system such as those defined above is provided, where the camera includes a camera of the RGB type or RGBD type or Depth type.

The advantage of the RGB camera is that it reduces the production cost of the system and enables the detection of the user's articular joints in two-dimensional space.

The advantage of the Depth camera is that it enables the detection of the user's articular joints in three-dimensional space.

The advantage of the RGBD camera is that it enables the detection of the user's articular joints in three-dimensional space with greater accuracy.

According to a further embodiment of the present invention, there is provided a seat system such as those defined above or a seat backrest system such as those defined above further comprising an infotainment system configured to transmit visual and/or audible signals to the user.

The advantage of this system is that it allows audio-visual feedback to be sent to the user to alert him or her that he or she has been sitting too long in the same position or that the sitting posture is asymmetrical. Audio-visual feedbacks are easily interpreted by the user and can guide him or her in improving posture and sitting conditions. For example, if the subject has been sitting for too long, audio-visual feedback can prompt him or her to get up and perform a walk for a few minutes, possibly performing lower limb movements to allow more blood flow to the lower body. For example, if the subject has been sitting in the same position for too long, audio-visual feedback can prompt him or her to perform a series of exercises, while sitting, to raise awareness and mobilize the lower spine area. For example, if the subject is maintaining an asymmetrical pose held for medium length of time, audio-visual feedback may prompt him to recover a more symmetrical posture and then to perform a series of exercises to enable him to regain awareness of his posture.

According to a preferred embodiment of the present invention, a seat system or a seat backrest system is provided, wherein the control unit is programmed to compare the user's posture with a reference posture and to determine a deviation from that reference posture and, if such deviation exceeds a predefined threshold, the control unit is programmed to control the infotainment system and/orthe one or more vibro-tactile actuators to cause visual and/or audible, and/or tactile signals to be emitted, respectively, in order to invite the user to perform at least one movement to achieve the reference posture.

Preferably, if the subject's posture deviates from the reference posture above a certain threshold, audio-visual and/or vibro-tactile feedback is provided to the user after a predefined time interval that is inversely proportional to how incorrect the posture is: the more the user's posture deviates from the reference posture, the less time the user is left in that position.

According to another aspect of the present invention, a system for postural detection is provided comprising: a seat system such as those defined above; and a seat backrest system such as those defined above.

The advantage of this system is that it allows the user's posture to be monitored, on a constant basis, with respect to the seat and seat backrest and, consequently, to intervene in a targeted and specific manner to correct any posture defects or problems related to excessive sedentariness. For example, this system allows intervention through ad hoc mini-workouts if the user sits for too long (e.g., more than half an hour at a time), or sits in the same position for too long (e.g., more than ten minutes at a time), or adopts an asymmetrical posture in sitting.

This system also has the advantage of increasing the user's awareness during sitting, in order to make him/her aware of the amount of time he/she remains immobile and/or sits asymmetrically in relation to the seat or seat backrest. The seat system is then configured to accompany the user on a path in which he/she activates all muscle groups of interest to correct posture.

According to a preferred configuration, the system for postural detection includes a seat and seat backrest integral with each other and mounted on a support base in contact with the ground; the seat and seat backrest can be configured to rotate about an axis perpendicular to the ground, and the system for postural detection can then advantageously include an angular measurement sensor to detect and quantify this rotation. For example, a measurement sensor is a rotary encoder or potentiometer.

According to a preferred configuration, the system for postural detection includes a seat equipped with sensors and a seat backrest equipped with sensors and a single camera.

According to another aspect of the present invention, an office chair is provided comprising a seat system such as those defined above, or a seat backrest system such as those defined above, or a system for postural detection.

The advantage of this configuration is that it allows the user's posture to be monitored during working hours spent sitting, helps the user become aware of his or her posture, and helps the user improve it through a series of lower and/or upper limb mobilization exercises.

According to a further embodiment of the present invention, a seat of a means of transportation, for example of a train, automobile, or airplane, is provided, including a seat system such as those defined above, or a seat backrest system such as those defined above, or a system for postural detection.

The advantage of this configuration is that it allows the driver's or rider's posture to be monitored while driving for the purpose of ensuring driving and passenger safety, if the seating, seat backrest, and/or system for postural detection is used for driver or rider seats. If, on the other hand, the seating, seat backrest, and/or system for postural detection is used for the seats of transport passengers, this solution promotes the mobilization of the subject during travel hours when freedom of movement is generally limited.

According to a further embodiment of the present invention, a method is provided for determining the posture of a user with respect to a support system, wherein the user has a weighted body and the support system is configured to support the user and transfer at least a portion of the user's weight to the ground, wherein the method comprises the following steps: a) Detect a weight distribution on the support system by a plurality of sensors placed in the support system; b) Transmit the data collected from the sensors, related to weight distribution, to a control unit; c) Process the data in order to derive the user's posture with respect to the support system. In this disclosure, it should be understood that the term "support system" means a seat and/or a seat backrest and/or a chair.

The advantage of this method is that it allows the subject's posture to be monitored, on a constant basis, with respect to sitting and, consequently, to intervene in a targeted and specific manner to correct any posture defects or problems related to excessive sedentariness. For example, this method allows intervention through ad hoc mini-workouts if the user sits for too long (e.g., more than half an hour at a time), or sits in the same position for too long (e.g., more than ten minutes at a time), or adopts an asymmetrical posture in sitting.

This method also has the advantage of increasing the user's awareness during sitting in order to make him/her aware of the amount of time he/she remains immobile and/or sitting asymmetrically on the seat. The seat system is then configured to accompany the user on a path in which he/she activates all muscle groups of interest to correct posture.

According to a preferred configuration, the method of the present invention allows a spatial distribution of the user's weight on the support system to be detected by the plurality of sensors.

According to a further embodiment of the present invention, a method is provided that further includes the following steps: d) Detect a user's position in space using a camera; e) Combine distribution and position in order to derive the user's posture with respect to the support system.

The advantage of this solution is that by combining the data collected by the sensors and the data collected in real time by the camera, an accurate estimate of the subject's posture can be made. Constant posture detection is used to constantly monitor the quality of postures adopted by the subject, providing suggestions on how to improve them. In addition, thanks to the camera, the system is able to detect the user's upper limb support plane, estimating its correct height and tilt and providing suggestions on what adjustments to make in order to be as close as possible to ergonomic guidelines.

According to a preferred configuration, step (e) includes providing a set of parameters related to a user's posture obtained through the sensors placed on the support system, such as the center of pressure, area of sway, and/or symmetry index, and additionally providing a set of parameters related to a user's posture obtained through the camera of the support system, for example, the absolute position of the user in space and/or with respect to the support system. In this way, the user's posture is more accurately defined and characterized than with a system for postural detection comprising only part of the sensors (e.g., only the force and/or pressure sensors or only the camera).

According to a further preferred configuration, step (e) includes determining a user's posture based on a first reference system defined by the sensors of the support system, then determining a user's posture based on a second reference system defined by the camera, and combining the two reference systems in order to determine a user's posture in a third reference system, obtained by applying an appropriate transformation on the first reference system and an appropriate transformation on the second reference system, so that the data from the sensors and the camera can be integrated.

According to a further embodiment of the present invention, a method is provided where step (d) includes detecting predefined elements of the user's body, preferably a plurality of the user's articular joints.

The advantage of this method is that it is possible to reconstruct a user's position from the position of one or more articular joints (e.g., shoulders and elbows) relative to the support system, where the positions of these articular joints can be detected by a camera.

According to a preferred configuration, the user sits in a postural sensing chair and leans against a table, such as a work desk. The camera can identify the table top and estimate its position and orientation in space, and can also detect how the user leans on the table, for example, whether and which of the user's articular joints are resting on the table. Through this function, it is possible to suggest what tilt and height adjustments to implement on the table top in order to optimize the subject's posture when interacting with the table top.

According to a preferred configuration, the user sits in a postural sensing chair equipped with arms and rests his or her upper limbs on the chair arms. The camera can identify the chair arms and estimate their position and orientation in space, and it can also detect how the user leans on them, for example, whether and which of the user's articular joints are resting on the chair arms. Through this function, it is possible to suggest what tilt and height adjustments to implement on the chair arms in order to optimize the subject's posture. According to a further embodiment of the present invention, a method is provided, where step (d) includes detecting a position of the user with respect to the support system.

The advantage of this method is that it makes it easy and accurate to determine whether the user is positioned correctly with respect to the support system.

For example, it is possible to determine whether the user is positioned asymmetrically with respect to the seat backrest.

According to a further embodiment of the present invention, a method is provided where the plurality of sensors includes force sensors, for example load cells, and step (a) includes determining the weight force applied by the user on a surface of the support system.

The advantage of this configuration is that force sensors allow the user to determine the weight force applied to the seat by the user and subsequently estimate the user's center of body pressure and sway in order to measure the amount of movement the subject makes in a time frame. In addition, force sensors allow for lower production costs.

The advantage of load cells is that they have a high and linear full-scale. For example, load cells can take advantage of strain-gauge or piezoelectric or resistive technology.

According to a further embodiment of the present invention, a method is provided, where the plurality of sensors includes pressure sensors and step (a) includes determining a distribution of pressure exerted by weight on a surface of the support system.

The advantage of this configuration is that the pressure sensors make it possible to determine the spatial distribution of the pressure exerted by the user on the seat and subsequently estimate the center of pressure of the user's body and its sway, in order to measure the amount of movement the subject makes in a time frame. Pressure sensors also make it possible to determine the subject's absolute position on the seat and the posture he or she is adopting in real time.

According to a further embodiment of the present invention, a method is provided, where step (c) includes determining a load center and swing area of the user's body on the support system and/or determining the symmetry index of the user's body on the support system.

Y1 The advantage of this solution is that it makes it possible to determine some of the parameters needed to define a user's posture and thus determine, for example, whether that posture is asymmetrical.

Preferably, the load center and swing area are determined with sensors placed on the seat.

Preferably, the symmetry index is determined with sensors placed on the seat backrest.

According to a further embodiment of the present invention, a method is provided, where the method for determining a user's posture is repeated a plurality of times at predefined time intervals, so that a sequence of postures is determined over time.

The advantage of this solution is that it allows accurate monitoring of the subject's posture and motor status throughout the day.

According to a further embodiment of the present invention, a method comprising the following steps is provided: f) Check whether the user's posture corresponds to a sitting condition for longer than a predefined threshold value; g) If so, emit an audible and/or visual signal via an infotainment system and/or a haptic signal via one or more vibro-tactile actuators placed on the support system to alert the user that at least one movement must be made.

The advantage of this method is that it allows audio-visual feedback to be sent to the user to alert him or her that he or she has been sitting for too long or has been sitting in the same position for too long. Audio-visual feedbacks are easily interpreted by the user and can guide the user in improving posture and sitting conditions. Haptic signals, on the other hand, have the advantage that they do not distract the user from work and do not disturb surrounding people. For example, if the subject has been sitting for too long, audio-visual feedback can prompt him or her to get up and take a walk for a few minutes, possibly making lower limb movements to allow more blood flow to the lower body. For example, if the subject has been sitting in the same position for too long, audio-visual feedback may prompt him to perform a series of exercises, while seated, to raise awareness and mobilize the lower spine area.

For example, at least one movement of the user includes movement of the pelvis and/or lower limbs or involves the user getting up from the seat. For example, the default threshold value for determining that the user has been sitting too long may be two hours.

According to a further embodiment of the present invention, a method is provided, where the method described above for determining a user's posture is repeated a plurality of times at predetermined time intervals, so that a sequence of postures is determined over time.

The advantage of this configuration is that it allows the user's posture to be monitored over time and to check, for example, that the user does not sit too long or maintain an incorrect posture for too long or that mobilization exercises are performed correctly.

According to a preferred configuration, the method for determining a user's posture is repeated a plurality of times at predefined time intervals, where the time intervals are equal and constant in duration. According to an alternative configuration, the method for determining a user's posture is repeated a plurality of times at predefined time intervals, where the time intervals have different and varying durations.

According to a further embodiment of the present invention, a method is provided that further includes the following steps: h) Compare the posture with a reference posture and determine the deviation from the reference posture; i) If the deviation exceeds a predefined threshold value, issue an audible and/or visual signal via an infotainment system and/or a haptic signal via one or more vibro-tactile actuators placed on the support system to invite the user to make at least one movement to approach that reference posture.

The advantage of this method is that it allows audio-visual feedback to be sent to the user to alert him or her that the sitting posture is asymmetrical or unbalanced. Audio-visual feedbacks are easily interpreted by the user and can guide the user in improving posture and sitting conditions. Haptic signals, on the other hand, have the advantage of not distracting the user from work and not disturbing the surrounding people. For example, if the subject is holding an asymmetrical pose held for medium length of time, audio-visual feedback can prompt him to recover a more symmetrical posture and then to perform a series of exercises to enable him to regain awareness of his posture. For example, the reference posture may be the correct sitting posture defined by health guidelines. For example, reference values can be set for the load center, swing area, symmetry index, and/or angles formed between articular joints, and these reference values can be compared with values calculated from sensor and/or camera data.

According to a further embodiment of the present invention, a method is provided, in which steps (h) and (i) are repeated a plurality of times at predetermined time intervals until the deviation from the reference posture is equal to or less than the threshold value.

This method has the advantage of increasing the user's awareness during sitting in order to make him/her aware of the amount of time he/she remains immobile and/or sitting asymmetrically on the seat. The seat system is then configured to accompany the user on a path in which he/she activates all muscle groups of interest to correct posture.

For example, predefined time intervals can be of equal duration with each other or of different durations. For example, the predefined time intervals can be of constant or variable duration. For example, the predefined time intervals can be equal to 10 min.

According to another aspect of the present invention, a computer program is provided that includes instructions that, when the program is executed by a computer, cause the computer to carry out one of the methods defined above.

The advantage of this solution is that the method for determining a user's posture can be effectively performed by means of a computer and thus can be easily implemented in environments where a computer is present, for example, in offices or on transportation vehicles.

According to a preferred configuration, the computer program to detect the user's posture may include a machine learning algorithm. The machine learning algorithm can detect the subject's posture in both static and dynamic conditions, can recognize the subject's main needs, and, through a proprietary algorithm, can suggest a set of suitable and adapted exercises accordingly. For example, if the subject is particularly immobile in his or her sitting postures, the machine learning algorithm will suggest performing pelvic mobilizations more frequently. For example, if the subject is often hunched over with a contracted chest, the machine learning algorithm will suggest shoulder movements so as to require more mobilization and opening of the subject's kyphotic posture. BRIEF DESCRIPTION OF THE FIGURES

The present invention will be described with reference to the attached figures in which the same reference numbers and/or signs indicate the same and/or similar and/or corresponding parts of the system.

Figure 1 schematically illustrates a side view of a system for postural detection according to an embodiment of the present invention.

Figure 2a schematically illustrates a three-dimensional view of a seat according to an embodiment of the present invention.

Figure 2b schematically illustrates a three-dimensional view of a seat according to an embodiment of the present invention.

Figure 3 schematically illustrates a side view of a seat according to an embodiment of the present invention.

Figure 4 schematically illustrates a front view of a seat according to an embodiment of the present invention.

Figure 5 schematically illustrates a front view of a seat backrest according to an embodiment of the present invention.

Figure 6 schematically illustrates a side view of a system for postural detection including a seat and seat backrest according to an embodiment of the present invention.

Figure 7 schematically illustrates a rotation with respect to an axis perpendicular to the ground of a system for postural detection according to an embodiment of the present invention.

Figure 8 schematically illustrates a side view of a system for postural detection including a seat and seat backrest according to an embodiment of the present invention.

Figure 9 schematically illustrates a three-dimensional view of a system for postural detection including a seat and seat backrest according to an embodiment of the present invention.

Figure 10 schematically illustrates a three-dimensional view of a system for postural detection according to an embodiment of the present invention. Figure 11 schematically illustrates a top view of a user sitting on the system for postural detection during one phase of a method for determining the user's thigh posture on the seat, according to an embodiment of the present invention.

Figure 12 schematically illustrates a method for determining the correctness of a user's posture, according to an embodiment of the present invention.

Figure 13 schematically illustrates a front view of a system for postural detection according to an embodiment of the present invention.

Figure 14a schematically illustrates a system for postural detection according to an embodiment of the present invention during a phase of use.

Figure 14b schematically illustrates a system for postural detection according to one embodiment of the present invention during a further phase of use.

Figure 14c schematically illustrates a system for postural detection according to one embodiment of the present invention during a further phase of use.

Figure 14d schematically illustrates a system for postural detection according to one embodiment of the present invention during a further phase of use.

Figure 15a schematically illustrates a system for postural detection comprising a dynamic seat according to an embodiment of the present invention during a phase of use.

Figure 15b schematically illustrates a system for postural detection comprising dynamic seat according to one embodiment of the present invention during a further phase of use.

Figure 15c schematically illustrates a system for postural detection comprising dynamic seat according to one embodiment of the present invention during a further phase of use.

Figure 15d schematically illustrates a system for postural detection comprising dynamic seat according to one embodiment of the present invention during a further phase of use.

Figure 16a schematically illustrates a system for postural detection according to an embodiment of the present invention during a phase of use. Figure 16b schematically illustrates a system for postural detection according to one embodiment of the present invention during a further phase of use.

Figure 17 schematically illustrates a system for postural detection including an infotainment system configured to transmit visual and acoustic signals to the user according to an embodiment of the present invention.

DETAILED DESCRIPTION

In the following, the present invention is described by reference to particular forms of embodiment, as illustrated in the attached figures. However, the present invention is not limited to the particular forms of embodiment described in the following detailed description and depicted in the figures, but rather the forms of embodiment described simply exemplify the various aspects of the present invention, the scope of which is defined by the claims. Further modifications and variations of the present invention will appear clear to the person in the art.

A system for postural detection 100" or a chair for postural detection 100" for a user 14, according to an embodiment of the present invention, is shown schematically in Fig. 1. The user 14 sits at a desk or table 13. The system for postural detection 100" of Fig. 1 includes a seat 12, a seat backrest 8, a camera 10, pressure sensors 16, 16' and/or force sensors 19, 19', a monitor or infotainment system 11 , vibro-tactile actuators 18, a data transmission unit 23, 23', and a control unit 20, 20'.

The seat 12 and seat backrest 8 are configured to support the user 14's lower limbs and trunk, respectively, and to unload the user 14's weight ergonomically to the ground. The sensing elements allow complete and accurate detection of the user's entire body 14 in three-dimensional space and include a camera 10, a plurality of pressure sensors 16, 16' and a plurality of force sensors 19, 19'. The monitor or infotainment system 11 is used to provide visual and acoustic feedback to the subject, while vibrotactile actuators 18 are used to provide haptic feedback to the subject. The data transmission unit 23, 23' is preferably integrated into the chair 100' and is configured both to collect data from sensors 16, 16' and 19, 19' and to transmit them, preferably wirelessly, to control unit 20, 20', and to receive data from control unit 20, 20' and to manage actuators 18, 18'. Finally, the control unit 20, 20' includes an electronic system that enables interfacing with sensors 16, 16', 19, 19' and actuators 18, 18', processing of received signals, enjoyment of monitor 11 content, and connection of the system to the Internet on a proprietary cloud platform 21. Although the system for postural detection 100" depicted in Fig. 1 includes both a seat 12 and a seat backrest 8 comprising sensors for detecting the user's position 14, it should be understood that a system for postural detection 100" according to the present invention could include only the seat 12 equipped with sensors or only the seat backrest 8 equipped with sensors, without going outside the scope of protection of the present invention.

The reference system used in this disclosure is schematically illustrated in Fig. 1. The reference system is also reproduced, for clarity, in Figures 2a through 17 and comprises a trio of axes, namely, the vertical axis v (axis perpendicular to the ground), the antero-posterior axis AP (axis parallel to an axis passing from the front to the back of the user, when seated as shown for example in Fig. 1), and the mid-lateral axis ML (axis parallel to an axis passing from the left to the right side of the user, when seated as shown for example in Fig. 1). In this reference system, "yaw," "roll," and "pitch" angles are defined with reference to rotations around the vertical, anteroposterior, and medio-lateral axes, respectively.

The structure of seat 12 is described in more detail with reference to Figs. 2a and 2b.

The seat 12 includes a rigid part 15, a padding part 17, and a plurality of sensors 16, 19 positioned between the rigid part 15 and the padding 17. The plurality of sensors 16, 19 can be arranged radially around the center of the seat 12, as shown in Fig. 2a, or, alternatively, can be arranged in rows and columns to form a matrix, as shown in Fig. 2b. The sensors 16, 19 are preferably embedded in a film of plastic material, capable of adapting to surfaces of various types and shapes and possibly integrating within the soft upholstery materials 17.

Seat 12 sensors 16, 19 may include force sensors, for example load cells, or pressure sensors. Load cells 16 can be based on strain gauge or piezoelectric technology and are configured to measure the weight force applied by the user 14 on seat 12 and to determine the center of load on seat 12. Given the size of the load cells of known type, the minimum number of load cells 16 needed to measure the weight force of user 14 and the load center is three. Preferably, four load cells 16 are applied on a seat 12. However, a different number of load cells 16 can also be applied on seat 12, for example, three, five, six or more.

Pressure sensors 19 are configured to measure the pressure applied by the user 14 at a predefined location on seat 12. Preferably, a plurality of pressure sensors 19 is used on the seat 12, so that a "map" of the pressures applied on the seat 12 is made. For example, the pressure sensors 19 may be arranged on a pressure mat applied to the seat 12. Given the size of pressure sensors of known types, the minimum number of pressure sensors 19 needed to measure the spatial distribution of pressure exerted by the user 14 on the seat 12 is eight. Preferably, the pressure sensors are arranged in rows and columns to form a sensor array of size 50x50.

It should be understood that the seat 12 according to the present invention may include either only load cells, or only pressure sensors, or even a combination of load cells and pressure sensors.

As can be seen in Fig. 2a and 2b, there are also vibrotactile actuators 18 inside the padding 17 of the seat 12 that are configured to transmit a haptic signal to the user 14 during the hours he spends sitting. For example, the vibrotactile actuators 18 can be used to transmit a haptic signal to the user 14 and to guide him in the movements performed via the postural chair 100", as described below. Preferably, the vibrotactile actuators 18 are distributed radially around the center C of the seat 12. Although eight vibrotactile actuators 18 are depicted in Fig. 2a and 2b, it should be understood that any numberof vibrotactile actuators 18 can be realized in seat 12, forexample, one, two, three, or more.

Seat 12 can be made to be free to rotate with two degrees of freedom, that is, to rotate around the antero-posterior AP and mid-lateral ML axes of seat 12.

The ability to rotate or swing the seat 12 is provided by a joint 9. Joint 9 can be, for example, a universal joint or a constant velocity joint. Preferably, the rigid portion 15 of the seat 12 is integral with the upper portion of the joint 9. The antero-posterior axis A P and the mid-lateral axis ML meet in the joint 9 of the seat 12.

The rotations of the seat 12 around the antero-posterior AP and mid-lateral ML axes are mediated by an unlocking mechanism 7. Unlocking mechanism 7 can be configured to mechanically lock seat 12 in a neutral position that allows user 14 to sit easily and unlock it when needed, thus allowing rotational movements around the antero-posterior AP and medio-lateral ML axes.

Unlocking mechanism 7 can also include passive electromechanical actuators, which can lock/unlock the seat 12, set predefined values of resistance to movement, limit the range of movement, and change the resistance as the user's position 14 and the seat 12 change.

Unlocking mechanism 7 can also include active electromechanical actuators, which can perform the same functions as passive electromechanical actuators, with in addition the ability to mobilize the user. It should be understood that the unlocking mechanism 7 according to the present invention can also be selective for a single movement, allowing only rotation around the antero-posterior axis AP or around the mid-lateral axis ML.

Seat 12 can also include an inertial sensor 22 consisting of a triaxial accelerometer and a triaxial gyroscope. Through the inertial sensor 22, the orientation of seat 12, rotations with respect to the antero-posterior AP and mid-lateral ML axes, and oscillations with respect to the equilibrium position can be uniquely identified in real time.

Fig. 3 shows schematically an oscillation of seat 12 with respect to a ML mid-lateral axis of seat 12. Oscillations are preferably limited to +/- 5° from the medio-lateral axis.

Fig. 4 shows schematically an oscillation of seat 12 with respect to an antero-posterior axis AP. Oscillations are preferably limited to +/- 5° with respect to the antero-posterior axis.

Seat backrest 8 of the system for postural detection 100" is described with reference to Fig. 5. Seat backrest 8 is divided into a first portion 8a and a second portion 8b. Each portion 8a, 8b comprises an outer layer of elastic material, which in turn comprises padding 17 and upholstery, and an inner layer of rigid material. The inner layer includes force and/or pressure sensors 16', 19' capable of reading the forces and/or pressures applied on each support portion. The force and/or pressure sensors 16', 19' applied to the seat backrest 8 are analogous to the force and/or pressure sensors 16, 19 applied to the seat 12 and described above.

There are also vibrotactile actuators 18' inside the padding 17 of the seat backrest 8 configured to transmit a haptic signal to the user's back 14 during the hours he spends sitting. For example, the vibrotactile actuators 18' can be used to transmit a haptic signal to user 14 and to guide him in movements performed via the postural chair 100", as described below. Although four 18' vibrotactile actuators are shown in Fig. 5, it should be understood that any number of 18' vibrotactile actuators can be realized in the seat backrest 8, for example, one, two, three, five, or more.

The seat backrest 8 can be made to rotate around a mid-lateral axis ML, so as to promote the mobility of the user's back 14. These rotations occur by means of a joint 29 comprising a torsional spring configured to allow the movement of the seat backrest 8 itself and to ensure its return to an upright position when required. The oscillation of the seat backrest 8 can be locked in the upright position by means of a handle 30 that acts on the joint 29, mechanically locking it. Fig. 6 shows schematically an oscillation of the seat backrest 8 with respect to a mid-lateral ML axis of the seat 12.

As shown in Fig. 6, seatback 8 also includes an inertial sensor 28 consisting of a triaxial accelerometer and a triaxial gyroscope. Through the inertial sensor 28, it is possible to uniquely and in real time identify the orientation of seatback 8 and the oscillations from the equilibrium position. In addition, it is possible to recognize seatback 8 from camera 10 and thus define its position and orientation in space, as will be described later.

Seat 12 and seat backrest 8 described above are preferably combined to form a system for postural detection 100" or a chair for postural detection 100" such as the one schematically shown in Fig. 7, 8 and 9. However, it should be understood that seat 12 and seat backrest 8 can also be made separately. For example, it is possible to realize a system for postural detection 100 in which the seat 12 is configured as described above, while the seat backrest is of the type known to the state of the art (e.g., the seat backrest may not include the force and/or pressure sensors described above and/or may not be configured to perform oscillations). Similarly, it is possible to make, for example, a system for postural detection 100' in which the seat backrest s is configured as described above, while the seat is of a type known to the state of the art (e.g., the seat may not include the force and/or pressure sensors described above and/or may not be configured to perform oscillations).

The system for postural detection 100" in Figs. 7, 8 and 9 is configured as an office chair. The chair for postural detection 100" includes seat backrest 8 and seat 12, which are mounted on top of a base 1 with an integrated gas spring 2 to adjust the height of the seat 12 and to cushion the weight of the user 14. The base 1 is supported by a plurality of casters 3 configured to smoothly move the chair 100" and to adjust the distance between the user 14 and the monitor or infotainment system 11. The seat 12 and seat backrest 8 are supported and connected by a support structure 6. Support structure 6 includes two integrated forearm supports 5, which are adjustable in height, and two unlocking mechanisms 7 for managing seat inclinations 12.

As seen in Fig. 7, the coupling between the support structure 6 and the gas spring 2 is released in rotation in the vertical axis (v). In this way, the user can make a rotation of the pelvis on a horizontal plane and parallel to the ground while keeping the trunk fixed. Fig. 7 schematically shows a rotation of seat 12 and seat backrest 8 around a vertical axis A1. The chair for postural detection 100" in Fig. 8 also includes a sensor 31 to evaluate the position of structure 6, including seat 12 and seat backrest 8, relative to the vertical axis v. Sensor 31 can measure the angle between support structure 6 and gas spring 2 and can be realized through multiple technologies (e.g., incremental encoder, absolute encoder, potentiometer, etc...). In addition, the reading of sensor 31 can be manually zeroed by the user 14 each time he/she positions himself/herself parallel to the monitor 11 , or through camera 10, by inserting appropriate references on the seat backrest 8 that camera 10 can track.

The system for postural detection 100" comprising a seat backrest 8 and/or seat 12 such as those described above, a data transmission unit 23, 23', and a control unit 20, 20' can be advantageously implemented not only in an office chair, as shown in the attached figures, but also in a seat of a means of transportation where many hours in a sitting position are expected, for example, an airplane or train seat.

As shown specifically in Fig. 10, the system for postural detection 100" also includes a camera 10 for determining the user's position 14, for example, with respect to the seat backrest 8 and with respect to the desk or table 13. Camera 10 can be of the RGB, RGBD or Depth type. Camera 10 can be placed on monitor 11 and allows estimation of the posture of the upper body portion of user 14, which is framed by the grip lines, as schematically shown in Fig. 13 and 16b. Thus, the anatomical components that can be analyzed are trunk, head, neck, shoulders, elbows, wrists, hands, and pelvis.

Preferably, during normal sitting the images are acquired at a low frequency (for example, in the range of 1 to 5 Hz), while during exercises they are acquired at a higher frequency (for example, around 30 Hz).

In order to respect the user's privacy, camera 10 can have a data exchange protocol with the processing unit through specific drivers, without recording images, and the data collected by camera 10 can only be used for detecting the posture of the user's upper body portion 14.

The combination of the data collected by sensors 16, 19, 16', 19' and camera 10 allows the user 14's position to be estimated and monitored with high accuracy during the interval of time he spends sitting. As explained above, the force sensors 16, 16' allow estimating the weight force exerted by user 14 on seat 12 and/or seat backrest 8 and calculating its load center, while the pressure sensors 19, 19' allow estimating a spatial distribution of the pressure exerted by user 14 on seat 12 and/or seat backrest 8. Camera 10 also makes it possible to capture the user 14's posture in relation to the plane on which the upper limbs rest and thus to estimate the quality of the upper body position and how it interacts with supports such as desks, tables, or control planks.

By analyzing the position of the body joints and combining this data with pressure information, it is possible to make an estimate of the quality of the posture the user 14 is taking and calculate a percentage value indicating postural goodness. This value, referred to as the postural score, is higher the closer the subject is to the ideal posture defined by ergonomic guidelines. The system for postural detection 100" can then provide suggestions to user 14 to make them make postural adjustments with the aim of getting as close as possible to the ideal posture defined by the guidelines. User 14 can, for example, consult his or her postural score to increase awareness of the correct posture to maintain for all body joints. In addition, the camera 10 can be configured to identify the tabletop 13 and estimate its position and orientation in space. Through this function, it is possible, for example, to suggestwhat tilt and height adjustments to implement on the tabletop 13 in order to optimize the user's posture 14 when interacting with the tabletop.

In cases where the system for postural detection 100' is used on transport vehicles, it is possible to analyze the position of the body joints and combine this data with information regarding the weight and/or pressure distribution of user 14 so as to determine user 14's posture for safe driving purposes. For example, it is possible to determine whether the user 14 assumes a posture that is not appropriate or compatible with safe driving conditions.

Thanks to the multitude of sensors and cameras used, it is possible to monitor the position of the subject 14 and guide him in performing exercises designed to improve his posture awareness and ability to make movements to prevent excessive musculoskeletal stiffness.

Specifically, by combining the parameters of the subject's posture measured through the sensors and the data on the subject's position obtained from the camera, it is possible to precisely define the user's position with respect to the seat and seat backrest ("sensor fusion" functionality). With the sensor fusion functionality, it is possible to view the subject's body segments, such as head, shoulders, trunk, and pelvis, in more detail than with a system including only the sensors or the camera. As a result, the sensor fusion functionality allows for more accurate monitoring of the subject's posture while sitting and while performing required exercises (e.g., exercises aimed at improving posture awareness and/or mobility of rigid segments and/or aimed at strengthening unstable body segments). In addition, thanks to the sensor fusion feature, it is possible to expand the range of exercises offered and make them more targeted and precise. In fact, the type of exercises can involve the simultaneous use of several sensors, which provide information that would not otherwise be available without their fusion.

A possible method for determining the user's posture based on data collected from the force 16 and/or pressure 19 sensors of the seat 12 is described below. This method makes it possible to estimate some parameters that define user 14 posture, such as center of pressure (COP) and sway area.

Through force sensors 16 it is possible to calculate the values of the weight force applied by user 14 on seat 12. Through pressure sensors 19, values of the pressure applied by user 14 on a unit area of seat 12 can be calculated. For each force sensor 16 or pressure sensor 16, a P, value corresponding respectively to a value of the weight force applied ora value of the pressure applied by user 14 on that sensor 16, 19 of seat 12 is estimated.

From these values, the COP along a direction at a given instant t, for example, an antero-posterior (AP) or mid-lateral (ML) direction, can be calculated with the following formula: where xt is the position of the individual force 16 or pressure 19 sensor and N is the total number of sensors.

From these values, the area of oscillation A in a given time interval can be calculated with the following formula:

A = 671 , is the variance of the distribution of COP(t) values along the AP axis over time, is the variance of the distribution of COP(t) values along the ML axis over time, and cov^ _p-ml is the covariance of the distribution of COP(t) values along the AP and ML axes over time.

A possible method for determining the user's posture based on data collected from the 16' force and/or 19' pressure sensors of the seat backrest 8 is described below. This method makes it possible to estimate a parameter that defines the user's 14 posture, such as the IS symmetry index. Preferably, force sensors 16' and/or pressure sensors 19' are equally divided between the two symmetrical portions 8a and 8b of the seat backrest 8. For example, each portion 8a or 8b may include an M number of sensors 16', 19'. For each force sensor 16' or pressure sensor 19', a P, value corresponding respectively to a value of the applied weight force or a value of the user- applied pressure 14 on that sensor 16', 19' of the seat backrest 8 is estimated. The load value C is evaluated for each right or left portion 8a, 8b, and it is defined as

The percentage symmetry index IS is then calculated with the following formula: 100, where Csx is the load of the left portion of the seat backrest and C _dx is the load of the right portion of the seat backrest.

With reference to Fig. 11 , a possible method is described for determining the user's posture based on data collected from the force 16 and/or pressure 19 sensors of seat 12. This method makes it possible to estimate a parameter that defines the user's posture 14, such as the "yaw" of the user's thigh 14.

In Fig. 1 1 , a top view of user 14 sitting on the system for postural detection 100" is schematically shown, and the left and right hip and knee joints of user 14, denoted AS, AD, GD, GD respectively, are schematically shown. Force sensors 16 and/or position 19 allow estimation of the position of the AS, AD, GS, GD articular joints with respect to seat 12. For example, the position of articular joints AS, AD, GS, GD with respect to seat 12 can be estimated by force sensors 16 and/or position 19 via a neural network trained on the basis of the positions detected by camera 10.

We can then define the vectors indicating the direction of the thighs with the following relations: One can then calculate the angles a and p that define the angle of the right thigh and left thigh, respectively, with respect to the antero-posterior axis with the following formulas:

Where V^> is the antero-posterior vector.

The postural attitude of the lower limbs, particularly the thighs, of user 14 can be estimated by calculating the following parameter 0, which indicates the deviation of user 14's thighs from the antero-posterior axis:

A flowchart is shown in Fig. 12 regarding a method for providing possible audible, visual, and/or vibro-tactile warnings to user 14 in case of incorrect posture and/or excessive immobility in posture. According to this method, the operating system performs a check at predefined time intervals, e.g., every second, and checks whether the user is sitting without performing any training. If not, i.e. , if the user is not sitting or is sitting but performing training, the system waits for the next check.

If so, i.e., if the user is sitting without performing any workout, the system checks whether 2 hours have elapsed since the last workout of user 14. If 2 hours or more have elapsed since the last workout, the system provides a visual, audible, and vibro-tactile alert in order to suggest the user to start a workout. If, on the other hand, 2 hours have not yet passed since the last workout, the system determines some parameters related to the posture of user 14, such as swing area A, symmetry index IS, and/or thigh "yaw" 0 described above, and compares them with corresponding reference values.

For example, the system can check whether the sway area A of the user's sitting positions is less than 400, or whether the symmetry index IS is greater than 5, or whether the thigh "yaw" 0 is greater than 15°. If the calculated parameters meet the ideal reference conditions (e.g., if A>400, or IS<5, or 0 <15°), the system does not issue a warning and waits for the next check. If, on the other hand, at least one of the calculated parameters does not meet the ideal reference conditions (for example, if A<400, or IS>5, or 0 >15°), the system provides a vibro-tactile warning. The system repeats this check at predefined time intervals, for example, every 2 minutes, and provides a visual and audible warning in order to suggest a postural change to the user if the calculated parameters A, IS, and 0 deviate from the predefined reference values.

For example, it is possible to develop a machine learning algorithm configured to train a neural network that receives as input a set of parameters related to the user's posture (e.g., sway area A, symmetry index IS and/or thigh "yaw" 0) and as output a value that identifies the user's posture as incorrect/correct. Following this training, a network is obtained that, from the input parameters related to the user independently determines whether the posture is correct or incorrect.

A controlled upper limb mobility exercise in abduction in the frontal plane is schematically shown in Fig. 13. This movement is useful, for example, to mobilize the shoulder joint capsule and unload the muscles of the trapezius and deep rotator cuff muscles. This exercise can be performed by the user under static sitting conditions and can be monitored via camera 10.

A possible sequence of exercises useful for improving pelvic mobility under static or fixed sitting conditions is shown schematically in Figures 14a-14d. This sequence of exercises is also useful for activating the muscles of the quadratus lumborum and abdominal corset, for neuro-motor activation, and for improving motion perception during a static sitting condition.

Fig. 14a shows schematically a lateral pelvic tilting exercise. Fig. 14b shows schematically an antero-posterior tilting exercise of the pelvis. Fig. 14c shows schematically an antero-posterior tilting exercise of the pelvis. Fig. 14d shows schematically a lateral tilting exercise of the pelvis. As shown in the figures, during these exercises, seat 12 remains in a static condition (i.e., it is not swung around a plane parallel and/or perpendicularto the ground), while user 14 moves the pelvis so as to perform swings. Following each swing, the distribution of weight and pressure exerted by user 14 on seat 12 varies and is detected by sensors 16, 19 in real time. The control unit 20 makes it possible to process this data detected by sensors 16, 19 and to reconstruct a trajectory of the positions assumed by the pelvis during the tilting. It is possible to compare this trajectory with a reference trajectory, for example, a circumference, and to evaluate the deviation from the reference trajectory, so as to determine the correctness of the movement performed by the user and, if necessary, guide him/her in performing a better movement. The system for postural detection 100" in Figs. 14a-14d is also configured to show the 3D graph of pressures applied on seat 12 in real time, so that the user better understands his or her posture errors, and to provide feedback of posture change during exercises (training). A possible sequence of exercises useful for improving pelvic mobility under dynamic sitting conditions is shown schematically in Figures 15a-15d. This sequence of exercises is also useful for activating the muscles of the quadratus of the loins and the abdominal corset, for neuro-motor activation, and for improving motion perception during a static sitting condition.

Fig. 15a shows schematically a lateral pelvic tilting exercise. Fig. 15b shows schematically an antero-posterior tilting exercise of the pelvis. Fig. 15c shows schematically an antero-posterior tilting exercise of the pelvis. Fig. 15d shows schematically a lateral tilting exercise of the pelvis. As shown in the figures, during these exercises, seat 12 is unlocked and thus is able to swing around a plane parallel to the ground. User 14 moves the pelvis so as to perform swings and so as to tilt seat 12. Following each swing, the distribution of weight and pressure exerted by user 14 on seat 12 varies and is detected by sensors 16, 19 in real time. The control unit 20 makes it possible to process this data detected by sensors 16, 19 and to reconstruct a trajectory of the positions assumed by the pelvis during the tilting. It is possible to compare this trajectory with a reference trajectory, for example, a circumference, and to evaluate the deviation from the reference trajectory, so as to determine the correctness of the movement performed by the user and, if necessary, guide him/her in performing a better movement. During this sequence of exercises, it is possible to take advantage of the inertial sensors 28 on seat 12 in order to estimate the orientation of the seat and pelvis. The system for postural detection 100" in Figs. 15a-15d is also configured to show the 3-D graph of the pressures applied on seat 12 in real time, so that the user better understands his or her posture errors, and to provide feedback of posture change during the exercises (training).

A possible sequence of exercises to improve controlled lateral flexion mobility of the trunk is shown schematically in Fig. 16a and 16b. This sequence of exercises is useful, for example, to mobilize the spine by unloading accumulated muscular tension from the back, quadratus lumborum, and deep muscles.

Fig. 16a schematically illustrates a lateral trunk flexion exercise and Fig. 16b schematically illustrates an antero-posterior trunk flexion exercise. The position of the trunk can be effectively monitored using camera 10, which allows estimation of trunk flexions with respect to the vertical v axis.

While performing the exercises shown for example in Figs. 13, 14a-14d, 15a-15d and 16a-16b, vibrotactile actuators 18, 18' located in seat 12 and seat backrest 8 can be used to provide vibrotactile feedback to user 14. For example, the vibro-tactile actuators can vibrate to indicate to the user the direction in which to move (either in static or dynamic); for example, the vibro-tactile actuators can vibrate with an increasingly higher frequency until the target is reached.

The system for postural detection 100" can be configured to send an audible and/or visual alert signal via the monitor 11 and/or a haptic alert signal via the vibro-tactile actuators 18, 18' under predefined conditions to counteract excessive user 14 immobility or incorrect posture. For example, the vibro-tactile actuators 18, 18' can vibrate and provide an alert to the user to indicate that a mini-workout needs to be started, without interruption on the work monitor 11 ; for example, such a signal can be issued every two hours. For example, the alert signal can be repeated after a predefined time interval if the system 100' detects no change in posture by the user 14.

For example, as schematically shown in Fig. 17, the system for postural detection 100" can beep and/or generate a visual signal on monitor 11 when the user 14 has been sitting for too long or has been sitting in the same position for too long. The user is then prompted to stand up and walk around for a few minutes, possibly performing lower limb movements (e.g., repeated getting up and sitting from the chair, "lunging" walking), to allow more blood flow to the lower body, or exercises to raise awareness and mobilize the lower spine area. For example, if the system for postural detection 100" detects that user 14 is not sitting on it for a predefined time interval, it resets a counter that calculates the subject's immobility time and keeps it zero until it detects that user 14 is sitting on the system for postural detection 100" again.

The system for postural detection 100" can also beep and/or generate a visual signal on monitor 11 when the user 14 is holding an asymmetrical pose over time, so as to prompt him or her to recover a more symmetrical posture and perform a series of exercises to enable him or her to regain awareness of his or her posture.

The system for postural detection 100" is preferably powered through a battery pack, with the possibility of magnetic cable charging, which is connected to the power supply via a mains cable. The magnetic cable transfers battery charging energy via electromagnetic induction technology and allows disconnection from the power unit only through force exerted on the cable in any direction. This prevents mechanical damage to the charging system if the chair is moved beyond the range of the magnetic cable. For example, the battery can be configured to power the system for postural detection 100" for at least one month, without recharging, with continuous use of 50 hours per week. Although the present invention has been described with reference to the forms of embodiment described above, it is clear to the person skilled in the art that various modifications, variations, and improvements of the present invention in light of the teaching described above and within the scope of the appended claims can be made without departing from the subject matter and scope of protection of the invention.

Finally, those areas that are believed to be known by experts in the field have not been described to avoid overshadowing the described invention unnecessarily.

For example, the mechanism of operation of the load cells, force and/or pressure sensors, and camera have not been described in detail because they are considered known to the expert in the art.

Accordingly, the invention is not limited to the forms of embodiment described above, but is only limited by the scope of protection of the appended claims.

REFERENCE NUMBERS

1 : postural detection chair base

2: height adjustment system

3: caster

5: forearm of the chair

6: postural detection chair support

7: seat unlocking mechanism

8: seat backrest

8a: first portion of the seat backrest

8b: second portion of the seat backrest

9: joint of the session

10: camera 11 : monitor or infotainment system

12: seat

13: desk/table

14: user

16, 16': force sensors

17: seat padding

18, 18': vibro-tactile actuators

19, 19': pressure sensors

20, 20': control unit

22: inertial seat sensor

23, 23': data transmission unit

28: inertial sensor

29: seat backrest joint

30: seat backrest handle

100: seat system

100': seat backrest system

100": system for postural detection

AP: antero-posterior axis

ML: mid-lateral axis

AS: left hip position

AD: right hip position GS: left knee position

GD: right knee position