System for analyzing performance when using a gliding board

Description

Domaine Technique

[0001] The invention relates to the field of boards for sliding on snow or water, and in particular alpine, cross-country or touring skis, or even snowboards or wakeboards.

[0002] The invention relates more particularly to a system for analyzing the performance of using a sliding board, that is to say a system capable of indicating to a user of a sliding board whether he meets objective performance criteria. Techniques antérieures

[0003] There are a large number of devices for estimating the performance of a snowboarder. For example, French patent application FR 2 891 998 proposes using a position sensor, integrated into a ski garment, to characterize a skier's performance based on the skier's movement speed.

[0004] Additionally, several mobile applications have been developed in recent years to measure and compare the performance of different skiers at a ski resort. These applications use the mobile's inertial sensor or gyroscope to estimate the skier's speed. A centralized database aggregates the performance of different skiers and allows a skier's mobile application to compare the measured performance with that of other skiers.

[0005] However, simply measuring a skier's speed is not enough to characterize their performance. Indeed, within the meaning of the invention, a skier's "performance" reflects not only speed but also the skier's technique.

[0006] To estimate a skier's technique, there is the applicant's PIQ product.

[0007] This PIQ product is a sensor mounted on a ski boot and configured to measure the power applied by the skier during each turn. The sensor communicates with the skier's smartphone in order to measure a large number of parameters during the skier's descent by associating the measurements from the phone's sensors with those of the PIQ sensor. The mobile application provided with the PIQ product allows the performance of several skiers to be compared by transmitting their performances to a database.

[0008] However, the PIQ sensor is particularly energy-intensive because it must power the power measurement means and the wireless communication means with the smartphone throughout a day of skiing. To do this, the PIQ sensor incorporates a battery and is supplied with a battery charging module. Thus, it is not possible to permanently integrate the PIQ sensor into a boot or ski because the user has the burden of ensuring regular recharging of the PIQ sensor.

[0009] Furthermore, it is known from American patent US 5,590,908 to measure the deformations of a sliding board by means of a piezoelectric sensor in order to obtain information on the contact points of the sliding board on the snow.

[0010] It is also known from patent EP 0 841 969 to use piezoelectric sensors to dampen the vibrations of a sliding board.

[0011] This type of sensor uses the intrinsic behavior of a piezoelectric element that converts mechanical deformation energy into electrical energy. Document US 2002 / 116147 A discloses a system for analyzing the performance of use of a sliding board according to the preamble of claim 1. Documents WO 2018 / 170119 A1 or US 2015 / 057112 A1 disclose a piezoelectric as an energy source for an electronic processing circuit in a ski.

[0012] To analyze the deformations of a sliding board using a piezoelectric sensor, it would be necessary to use an electronic analysis circuit which is permanently powered.

[0013] Thus, the use of an electrical energy source providing a constant voltage, such as an electrochemical battery or any other known means, is necessary.

[0014] However, an electrochemical battery has constraints in terms of size and weight, cold resistance, and storage, which are generally not compatible with a snow board. Indeed, a snow board can be used at temperatures close to -20°C. In this operating temperature range, conventional electrochemical batteries are inefficient or even unusable. In addition, batteries discharge quickly in the cold and must often be replaced or recharged by the user, which is very restrictive. In addition, a snow board is often used occasionally, for example, for a few days each winter.

[0015] An electrochemical battery on a snowboard would therefore have long periods of inactivity, at least between spring and autumn, during which the electrochemical battery would be completely discharged. Furthermore, a snowboard is a mechanical element subject to significant stresses, such as twisting or shocks.

[0016] Concrete applications involving the use of an electronic circuit and a piezoelectric element embedded on a sliding board are therefore limited and the vast majority of measuring devices existing in other application areas cannot be transposed onto a sliding board due to these specific constraints.

[0017] Document WO 2011 / 160040 describes a board of skateboard with light-emitting diodes arranged under the board to display light effects on the floor.

[0018] The diodes are normally powered by a battery, but one embodiment proposes using a piezoelectric transducer to power these light-emitting diodes. In addition to this display device, this document also proposes incorporating an electronic circuit on the board. skateboard in order to take measurements over time. This electronic circuit is powered by a battery and can integrate a motion sensor as described previously, i.e. a piezoelectric sensor using a deformation measurement from a piezoelectric element.

[0019] However, the teaching of this document is not adapted to the field of sliding boards corresponding to the invention, that is to say boards for sliding on snow or on water, and in particular alpine, cross-country or touring skis, or even snowboards or wakeboards. Indeed, for these sliding boards, the lower face of the sliding boards is intended to come into contact with the surface on which the board moves, unlike a skateboard. It is therefore not useful to have the luminous elements under the sliding board of the invention because these elements would not be visible. Furthermore, this document only describes a conventional method of powering the electronic circuit carrying out the measurements, that is to say the use of a battery.

[0020] The technical problem that the invention aims to solve is therefore to find out how to analyze the performance of a user of a sliding board by obtaining information linked to the use of a sliding board while doing away with an additional power source, and in particular an electrochemical battery. Exposé de l'invention

[0021] The invention proposes to address this technical problem by using a sensor comprising at least one piezoelectric element secured to a sliding board and by using this piezoelectric element to power an electronic circuit for processing the sensor making it possible to estimate a duration of the deformation phases of the sliding board and an image of the mechanical energy dissipated during the deformations of said sliding board.

[0022] To this end, the invention relates to a system for analyzing the performance of using a sliding board comprising: a database storing reference performances; a sensor sensitive to the deformations of said sliding board; and a monitoring unit comprising: means for determining the usage performances of said sliding board based on measurements from said sensor; and means for comparing said usage performances with said reference performances.

[0023] The invention is characterized in that said sensor is secured to said sliding board and comprises: at least one piezoelectric element secured to said sliding board and configured to generate electrical energy during deformations of said sliding board; and an electronic processing circuit, powered exclusively by said electrical energy generated by said at least one piezoelectric element, configured to estimate a duration of the deformation phases of said sliding board and to estimate an image of the mechanical energy dissipated during the deformations of said sliding board; said usage performances including a stress time, corresponding to said duration of the deformation phases of said sliding board, and an image of the average stress power corresponding to the ratio between the image and said duration of the deformation phases; said reference performances being determined by a sensor, similar to said sensor secured to said sliding board, so as to obtain a reference stress time and an average reference stress.

[0024] The invention thus makes it possible to obtain two pieces of information, the stress time and the average stress power, linked to the use of a sliding board, while avoiding the need for an additional power source, and in particular an electrochemical battery.

[0025] A user of a gliding board can reset this information before a descent and retrieve the information acquired following the descent. Preferably, the user has a mobile application and a smartphone configured to work with the sensor attached to the gliding board. Any other device similar to a smartphone could be used to replace this smartphone, such as for example a connected watch, or a connected object positioned or integrated into clothing. For example, the sensor can integrate a radiofrequency antenna intended to cooperate with an antenna of the smartphone via the NFC protocol, for "Near Field Communication". According to one embodiment, said monitoring device is integrated into a mobile application of a smartphone.

[0026] This technology allows the electromagnetic power of the radiofrequency signal emitted by the smartphone to be used to power the sensor and write or retrieve information contained in a chip.

[0027] In addition, this information can be correlated with other information acquired by the smartphone or a similar device that includes other types of sensors, independent of the sensor attached to the sliding board.

[0028] According to one embodiment, said usage performance includes a speed measured by a position sensor; this measured speed being compared to a reference speed. A position sensor may correspond to a GPS type sensor, for “Global Positioning System”.

[0029] According to one embodiment, said usage performance includes a number of turns made detected by a gyroscope; this number of turns made being compared to a reference number of turns made. Alternatively or additionally, the number of turns can be determined by other components of a smartphone, such as an accelerometer or a magnetometer.

[0030] Thus, by using the position sensor and the gyroscope of the smartphone, it is possible to compare the time of solicitations, the average power of solicitations, the speed and the number of turns made by a user of a sliding board compared to another reference user whose performances are stored in a database.

[0031] Preferably, the reference user corresponds to a professional or expert skier who takes a predetermined route with a desired level of mastery. For example, to determine whether a skier correctly descends a green slope with the snowplough technique, it is not sufficient to analyze the descent speed or the number of turns because a user can descend a slope very quickly without mastering the turns or he can make a large number of turns without mastering the support power in each turn to guarantee his stability.

[0032] To detect these lacks of control, a professional equipped with the invention takes the green slope before the skier, practicing snowploughing and descending the slope gently with correctly supported turns.

[0033] Following the professional's descent, the professional's performance is sent to the database, via his smartphone and the mobile application forming the monitoring body. To do this, the mobile application preferably includes data processing means to form the reference performances.

[0034] Following this phase of recording the reference performances, a user equipped with the invention can take the same track and the supervisory body can compare his performances with those of the reference user.

[0035] Preferably, said supervisory body is configured to authorize access to a higher level course when said request time is less than a reference request time and said average request power is greater than a reference average request power. With this embodiment, the comparison of the skier and the reference professional makes it possible to indicate to the skier his skiing level, to advise him to continue practicing on the slope already covered or to indicate to him that he can ski on a more difficult slope. This comparison can also make it possible to automatically authorize access to certain slopes in an area so that the users of a slope have certainty of having the skills necessary to use the slope.

[0036] With this in mind, the monitoring device can be installed at the entrance to a ski lift access gate instead of being carried on a smartphone of the user of the ski board. Before being able to access a ski lift leading to a slope of a particular difficulty, for example a black slope, the user must then pass his ski in front of the reader so that the reader retrieves performance information related to a previous descent of a lower level, for example a red slope.

[0037] If the user has the required qualities, that is to say, he exceeds the criteria imposed by the reference performances, at least in terms of descent time and average power of solicitation, he will actually be able to access the black slope.

[0038] Additionally, a skier's pass can be automatically updated by entering access rights into a radio frequency tag to authorize future access requests at that difficulty level. Conversely, if the user does not exceed the imposed criteria, access to the slope may be denied.

[0039] Of course, this embodiment can also be implemented with a greater number of criteria. For example, in one embodiment, said supervisory body is configured to authorize access to a higher level course when said speed and said number of turns made are greater than said reference speed and said reference number of turns made.

[0040] The invention also allows for many other new uses. For example, in one embodiment, said supervisory body is configured to classify a user of a sliding board with respect to predefined level classes based on said comparison made by said supervisory body. This embodiment makes it possible to deliver a classification of a skier in recognized categories, such as classes 1, 2, 3 and 4, as established by the French Ski School for example. In this case, class 1 corresponds to the beginner level, while class 4 corresponds to the competition level.

[0041] It is also possible to compare users with each other in a video game environment in which players compete against each other using their real-life performance.

[0042] However, the two users may have differences in equipment and the capabilities of the board, and in particular its flexing capabilities, may cause the performance captured by two identical sensors mounted on two separate boards to vary. To solve this problem, one solution is to compare corrected usage performance based on a variable relating to a specific flexing stiffness for each board.

[0043] To this end, according to one embodiment, said means for determining usage performance are configured to determine corrected usage performance as a function of said usage performance and a variable relating to a bending stiffness of said sliding board; said comparison means being implemented from said corrected usage performance.

[0044] For example, said variable relating to a deformation capacity of said sliding board can be obtained from the model of said sliding board and a database storing different models of sliding boards and the corresponding bending stiffness coefficients. The model of the sliding board can be entered directly into the mobile application of a smartphone or a similar device. Alternatively, this model can be captured by the smartphone by scanning a tag placed on the sliding board in which the name of the model or a reference to the model is stored.

[0045] Furthermore, variations in the flexion of the sliding board can also appear due to the size of the user's shoe because, for the same sliding board, the length of the free beam in flexion varies between two shoe sizes. Thus, the variable relating to a deformation capacity of said sliding board can also be determined based on a shoe size entered in the mobile application of a smartphone.

[0046] This shoe size variable can also help correct user-recorded usage performance.

[0047] Other variations appear due to variations in the medium on which the two users operate.

[0048] Indeed, between two periods of the year and between two different moments of the same day, the snow changes texture and the information obtained by the sensor of the invention can be very different for the same user.

[0049] To address this problem, said means for determining usage performance are configured to determine corrected usage performance based on said usage performance and a variable relating to the type of snow on which said sliding board moves; said comparison means being implemented from said corrected usage performance.

[0050] For example, the said variable relating to the type of snow on which the said sliding board is moving is obtained from a temperature sensor. Preferably, the temperature sensor is integrated into a smartphone.

[0051] Alternatively, said variable relating to the type of snow on which said sliding board is moving is obtained from a position sensor and a database storing meteorological information relating to different positions. Description sommaire des figures

[0052] The manner of carrying out the invention, as well as the advantages which result therefrom, will emerge clearly from the description of the embodiments which follow, supported by the appended figures in which: [ Fig 1 ] there figure 1 is a schematic representation of a system for analyzing the performance of using a sliding board according to one embodiment of the invention; [ Fig 2 ] there figure 2 is a flowchart of the steps for recording and comparing usage performance acquired with the analysis system of the figure 1 ; [ Fig 3 ] there figure 3 is an electrical diagram of a sensor mounted on the sliding board of the figure 1 according to a first embodiment; [ Fig 4 ] there figure 4 is an electrical diagram of a sensor mounted on the sliding board of the figure 1 according to a second embodiment; [ Fig 5 ] THE figures 5a à 5e are temporal representations of acquisition of different parameters, carried out using the sensor of the figure 3 , on which the figure 5a represents the deformations of the sliding board (D), the figure 5b represents the voltage across the capacitive storage element, the figure 5c represents a duration (T) deformation phases, and the figures 5d et 5e represent an image (M) of the average power of the deformation phases recorded in a buffer memory and in the non-volatile memory; [ Fig 6 ] THE figures 6a à 6e are temporal representations of acquisition of different parameters, carried out using the sensor of the figure 4 , on which the figure 6a represents the deformations of the sliding board (D), there figure 6b represents the voltage across the capacitive storage element, the figure 6c represents a duration (T) deformation phases, and the figures 6d et 6e represent an image (M) of the average power of the deformation phases recorded in a buffer memory and in the non-volatile memory; [ Fig 7 ] there figure 7 is a top view of a sliding board according to the invention; [ Fig 8 ] there figure 8 is a side view of the front part of the sliding board of the figure 7 ; [ Fig 9 ] there figure 9 is an exploded perspective view of the front elements attached to the sliding board of the figure 7 ; [ Fig 10 ] there figure 10 is a partial top view of the sliding board of the figure 7 in a first sensor mounting position; [ Fig 11 ] there figure 11 is a partial top view of the sliding board of the figure 7 in a second sensor mounting position; [ Fig 12 ] there figure 12 is a partial top view of the sliding board of the figure 7 in a third sensor mounting position; [ Fig 13 ] there figure 13 is a partial top view of the sliding board of the figure 7 in a fourth sensor mounting position; [ Fig 14 ] there figure 14 is a vertical sectional view of the sliding board of the figure 7 according to a first embodiment of the invention; and [ Fig 15 ] there figure 15 is a vertical sectional view of the sliding board of the figure 7 according to a second embodiment of the invention.

[0053] Of course, the dimensions and proportions of certain constituent elements of the invention may have been distorted, exaggerated and deviate from reality, in order to make the invention clear. Manière de réaliser l'invention

[0054] There figure 1 illustrates an analysis system 200 performance of using a sliding board 25. In the following description, the sliding board 25 corresponds to a ski.

[0055] Of course, other sliding boards can be used without changing the invention, in particular such as cross-country skis or snowboards receiving both feet of the user on the same board.

[0056] The sliding board 25 is instrumented by a sensor 100 and a wireless transmission system, which may be a radio frequency tag 221 or a Bluetooth system. The skier carries a smartphone 203able to communicate with the sensor 100 and the tag 221 by radio frequencies. For example, the smartphone 203 may include an NFC chip 206, for “Near Field Communication”, allowing the use of electromagnetic waves to power the sensor 100 or the tag 221 and receive information contained in an internal chip 19 to the sensor 100 or to the tag 221. In the case of using a Bluetooth system at the sensor level, this Bluetooth system is powered by the piezoelectric element positioned on the sliding board.

[0057] The tag 221 aims only to convey information about the model of the board 25 while the sensor 100 allows information to be transmitted relating to the deformations undergone by the sliding board 25 during a descent.

[0058] The NFC chip 206of the smartphone 203 is connected to a supervisory body 204. For example, the supervisory body 204 may correspond to a mobile application running on a processor integrated into the smartphone 203. This supervisory body can also include functions that are deported and processed on a remote server.

[0059] This supervisory body 204 is also connected to other chips in the smartphone, such as a GPS chip 207, for “Global Positioning System”, allowing the position and trajectory of the smartphone to be determined 203 over time, or a gyroscopic chip 208, to indicate the angular movements of the smartphone 203 to identify turns or even a temperature sensor 209, allowing the outside temperature to be captured around the smartphone 203.

[0060] Other sensors, such as an accelerometer, a magnetometer, a barometer, or even a camera, could also be connected to this monitoring device to carry out more comprehensive analyses.

[0061] The supervisory body 204 has the main function of comparing the performance acquired during a skier's descent with reference performance stored in a database 202. This database 202 can be hosted on a server 201 from a winter sports equipment manufacturer or at a ski resort. To communicate with the server 201, the smartphone 203 preferentially uses a wireless data transmission network, such as WiFi, 3G, 4G or 5G networks. In the example of the figure 1 , the smartphone 203 uses a 4G chip 205 to communicate with the server 201.

[0062] In addition, the smartphone 203 is also connected with a weather server 222 so that the smartphone 203 can obtain weather information based on the skier's position Coord transmitted to the weather server 222. This position of the skier Coord is preferentially obtained by the GPS chip 207.

[0063] This analysis system 200 allows the skier's performance to be compared with that of a reference skier. To do this, as illustrated in the figure 2 , the same route X will be carried out by a reference skier, who may be a professional, and also by the skier, at a different time compared to the reference skier. Before carrying out route X, it is necessary to reset the sensor data 100positioned on the ski, both for the reference skier and for the skier. More precisely, this reset is carried out by tagging the sensor 100 with the smartphone 203. Then the start of data recording in the sensor 100 is automatic as soon as the reference skier or the skier begins his course X given that the sensor 100 only records data when the ski deforms statically and / or dynamically.

[0064] In a first step 300, the reference skier or the professional chooses a route X. Before starting route X, in a stage 301, the professional resets the sensor 100. To do this, the professional can use his smartphone 203 to communicate with non-volatile memory 19 integrated into the sensor 100 so as to reset information over a period of timeT phases of deformation of its sliding board 25 and information from an image M mechanical energy dissipated during deformations of the sliding board 25. When this information T, M are reset, the professional can carry out the descent of the X course, in one stage 302. During the descent, the professional must ensure that he descends course X by pressing in the turns with a level adapted to the level of course X, so as to obtain adapted trajectories, average support forces on the skis and consequently, a time of use or completion of course X as well as an average power representative of the level corresponding to course X.

[0065] At the end of route X, in a stage 303, the professional scans the sensor 100 using the smartphone 203 in order to recover the data T AndM estimated by the sensor 100 and the supervisory body 204 determines both information Tref And Pref from this data T And M. In the case of using a Bluetooth system on the board, the data T And M are automatically transmitted to the supervisory body 204.

[0066] The duration Tref corresponds directly to a time account T obtained by the sensor 100 while the image Pref the average power of requests is determined by the ratio between an activation count M and the time account T stress phases estimated by the sensor 100.

[0067] In addition to this information T And M, a step 304can also be implemented to retrieve contextual data, such as the model of the professional's skis or the type of snow on which the professional performed the descent of course X.

[0068] Course X can be part of a park of imposed slopes, each of the slopes representing a level of skiing with specific exercises corresponding to this level, the slope generally being equipped with stakes forming a specific layout, making it possible to impose the type of turns to be made.

[0069] Course X can also correspond to a free slope, that is to say to any slope located in the ski resort and not equipped with poles, the slope being however referenced by its slope, and in particular in a known manner by green, blue, red and black colors, going from the lowest slope corresponding to a less technical slope, to the highest slope, corresponding to the most technical slope. As for the exercises proposed on free slope, they can include tight or wider turns, straight lines or crossings, or exercises of the skating step type, or any other type of exercise important in learning to ski.

[0070] To detect the model, the professional can simply scan the tag 221 present on the sliding board 25 in which the model information is present. Alternatively, it can provide this model on a mobile application of the smartphone 203.

[0071] As for the type of snow, it can be characterized based on the weather information transmitted by the server 221 depending on the coordinates Coord from the professional or they can be determined based on the temperature measured by the temperature sensor 209. In addition to this contextual data, the step 305 possibly also offers to recover data collected during the descent by the professional using sensors integrated into the smartphone 203. For example, this step 305 can recover speed Vs measured by the position sensor 207 or a number of turns Ns performed and detected by the gyroscope 208. Of course, many other sensors of the smartphone 203can be implemented, such as an accelerometer, a magnetometer, a barometer or even a camera integrated into the smartphone 203.

[0072] Alternatively and in addition, data can also be captured during the descent by other devices connected to the smartphone. 203, such as a smartwatch, a sensor integrated into the professional's clothing or a camera mounted on the professional in an area close to their center of gravity.

[0073] Typically, an accelerometer provides information on the thrust experienced by the professional in turns, a magnetometer used as a compass allows the detection of variations in the professional's heading, a barometer allows the precise detection of changes in altitude experienced by the professional and a camera allows an image of the professional's skis to be recorded throughout the descent to assess the skier's ability to keep their skis parallel in particular.

[0074] In one step 306, all of this data is recorded in the database 202 to form benchmark performances (Tref, Pref, Vref, Nref...) of the X course, provided by the reference skier.

[0075] So when a skier uses a system 200 analogous, it can reproduce the same steps 300 has 305and achieve performance comparable to that of the professional for the same route X. If route X corresponds to a free slope, the mobile application indicates to the skier the level of the slope to descend (green, blue, red, black) as well as the exercise to perform. If route X is traced on a compulsory slope, the exercise to perform is linked to the slope.

[0076] To effectively compare the skier's performance with that of the professional, it is best to correct the skier's performance Ts, Ps, Vs, Ns, depending on the disparities between the contextual data of the professional and those of the skier.

[0077] To do this, the difference in bending stiffness between the professional's ski model and the skier's ski model is determined from a database 220, hosted on the server 201 or on an external server. This database 220integrates correspondences between ski models and stiffness coefficients. The difference between the two stiffness coefficients of the two ski models makes it possible to obtain a variable αm relative to the flexural stiffness of the skier's skis. This variable αm can also be determined based on a difference in shoe size between the professional and the skier.

[0078] The skier's performance Ts, Ps, Vs, Ns can also be corrected by a variable αn relating to the difference between the hardness of the professional's snow and the hardness of the skier's snow.

[0079] To determine this variable αn , the supervisory body 204 can query the weather server 222 to obtain an estimate of the hardness of the snow based on the skier's position.

[0080] Alternatively, snow hardness can be determined from a temperature sensor measurement 209, especially integrated into the smartphone.

[0081] With these different possible corrections, the step 307 allows for corrected performance Tsc, Psc, Vsc, Nsc allowing better comparison with reference performances Tref, Pref, Vref, Nref acquired by the professional. Thus, in one step 308, the comparison is made for all measured and comparable performances.

[0082] The result of this comparison can be exploited in different ways without changing the invention. For example, as illustrated in the figure 2 , if the comparison shows that the skier has exceeded the performance Tref, Pref, Vref, Nref of the professional, that is to say: if the duration of the deformation phases Tsc of the skier is less than the duration of the deformation phases Tref of the professional; and if the average power of requests Psc of the skier is greater than the average power of requests Pref of the professional, and if the speed Vsc of the skier is greater than the speed Vref of the professional, and if the number of turns Nsc of the skier is greater than the number of turns Nref of the professional, then the skier can be considered as having successfully completed course X and authorized to move on to a course of higher difficulty, in a stage 309. Otherwise, the skier may be required to repeat route X.

[0083] A simpler comparison can be made solely on performance criteria Tsc And Psc, in comparison with Tref And Pref. Furthermore, a more in-depth comparison can be made by adding to the criteria Ts, Ps, Vs And Ns other criteria taken alone or in combination which would come from sensors such as accelerometers, magnetometers, barometers or even cameras.

[0084] The comparison between the skier's performance and that of the professional who is the reference skier can also be used to determine the skier's level and then to advise him in his learning to ski by indicating the most suitable imposed route X, or by indicating the specific types of exercises to be carried out on a free slope, or to advise him on a ski course adapted to his level, in a ski school, or to advise him on a ski model adapted to his skiing level. The comparison can also be used to enter the recorded data into a video game application.

[0085] To determine the level of a skier, in addition to the elements previously described, the supervisory body 204may use processing and classification or regression algorithms based on supervised learning, such as decision trees or neural networks. To do this, the classification model must be built using a learning phase with skiers of several levels evaluated by professionals for whom at least the performances will be recorded Tref, Pref as well as the reference speed Vref. Recording other parameters such as the number of turns Nref, or even reference performances from accelerometers and / or a magnetometer will provide more precise information on the different types of skiers. Thus, a classification of skiers by level can be built in a database by defining thresholds for the different levels of skiers.

[0086] In other words, to assess the skier's level, it is planned to offer him the opportunity to complete a course X of average difficulty, then to compare his recorded and corrected performances Tsc, Psc, or even also Vsc, Ns, with the thresholds established for each of the level classes (corresponding for example to classes 1 to 4 of the ESF) and recorded in the database.

[0087] Analysis of skier performance Ts, Ps And Vs easily position the skier in a level class to define the skier's level.

[0088] Analysis of skier performance Ts, Ps And Vs to which we add other skier performances, such as the number of turns Ns, or data from a magnetometer or data from accelerometers make it possible to position the skier in a sub-class of a level class to establish the skier's level with great precision.

[0089] More precisely, comparing the skier's recorded and / or corrected performances by associating the recorded parameter of speed Vs or Vsc makes it possible to define the skier's level in a class.

[0090] Additional analysis of one of the following recorded parameters

[0091] For the purposes of the invention, the comparison must be carried out at least with data integrating a duration Ts deformation phases and an image Ps the average power of the sliding board's stresses 25 of the skier. The duration Ts corresponds directly to a time account T obtained by the sensor 100 while the image Ps the average power of requests is determined by the ratio between an activation count M and the time account T stress phases estimated by the sensor 100. When calculating the ratio Ps between M And T, a multiplier coefficient can be applied to the activation account M.

[0092] THE figures 3 And 4 represent two embodiments of an electrical diagram of a sensor 100 of using a sliding board 25 allowing information to be measured T And M. This sensor 100 is attached to a sliding board 25 as will be illustrated by the figures 7 à 15 .

[0093] According to these two embodiments, the sensor 100comprises, on the one hand, at least one element intended to produce electrical energy following deformation, such as a piezoelectric element 11a, 11b and, on the other hand, an electronic processing circuit 15. The electronic processing circuit 15 includes a part relating to the storage and management of electrical energy 101, as well as a part 102 relating to the determination of at least one piece of information linked to the use of the sliding board 25, this part 102 including elements ensuring estimates and calculations related to the use of the sliding board 25.

[0094] In order to memorize information related to the use of the sliding board 25, the electronic processing circuit 15 further includes a part 103relating to data storage. And finally, to ensure the communication of this recorded data to a device external to the sensor 100, the electronic processing circuit 15 includes a part 104 relating to communication.

[0095] Common to both embodiments, the sensor 100 comprises at least one piezoelectric element 11a, 11b, here in number of two. The piezoelectric elements 11a, 11b are not directly connected to each other. Piezoelectric elements 11a, 11b can be electrically arranged in parallel. Alternatively, the piezoelectric elements 11a, 11b are electrically arranged in series with each other.

[0096] The two piezoelectric elements 11a, 11b are intended to generate an electrical signal during use of the sliding board 25. More precisely, each piezoelectric element 11a, 11b generates an electrical voltage Vpa, Vpb in response to a mechanical deformation that it undergoes. In the presence of several piezoelectric elements 11a, 11b this electrical voltage Vpa, Vpb may vary from piezoelectric element 11a, 11b to the other.

[0097] The electronic processing circuit 15 is powered only by the piezoelectric elements 11a, 11b. So the sensor 100, forming itself an electronic circuit composed of piezoelectric elements 11a, 11b as well as the electronic processing circuit 15, is autonomous, that is to say it does not require a power source external to the sensor 100, such as for example a rechargeable or non-rechargeable battery.

[0098] In other words, piezoelectric elements 11a, 11b both act as a source of information for determining the use of the board 25and the role of power source, as will be described later.

[0099] The tension Vpa, Vpb generated by each piezoelectric element 11a-11b is an alternating, not direct, voltage which exhibits great variability in amplitude and frequency.

[0100] As illustrated by the figures 5a And 6a , during a phase P1 called start-up and during a phase P2 called writing, the sliding board 25 deforms in bending when used and a surface 12 of the sliding board then undergoes deformations transmitted to the piezoelectric elements 11a-11b which generate tension Vpa, Vpb which varies according to the deformations undergone by the surface 12. During a phase P3, called stop, and a phase P4, called extinction, the sliding board 25is stopped and, therefore, it is no longer deformed, so the surface 12 does not undergo deformation and tension Vpa, Vpb generated by piezoelectric elements 11a-11b becomes zero.

[0101] Common to both embodiments, the part relating to the storage and management of electrical energy 101 includes at least one voltage converter 14, at least one capacitive storage element Cs and at least one voltage comparator 22.

[0102] The tension Vpa, Vpb, intrinsically variable, is injected into a voltage converter 14 which provides a rectified or direct voltage from the voltage Vpa, Vpb generated by each piezoelectric element 11a-11b.

[0103] According to the two embodiments, this voltage converter 14 is achieved by a diode bridge which provides a rectified voltage.

[0104] According to an alternative embodiment, the voltage converter 14 is achieved by a "buck", "boost" or "buck-boost" type chopper, these choppers have the advantage of providing a direct voltage. It should be noted that each piezoelectric element 11a-11b is connected without intermediate element to the voltage converter 14. In the case where the piezoelectric elements 11a, 11b are electrically arranged in series or in parallel, a single voltage converter is advantageously provided 14, which can represent a significant manufacturing saving.

[0105] At the output of this voltage converter 14, the tension Vpa, Vpb generated by piezoelectric elements 11a-11b is stored in a capacitive storage element Cs, supercapacitor or capacitor type. The capacitive storage element Cs may comprise several supercapacitors or capacitors without changing the invention. In the case where several capacitors are used, they are then electrically arranged in parallel with each other, the sum of the capacities of each of the capacitors making it possible to obtain the equivalent capacity of all the capacitors.

[0106] THE figures 5b And 6b illustrate the tension Vcs across the capacitive storage element Cs. In the initial state, that is to say when the board slides 25 is not used, the capacitive storage element Cs is completely discharged. In the starting phases P1 and writing P2, the sliding board 25 is used and deforms in flexion, especially on snow. In the starting phases P1 and writing P2, deformations of the sliding board 25, and therefore of the surface12, allow the capacitive storage element to be charged Cs through piezoelectric elements 11a, 11b.

[0107] During the shutdown phases P3 and extinction P4, the sliding board 25 no longer being used, the capacitive storage element Cs discharges. The part 101 relating to the storage and management of electrical energy further comprises at least one voltage comparator 22, 22a configured to control the power supply of the part 102 relating to the determination of at least one piece of information linked to the use of the sliding board 25.

[0108] For this, the voltage comparator 22, 22a is configured to compare the voltage Vcs at the output of the capacitive storage element Cs at two threshold voltage values S1h, S1b, S0h, S0b, as will be described later in relation to the figure 5b And6b .

[0109] Common to both embodiments, the voltage comparator 22 is connected on the one hand to the capacitive storage element Cs by a power terminal Vcc, to a switch 21 at the output, to one or more resistors R1, R2, R3 on its positive terminal and to a voltage reference F on its negative terminal. Advantageously, at the output of the voltage comparator 22, a signal inverter 10 is arranged. It should be noted that the switch 21 is, for example, a PMOS type transistor. Of course, this switch 21 can also be an NMOS type transistor and, in this case, the architecture of the processing electronic circuit 15 will have to be adapted.

[0110] Furthermore, the part 103 relating to data storage includes at least one non-volatile memory 19,as will be described later. It should be noted that a memory is said to be non-volatile, since its power-down does not cause the loss of recorded data.

[0111] As for the part 104 relating to communication, this includes an antenna 20, which will also be described later in the description.

[0112] According to the first embodiment illustrated by the figure 3 , the electronic processing circuit 15, and in particular its part 102 relating to the determination of at least one piece of information linked to the use of the sliding board 25, includes a microcontroller 18.

[0113] The microcontroller 18 performs binary accounts T, M and it is configured to compare its supply voltage with respect to at least one reference voltage value REFmax, REFmin. According to this embodiment, the microcontroller 18performs two binary counts, a time binary count T corresponding to a duration of use of the sliding board 25 and a binary account M, called activation count, which aims to represent information linked to the amplitude of the deformations of the sliding board 25.

[0114] In other words, according to this embodiment, the microcontroller 18 estimates both the duration of use and the amplitude of deformations of the sliding board 25.

[0115] It should be noted that, according to this embodiment, a single voltage comparator 22 is planned. This voltage comparator 22 performs the hysteresis comparator function allowing the closing or opening of the switch 21 in order to connect, respectively disconnect, the microcontroller 18 to the capacitive storage element Cs. For this, two thresholds are defined S1h And S1b , respectively called in the following description supply threshold S1h and cut-off threshold S1b . In other words, this voltage comparator 22 is configured to control the power supply of the microcontroller 18 depending on the power threshold S1h and the cut-off threshold S1b.

[0116] When the tension Vcs across the capacitive storage element Cs reached the power threshold S1h , the output of the voltage comparator 22 goes high.

[0117] This inverted signal allows the switch to be controlled 21, which, when closed, connects the capacitive storage element Cs to the microcontroller 18.

[0118] On the figure 5b , after reaching the power threshold S1h , the tension Vcs decreases slightly in response to microcontroller power-up 18.

[0119] At the end of the sliding board's requests 25 (phases P3, P4), the capacitive storage element Cs no longer powered by the piezoelectric elements 11a, 11b, a discharge of the capacitive storage element appears Cs. Due to the positive counter-reaction of the resistors R1, R2, R3 on the voltage comparator 22, the cut-off threshold S1b is set to a voltage value equal to S1b = S1h - ΔV1, Or ΔV1 represents the hysteresis generated by the parallel connection of the resistors R1 And R3.

[0120] So when the tension Vcs across the capacitive storage element Cs falls below the cut-off threshold S1b , the output of the voltage comparator 22returns to the low state, allowing the switch to open 21 and disconnecting the capacitive storage element Cs to the microcontroller 18.

[0121] In the following, the operating method of the part 102 relating to the determination of at least one piece of information linked to the use of the sliding board 25 will be described according to the first embodiment of the figures 5a, 5b, 5c, 5d et 5e .

[0122] Once the microcontroller 18 undervoltage and that the piezoelectric elements 11a, 11b continue to supply electrical energy to the capacitive storage element Cs (phase P2 ), the tension Vcs then reaches a maximum reference value REFmax. When the tension Vcs reached the maximum reference value REFmax, the microcontroller 18 is configured to increment the activation count Mand write it to non-volatile memory 19, as represented by the figure 5c . This increment as well as this registration in memory of the activation account M consumes energy represented by a voltage drop ΔV2 on the figure 5b . According to this method of operation, the activation account M, representing the mechanical energy imposed on the sliding board 25, is incremented by the value 1 each time the maximum reference value REFmax is reached by the tension Vcs, as illustrated by the figure 5c .

[0123] In other words, the activation account M counts the number of peaks P where the tension Vcs reached the maximum reference value REFmax during the period of use of the sliding board 25.

[0124] Plus these peaks Pare tight, the more stress there is on the sliding board 25 by the user is important, and the more peaks P are spaced, the more stress there is on the sliding board 25 by the user is low.

[0125] According to this embodiment, the time account T is determined by an internal clock in the microcontroller 18 which is activated as soon as the microcontroller is powered up 18, as shown in the figure 5d . In other words, the time account T starts as soon as the voltage Vcs reached the power threshold S1h.

[0126] When the board flexes 25 interrupt, the piezoelectric elements 11a, 11b stop supplying electrical energy to the capacitive storage element Cs, whose tension Vcs gradually decreases through a minimum reference value REFmin. According to this method of operation, as soon as the voltage Vcs reached this minimum reference value REFmin, the microcontroller 18 is configured to register the time account T in non-volatile memory 19.

[0127] It should be noted that the registration of this time account T induces a voltage drop ΔV3. In this first embodiment, the thresholds are defined so that: S1b < S1h < REFmin < REFmax.

[0128] During the phases P2 And P3, the electronic processing circuit 15 performs at least one binary account T, M using voltage Vcs across the capacitive storage element Cs.

[0129] In the phases P3 And P4, when the activity of the sliding board 25 is stopped, counting the number of activationsM is automatically stopped since the maximum reference value REFmax is no longer reached, while the counting of the duration of use T by the microcontroller 18 is stopped at the end of the phase P3, and at the beginning of the phase P4 when the tension Vcs is less than or equal to the cut-off threshold S1b ( figure 5d ). However, according to this method of operation the counting of the duration of use T by the microcontroller 18 after time tRefmin is not stored in non-volatile memory 19 (cf. fig. 5e ).

[0130] When the tension Vcs across the capacitive storage element Cs reached the cut-off threshold S1b , the microcontroller 18 is powered off and the data relating to binary accounts T And M remain in non-volatile memory 19,as illustrated by the figures 5c et 5e .

[0131] In the following, the elements specific to the second embodiment illustrated by the figure 4 are detailed. According to this second embodiment, the microcontroller 18 creates a single binary account, the activation account M. In other words, according to this embodiment, the microcontroller 18 estimates the amplitude of the deformations of the sliding board 25.

[0132] Indeed, the temporal account T is obtained by an oscillator 16, a counter 17 which are here distinct elements of the microcontroller 18.

[0133] The oscillator 16 allows a periodic signal to be delivered to the counter 17. At each period of the periodic signal of the oscillator 16, the counter 17 increments the time count T. For example, the oscillator 16can be a quartz oscillator and the counter 17 can be achieved by cascading a series of T flip-flops.

[0134] In this second embodiment, the oscillator 16 and the meter 17 are powered by the capacitive storage element Cs using a second voltage comparator 22a.

[0135] This second voltage comparator 22a, equipped with an external reference Fa and surrounded by resistance R1a , R2a, R3a, performs the hysteresis comparator function allowing the closing, respectively the opening, of the switch 21a in order to connect, respectively to disconnect, the oscillator 16 and the meter 17 to the capacitive storage element Cs.

[0136] For this, two thresholds are defined S0h And S0b, respectively called in the rest of the description counting threshold S0h and deactivation threshold S0b. In other words, the sensor 100, according to this second embodiment, comprises two voltage comparators 22, 22a, with a first voltage comparator 22 configured to control the microcontroller power supply 18 depending on the power threshold S1h and the cut-off threshold S1b and a second voltage comparator 22a configured to control the oscillator power supply 16 and the meter 17 depending on the counting threshold S0h and the deactivation threshold S0b.

[0137] In this second embodiment, the thresholds are defined so that: S0b < S0h < S1b < S1h.

[0138] When the tension Vcs across the capacitive storage element Cs reached the counting threshold S0h, the output of the second voltage comparator 22a goes high, allowing control of the switch 21a, which, when closed, connects the capacitive storage element Cs to the oscillator 16 and on the meter 17. On the figure 6b , after reaching the counting threshold S0h, the tension Vcs decreases slightly in response to turning on the oscillator 16 and the meter 17. From the counting threshold S0h, a counting phase P1a starts until the oscillator is powered off 16 and the meter 17.

[0139] As the demands continue, the tension Vcs across the capacitive storage element Cs reached the power threshold S1h , which allows power to be supplied to the microcontroller 18 via the first voltage comparator 22,as described previously.

[0140] At the end of the sliding board's requests 25, the capacitive storage element Cs no longer powered by the piezoelectric elements 11a, 11b, a discharge of the capacitive storage element then appears Cs.

[0141] So when the tension Vcs across the capacitive storage element Cs falls below the cut-off threshold S1b , the output of the first voltage comparator 22 returns to the low state, allowing the switch to open 21 and disconnecting the capacitive storage element Cs to the microcontroller 18. Moreover, although the microcontroller 18 has been disconnected, the discharge of the capacitive storage element Cs continues.

[0142] Due to the positive counter-reaction of the resistors R1a-R3a on the second voltage comparator 22a, the deactivation threshold S0b is set to a voltage value equal to S0b = S0h - ΔV4, Or ΔV4 represents the hysteresis generated by the parallel connection of the resistors R1a And R3a.

[0143] So when the tension Vcs across the capacitive storage element Cs falls below the deactivation threshold S0b , the output of the second voltage comparator 22a returns to the low state, allowing the switch to open 21a and disconnecting the capacitive storage element Cs of the oscillator 16 and the meter 17.

[0144] The operating method of the part 102 relating to the determination of at least one piece of information linked to the use of the sliding board 25is then described according to the second embodiment using the figures 6a, 6b, 6c, 6d et 6e .

[0145] Once the oscillator 16 and the meter 17 undervoltage and that the piezoelectric elements 11a, 11b continue to supply electrical energy to the capacitive storage element Cs, the time account T is incremented and then stored in a buffer memory, that is, a temporary memory which is erased when powered off. The buffer memory evolves at the frequency of the counter 17. In the same way as before, once the microcontroller 18 undervoltage (phase P2), the microcontroller 18 is configured to increment the activation count M and write it to non-volatile memory 19 as soon as the tension Vcs reached the maximum reference value REFmax, as represented by the figure 6c .

[0146] This increment, as well as this registration in memory of the activation account M, consumes energy represented by a voltage drop ΔV2 on the figure 6b .

[0147] When the board flexes 25 interrupt, the piezoelectric elements 11a, 11b stop supplying electrical energy to the capacitive storage element Cs, whose tension Vcs gradually decreases through a minimum reference value REFmin.

[0148] As soon as the tension Vcs reached this minimum reference value REFmin, the microcontroller 18 is configured to read the time account T write to the buffer and write it to non-volatile memory 19. It should be noted that the registration of this time account T induces a voltage drop ΔV3.

[0149] Additionally, in order to match the voltage levels between the meter 17 and the microcontroller 18, the electronic processing circuit 15 includes buffers.

[0150] In this second embodiment, the thresholds are defined so that: S0b < S0h < S1b < S1h < REFmin < REFmax.

[0151] During the phases P1, P2 And P3, the electronic processing circuit 15 performs at least one binary account T, M using voltage Vcs across the capacitive storage element Cs. In the phases P3 And P4, when the activity of the sliding board is stopped, the counting of requests M is automatically stopped since the maximum reference value REFmax is no longer reached, while the counting of the duration of use T by the oscillator16 and the meter 17 continues. When the tension Vcs across the capacitive storage element Cs reached the cut-off threshold S1b , the microcontroller 18 is powered off and the data relating to binary accounts T, such as duration of use T2 and the number of activations M1 , remain in non-volatile memory 19, as illustrated by the figures 6c et 6e .

[0152] It should be noted that the duration of use T2 is greater than the duration of use T1 calculated with the first embodiment, because the counting by the counter 17 was implemented earlier.

[0153] Counting the duration of use T is stopped at the end of the phase P1a , when the voltage Vcs is less than or equal to the deactivation threshold S0b. However, turning off the oscillator 16 and the meter 17 has the effect of resetting the buffer memory, as shown in figure 6d .

[0154] Furthermore, as illustrated by the figure 6e , the storage of the time account T in non-volatile memory 19 is carried out in time tREFmin, therefore the duration counted after tREFmin is lost.

[0155] Whether for the first embodiment illustrated by the figure 3 or for the second embodiment illustrated by the figure 4 , variants of the operating method have been identified.

[0156] According to a first variant of the operating method, it is possible to provide that, as soon as the voltage Vcs across the capacitive storage element Cs reached the maximum reference value REFmax, the microcontroller 18is configured to write to non-volatile memory 19 both the activation account M and the time account T. Such a variant makes it possible to avoid the minimum reference value REFmin. According to a particular variant, the maximum reference value REFmax is equal to S1h , which allows us to free ourselves from references.

[0157] According to a second variant of the operating method, it is possible to provide that, as soon as the voltage Vcs across the capacitive storage element Cs reached the maximum reference value REFmax, the microcontroller 18 is configured to write to non-volatile memory 19, alternately the activation account M then the time account T. The alternation is preferably regular, such as once in N, where N is for example equal to two.

[0158] In this case, the activation account M is incremented by the value N each time the maximum reference value REFmax is reached by the tension Vcs.

[0159] According to a third variant of the operating method, in which the non-volatile memory 19 includes several data storage boxes, it is possible to provide that, as soon as the microcontroller 18 is powered, that is to say as soon as the voltage Vcs across the capacitive storage element Cs reached the power threshold S1h , it writes in a first box of non-volatile memory 19 the time account T. When the tension Vcs across the capacitive storage element Cs reaches the power threshold again S1h , the microcontroller 18 enters the new time account Tin a second box of non-volatile memory 19 and so on, so as to form a stacked memory.

[0160] The sum of the stacked boxes or the last stacked box, depending on whether the internal clock 18 or the meter 17 is reset to zero or not at each registration, corresponds to an estimate of the duration of use of the sliding board 25. According to this third variant of the operating method, the activation account M is equal to the number of stacked boxes. A stacked box is a box in which data has been recorded. The value M1 from the activation account M is then determined at the end of the recording, for example when reading the data recorded in the non-volatile memory 19.

[0161] In all cases, except the case of the third operating method variant previously described, when writing to non-volatile memory 19, the microcontroller 18 is configured to perform: a reading of the temporal account T and the activation account M which were previously stored in non-volatile memory 19, for example during previous recordings corresponding to previous uses of the sliding board; an update of the time account T and the activation account M by incrementing the values T And M previously recorded by the values T And M which have just been calculated; and a record of the new time account T and the new activation account M in non-volatile memory 19.

[0162] For the case of the third operating method variant, when writing to non-volatile memory 19, the microcontroller 18 is configured to: identify an empty cell adjacent to a filled cell or the first empty cell in the case of a first write to memory, and record the value of the time count T in the box identified in the previous step.

[0163] Thus, regardless of the operating method variant chosen, non-volatile memory 19 contains the value T, corresponding to the time of use of the sliding board since its first use on the snow as well as the value M, corresponding to the level of stress on the sliding board since its first use on the snow

[0164] We understand that the temporal account T contains information related to the surface deformation time12 of the sliding board and therefore information linked to the time of use of the sliding board.

[0165] By making the approximation that the start-up phase P1 of the capacitive storage element is very low compared to the phases during which the microcontroller 18 is active, that is, the phases P2 And P3, it is possible to assimilate the temporal account T the duration of use of the sliding board 25.

[0166] Moreover, the counting of this time account T uses low-power operations or components, for example with a power of less than 5µWatts.

[0167] The sensor 100 could only provide this first parameter corresponding to the time account T. On the other hand, the invention can also give access to other values ​​than Tdepending on the electronic components chosen to form the electronic processing circuit 15.

[0168] Also, in particular, the invention proposes to provide a second parameter which is the activation account M. This activation account M, aims to represent information linked to the amplitude of surface deformations 12. In other words, this information represents the intensity of the activity of the sliding board, or the way in which the sliding board is actually used.

[0169] More specifically, the operations of reading the previous number and writing the new number into memory by the microcontroller consume significant electrical power.

[0170] The activation account M therefore represents the number of times that the microcontroller 18consumed this amount of energy, so it is related to the amount of energy consumed by the microcontroller 18 in its active mode. By making the approximation that the realization of the temporal account T and that the start and stop phases of the microcontroller 18 have negligible consumption compared to the amount of energy consumed when increasing this activation count M, it is possible to link the activation account M to the amount of energy stored in the capacitive storage element Cs, and the amount of energy generated by the deformation of the surface 12. So, the more the account M is high, the more the board slides 25 was in high demand.

[0171] By making the connection between the activation account M and the duration of use T, it is possible to estimate the power applied by the user.

[0172] This power can either be calculated using appropriate electronic elements added to the processing electronic circuit 15, not shown, then be stored in non-volatile memory 19, either be calculated after transmission of the values ​​of the time accounts T and activation M to an external reader, not shown.

[0173] Results of measurements carried out on alpine skis gave values ​​of the activation count M very different depending on the skier's level. Indeed, for example, an adult user with a good skiing level makes 100 memory writes (i.e. increments of the account M of 100) in 10s, while a young child starting out in snowplough only makes 2 memory writes (i.e. incrementing the count M of 2) in 10s. The activation account Mis therefore a good indicator of skiing activity, and therefore of the skier's level. The higher the value M is greater after a defined period of use, the higher the skier's activity level and therefore the higher their skiing level, the sliding board having then been used significantly.

[0174] Finally, by making the approximation that the electrical power of the electronic processing circuit 15 is consumed mainly by the microcontroller 18 when writing accounts T, M in memory, it is possible to estimate a state of wear of the sliding board, or a level of commitment of a skier by knowing the activation count M and the energy consumed by the microcontroller 18 at each increment of the activation count M.

[0175] It is thus possible to know the actual use of the ski, and thus to know if the skier uses his ski little or a lot, which can inform a skier about the difference in energy imposed on one ski compared to another, in the case where both skis of the pair of skis are equipped with a sensor. 100. For example, it is possible to know if a skier is using one leg too much compared to the other.

[0176] After recording the time account values T and the activation account M in non-volatile memory 19, the microcontroller 18 or the meter 17 is reset, due to their power being switched off. However, it is possible, in the case of the second embodiment illustrated by the figure 4 , to provide that the microcontroller 18 is configured to reset the counter 17 before the cut-off threshold S1b is not reached or after a write in memory of the time account T.

[0177] Resetting the microcontroller 18 or the meter 17 prevents exceeding the maximum value that the counter can contain 17, this excess resulting in its automatic resetting to zero, which would imply an error in the calculation of the time account T.

[0178] In addition, the values ​​of the accounts T And M can be extracted from the electronic processing circuit 15 to obtain information related to the deformation time of the sliding board and therefore to the duration of use of the sliding board from the account T and / or information related to the amplitude of the deformations of the sliding board from the account M.It is also possible to calculate the mechanical power generated by the user and in particular by the skier. Indeed, as described previously, the calculation of the magnitude M / T reflects the mechanical power generated by the user which can be correlated to the skier's level. The values M And M / T also provide information on the actual wear of the board as well as on the user's actual activity in relation to their performance and level.

[0179] In order to ensure communication and retrieval of values ​​stored in non-volatile memory 19, the electronic processing circuit 15 includes a part 104 relating to communication.

[0180] This part 104 may optionally include a wired connector ensuring data transmission but, preferably, the electronic processing circuit15 has a radio frequency antenna 20 configured to power non-volatile memory by electromagnetic coupling 19.

[0181] So an external reader can wirelessly obtain the accounts T And M. This "RFID" transmission system includes a passive tag which uses the wave from the interrogator / reader to power the non-volatile memory 19 and thus transmit the accounts T And M to the questioner / reader.

[0182] Preferably, the external reader can also control the microcontroller 18 to reset the value of the accounts T And M in non-volatile memory 19.

[0183] The external reader can be present at a ski rental shop or a skier behavior study center in order to centralize the information captured on each ski, or can be directly accessible by the user himself using a "Smartphone" type device for example.

[0184] So the external reader can extract the accounts T And M to obtain information relating to the duration of use of the sliding board and / or the amplitude of deformations of said surface 12 and / or to calculate the mechanical power generated by the user and in particular by the skier.

[0185] The integration of such a sensor 100 to a sliding board 25 is described in the following description. In the following description, relative terms such as “front”, “rear”, “upper”, “lower”, are defined in relation to the sliding board 25.

[0186] More specifically, these terms are defined in relation to a longitudinal axis, a transverse axis and a vertical axis of the board. 25, the longitudinal axis being the axis along which a maximum length of the board slides 25 is measured, the vertical axis being the axis orthogonal to the plane of the sliding board 25 and the transverse axis being orthogonal to both the longitudinal axis and the vertical axis. The terms "front" and "rear" are defined along the longitudinal axis of the board 25, relative to the position of the skier or the binding. The terms "upper" and "lower" are defined along the vertical axis of the board 25, with the lower part being intended to be in contact with snow, ground or water.

[0187] The invention is illustrated in particular on the figures 7 à 15 on a ski board which is an alpine ski or a touring ski.

[0188] There figure 7 illustrates a sliding board 25 presenting a front part 27, a rear part 28 and a central area 26 intended for mounting the fixing, arranged between these two parts 27, 28. The front part 27 refers to the part of the board that slides 25 which is normally positioned in front of the skier and which forms the spatula while the rear part 28 refers to the part of the board that slides 25 which is normally positioned behind the skier and which forms the heel of the sliding board 25.

[0189] The fastening elements, not shown, are mounted on an interface element which is composed, in the illustrated embodiment, of mounting and guide rails 30 And 31,the binding elements can slide on these rails to be adjusted to the length of the skier's boot. These mounting rails are secured to the upper face of the ski board 25. This binding is oriented so that the skier is facing the front part 27 downhill.

[0190] In a variant not shown, the interface element may be composed of at least one plate on which the binding elements are fixed, this making it possible to raise the binding elements relative to the upper surface of the sliding board. 25.

[0191] The sliding board 25 has a streamlined shape suitable for snow skiing. Alternatively, all types of sliding board 25 can be used without changing the invention.

[0192] The attachment, not shown, has a front stop intended to be positioned in the front rail 30, to fix the front part of the skier's boot, and a rear heel piece intended to be positioned in the rear rail 31, to fix the back of the skier's boot.

[0193] This front stop and this rear heel piece form the elements that attach the shoe to the sliding board.

[0194] Alternatively, the shape, type of binding, type of rails or mounting interface of the binding on the sliding board may also vary without changing the invention.

[0195] In the case of the sliding board 25 of the figure 7 , the areas Z1 And Z2 illustrate the two areas in which the board slides 25 undergoes maximum deformation when the sliding board bends 25 when using it on snow.

[0196] These areas Z1 And Z2 are also areas where the board slides 25 is subject to high risks of impact. For example, a skier's two skis may cross in these areas Z1 And Z2.

[0197] To recover the mechanical energy linked to the deformation of the sliding board 25, the invention proposes to use at least one piezoelectric element 11a-11b. In the illustrated embodiment, these piezoelectric elements 11a-11b are preferably arranged between the front rail 30 supporting the fixing stop and the area Z1 undergoing maximum deformation.

[0198] In other words, these piezoelectric elements 11a-11b are positioned very close to the area Z1, in an area where the deformations remain sufficient, and where they remain sufficiently protected, in particular from external shocks.

[0199] It is nevertheless possible to position the piezoelectric elements 11a-11b in the zones of maximum deformation Z1 And Z2 without changing the invention. In this case, protective elements may be added, in particular on the lateral sides of the piezoelectric elements 11a-11b.

[0200] The energy generated by these piezoelectric elements 11a-11b is transmitted to an electronic processing circuit 15.

[0201] Preferably as shown in the figure 9 , this electronic processing circuit 15 is arranged very close to the piezoelectric elements 11a-11b this is to facilitate the connection of electrical wires between the piezoelectric elements 11a-11b and the electronic processing circuit 15.

[0202] In particular, the electronic processing circuit 15is mounted in a housing positioned above the two piezoelectric elements, at the end of the front mounting rail 30 of the binding stop.

[0203] In other embodiments, not illustrated, the electronic box containing the electronic circuit could be mounted in any other position of the sliding board. 25, preferably close to the mounting area of ​​the bindings 26, at the front or rear of this area, or even between the front and rear binding elements of the shoe, or even inside a plate inserted between the sliding board 25 and ski binding.

[0204] THE figures 10 à 13 illustrate the assembly of piezoelectric elements 11a-11b and the electronic circuit 15 on the board 25. As illustrated on the figure 10 , piezoelectric elements 11a-11b are attached to the sliding board 25and more precisely on a surface of an element of the sliding board, a surface which can be internal or external to the sliding board. They can either be added by gluing after the sliding board has been molded 25 on one of the layers of the structure of the sliding board 25, either be drowned and therefore integrated inside the structure of the sliding board 25 during the molding of the sliding board 25.

[0205] THE figures 10 à 13 illustrate the arrangement of two piezoelectric elements 11a-11b juxtaposed.

[0206] Alternatively, a single piezoelectric element may be arranged. The number of piezoelectric elements 11a-11b is chosen so that the energy recovery is sufficient to power the electronic processing circuit 15 partner.

[0207] According to the illustrated example, each piezoelectric element 11a-11b has an upper circular central part forming the active part of the piezoelectric material, configured to capture the deformations of a surface 12 of the sliding board 25, and a lower circular part, arranged below the central circular part and of larger dimensions than the latter, forming a reference mass.

[0208] Of course, other shapes of piezoelectric elements can be used, such as quadrilateral piezoelectric elements. Electrical energy produced when the surface is deformed 12 of the sliding board 25 is captured between the upper circular central part and the lower circular part. Alternatively, other forms of piezoelectric element 11a-11b can be used without changing the invention. It should be noted that the electrical energy produced by each piezoelectric element 11a, 11b is proportional to the volume of piezoelectric material it contains.

[0209] The internal structure of the sliding board 25 is described in the following paragraphs with reference to the figures 14 et 15 to illustrate the integration of piezoelectric elements 11a-11b on the board 25 and in particular to show on what surface 12 of the sliding board 25 les piezoelectric elements can be attached.

[0210] The sliding board 25 has a lower set 37, and a superior set 38, separated by a nucleus 39.

[0211] More precisely, the lower set 37 has a sliding sole 40, typically polyethylene-based, on which the fins of the metal edges rest laterally 41. In the form illustrated, this lower assembly 37also includes a reinforcement layer 42.

[0212] The sliding board 25 also includes a superior set 38 including a decorative and protective layer 43, resting on a reinforcing layer 44.

[0213] The decorative and protective layer 43 can be made in different ways, and include on its lower face printed areas visible from the upper face of the board, or even transparent areas, allowing the reinforcement layer to be visible from the outside 44.

[0214] The upper sets 38 and lower 37 are separated mainly by the nucleus 39, which is bordered laterally by the side edges 45 which protect the core 39from external humidity, and which ensure the transmission of forces from the upper assembly to the edges 41. In other variations of sliding board structures 25, not shown, the structure could not have side edges, and be of the “shell” type for example, or could have several layers of reinforcement, or could not have edges.

[0215] In the first embodiment of the figure 14 , piezoelectric elements 11a-11b are fixed directly onto the decorative and protective layer 43. Preferably, piezoelectric elements 11a-11b are fixed by gluing on the decorative and protective layer 43or on the support layer. To do this, it is preferable to use a rigid glue with high shear strength, for example an epoxy glue, this is to avoid modifying and reducing the actual deformation values ​​of the sliding board. 25. However, a double-sided adhesive element, of very thin thickness, creating little shear within this layer, can be considered.

[0216] In a variation of this embodiment, a rigid support layer may be attached to the decorative and protective layer. 43 to support piezoelectric elements 11a-11b. For example, an aluminum backing layer can be used.

[0217] In the second embodiment of the figure 15 , piezoelectric elements 11a-11b are fixed on the reinforcement layer 44. To do this, the decorative and protective layer 43is hollowed out at surface level 12 fixing of piezoelectric elements 11a-11b, the piezoelectric elements then being arranged in this recess.

[0218] As in the first embodiment of the figure 12 , a fixing by gluing of the piezoelectric elements 11a-11b can be done either during the molding of the sliding board or after the molding of the sliding board.

[0219] The invention also requires the positioning of the electronic circuit 15 on the board 25. Also, a support 32 is reported on the sliding board 25 to support the electronic processing circuit 15, as illustrated in the figure 11 .

[0220] Preferably, this support 32 is removable so that maintenance can be carried out on the electronic processing circuit 15by separating the electronic processing circuit 15 of the sliding board 25. This support 32 can be connected by clipping or screwing with the sliding board 25 or the mounting rail 30 of the fixing stop. For example, the support 32 may include lugs intended to cooperate with bores made in the front part of the mounting rail 30.

[0221] This support 32 also defines the position of the electronic processing circuit 15 on the board 25.

[0222] In the example of the figures 7 à 13 , the electronic processing circuit 15 is arranged at the front of the front mounting rail 30 from the fixing stop and above the piezoelectric elements 11a-11b. Alternatively, the electronic circuit 15 can be arranged on the piezoelectric elements 11a-11b unrelated to the mounting rail 30 or the front stop of the binding, being fixed to the sliding board.

[0223] Furthermore, as illustrated on the figure 11 , the electronic processing circuit 15 can be screwed onto the bracket 32, or clipped or glued. The electronic processing circuit 15 is then electrically connected with the piezoelectric elements 11a-11b using wires or suitable connectors.

[0224] As illustrated on the figure 12 , a protective cover 33 is mounted on the support 32 so as to protect the electronic processing circuit 15 and piezoelectric elements 11a-11b. The protective cover 33 can also be fixed by screwing or gluing, for example with the support 32.

[0225] Also, the set formed by the support 32 and the protective cover33 forms a box receiving the electronic processing circuit 15 and this box is preferably waterproof to protect the electronic components from snow or water, this box being easily removable from the sliding board.

[0226] This protective cover 33 preferably has an aerodynamic shape to limit the wind resistance of the sliding board 25 and limit the risk of shock to the electronic processing circuit 15 or piezoelectric elements 11a-11b.

[0227] In the example shown, the sensor 100 is composed of a box containing the electronic processing elements attached to the sliding board and piezoelectric elements independent of the box linked to the sliding board, connected to the electronics.

[0228] In another embodiment not shown, the sensor 100could be composed of a single box which would contain the electronic processing elements and which would have under its lower surface a layer including the piezoelectric elements, connected to the electronics. This assembly would then be secured to one of the surfaces of the sliding board.

[0229] In the case of a sliding board 25 which is a cross-country ski, the location of the piezoelectric elements and the electronic processing box can be similar to that proposed for alpine skiing, or it may be advantageous to position the piezoelectric elements further in front of the front stop of the binding by a few centimeters, or even a few tens of centimeters to obtain more amplitude of deformations. This sensor 100 will be perfectly usable in the case of cross-country skiing due to its very low weight, of the order of 10 to 50g, provided by the components of the sensor 100.

[0230] In the case of a sliding board 25 which is a snowboard supporting the user's two feet, the sliding board 25 would be equipped with two separate fixings. The piezoelectric elements as well as the electronic processing box could be positioned on the lateral side of one or the other of the fixings, on the end side of the board, or could be positioned between the two fixings, in a relatively protected area.

[0231] This invention combining piezoelectric elements 11a-11b and electronic processing circuit 15 has the advantage of storing data T, representing the actual time of use of the sliding board 25, And M representing the intensity of use of the board 25, this data comes from the sliding board 25 when the sliding board is stressed 25.

[0232] The analysis starts automatically as soon as the board slides 25 is in motion and the user does not have to worry about starting the system, its power supply, or the electrical recharging of the system, since the electronic processing circuit 15 is autonomous because it is powered directly by piezoelectric sensors 11a-11b. The user can then access the data T, M recorded in memory 19 boarded on the board 25, this later, when the board slides 25 is no longer used.

[0233] Thus, the invention presents the use of at least one piezoelectric element 11a-11b: which is both a generator of electrical energy for the electronic processing circuit 15,and which is also a sensor for measuring the deformations of the sliding board in the direction where the tension Vpa, Vpb delivered by at least one piezoelectric element 11a-11b is used by the electronic processing circuit 15 which is configured to estimate values ​​representative of the use of the sliding board, such as a duration of use and / or a level of amplitude of the deformations of the sliding board from the tension Vpa, Vpb delivered.

[0234] The invention thus makes it possible to analyze the performance of a user of a sliding board by obtaining information linked to the use of a sliding board while avoiding the need for an additional power source, and in particular an electrochemical battery.

[0235] The invention makes it possible to analyze a user's performance in relation to reference performance in order to establish their skiing level, and to advise them on exercises adapted to their level, ski lessons adapted to their level, and skis adapted to their level.

Claims

1. A system for analysis (200) of the performance in use of a sliding board (25) comprising: - a database (202) storing baseline performance; - a sensor (100) sensitive to the deformations of said sliding board (25); and - a monitoring body (204) comprising: - means for determining the performance in use of said sliding board (25) based on measurements from said sensor (100); and - means for comparing said performance in use with said baseline performance; said sensor (100) being secured to said sliding board (25) and comprising: - at least one piezoelectric element (11a-11b) secured to said sliding board (25) and configured to generate electric energy during the deformations of said sliding board (25); and - an electronic processing circuit (15), powered exclusively by said electric energy generated by said at least one piezoelectric element (11a-11b), configured to estimate a duration (T) of the phases of deformations of said sliding board (25) and to estimate an image (M) of the mechanical energy dissipated during the deformations of said sliding board (25); said performance in use including a stressing time (Ts), corresponding to said duration (T) of the phases of deformation of said sliding board (25), and an image of the mean stressing power (Ps) corresponding to the relationship between the image (M) and said duration (T) of the deformation phases; said baseline performance being determined by a sensor (100), analogous to said sensor (100) secured to said sliding board (25), so as to obtain a baseline stressing time (Tref) and a baseline stressing mean (Pref), characterized in that said at least one piezoelectric element (11a-11b) is ensuring both the role of information source for determining the performance of the sliding board (25) and the role of power source for an electronic processing circuit (15).

2. The analysis system according to claim 1, wherein said performance in use includes a speed (Vs) measured by a position sensor (207); this measured speed (Vs) being compared to a baseline speed (Vref).

3. The analysis system according to claim 1 or 2, wherein said performance in use includes a number of turns made (Ns) detected by a gyroscope (208); this number of turns made (Ns) being compared to a baseline number of turns made (Nref).

4. The analysis system according to one of claims 1 to 3, wherein said means for determining the performance in use are configured to determine corrected performance in use (Tsc, Psc, Vsc, Nsc) based on said performance in use (Ts, Ps, Vs, Ns) and on a variable (αm) related to a flexural rigidity of said sliding board (25); said means for comparing being implemented from said corrected performance in use (Tsc, Psc, Vsc, Nsc).

5. The analysis system according to claim 4, wherein said variable (αm) related to a flexural rigidity of said sliding board (25) is obtained from the model of said sliding board (25) and from a database (220) storing different models of sliding boards and corresponding flexural rigidity coefficients.

6. The analysis system according to one of claims 1 to 5, wherein said means for determining the performance in use are configured to determine corrected performance in use (Tsc, Psc, Vsc, Nsc) based on said performance in use (Ts, Ps, Vs, Ns) and on a variable (αm) related to the type of snow over which said sliding board (25) is progressing; said means for comparing being implemented from said corrected performance in use (Tsc, Psc, Vsc, Nsc).

7. The analysis system according to claim 6, wherein said variable (αn) related to the type of snow over which said sliding board (25) is progressing is obtained from a temperature sensor (209).

8. The analysis system according to claim 6, wherein said variable (αn) related to the type of snow over which said sliding board (25) is progressing is obtained from a position sensor (207) and from a database (222) storing weather information related to different positions.

9. The analysis system according to one of claims 1 to 8, wherein said monitoring body (204) is configured to authorize access to a high-level route when said stressing time (Ts) is less than a baseline stressing time (Tref) and when said mean stressing power (Ps) is greater than a baseline mean stressing power (Pref).

10. The analysis system according to claims 2, 3 and 9, wherein said monitoring body (204) is configured to authorize access to a high-level route when said speed (Vs) and said number of turns made (Ns) are greater than said baseline speed (Vref) and than said baseline number of turns made (Nref).

11. The analysis system according to one of claims 1 to 10, wherein said monitoring body (204) is configured to classify a user of a sliding board (25) in relation to classifications of predefined levels based on said comparison carried out by said monitoring body (204).

12. The analysis system according to one of claims 1 to 11, wherein said monitoring body (204) is integrated into a mobile application of a smartphone (203).