LEVEL OF STRUCTURAL INTEGRITY OF POLES OR THE LIKE

TECHNICAL FIELD

The field of the invention is that of the predictive maintenance of infrastructures, such as poles and pylons, in particular poles on site, aimed at identifying early, by means of the analysis of specific physical quantities, the occurrence of conditions that could cause structural failure. It is therefore possible to intervene in a preventive manner, preventing the potential effects - collateral or not - due to said events, such as for example breakages or sudden failures of infrastructures which can in turn cause damage, problems with the circulation of vehicles and in some cases even mortal accidents.

In particular, the present invention relates to a device and a method for the measurement and verification, autonomously, automatically and/or continuously over time, of the level of structural integrity of poles which can be used for various purposes, such as, by way of example but not limited to, lighting in public or private areas, electrical distribution systems, signage, support for ski lifts and so on.

STATE OF THE ART

As is known, the poles or pylons present in the environment, usually installed outdoors for the most varied purposes, are subject to deterioration following erosion, shifting of the terrain on which they are installed or accidents.

In the event of erosion, progressive structural deterioration may occur until reaching a condition in which the pole is no longer able to withstand the stresses and normal operating loads, resulting in failure of the same.

In the event of an accident, the pole may undergo sudden deformation or be compromised due to an impact or other significant mechanical stress.

Finally, in the event of shifting of the installation terrain, it is possible to observe a progressive or sudden reduction in the level of structural integrity.

Each of the three cases determines, during a variable time interval, the modification, among others, of two characteristics of the pole or pylon:

• its inclination, which can vary with or without a change in the shape of the pole itself; and

• the way in which the pole reacts to the mechanical stresses administered in the form of vibrations.

In particular, the reaction of the pole or pylon to the mechanical stresses administered in the form of vibration changes, highlighting

• a variation of the natural resonance frequency of the pole or pylon and/or a variation in the displacement of the pole or pylon subjected to mechanical stress.

In fact, it should be considered that when the pole or pylon is in optimal conditions, it has a given natural resonance frequency.

Furthermore, when subjected to mechanical stresses in the form of vibration at its natural frequency, the same shows an oscillation which gives rise to a given natural displacement.

Nowadays, the periodic verification of infrastructures, such as poles and pylons, is an issue of increasing interest, so much so that in some countries, such as Switzerland for example, the control of the structural integrity and reliability of poles and pylons is required by law. Currently, structural integrity verifications are carried out as part of dedicated inspection campaigns and require the intervention of personnel with specific technical skills capable of using the devices necessary to carry out the measurements.

The control verifications carried out using the known devices are generally based on non-destructive techniques which subject the pole or pylon under examination to traction or forces which induce oscillations and vibrations, then detecting the effect of the application of said forces in terms of displacement of the same which, as seen before, in the event of deterioration the pole can be subjected to modifications. The displacement is measured with special instruments based on the use of lasers or ultrasound or the like. In order to obtain comparable measurements so as to possibly detect a variation in the measured displacement, it is essential that stresses of the same magnitude are always administered at the same stress point and the measurements are always taken at the same measurement point.

The known devices used in inspection campaigns often have considerable dimensions as well as a high structural complexity which makes them particularly fragile and delicate. Despite their construction usually in the form of a portable and self-propelled device, the size and delicacy of said devices make the inspection and verification campaigns of poles and pylons particularly demanding, expensive, and complex. Furthermore, the complexity and dimensions of said devices hinder the integration thereof within the poles or pylons.

Considering the need to carry out periodic verifications of the structural integrity of poles or pylons in order to guarantee the safety and continuity of services, the need to create measurement and verification devices capable of operating autonomously and automatically is strongly felt, both in the execution of the tests, both in the survey and in the analysis of the measured data. Furthermore, an interest is felt in integrating the measurement and verification devices directly within the poles or pylons in order to ensure accuracy in the location of the stress administration and in the measurement point. Furthermore, in the hypothesis of integration of the measurement and verification devices in the poles or pylons, the need to optimize the transfer of the collected data and to define adequate transmission systems vividly emerges.

Document US 2021/096038 describes a method for the nondestructive testing of the condition of cylindrical elements made of wood, or other materials, which determines the frequency of the ovalization mode and the amplitude of the ovalization mode, by comparing the same with reference values for produce a structural integrity report of the cylindrical object. The test is carried-out by using two vibration inducers, then two stress points, applied on the surface of the cylindrical element, in diametrically opposite positions, at the same height H1, for the generation of synchronous vibrations on the cylindrical object. However, said verification method is not applicable to the vast majority of poles on site since these are not cylindrical, but are conical or tapered. In the second case they have the shape of a series of concentric cylinders welded together and which, therefore, cannot be temporarily isolated without destroying the pole.

US 4342229 discloses a device and a method for measuring the degradation in the physical integrity of structural parts by measuring the rate of decay of the amplitude of vibration of the structural part in a specific period of time, after it has been set into vibration at its free resonant frequency mode. The presence of imperfections or damage in fact causes an increase in the rate of decay of the amplitude of vibration. As described and illustrated the part to be tested is held suspended and is struck by a rigid spike element and set into vibration so that the vibrational amplitude can then be converted into an electrical signal. Said procedure is not applicable to poles or pylons on site as these are solidly fixed to the ground where they are installed.

OBJECTS AND SUMMARY OF THE INVENTION

The aim of the present invention is to overcome the drawbacks and fill the gaps of the prior art. In particular, within the scope of said aim, the object of the present invention is to provide a measurement and verification device of the level of structural integrity of poles or the like on site which can be permanently installed on a respective pole to operate in autonomously and automatically a periodic verification of the level of structural integrity of the same.

In particular, the object of the present invention is to provide a device, a system and a method which allows the verification of the structural integrity of poles or the like, which is simple, inexpensive and that allows continuous monitoring over time.

A further object of the present invention is to conceive a device and a method for the measurement and verification of the level of structural integrity of poles or the like which allow to autonomously carry out periodic verifications, to process the state of integrity of the pole or the like on the basis of the acquired data and to transmit the processed data to a central processing unit.

A further object of the present invention is to develop a device and a method for the measurement and verification of the level of structural integrity of poles or the like that allow the processed data to be transmitted over a long range while keeping the related energy consumption low, facilitating the installations, and making the system simpler and more sustainable .

Another object of the present invention is to study a device and a method for the measurement and verification of the level of structural integrity of poles or the like capable of minimizing the volume of data transferred to the central processing unit and memorized by the same.

The above aim, as well as the objects of the present invention are achieved by means of a measurement and verification device of the level of structural integrity of poles or the like according to the attached Claim 1.

According to a first aspect thereof, the invention therefore relates to a measurement and verification device of the level of structural integrity of poles or the like, which pole is fixed to the ground or to a support element and has an end, opposite to said constraint, free to oscillate, comprising an electronic processing unit to which are connected: - an oscillatory mechanical stress generating unit configured to impart an oscillatory mechanical stress to said end of the pole left free to oscillate;

- a module for acquiring measurement values of physical quantities of the pole, to the acquisition module being connected at least a first transducer configured for the acquisition of measurement values of a physical quantity caused in the pole by the oscillatory mechanical stress, the physical quantity being suitable for the elaboration of at least one indicative parameter of the state of the pole; and

- at least one connection interface with a communication system for the transmission of at least one parameter indicative of the state of the pole to a remote unit, wherein the electronic processing unit comprises software means configured to process the measurement values acquired by the acquisition module and obtain the at least one indicative parameter of the state of said pole 9.

The Applicant has advantageously obtained a device capable of imparting, to a pole or a similar elongated infrastructure installed on site, namely, which is fixed to the ground or to a support element, for example a pole fixed to the ground or a pole fixed to a base, an oscillatory mechanical stress, to detect a physical quantity induced in the pole and suitable for processing at least one parameter indicative of the state of the same, as well as to transmit said parameter. By way of example, the measured quantity can be a set of accelerations induced by the vibratory stress and the indicative parameter can be the vibration frequency. In this way, it is possible on the one hand to produce a device that can be integrated within the same pole. On the other hand, by implementing part of the analysis of the measurement values acquired directly on board the integrated device, it is possible to optimize the amount of data that must be transmitted to the remote unit.

The Applicant has therefore advantageously implemented a measurement and verification device of the level of structural integrity of poles or the like capable of implementing predictive analyses and predictions of breakages, accidents, structural failures, and non-conformities in a completely automatic way, with great advantage for all activities that involve the maintenance of the poles and the services they provide.

In said regard, the measurement and verification device of the level of structural integrity according to the present invention allows to determine whether the state of integrity of the pole installed is such as to consider the same reliable or if maintenance is required without the need for a dedicated measurement campaign.

Also, object of the present invention is a method for the measurement and verification of the level of structural integrity of poles or the like according to the attached Claim 9 and a system for the measurement and verification of the level of structural integrity of a plurality of poles or the like according to attached Claim 14.

Advantageously, the method and system for the measurement and verification offer the same advantages disclosed above with reference to the measurement and verification device. Obviously, as described above, the device, method and system object of the present invention can be used for measurement and the verification of the level of structural integrity not only of poles installed but also of other similar infrastructures, preferably elongated bodies fixed in at least one point to the ground or to a base or to a support element and provided with one end left free to oscillate.

Further characteristics of the preferred embodiments of the device and of the method for the measurement and verification of the level of structural integrity of poles or the like according to the present invention are the subject of the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become more evident from the following detailed description of some preferred, but not exclusive embodiments thereof, made with reference to the attached drawings.

In said drawings,

- Figure 1 is a schematic illustration of the reaction of a pole, fixed to a base, to an oscillatory mechanical stress;

Figure 2 is a schematic representation of a preferred embodiment of a measurement and verification device of the level of structural integrity of poles or the like according to the present invention;

- Figure 3 is a flowchart of a method for the measurement and verification of the level of structural integrity of poles or the like according to the present invention; and

- Figure 4 is a schematic representation of a communication system for collecting the data acquired by means of a plurality of devices for the measurement and verification of the level of structural integrity of poles or the like according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, for the illustration of the figures, identical reference numbers or symbols are used to denote construction elements with the same function. Furthermore, for clarity of illustration, some references may not be repeated in all the figures.

While the invention is susceptible to various modifications and alternative constructions, some preferred embodiments are shown in the drawings and will be described in detail in the following. It is to be understood, however, that there is no intention to limit the invention to the specific embodiment illustrated, but, on the contrary, the invention is intended to cover all modifications, alternative and equivalent constructions which fall within the scope of the invention as defined in the claims.

The use of "for example", "etc", "or" indicates non-exclusive alternatives without limitation unless otherwise indicated. The use of "comprises" and "includes" means "comprises or includes, but not limited to" unless otherwise indicated.

In particular, the device, the method and the system object of the present invention are described with reference to a pole or the like, and by the like is meant any elongated infrastructure installed on site or fixed to the ground, to a base or to a support element namely, fixed in one point and provided with one end left free to oscillate

With reference to Figure 1, the reaction of a pole 9 to mechanical stress is shown.

The figure shows a pole 9 fixed to a base, namely, a pole 9 installed on site which is fixed to the ground or to a support element and has one end, opposite to said constraint, left free to oscillate.

The oscillatory mechanical stress imparted in the form of vibrations to the free end of the pole 9 by means of a mechanical oscillator induces an oscillation in the pole 9 which depends on:

• the intensity of the stress,

• varies according to whether the frequency of the stress coincides or not with the natural resonance frequency of the pole, if the stress is applied in the form of vibration,

• as well as depending on the height at which the displacement is measured.

By displacement measurement is meant the measurement of the displacement of the point, namely, the modification of the position in space in which the transducer 30 is arranged, as described in the following.

In Figure 1, the pole 9 is shown, fixed in one point and with one of its ends, which oscillates or vibrates on a plane perpendicular to its longitudinal axis X.

In fact, at least one device is applied to one or more poles on site, for example light poles, fixed to the ground, to determine the state of integrity. A second device 1 could be provided for safety, in order to replace the first, possibly a non-working one.

At height "A" the pole undergoes a displacement equal to segment D.

The pole 9 of Figure 1 is subjected to an oscillatory mechanical stress in the form of vibrations generated by an oscillatory mechanical stress generating unit 70, not illustrated, fixed to the free end of said pole 9.

In particular, said oscillatory mechanical stress generating unit 70 is fixed to the outer surface of the pole 9 and/or inside said pole 9.

Thanks to the fact that it comprises means for measuring the frequency and amplitude of the oscillations which are compared with reference values, the device allows the status of stability of the pole 9 to be determined.

It is therefore clear that - as previously mentioned - in order to obtain comparable measurements, it is essential that the stresses are administered at equal intensity, always at the same stress point and the measurements are always taken at the same measurement point, namely, that:

• the application of the oscillatory mechanical stress takes place in a point always placed at the same distance from the fixing point of the pole to the ground or to the support element,

• the measurement of the frequency and/or amplitude of the oscillations and/or displacement always takes place at the same point. Figure 2 shows a measurement and verification device of the level of structural integrity of poles according to a preferred embodiment of the present invention, indicated as a whole with 10.

At least one device 10 can be installed on each pole to be monitored and consequently allows continuous (for example periodically), autonomous and automatic monitoring (it is in fact possible that the device and/or system object of the present invention is activated in an autonomous and automatic manner at a pre-set frequency), of a large number of operational poles 9, namely, which are performing the function for which they were designed, remotely, given that the data on the state of the pole 9 are communicated to a central unit to which users can connect telematically, as described in detail in the following. The measurement and verification device 10 comprises a processing unit 40 for managing the components of the device and data exchange.

The processing unit 40 in turn comprises software means 41 configured for the implementation of the method for the measurement and verification of the level of structural integrity according to the present invention, described in the following.

At least the following are connected to the processing unit 40:

- an oscillatory mechanical stress generating unit 70;

- a measurement value acquisition module 20 to which at least a first transducer 30 is in turn connected for the acquisition of measurement values of a physical quantity, in particular a physical quantity which allows to obtain a parameter indicative of the state of the pole such as for example the vibration frequency and/or the amplitude of vibration and/or the displacement of the pole resulting from an oscillatory mechanical stress;

- a memory unit 50; and

- at least one connection interface 60,61 with a communication system 95,200.

The oscillatory mechanical stress generating unit 70 comprises an actuator 71, preferably an electric motor, which sets in motion an element 72,73 configured to impart vibratory mechanical stresses. In the embodiment of Figure 2, the element for imparting vibratory stresses comprises an eccentric mass 72 set in rotation by the actuator 71, namely, an element to whose free end 72a a mass 73 is fixed.

Advantageously, the fabrication of the oscillatory mechanical stress generating unit 70 as described above allows the measurement and verification device 10 to be made compact in size, making it possible to house the same inside or outside the pole 9 which device 10 can advantageously be used to check the integrity of poles 9 installed on site. Furthermore, in this way, the problems related to the transport and the fragility of the measurement device and the problems related to the complexity of the known devices normally used to verify the integrity of structural elements are advantageously overcome. Furthermore, it is conveniently ensured that the stresses are always imparted at precisely the same stress point.

The oscillatory mechanical stress generator therefore is formed by an electric motor and an eccentric element with a weight at the end or by an electromechanical solenoid element.

The oscillation frequency in Hz can be equal to twice the motor rotation speed in revolutions per second.

The acquisition module 20 preferably comprises at least one analogical/digital converter (not illustrated) configured to transform the electrical impulses coming from the at least one transducer 30 into a digital signal and transmit the same to the processing unit 40 which is configured to process the data acquired by at least one transducer 30 and converted by the acquisition module 20.

In the specific case of detecting vibrations, the at least one first transducer 30 comprises one or more accelerometers.

Preferably three accelerometers arranged on three orthogonal axes or a single accelerometer with three axes.

The acquisition module 20 can be additionally connected to at least one second transducer (not illustrated). By way of non- exhaustive example, the at least one second transducer comprised in the device 10 is one or more of the following sensors:

- temperature sensors,

- humidity sensors,

- inclinometers,

- accelerometers,

- PH meters,

- meters or identifiers of gases or other chemicals,

- ultrasound sensors,

- acoustic sensors or any other type of sensor dedicated to monitoring the pole 9 or the surrounding area and environment.

The connection interface 60,61 with the communication system 95 preferably comprises a physical connection interface 60 and/or a wireless connection interface 61.

By way of non-limiting example, the physical connection interface 60 of each device 10 is a connection interface to a power line transmission system or the like, for data transmission by means of a pre-existing electrical network.

Similarly, by way of non-limiting example, the wireless connection interface 61 is a cellular communication interface, such as for example GPRS, 3G, 4G, LTE or 5G.

Similarly, by way of non-exhaustive example, the wireless connection interface 61 can be based on a non-mesh or long-range mesh transmission technology, such as for example Lo.Ra. or low consumption, such as for example "ESP-NOW".

In the example of Figure 2, the communication system 95 is represented in exemplifying terms as a telematic or cellular network for exchanging data with a remote unit 90, for example a central processing unit comprising a database for storing, processing, the analysis and/or consultation of the measurement data collected.

The memory unit 50 is configured for the temporary storage of measurement data coming from the acquisition module 20 and data processed by the processing unit 40 by means of the software means 41.

The method of measurement and verification 100 of the level of structural integrity of one or more poles 9 or the like according to the present invention implements a series of operations - schematized in Figure 3 - which is repeated at each measurement and verification cycle. Each measurement and verification cycle is repeated over time, for a continuous verification of the integrity of the pole 9 in question and

• the application of the oscillatory mechanical stress by means of said measurement and verification device (10) placed on each pole (9) always takes place at the same point, namely, in a point always placed at the same distance from the fixing point of the pole (9) to the ground or to the support element, and

• the measurement of the frequency and/or amplitude of the oscillations and/or of the displacement always takes place at the same point. The measurement and verification device 10 is activated (step 110) periodically in an autonomous and automatic manner according to a pre-set time interval.

Once active, the processing unit 40 of the device 10 commands the oscillatory mechanical stress generating unit 70, so that, by means of the appropriate element 72, 73, different series of oscillatory mechanical stresses are imparted (step 120) each at its own oscillation frequency. Simultaneously with the generation of mechanical stresses, the processing unit 40 receives the signals acquired by means of the acquisition module 20 and the transducer 30, connected to the same, registers (step 130) the amplitude of vibrations detected by the transducer 30.

Therefore, series of stresses, with a higher oscillation frequency than the previous one, are generated and it is verified whether the amplitude of vibrations registered by the transducer 30 on the pole 9 increases in turn (step 140). Said procedure is repeated until the processing unit 40 registers an increase in the amplitude of vibrations.

When the peak is reached, namely, when, as the oscillation frequency of the series of stresses increases, the amplitude of vibrations registered by the transducer 30 on the pole 9 begins to decrease, the oscillation frequency is registered (step 150) at which the amplitude of vibration of the pole 9 is maximum, also indicated as "dominant frequency".

The dominant frequency is then transmitted (step 160) to the remote central unit 90 for subsequent processing, for example for a comparison thereof with the characteristic data of the pole 9, such as for example its natural resonant frequency, in order to discriminate whether the level of structural integrity is such as to require or not require maintenance, repair and/or replacement .

Preferably the method provides for the verification of variations in the oscillation frequency and/or in the amplitude of the oscillation and/or in the displacement of the pole 9 with respect to the reference values.

Thanks to the present invention, the variation in the natural frequency and in the amplitude of vibrations that the modification of the rigidity of the pole induces for the same stress is measured and evaluated.

Furthermore, it is advantageously possible to provide that the at least one indicative parameter of the state of each pole 9 acquired by the device 10 placed on said pole 9 is transmitted to one or more neighbouring devices 10, namely, placed on neighbouring poles 9, and subsequently transferred to said remote central processing unit 90, by means of a "mesh" communication model. This allows each device 10 placed on a pole 9 to act both as a transmitter and as a repeater for the others, making it possible to create a very secure transmission system. In fact, if a device 10 fails to transmit to said remote central processing unit 90, it can be replaced by a similar device 10 placed on another pole. Furthermore, it is thus possible to create systems which cover very large areas at reduced costs. The poles 9, in fact, are placed in lines that extend for kilometres along the roadsides. The devices 10 used as transmitters and/or repeaters of the signal to be transferred make it possible to monitor a network of light poles even in situations in which the line of poles moves away quickly from the receiving point, namely, from a receiving antenna or from the remote central processing unit 90, which is preferably arranged in a protected place and energetically powered in a safe and constant manner over time.

Figure 4 schematically shows a digital data communication system 200 by means of which it is possible to optimize the transmission of the data detected by the measurement and verification devices 10 each integrated in a respective pole 9.

It is possible to provide two or more devices 10 integrated in each pole 9, in order to always allow monitoring of the integrity of the pole 9 even if one of the devices 10 of each pole 9 is malfunctioning.

The digital data communication system 200 comprises a plurality of data transmission subsystems 210 preferably of the long-range radio type, such as, for example, Lo.Ra., Sigfox, Esp- Now or the like or of the wired powerline type, which implement the connection of a subgroup of measurement and verification devices 10 to one another and/or to an intermediate processing unit 91 or concentrator.

The intermediate processing units 91 have the purpose of collecting the data coming from a group of poles 9 located in a specific geographical position and/or at a suitable distance and within the transmission range of the respective data transmission subsystem 210.

In particular, in said embodiment, the wireless connection interface 61 of each device 10 is a connection interface to a non-mesh long-range radio transmission system, such as, for example, Lo.Ra., WAN, Sigfox, Esp-Now or the like or is a connection interface to a long-range mesh radio transmission system, such as, for example, Lo.Ra.mesh, Esp-Now mesh or the like.

The intermediate processing units 91 of each data transmission subsystem 210 are in turn connected to the central processing unit 90 to which are transmitted the set of data received from the measurement and verification devices 10. In particular, the connection between the intermediate processing units 91 and the central processing unit 90 is preferably implemented by means of a fast transmission communication system 95, such as a GPRS, 3G, 4G, LTE or 5G cellular network.

In the central processing unit 90 therefore all the measurement data of the poles 9 monitored in terms of physical quantity detected, for example the dominant frequency of each pole and/or amplitude of vibration and/or displacement, converge. The central processing unit 90 allows the processing, evaluation, storage, and consultation of the reference data and of the data collected by one or more devices 10.

Said data are made accessible to operators who, for this purpose, can simply connect telematically to the central processing unit 90.

Thanks to the device and method for the measurement and verification of the level of structural integrity of poles 9 or similar infrastructures according to the present invention it is possible to carry out a continuous and automatic verification of the structural integrity of the poles in operating conditions, namely, when they are fixed to the ground or to a support element in carrying out the function for which the same were designed by means of the installation on each pole of a measurement and verification device of the oscillation variations of the free end of the pole 9 or the like. Furthermore, the measurement data can be communicated in an optimized way to the central processing unit, making the same easily and quickly accessible to operators by way of a telematic connection .

Advantageously, consequently, the present invention allows remote monitoring of an indefinite number of poles.

Furthermore, thanks to the possibility of carrying out frequent and automatic verifications, the present invention allows to collect sufficient data to apply suitable predictive algorithms based on statistical systems which make it possible to predict the imminence of a structural failure of the pole or pylon, by signalling said condition to operators in a preventive manner.

As will be evident to the skilled in the art, one or more steps of the method described above can be performed in parallel with one another or with a different order from the one presented above. Similarly, one or more optional steps can be added or removed from one or more of the procedures described above.

The invention thus conceived is therefore susceptible to numerous modifications and alternatives and the above examples must not be interpreted in a limiting manner. Naturally, all the details can be replaced by other technically equivalent elements.

In conclusion, the materials used, as well as the contingent shapes and dimensions of the above-mentioned devices, apparatuses and terminals may be any according to the specific implementation requirements without thereby departing from the scope of the following claims.