The present invention refers to a method for determining a torque to be applied in an electric power steering system of a steering system of an ego vehicle with at least one steering support function acting on the electric power steering system, comprising the step of receiving a requested torque from the at least one steering support function.

The present invention also refers to an electric power steering system for determining a torque to be applied to a steering system of an ego vehicle with at least one steering support function acting on the electric power steering system, comprising a control unit and a driving unit controlled by the control unit to apply the determined torque to the steering system, wherein the control unit receives a requested torque from the at least one steering support function.

Furthermore, the present invention refers to a steering support system, in particular as lane centering system or lane keeping system, comprising the above electric power steering system.

Different kinds of driving support systems are known e.g. to support a human driver when driving an ego vehicle. Such driving support systems to support the human driver are frequently referred to commonly as ADAS (advanced driver assistance systems). Other driving support systems can provide autonomous driving functionality and/or provide support to an autonomous driving system of the ego vehicle. Different levels of autonomous driving can be applied with a maximum level 5 for fully autonomous driving.

In this area, driving support systems comprises systems, which provide support for steering the vehicle, also referred to as steering assist functions (SAF) or steering support functions. In this context, steering assist functions like lane centering systems (LCS) or lane keeping systems (LKS) help human drivers to keep the ego vehicle on a predetermined driving path, usually at a center of the driving lane in case of the lane centering systems or within lane boundaries in case of the lane keeping systems. The SAF functions affect the heading direction of the ego vehicle by commanding the steering system of the ego vehicle using in particular electric power steering (EPS). EPS, sometimes also referred to as motor-driven power steering (MDPS), uses an electric motor instead of a conventional hydraulic system to assist the human driver of the ego vehicle. Sensors detect a steering wheel position and a torque exerted inside the steering column, and a computer module applies assistive torque via the electric motor, which connects either to the steering gear or steering column. This allows different kinds of assistance to be applied including the already mentioned features such as lane assist, wind drift correction, or others. Typical EPS systems provide a variable assistance, in particular depending on the velocity of the ego vehicle. Hence, also different levels of assistance can be applied, which can depend e.g. on driving conditions like a velocity of the ego vehicle.

Hence, when SAF are active, the ego vehicle typically acts via the EPS system on a steering angle of the ego vehicle. However, in some situations, the driver of the ego vehicle may need or want to affect the driving path of the ego vehicle, e.g. to avoid a pothole or to maintain a distance from an adjacent vehicle, which can be a requirement different to LCS or LKS. Other driving situations, where the human driver of the ego may need or want to influence the driving path of the vehicle, include overtaking trucks, in particular on a highway, or even passing a parked vehicle on urban/inter-urban roads. In order to change the driving path of the ego vehicle, the human driver may need to overcome the torque applied by the SAF system and additionally apply a torque to change the driving path. This may be uneasy or uncomfortable for the human driver as he/she may feel the SAF opposing his/her steering inputs as the SAF attempts to maintain its driving path as determined by the SAF, e.g. to locate the ego vehicle on a predetermined reference position within a driving lane in case of the LCS.

To overcome this problem, the SAF functions monitor the steering wheel angle state, e.g. position and speed, and the torque applied by the human driver. In case the SAF determines that the human driver overrides the SAF, the SAF can temporarily deactivate itself in order to allow the human driver to modify the driving path without the SAF opposing to the steering inputs of the driver. Alternatively, the SAF may temporarily apply a different torque, e.g. by scaling the torque based on the steering torque applied by driver. Setting a logic and thresholds for deactivation of the SAF based on an override by the human driver is complicated. More sensitive settings for deactivation often lead to false positive deactivations. In contrast, less sensitive settings lead to a decrease in comfort for the driver. Decreasing the torque applied by the SAF may provide more comfort to the driver as the driver is able to steer more freely, but still be able to feel SAF system intervention. However, both methods may lead to unwanted changes of the driving path of the ego vehicle in the case the system performs a false positive deactivation of the SAF.

In this context, document US 2015 0012182 A1 refers to assisting a vehicle driver in a bottleneck, including the tasks of reading in, evaluating, and providing. In the reading in, a piece of information about a negotiable corridor in the bottleneck, a piece of information about an instantaneous trajectory of the vehicle in the bottleneck, and a piece of information about a steering torque which is presently applied by the driver to a steering of the vehicle are read in. In the evaluating, the pieces of information about the corridor, the trajectory, and the steering torque are evaluated by using known dimensions of the vehicle to recognize an anticipated violation of the corridor by at least one part of the vehicle. In the providing, a control signal is provided for a counter torque which acts against the steering torque when the violation is recognized to assist the driver with avoiding the violation.

Each of documents US 2016 0152233 A1 as well as US 2018 0072310 A1 refers to assessing driver behavior include monitoring vehicle systems and driver monitoring systems to accommodate for a driver's slow reaction time, attention lapse and/or alertness. When it is determined that a driver is drowsy, for example, the response system may modify the operation of one or more vehicle systems. The systems that may be modified include visual devices, audio devices, tactile devices, antilock brake systems, automatic brake prefill systems, brake assist systems, auto cruise control systems, electronic stability control systems, collision warning systems, lane keep assist systems, blind spot indicator systems, electronic pre-tensioning systems and climate control systems.

Document US 2019 0315403 A1 refers to a vehicle control system installed on a vehicle including an automatic steering control device configured to execute automatic steering control that determines a steering angle command value and controls steering of the vehicle such that an actual steering angle follows the steering angle command value. A stop state detection device is configured to detect a stop state of the vehicle. An override detection device is configured to detect an override operation by a driver of the vehicle. When the override operation is detected in the stop state, the automatic steering control device prohibits variation in the actual steering angle due to the automatic steering control, until the vehicle starts moving.

It is an object of the present invention to provide a method for determining a torque to be applied in an electric power steering system of a steering system, an electric power steering system for determining a torque to be applied to a steering system, and a steering support system comprising the above electric power steering system, which increases safety in steering assist functions, improves driver comfort when overriding steering assist functions and by decreasing the false positive detections of such overrides.

This object is achieved by the independent claims. Advantageous embodiments are given in the dependent claims.

In particular, the present invention provides a method for determining a torque to be applied in an electric power steering system of a steering system of an ego vehicle with at least one steering support function acting on the electric power steering system, comprising the steps of receiving a requested torque from the at least one steering support function, determining a torque applied by a human driver to the steering system, determining an intention of the human driver to apply the torque to the steering system, and determining the torque to be applied in the electric power steering system based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system.

The present invention also provides an electric power steering system for determining a torque to be applied to a steering system of an ego vehicle with at least one steering support function acting on the electric power steering system, comprising a control unit and a driving unit controlled by the control unit to apply the determined torque to the steering system, wherein the control unit receives a requested torque from the at least one steering support function, the control unit receives information regarding a torque applied by a human driver to the steering system, the control unit receives information regarding an intention of the human driver to apply the torque to the steering system, and the control unit determines the torque to be applied to the steering system by controlling the driving unit based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system.

The present invention also provides a steering support system, in particular as lane centering system or lane keeping system, comprising the above electric power steering system.

The basic idea of the invention is to confirm that a torque applied by a human driver to the steering system is applied intentionally. This is based on the determination of the torque applied by the human driver together with the determination of the intention of the human driver to apply the torque to the steering system. This enables implementation of improved steering assist functions with increased safety, improved driver comfort when overriding steering assist functions and decreasing a number of false positive detections of such overrides. A determined torque intentionally applied to steering system by the human driver is processed differently than a determined torque applied to the steering system without intention.

The at least one steering support function, also referred to as steering assist function (SAF), requests a torque to be applied to the steering system in order to follow a determined driving path, whereby the driving path is determined by the respective steering support function. Hence, when the SAF is active, the SAF requests to the electric power steering (EPS) system to apply the torque to the steering system to follow a driving path determined by the SAF.

However, in some situations, the human driver of the ego vehicle may need or want to follow a different driving path, e.g. to avoid a pothole or to maintain a distance from an adjacent vehicle. In this case, the human driver intentionally applies a torque to the steering system, in particular by turning a steering wheel of the steering system. In this case, the intention of the human driver to apply the torque to the steering system is determined, so that the torque to be applied by the EPS system can be determined based on the intended or desired override of the torque requested from the SAF. In this case, the human driver can easily change the driving path of the ego vehicle based on the torque he/she applies.

However, in other situations, the human driver of the ego vehicle unintentionally turns the steering wheel and unintentionally applies a torque to the steering system, e.g. while grabbing the steering wheel and moving. In this case, a lack of intention of the human driver to apply the torque to the steering system is determined, so that the torque to be applied in the electric power steering system can be determined based on the unintended or undesired application of the torque to the steering system. Hence, the override of the SAF does not take place, a limited override can be performed, or even a counter torque can be applied to the steering system in order to obtain the goals as defined by the respective driving support function(s). In each case, an overall torque to be applied in the EPS system of the steering system of the ego vehicle is determined and applied. The determination is performed by the control unit of the electric power steering system, which controls the driving unit to apply the determined torque to the steering system.

The ego vehicle refers to a vehicle with a steering system and an electric power steering system, for which the method for determining a torque to be applied in the electric power steering system is performed. The ego vehicle can be any kind vehicle including passenger vehicles (cars or buses), trucks, lorries and others.

The electric power steering system, sometimes also referred to as motor-driven power steering (MDPS) system, is a system that uses an electric motor instead of a conventional hydraulic system to assist the human driver of the ego vehicle. Sensors detect a steering wheel position and a torque exerted inside the steering column, and the driving unit is controlled to apply a torque to the steering system. The electric power steering system can be any electrically or electronically powered steering system.

The steering system refers to a system functionally connecting a steering wheel located in a passenger compartment of the ego vehicle and the steered wheels of the ego vehicle, typically the front wheels. The steering wheel is mounter on a steering column, which transmits steering movement via a steering gear to the steered wheels. In some vehicles, parts of the steering system are provided electronically, also known as steer- by-wire. However, the principles of the present invention apply in the same way.

The at least one steering support function provides support for steering the vehicle. In this context, steering assist functions like lane centering systems (LCS) or lane keeping systems (LKS) help human drivers to keep the ego vehicle on a predetermined driving path, usually at a center of the driving lane in case of the lane centering systems or within lane boundaries in case of the lane keeping systems. The SAF affect the heading direction or driving path of the ego vehicle by commanding the steering system of the ego vehicle by requesting a torque to the electric power steering system to be applied to the steering system. Thereby, the SAF acts on the EPS system. One or more steering support functions can be activated at the same time, whereby multiple steering support functions commonly request the torque to the EPS system, or each of the EPS systems requests a torque and the EPS systems chooses a torque based on the different requests. Furthermore, one of the SAF can be permanently active, whereas another SAF is only active in case of emergencies, so that the permanently active SAF continuously requests the torque and the SAF is active in case of emergencies overrides the permanently active SAF in case of emergency.

Alternatively to receiving the requested torque from the at least one steering support function, the EPS system can receive a requested steering angle from the at least one steering support function, which is used as basis for determining the torque according to the request from the at least one steering support function.

The at least one steering support function and the electric power steering system can be implemented integrally in the ego vehicle or as independent systems connected via any kind of data connection.

The torque applied by the human driver to the steering system can be determined differently, e.g. using a respective torque sensor or e.g. based on an electrical power required by the driving unit to apply the determined torque.

The intention of the human driver to apply the torque to the steering system is determined based on a behavior of the human driver. This behavior of the human driver can be an intentional behavior, e.g. in case the human driver tries to pick up an item from the floor of the passenger compartment, or an unintentional behavior, e.g. in case of a medical problem like a heart stroke or others. Furthermore, the behavior of the human driver can be easily determined based on a movement of e.g. arms or legs of the human driver. In other cases, the behavior of the human driver can be determined based e.g. on an eye movement of the eyes of the human driver of the ego vehicle. It is e.g. known to determine a state of fatigue of a human based on eye movement.

Determining the torque to be applied in the electric power steering system refers to determining the torque finally applied to the steering system. The torque is determined based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system. Hence, in case no torque is applied by the human driver, the torque requested from the at least one steering support function is applied by the electric power steering system.

Determining the torque to be applied in the electric power steering system based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system can include that the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system are used to determine e.g. if the requested torque is applied or if a different torque is applied. Determining the torque to be applied in the electric power steering system based on the torque requested from the at least one steering support function, the torque applied by the human driver to the steering system and the intention of the human driver to apply the torque to the steering system does not require that the torque is calculated or determined using any logical combination of all of the torque requested from the at least one steering support function, the torque applied by the human driver to the steering system and the intention of the human driver to apply the torque to the steering system.

In case the human driver applies a torque, the electric power steering system performs a validation of the torque applied by the human driver based on the determined intention of the human driver to apply the torque to the steering system. Hence, in case the torque is applied intentionally by the human driver, the torque to be applied in the electric power steering system is determined based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system. This can include determining the torque to be applied based on the requested torque, which is modified based on the torque applied by the human driver to the steering system and/or the determined intention of the human driver to apply the torque to the steering, as discussed below in more detail. This can even include a full override or deactivation of the electric power steering system, i.e. the electric power steering system does not apply a torque on the steering system.

The control unit determines the torque to be applied in the electric power steering system of the steering system of the ego vehicle. The control unit controls the driving unit to apply the determined torque to the steering system. The control unit and the driving unit are connected via a control connection, which can be any kind of analog or digital connection. The control unit can be any kind of control unit suitable for use in the ego vehicle. Such control units are typically known as ECU (electronic control unit) in the automotive area. The control unit can be shared for performing multiple tasks or applications. The control unit processes the received information, as further discussed below.

The driving unit comprises e.g. an electrically driven motor and applies a driving current based on control signals received from the control unit. This way, the driving unit can apply the determined torque to the steering system. The driving unit is typically connected to a steering column of the steering system and exerts the torque on the steering column.

The intention of the human driver to apply the torque to the steering system is in general based on the driver being focused on driving and actively and intentionally applying the torque. In case the human driver of the ego vehicle is disturbed, distracted or in any other condition, which does not allow to intentionally apply the torque, the SAF may help to overcome this situation and to safely follow a predetermined driving path. In these cases, overriding of the SAF and the torque requested by the SAF may lead to dangerous driving situations. Especially when the SAF is tuned more on the comfort side, unintentional application of a torque by the human driver is prevented. However, based on the confirmation using the determining an intention of the human driver to apply the torque to the steering system, unintentional deactivation or override of the SAF and the torque requested from the SAF can be prevented. Therefore, the verification based on the determined intention of the human driver to apply the torque to the steering system allows on the one and side to provide a more comfortable driving experience with an improved ability to easily change the driving path of the ego vehicle for intended changes of the driving path, while on the other hand side prevents unintentional changes of the driving path e.g. by providing a reliable resistance against an unintentionally applied steering torque by the human driver.

According to a modified embodiment of the invention, the step of determining an intention of the human driver to apply the torque to the steering system comprises determining the intention of the human driver to apply the torque to the steering system based on an input received from a driver monitoring system. The driver monitoring system (DMS) may be an independent system or it may be integrated into the SAF. Any set of sensors and sources of information to measure or estimate the intention of the driver may be used, e.g. cameras, driver steering torque sensor, wearable devices, entertainment system, hands free system. The intention of the driver can be determined e.g. based on a state and/or attention of the human driver, which is commonly provided as an output of the DMS. Hence, already existing driver monitoring systems can be used to provide a suitable input for determining the intention of the human driver to apply the torque to the steering system. Such DMS are known in the Art and can determine e.g. fatigue of the human driver.

According to a modified embodiment of the invention, the electric power steering system comprises a driver monitoring system for determining the information regarding the intention of the human driver to apply the torque to the steering system and providing the information to the control unit. The DMS can additionally provide an output for use by other functions and/or systems of the ego vehicle, e.g. to determine fatigue of the human driver and to create a warning in such cases.

Alternatively, the driver monitoring system is provided independently from the electric power steering system and provides the information regarding the intention of the human driver to apply the torque to the steering system to the electric power steering system, in particular the control unit. Accordingly, the DMS can be a general purpose system used by different functions and/or systems of the ego vehicle. According to a modified embodiment of the invention, the step of determining an intention of the human driver to apply the torque to the steering system comprises determining the intention of the human driver to apply the torque to the steering system based on at least one out of a detection of the hands of the driver positioned at the steering wheel, detection of a driver distraction/attention for driving the ego vehicle, detection of a drowsiness and/or fatigue of the driver of the ego vehicle, detection of a health state of the driver of the ego vehicle, detection of a glare of the driver of the ego vehicle, detection of the driver of the ego vehicle actively having a phone call, actively using a mobile device, and/or actively using any device of the ego vehicle, e.g. an entertainment system, and detection of a surrounding of the ego vehicle, in particular in respect to presence of potholes, parked cars, or any kind of obstacles or other objects, in particular for validation of the determined intention of the human driver to apply the torque to the steering system. In case the hands of the human driver are positioned at the steering wheel, it can be assumed that human driver is attending and therefore will only intentionally apply torque to the steering system. Distraction and lack of attention can indicate lack of intention to apply torque to the steering system, e.g. when the human driver performs movements based on other activities and due to such a movement applies the torque to the steering system. Drowsiness or fatigue typically indicate or at least increase a probability of not acting intentionally, i.e. the human driver lacks intention to apply the torque to the steering system. Depending on the health state, the human driver can be unable to intentionally apply the torque to the steering system, e.g. in case of unconsciousness or death. Glare of the driver can occur due to sunlight and/or lights of oncoming vehicles. This can be identified e.g. based on particular movements of the human driver like closing the eyes or others, which makes it difficult for the human driver of the ego vehicle to intentionally control the ego vehicle and therefore, to intentionally apply the torque to the steering system. Usage of mobile phones or other mobile devices when driving the ego vehicle is also a typical indication of the human driver not being attentive. Consequently, the human driver will not intentionally apply the torque to the steering system.

Overall, the provided information is processed to determine information about the human driver, e.g. a state measured or estimated together with a focus or intention of the human driver, whether the human driver intentionally applies the torque to the steering system or not. Furthermore, the driver steering intention, i.e. the intention of the human driver to apply the torque to the steering system, may be determined/validated based on the detection of the surrounding of the ego vehicle, i.e. externally detected objects/obstacles like potholes, parked vehicles etc. in the environment of the ego vehicle. Accordingly, a determination can be performed to verify if the determined intention of the human driver to apply the torque to the steering system matches with the external environment. E.g., it is likely that the human driver intentionally applies the torque to the steering system in case a pothole or any obstacle is located ahead of the ego vehicle.

According to a modified embodiment of the invention, the step of determining an intention of the human driver to apply the torque to the steering system comprises determining the intention of the human driver to apply the torque to the steering system as quantified intention level, in particular between a minimum intention and a maximum intention, and the step of determining the torque to be applied in the electric power steering system based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system comprises determining the torque to be applied in the electric power steering system based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention level. Hence, the determined intention level can be used to determine the torque to be applied in the electric power steering system in a detailed way, in particular by a calculation using the determined intention level as input. Furthermore, the determined intention level can be compared to thresholds, which can be defined e.g. to determine the torque in different ways. In particular, multiple thresholds can be defined indicating e.g. high, medium, low degree of intention to determine and apply the torque differently. Furthermore, the intention level enables a simple determination of the torque to be applied e.g. based on the requested torque and modified based on the intention level, e.g. as a simple mathematical calculation, in particular when the intention level is provided as a number. In particular, the intention level can be determined based on the input received from the driver monitoring system.

According to a modified embodiment of the invention, the step of determining the torque to be applied in the electric power steering system based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system comprises determining the torque to be applied in the electric power steering system by modifying the torque requested from the at least one steering support function, in particular in a binary, step-wise or continuous manner, based on the determined torque applied by the human driver to the steering system and/or the determined intention of the human driver to apply the torque to the steering system. Hence, each of the torque applied by the human driver to the steering system and the intention of the human driver to apply the torque to the steering system can be used alone or in combination for modifying the requested torque to determine the torque to be applied in the electric power steering system. By way of example, one or more out of an absolute value of the torque applied by the human driver to the steering system, a difference between the requested torque and the torque applied by the human driver to the steering system, an intention level of the intention of the human driver to apply the torque to the steering system, derivatives thereof can be used to modify the requested torque to determine the torque to be applied in the electric power steering system. The modification can be a simple switch between two states, e.g. the requested torque and zero, or more states, e.g. the requested torque, different percentages of the requested torque and zero, or a calculation based on a mathematical formula like torque equal to requested torque minus torque applied by the human driver. The torque can in particular be modified by a factor, which can in particular be based on the determined torque applied by the human driver to the steering system and/or (in particular and) the determined intention of the human driver (in particular the intention level).

According to a modified embodiment of the invention, the step of determining the torque to be applied in the electric power steering system based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system comprises at least one out of providing modified limits for the torque to be requested from the at least one steering support function, in particular i.e. a saturation of the steering torque, determining the torque to be applied by scaling the torque requested from the at least one steering support function by a factor, changing an algorithm responsible for determining the torque to be applied based on the torque applied by the human driver to the steering system, changing feedback controller parameters in a feedback controller for determining the torque to be applied in the electric power steering system, and changing a deactivation condition based on human driver override for deactivation of the application of torque in the electric power steering system. Some of the above options can be applied to adaptively change a “resistance” of the steering wheel against the driver steering, i.e. a torque that has to be exerted by the human driver of the ego vehicle, to be able to move the steering wheel and steer the ego vehicle as desired. Some of the above options can be applied to enable adaptive changes of conditions leading to deactivation of the electric power steering system, i.e. no torque is applied by the electric power steering system. In this context, the limits for the torque to be requested from the at least one steering support function can be modified in the respective steering support function or in the electric power steering system or both. Scaling the torque requested from the at least one steering support function by a factor can refer to or comprise determination of the torque to be applied in the electric power steering system with a torque value calculated with the requested torque as starting point and modifying this torque value by the factor, in particular depending on the torque applied by the human driver to the steering system and/or the intention of the human driver to apply the torque to the steering system. Also, a modification can be applied based on the torque applied by the human driver to the steering system. The feedback controller enables a respective feedback control to smoothen the torque to be applied in the electric power steering system. Modification of parameters of the feedback controller enables quicker or slower adaptations of the torque to be applied in the electric power steering system. The deactivation condition of the deactivation of the application of torque in the electric power steering system can be modified so that e.g. in case of the human driver being less focused on the driving and therefore applying steering torque with less intention, the deactivation condition is made stricter to prevent the deactivation from taking place. The other way around, e.g. in case of the human driver being highly focused on the driving and therefore applying steering torque in general intentionally, the deactivation condition is made less strict to enable quick deactivation, assuming as a pre-condition that the human driver intentionally applies the torque to the steering system. Overall, different possibilities exist to determine the torque to be applied in the electric power steering system. These possibilities can be applied individually or in any suitable combination.

According to a modified embodiment of the invention, the step of determining the torque to be applied in the electric power steering system based on the torque requested from the at least one steering support function, the determined torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system comprises determining the torque to be applied by scaling the torque requested from the at least one steering support function by a factor. In particular, scaling the torque requested from the at least one steering support function by a factor can refer to or comprise determination of the torque to be applied in the electric power steering system with a torque value calculated with the requested torque as starting point and modifying this torque value by the factor, in particular depending on the torque applied by the human driver to the steering system and the intention of the human driver to apply the torque to the steering system (in particular the intention level). In other words, the factor can in particular depend on or be based on the torque applied by the human driver to the steering system and the intention of the human driver to apply the torque to the steering system (in particular the intention level).

According to a modified embodiment of the invention, the torque to be applied in the electric power steering system is to follow a determined driving path. In particular, the driving path is determined by the respective steering support function. In particular it can be a center of a driving lane (e.g. in case of the lane centering system (or function), or within lane boundaries (or boundaries of the driving lane) (e.g. in case of the lane keeping system (or function)). In particular, the torque to be applied in the electric power steering system can be to keep the ego vehicle at or within a center of a (or the) driving lane. In particular, when the steering support function is active, the steering support function can request to the electric power steering system to apply the torque to the steering system to follow a driving path determined by the steering support function.

According to a modified embodiment of the invention, the steering support function can be a lane centering system (or function) or a lane keeping system (or function), in particular to keep the ego vehicle on a predetermined driving path (e.g. at a center of the driving lane in case of the lane centering system (or function) or within lane boundaries in case of the lane keeping system (or function)).

According to a modified embodiment of the invention, the method comprises a step of generating a warning to the human driver in case determining a mismatch between the torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system. The mismatch between the torque applied by the human driver to the steering system and the determined intention of the human driver to apply the torque to the steering system refers to a situation, where the human driver unintentionally applies the torque to the steering system. In this case, the warning can alert the human driver to prevent further unintentional applications of torque to the steering system. The warning can be an audible and/or a visual warning, which can be generated using any kind of user interface device of the ego vehicle.

According to a modified embodiment of the invention, the electric power steering system comprises at least one sensor providing sensor information for determining the intention of the human driver to apply the torque to the steering system to the control unit. The direct usage of the at least one sensor overcomes limitations, which may exist using known driver monitoring systems, which are currently focusing on a state/condition of the human driver. Hence, the electric power steering system can determine the intention of the human driver to apply the torque to the steering system independent from such limitations.

According to a modified embodiment of the invention, the at least one sensor providing sensor information for determining the intention of the human driver to apply the torque to the steering system to the control unit comprises at least one out of an optical camera arranged in a passenger compartment of the ego vehicle monitoring at least partially a driver of the ego vehicle, and a hands-on sensor provided in/at the steering wheel of the ego vehicle. The optical camera can be arranged to monitor a body/chest of the human driver, e.g. to determine a position of the body/chest of the human driver. A body/chest displaced from a “normal” driving position can indicate unintentional application of torque by a human driver to the steering system, e.g. when hands grabbing the steering wheel follow a movement of the body/chest. The optical camera can be arranged to monitor the hands of the human driver, e.g. to determine a position of the hands. When the hands are positioned at the steering wheel, this can indicate an intention of the human driver to apply the torque to the steering system. The same applies when the hands-on sensor identifies that the hands of the human driver are positioned at the steering wheel. The optical camera can be arranged to monitor a head/face of the human driver, e.g. to determine a viewing direction, an expression indicating fatigue or a medical problem, an abnormal position of the head, e.g. in case the driver bends down to grab an item, or others. The optical camera can be arranged to monitor in particular the eyes of the human driver, e.g. to determine a viewing direction, an eye movement indicating e.g. fatigue or a medical problem, or others. Still further, the optical camera can be arranged to monitor further occupants of the ego vehicle. E.g. when the human driver talks to the further occupants, this can indicate that he/she is not focusing on driving the ego vehicle, and the torque applied by the human driver to the steering system is considered as not intentionally applied.

According to a modified embodiment of the invention, the control unit receives the requested torque from a steering support system providing the at least one steering support function, in particular a lane centering system or a lane keeping system.

Feature and advantages described above with reference to the inventive method apply equally to the inventive electric power steering system as well as the inventive steering support system and vice versa.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. Individual features disclosed in the embodiments can constitute alone or in combination an aspect of the present invention. Features of the different embodiments can be carried over from one embodiment to another embodiment.

In the drawings:

Fig. 1 shows a schematic view of an ego-vehicle with a steering support system comprising environment sensors and a control unit according to a first, preferred embodiment,

Fig. 2 shows an electric power steering system for determining a torque to be applied to a steering system of the ego vehicle of figure 1 according to the first embodiment comprising a control unit and a driving unit,

Fig. 3 shows a top view on the ego vehicle moving along a driving path in a center of a driving lane between lane boundaries together with a pothole ahead of the ego vehicle and an alternative driving path avoiding the pothole, Fig. 4 shows a first example of a method for determining a torque to be applied in the electric power steering system of figure 2 of a steering system of the ego vehicle of figure 1 , where a human driver of the ego vehicle intentionally applies a torque to the steering system resulting in an override of the torque requested by the steering support system being applied as torque in the electric power steering system,

Fig. 5 shows a second example of a method for determining a torque to be applied in the electric power steering system of figure 2 of a steering system of the ego vehicle of figure 1 , where a human driver of the ego vehicle unintentionally applies a torque to the steering system resulting in the torque requested by the steering support system continuously being applied as torque in the electric power steering system,

Fig. 6 shows a third example of a method for determining a torque to be applied in the electric power steering system of figure 2 of a steering system of the ego vehicle of figure 1 , where a human driver of the ego vehicle intentionally applies a torque to the steering system resulting in the torque to be applied in the electric power steering system is determined as the torque requested by steering support system being reduced by a factor based on the intention level and the torque applied by the human driver, and

Fig. 7 shows a flow chart of a method for determining a torque to be applied in the electric power steering system of figure 2 of a steering system of the ego vehicle of figure 1 with the steering support function acting on the electric power steering system.

Figure 1 shows an ego vehicle 10 with a steering support system 12 according to a first, preferred embodiment. The ego vehicle 10 can be any kind vehicle including cars, buses, trucks, lorries and others. The steering support system 12 of the first embodiment realizes a steering support function (SAF), which is by way of example a lane centering system (LCS). In an alternative embodiment, the steering support system 12 is a lane keeping systems (LKS). Hence, the steering support system 12 supports a human driver of the ego vehicle 10 to keep the ego vehicle 10 at a center of a respective driving lane.

The steering support system 12 comprises environment sensors 14, 16 for monitoring an environment 18 of the ego vehicle 10. In detail, the steering support system 12 of the first embodiment comprises a front LiDAR-based environment sensor 14, further referred to as front LiDAR, and an optical camera 16, which is directed to a front side of the ego vehicle 10. Hence, when driving forward, as indicated by forward driving direction 20, the front LiDAR 14 and the optical camera 16 monitor the surrounding 18 of the ego vehicles 10 in the driving direction 20 ahead of the ego vehicle 10. Each of the environment sensors 14, 16 generates sensor information, which can comprise raw data or pre-processed data. In an alternative embodiment, the steering support system 12 may comprise different environment sensors 14, 16 including any single environment sensor 14, 16 or any combination of environment sensors 14, 16 of the same or of a different kind out of the front LiDAR-based environment sensor 14, the optical camera 16 directed to a front side of the ego vehicle 10, and a front side radar sensor.

The ego vehicle 10 of the first embodiment further comprises a control device 22 and a data connection 24, which interconnects the environment sensors 14, 16 and the control device 22. The control device 22 can be any kind of control device 22 suitable for the use in the ego vehicle 10. Such control devices 22 are typically known as ECU (electronic control unit) in the automotive area. The control device 22 can be shared for performing multiple tasks or applications. The control device 22 receives the sensor information from the environment sensors 14, 16 and processes the received sensor information, as further discussed below. The sensor information can be provided from the environment sensors 14, 16 of the ego vehicle 10 in any suitable way and format. The sensor information can be pre-processed or raw sensor data.

The data connection 24 can be a dedicated connection between the environment sensors 14, 16 and the control device 22, or a data bus. Furthermore, the data connection 24 can be a shared data connection 24 used by different kinds of devices of the ego vehicle 10, e.g. a multi-purpose data bus. The data connection 24 can be implemented e.g. as CAN-bus, LIN-bus, or others. The data connection 24 can be a single data connection 24 connecting the environment sensors 14, 16 and the control device 22. Although a single data connection 24 is depicted in figure 1 , multiple data connections 24 or data busses can be provided in parallel for connecting environment sensors 14, 16 to the control device 22. In this case, the multiple data connections 24 or data busses can be considered together as data connection 24.

The sensor information from the environment sensors 14, 16 is transferred to the control device 22 via the data connection 24. Although a single control device 22 is depicted in figure 1 , multiple individual devices can be provided, which together implement the control device 22.

The ego vehicle 10 further comprises an electric power steering system 26 for determining a torque to be applied to a steering system 28 of the ego vehicle 10. The electric power steering system 26 is sometimes also referred to as motor-driven power steering (MDPS) system. The steering support system 12 is connected to the electric power steering system 26 and acts on the electric power steering system 26 to exert a torque on the steering system 28. Hence, apart from determining the torque, the electric power steering system 26 also applies the torque to the steering system 28. The electric power steering system 26 is shown together with the steering system 28 in figure 2.

Accordingly, the electric power steering system 26 comprises a control unit 30 for determining the torque to be applied to the steering system 28. The control unit 30 can be any kind of control unit 30 suitable for use in the ego vehicle 10. The control unit 30 is connected in a way not shown in the figures via the data connection 24 to the control device 22 of the steering support system 12.

The electric power steering system 26 further comprises a driving unit 32, which is connected via control connection 34 to the control unit 30. The control unit 30 controls the driving unit 32 via the control connection 34, which can be any kind of analog or digital connection, to apply the determined torque to the steering system 28. Hence, the driving unit 32 comprises an electrically driven motor to apply a driving current based on control signals received from the control unit 30. This way, the driving unit 32 applies the torque determined by the control unit 30 to the steering system 28. The steering system 28 comprises a steering wheel 36, a steering column 38, and a steering gear, which is not shown in the figures, and which provides a steering connection between the steering column 38 and the front wheels of the ego vehicle 10. The steering column 38 is rotatably held with bearings 40. The steering column 38 can be rotated according to rotation direction 42 by the driving unit 32, which is connected to the steering column 38 of the steering system 28 and exerts the torque on the steering column 38.

The electric power steering system 26 further comprises an interior optical camera 44 as sensor for providing sensor information, as discussed in more detail below. The interior optical camera 44 is arranged in a passenger compartment of the ego vehicle 10. The interior optical camera 44 is connected via the data connection 24 to the control unit 30. In an alternative embodiment, the interior optical camera 44 is provided separately from the power steering system 26 for use by different systems of the ego vehicle 10.

The steering support system 12 and the electric power steering system 26 are provided separately according to the first embodiment. In an alternative embodiment, the steering support system 12 and the electric power steering system 26 can be implemented integrally in the ego vehicle 10.

Figure 7 depicts a flow chart of a method for determining a torque to be applied in the electric power steering system 26 of the steering system 28 of the ego vehicle 10 with the steering support system 12 acting on the electric power steering system 26 according to the first embodiment. The method is performed with the ego vehicle 10 including the steering support system 12, the steering system 28 and in particular the electric power steering system 26. The method is discussed with additional reference to figure 3, which shows the ego vehicle 10 moving along a driving path 46 in a center of a driving lane 48 between lane boundaries 50. Figure 3 further shows a pothole 52 in forward driving direction 20 ahead of the ego vehicle 10 and an alternative driving path 54 avoiding the pothole 52.

The method starts in step S100 with receiving a requested torque from the steering support system 12. Hence, the control device 22 of the steering support system 12 receives sensor information from the front LiDAR 14 and the optical camera 16 and determines the driving path 46 for driving at a center of the driving lane 48, as can be seen in figure 3. The steering support system 12 determines a torque to be applied to the steering system 28 and sends the respective request to the electric power steering system 26 to affect the driving path 46 of the ego vehicle 10. The steering support system 12 is permanently active in a current driving state and permanently requests the torque to the electric power steering system 26.

The control unit 30 receives the requested torque from the electric power steering system 26.

Step S110 refers to determining a torque applied by a human driver to the steering system 28.

The torque applied by the human driver to the steering system 28 can be determined differently, e.g. using a respective torque sensor or e.g. based on an electrical power required by the driving unit 32 to apply a torque. Hence, control unit 30 receives information regarding the torque applied by the human driver to the steering system 28 from the respective sensors or e.g. as a feedback information from the driving unit 32.

Step S120 refers to determining an intention of the human driver to apply the torque to the steering system 28.

The intention of the human driver to apply the torque to the steering system 28 is determined based on a behavior of the human driver, which can be an intentional behavior, e.g. in case the human driver tries to pick up an item from the floor of the passenger compartment, or an unintentional behavior, e.g. in case of fatigue or a medical problem like a heart stroke or others. Hence, the intention of the human driver to apply the torque to the steering system 28 is in general based on the driver being focused on driving and actively and intentionally applying the torque. In case the human driver of the ego vehicle is disturbed, distracted or in any other condition, which does not allow to intentionally apply the torque, the steering support system 12 safely follow the predetermined driving path 46, he/she does not have the intention to apply the torque to the steering system 28. Hence, the electric power steering system 26 receives camera images as sensor information, which are provided from the interior optical camera 44 as sensor, to monitor at least partially a human driver of the ego vehicle 10. The interior optical camera 44 can be arranged to monitor a body/chest of the human driver, e.g. to determine a position of the body/chest of the human driver. A body/chest displaced from a “normal” driving position can indicate unintentional application of torque by a human driver to the steering system 28, e.g. when hands grabbing the steering wheel 36 follow a movement of the body/chest. The interior optical camera 44 can be arranged to monitor the hands of the human driver, e.g. to determine a position of the hands. When the hands are positioned at the steering wheel 36, this can indicate an intention of the human driver to apply the torque to the steering system 28. The interior optical camera 44 can be arranged to monitor a head/face of the human driver, e.g. to determine a viewing direction, an expression indicating fatigue or a medical problem, an abnormal position of the head, e.g. in case the driver bends down to grab an item, or others. The interior optical camera 44 can be arranged to monitor in particular the eyes of the human driver, e.g. to determine a viewing direction, an eye movement indicating e.g. fatigue or a medical problem, or others. Still further, the interior optical camera 44 can be arranged to monitor further occupants of the ego vehicle 10. E.g. when the human driver talks to the further occupants, this can indicate that he/she is not focusing on driving the ego vehicle 10, and the torque applied by the human driver to the steering system 28 is considered as not intentionally applied. Also, when the human driver checks his/her mobile phone or even uses the vehicle’s infotainment system (GPS, radio etc.), this can indicate that he/she is not focusing on driving the ego vehicle 10, and the torque applied by the human driver to the steering system 28 is considered as not intentionally applied. Any of the above mentioned actions can be performed alone or in combination to monitor the human driver and to determine an intention of the human driver to apply the torque to the steering system 28.

In particular, as already partially mentioned above, the information regarding the human driver of the ego vehicle can be processed to determine the intention of the human driver to apply the torque to the steering system 28 based on at least one out of a detection of the hands of the driver positioned at the steering wheel 36, a detection of a driver distraction/attention for driving the ego vehicle 10, a detection of a drowsiness and/or fatigue of the driver of the ego vehicle 10, a detection of a health state of the driver of the ego vehicle 10, a detection of a glare of the driver of the ego vehicle 10, and a detection of the driver of the ego vehicle 10 actively having a phone call, actively using a mobile device, and/or actively using any device of the ego vehicle 10, e.g. an entertainment system. In case the hands of the human driver are positioned at the steering wheel 36, it can be assumed that human driver is attending and therefore will only intentionally apply torque to the steering system 28. Distraction and lack of attention can indicate lack of intention to apply torque to the steering system 28, e.g. when the human driver performs movements based on other activities and due to such a movement applies the torque to the steering system 28. Drowsiness or fatigue typically indicate or at least increase a probability of not acting intentionally, i.e. the human driver lacks intention to apply the torque to the steering system 28. Depending on the health state, the human driver can be unable to intentionally apply the torque to the steering system 28, e.g. in case of unconsciousness or death. Glare of the driver can occur due to sunlight and/or lights of oncoming vehicles. This can be identified e.g. based on particular movements of the human driver like closing the eyes or others, which makes it difficult for the human driver of the ego vehicle 10 to intentionally control the ego vehicle 10 and therefore, to intentionally apply the torque to the steering system 28. Usage of mobile phones or other mobile devices when driving the ego vehicle 10 is also a typical indication of the human driver not being attentive. Consequently, the human driver will not intentionally apply the torque to the steering system 28.

The control unit 30 receives the information regarding an intention of the human driver to apply the torque to the steering system 28 and determines the intention of the human driver to apply the torque to the steering system 28 as quantified intention level, in particular between a minimum intention and a maximum intention, based on the above criteria.

Step S130 refers to determining the torque to be applied in the electric power steering system 26 based on the torque requested from the steering support system 12, the determined torque applied by the human driver to the steering system 28 and the determined intention of the human driver to apply the torque to the steering system 28. The control unit 30 determines the torque to be applied to the steering system 28.

Furthermore, the determined torque is applied by the control unit 30, which controls the driving unit 32 according to the determined torque. The torque to be applied in the electric power steering system 26 is determined by modifying the torque requested from the steering support system 12 in a binary, step- wise or continuous manner based on the determined torque applied by the human driver to the steering system 28 and/or the determined intention of the human driver to apply the torque to the steering system 28, wherein the determined intention level is used as intention of the human driver to apply the torque to the steering system 28. Hence, each of the torque applied by the human driver to the steering system 28 and the intention of the human driver to apply the torque to the steering system 28 can be used alone or in combination for modifying the requested torque to determine the torque to be applied in the electric power steering system 26.

Overriding of the torque requested by the SAF steering support system 12 does not take place in case the human driver of the ego vehicle 10 does not apply the torque intentionally to the steering system 28. Hence, based on the determination of the intention of the human driver to apply the torque to the steering system, unintentional deactivation or override of the steering support system 12 or the torque requested from the steering support system 12 is prevented. This refers e.g. to intention level zero and refers to a binary modification of the requested torque.

Otherwise, one or more out of an absolute value of the torque applied by the human driver to the steering system 28, a difference between the requested torque and the torque applied by the human driver to the steering system 28, the intention level of the intention of the human driver to apply the torque to the steering system 28, derivatives thereof can be used to modify the requested torque to determine the torque to be applied in the electric power steering system 26. The modification can be a simple switch between two or more states, e.g. the requested torque, different percentages of the requested torque and zero, or a calculation based on a mathematical formula like torque equal to requested torque minus torque applied by the human driver.

In particular, determining the torque to be applied in the electric power steering system 26 additionally comprises one or more out of providing modified limits for the torque to be requested from the steering support system 12, i.e. a saturation of the steering torque, determining the torque to be applied by scaling the torque requested from the at least one steering support function by a factor, changing an algorithm responsible for determining the torque to be applied based on the torque applied by the human driver to the steering system 28, changing feedback controller parameters in a feedback controller for determining the torque to be applied in the electric power steering system 26, and changing a deactivation condition based on human driver override for deactivation of the application of torque in the electric power steering system 26. Some of the above options can be applied to adaptively change a “resistance” of the steering wheel 36 against the driver steering, i.e. a torque that has to be exerted by the human driver of the ego vehicle 10, to be able to move the steering wheel 36 and steer the ego vehicle 10 as desired. Some of the above options can be applied to enable adaptive changes of conditions leading to deactivation of the electric power steering system 26, i.e. at least temporarily no torque is applied by the electric power steering system 26.

The above limits for the torque to be requested from the steering support system 12 can be modified in the respective steering support function or in the electric power steering system 26 or both. Scaling the torque requested from the steering support system 12 by a factor refers to determination of the torque to be applied in the electric power steering system 26 with a torque value calculated with the requested torque as starting point and modifying this torque value by the factor, in particular depending on the torque applied by the human driver to the steering system 28 and/or the intention level of the human driver to apply the torque to the steering system 28. The feedback controller enables a respective feedback control to smoothen the torque to be applied in the electric power steering system 26. The deactivation condition of the deactivation of the application of torque in the electric power steering system 26 can be modified to be stricter to prevent the deactivation from taking place or less strict to enable quick deactivation. These possibilities can be applied individually or in any suitable combination.

Step S140 refers to generating a warning to the human driver in case determining a mismatch between the torque applied by the human driver to the steering system 28 and the determined intention of the human driver to apply the torque to the steering system 28.

The mismatch between the torque applied by the human driver to the steering system 28 and the determined intention of the human driver to apply the torque to the steering system 28 refers to a situation, where the human driver unintentionally applies the torque to the steering system 28, as discussed above in detail. The warning can be an audible and/or a visual warning, which can be generated using any kind of user interface device of the ego vehicle 10.

Subsequently will be discussed three possible application of the above method with respect to figures 4 to 6.

Figure 4 refers to a first example and indicates in the upper diagram different courses of torques. First, a torque 56 requested by steering support system 12 is shown, which runs together with the torque 60 determined by the electric power steering system 26 until time td is reached. Hence, the steering support system 12 is actively steering the ego vehicle 10 to follow the driving path 46 shown in figure 3. Figure 4 further shows the torque 58 applied by the human driver of the ego vehicle 10. The torque 58 applied by the human driver is small until time ti, referring to a phase 62 without torque 58 applied by the human driver. Hence, the human driver is holding the steering wheel 36, but does not actively try to exert a torque on the steering system 28 via the steering wheel 36.

However, the torque 58 applied by the human driver increases starting at time ti, since the human driver starts to apply actively the torque 58 on the steering system 28 via the steering wheel 36. It is assumed in this example that the human driver intentionally wants e.g. to follow the alternative driving path 54 due to the presence of the pothole 52 in the driving lane 48.

The control unit 30 processes the received torque 56 requested by steering support system 12, the torque 58 applied by the human driver and the camera images received from the interior optical camera 44. The control unit 30 determines the intention level of the human driver to apply the torque 58 on the steering system 28. In case the control unit 30 receives information regarding externally detected objects/obstacles like potholes 52, parked vehicles, or others, which are located in the surrounding 18 of the ego vehicle 10, the control unit 30 can process this information to verify/validate if the determined intention of the human driver to apply the torque to the steering system matches with the information regarding the external environment.

The control unit 30 determines the torque 60 to be applied in the electric power steering system 26 as the torque 56 requested by steering support system 12, until time td is reached. At time td, the control unit 30 overrides the torque 56 requested by steering support system 12 and determines the torque 60 to be applied in the electric power steering system 26 as zero, so that only the torque 58 applied by the human driver acts on the steering system 28. The time td depends on various conditions and may vary for different situations based on the torque 58 applied by the human driver and the particular intention level over time. In this example, at time td, the intention level reaches its maximum.

Based on the torque 58 applied by the human driver and the override of the torque 56 requested by steering support system 12, the ego vehicle 10 deviates from the driving path 46 as determined by the steering support system 12. The lower diagram of figure 4 indicates a position error 66 which is a difference between the driving path 46 determined by the steering support system 12 and the alternative driving path 54 followed according to the intervention of the human driver.

At time ta, the human driver stops to apply actively the torque 58 on the steering system 28 via the steering wheel 36, he only holds the steering wheel 36. However, in the example of figure 4, the override of the torque 56 requested by steering support system 12 continues after time ta, when the human driver stops to apply actively the torque 58 on the steering system 28. In another example, at time ta, the override ends and the control unit 30 returns to determine the torque 60 to be applied in the electric power steering system 26 as torque 56 requested by steering support system 12 to reduce the position error 66.

Figure 5 refers to a second example and indicates in the upper diagram different courses of torques. First, a torque 56 requested by steering support system 12 is shown, which runs together with the torque 60 determined by the electric power steering system 26. Hence, the steering support system 12 is actively steering the ego vehicle 10 to follow the driving path 46 shown in figure 3. Figure 5 further shows the torque 58 applied by the human driver of the ego vehicle 10. The torque 58 applied by the human driver is small until time ti, referring to a phase 62 without torque 58 applied by the human driver. Hence, the human driver is holding the steering wheel 36, but does not actively try to exert a torque on the steering system 28 via the steering wheel 36.

The torque 58 applied by the human driver increases starting at time ti, since the human driver starts to apply actively the torque 58 on the steering system 28 via the steering wheel 36. It is assumed in this example that the human driver applies the torque unintentionally.

The control unit 30 processes the received torque 56 requested by steering support system 12, the torque 58 applied by the human driver and the camera images received from the interior optical camera 44. The control unit 30 determines the intention level of the human driver to apply the torque 58 on the steering system 28. In this example, the intention level is low between times ti and t2. Based on this, the control unit 30 determines the torque 60 to be applied in the electric power steering system 26 as the torque 56 requested by steering support system 12. The torque 60 to be applied in the electric power steering system 26 is determined continuously as the torque 56 requested by steering support system 12, since the torque 58 applied by the human driver together with the intention level indicates that the human driver does not want to apply the torque 58 on the steering system 28.

Based on the torque 58 applied by the human driver and the torque 56 requested by steering support system 12, which is the torque 60 to be applied in the electric power steering system 26, ego vehicle 10 deviates from the driving path 46 according to the position error 66 indicated in the lower part of figure 5. Since the torque 56 requested by steering support system 12 is the torque 60 to be applied in the electric power steering system 26, the steering support system 12 continues to act on the electric power steering system 26 to keep the ego vehicle 10 within the center of the driving lane 48. When the human driver stops to apply the torque 58 on the steering system 28, the torque 56 requested by steering support system 12 enables a reduction of the position error 66 and the ego vehicle 10 returns to the driving path 46.

Figure 6 refers to a third example and indicates different courses of torques. First, a torque 56 requested by steering support system 12 is shown, which runs together with the torque 60 determined by the electric power steering system 26. Hence, the steering support system 12 is steering actively the ego vehicle 10 to follow the driving path 46 shown in figure 3. Figure 6 further shows the torque 58 applied by the human driver of the ego vehicle 10. The torque 58 applied by the human driver is small until time ti, referring to a phase 62 without torque 58 applied by the human driver. Hence, the human driver is holding the steering wheel 36, but does not actively try to exert a torque on the steering system 28 via the steering wheel 36. The torque 58 applied by the human driver increases starting at time ti, since the human driver starts to apply actively the torque 58 on the steering system 28 via the steering wheel 36. It is assumed in this example that the human driver applies the torque intentionally.

The control unit 30 processes the received torque 56 requested by steering support system 12, the torque 58 applied by the human driver and the camera images received from the interior optical camera 44. The control unit 30 determines the intention level of the human driver to apply the torque 58 on the steering system 28. In this example, the intention level is high between times ti and t2. Based on this, the control unit 30 determines the torque 60 to be applied in the electric power steering system 26 as the torque 56 requested by steering support system 12, which is reduced according to a factor based on the intention level and the torque 58 applied by the human driver. Hence, the torque 60 to be applied in the electric power steering system 26 is reduced compared to the second example of figure 5.

Reference signs list

10 ego vehicle

12 steering support system

14 front LiDAR, environment sensor

16 optical camera, environment sensor

18 surrounding

20 forward driving direction

22 control device

24 data connection

26 electric power steering system

28 steering system

30 control unit

32 driving unit

34 control connection

36 steering wheel

38 steering column

40 bearing

42 rotation direction

44 interior optical camera, sensor

46 driving path

48 driving lane

50 lane boundary

52 pothole

54 alternative driving path

56 torque requested by steering support system

58 torque applied by human driver

60 determined torque

62 phase without torque applied by the human driver

64 phase with torque applied by the human driver

66 position error