A claw-type power meter with independent full-bridge detection

Abstract

The present invention relates to a claw-type power meter with independent full-bridge detection, belonging to the field of power detection technology. The claw-type power meter comprises: a claw main body, comprising N connecting shafts; N detecting units; each detecting unit comprising two strain gauges; each strain gauge comprising two resistors; each detecting unit being respectively arranged on a connecting shaft, and a strain gauge being respectively arranged on the opposite surface of each connecting shaft; the two strain gauges in each detecting unit being connected so that the four resistors of each detecting unit form a full-bridge circuit; a main board connected to the output ends of the N full-bridge circuits; wherein each full-bridge circuit is used to detect the torque value of the connecting shaft in which it is located; the main board is used to determine the total torque value based on the N torque values, and calculate the power based on the total torque value. By performing a separate full-bridge measurement on each connecting shaft, the measurement influence caused by machining errors of different shafts is reduced, thereby improving the measurement accuracy and the reliability of the measurement data of the claw-type power meter.

Description

Technical Field

[0001] The invention belongs to the technical field of power measurement and relates to a claw-type power meter with independent full-bridge detection. Background Art

[0002] In recent years, with the development of smart cycling devices, sports monitoring systems, and electric-assisted bicycles, the demand for high-precision, real-time power measurement has rapidly increased. As a core component for cycling analysis and training feedback, power meters primarily measure pedaling torque and cadence to calculate the cyclist's mechanical power output in real time, helping to assess athletic performance and regulate training intensity.

[0003] A claw-type power meter is a commonly used power calculation device on cycling equipment. This high-precision device measures the power of rotating mechanical shafts. Using a claw structure clamped onto the drive shaft, it uses strain gauges to detect minute deformations of the connecting shaft and calculates power based on the rotational speed.

[0004] The existing structure of a disc-claw power meter is as follows: a strain gauge is placed on each of the four connecting shafts, and the resistors of the four strain gauges are connected in series to form a full bridge. When the rider applies force, the connecting shaft is deformed by torque, which in turn causes the strain gauge to deform, resulting in a change in resistance. This change in resistance causes a change in the current or voltage passing through the resistor. The electrical signal from the strain gauge is converted to digital form, ultimately outputting power data.

[0005] However, research has found that there will be processing consistency issues in the production of the disc-claw structure. That is, there will be slight differences in the various connecting axes of some disc-claw structures during the production process. The current connection method connects the strain gauge resistors of each connecting axis in series to form a full bridge, which is easily affected by process errors during the processing of different connecting axes, thereby affecting the measurement accuracy and reducing the reliability of the measurement data. Summary of the Invention

[0006] In order to solve the above-mentioned problems in the prior art, the present invention provides a claw-type power meter with independent full-bridge detection.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] In the first aspect, the present invention provides a disk claw type power meter with independent full-bridge detection, comprising: a disk claw main body, comprising N connecting shafts; N is a positive integer; N detection units; wherein each detection unit comprises two strain gauges; each strain gauge comprises two resistors; each detection unit is respectively arranged on a connecting shaft, and a strain gauge is respectively arranged on the opposite surface of each connecting shaft; wherein the two strain gauges in each detection unit are connected so that the four resistors of each detection unit form a full-bridge circuit; a main board, connected to the output ends of the N full-bridge circuits; wherein each full-bridge circuit is used to detect the torque value of the connecting shaft in which it is located; the main board is used to determine the total torque value based on the N torque values, and calculate the power based on the total torque value.

[0009] Optionally, N is four; wherein the angle between two adjacent connecting axes among the four connecting axes is 90 degrees.

[0010] Optionally, the mainboard is further configured to determine the total torque value using the following formula: ;in, Indicates the total torque value; Indicates the Torque value of the connecting shaft; Indicates the Torque value of the connecting shaft; Indicates the Sensitivity coefficient of the connected axes; Indicates the The first connecting shaft and the Nonlinear coupling coefficient of the connected axes; Represents the bias term, which is used to compensate for zero drift.

[0011] Optionally, the main board is also used to obtain a first torque curve and a second torque curve, and determine the alternating state of the user's left and right feet during riding based on the peak changes of the first torque curve and the second torque curve; wherein, the first torque curve corresponds to the first connecting axis, and the second torque curve corresponds to the second connecting axis; the first connecting axis and the second connecting axis are two connecting axes arranged opposite to each other.

[0012] Optionally, the disc claw power meter is installed on the cycling device and is located on the right side of the chainring, and the first connecting shaft is closer to the right crank of the cycling device than the second connecting shaft; the main board is also used to determine that the current user's right foot is exerting force when the peak of the first torque curve is higher than the peak of the second torque curve, and to determine that the current user's left foot is exerting force when the peak of the second torque curve is higher than the peak of the first torque curve.

[0013] Optionally, the mainboard is also used to determine the waveform period based on the peak of the first torque curve and / or the second torque curve; determine the user's pedaling frequency based on the waveform period, and calculate the angular velocity based on the user's pedaling frequency; accordingly, the mainboard is also used to calculate the power based on the angular velocity and the total torque value.

[0014] Optionally, the mainboard is also used to determine the current ambient temperature; compensate the total torque value based on the current ambient temperature and the temperature compensation curve, and calculate the power based on the compensated total torque value; wherein, the temperature compensation curve is determined by placing the disk claw type power meter in a temperature box and setting different temperature values ​​to detect and determine the disk claw type power meter.

[0015] Optionally, the mainboard is further configured to, when it is detected that the riding device is in a stationary state, use the torque values ​​of the N full-bridge circuits as zero point values ​​if the torque values ​​of the N full-bridge circuits are collected.

[0016] Optionally, the output end of each full-bridge circuit is connected to the mainboard via a twisted pair cable.

[0017] Optionally, the mainboard includes: N operational amplifier modules, an analog-to-digital conversion module and a processing chip; wherein, each of the N full-bridge circuits is connected to an operational amplifier module, and each operational amplifier module is used to amplify and filter the measurement value of the full-bridge circuit to which it is connected; the analog-to-digital conversion module is connected to the N operational amplifier modules, and is used to perform analog-to-digital conversion of the signal to obtain N torque values; the processing chip is connected to the analog-to-digital conversion module, and is used to determine the total torque value based on the N torque values, and calculate the power based on the total torque value.

[0018] The present application provides a claw-type power meter with independent full-bridge detection, the beneficial effects of which include at least the following: considering that the current claw structure will have processing differences on each connecting shaft during the processing, especially for aluminum alloy claws, if the strain gauges on each connecting shaft are connected in series to form a full bridge, it is easily affected by the process errors during the processing of different connecting shafts, thereby affecting the measurement accuracy and reducing the reliability of the measurement data. Therefore, the present application provides a claw-type power meter with independent full-bridge detection, which sets corresponding detection units according to the number of connecting shafts, each detection unit includes two strain gauges, each strain gauge includes two resistors, and then the four resistors of each detection unit are connected in series to form a full-bridge circuit. In other words, a full-bridge circuit for detection is set for each connecting shaft, and each full-bridge circuit can measure the deformation (corresponding torque value) of the connecting shaft. That is, each connecting shaft can perform full-bridge measurement separately. After each connecting shaft performs full-bridge measurement separately, the total torque value is calculated, and the power is calculated. This method, firstly, can realize independent detection of each connecting axis, which helps to finely evaluate the user's riding performance (the existing method can only calculate the total torque). Secondly, the full-bridge circuit is constructed by connecting resistors in series on the same connecting axis, and the strain gauges on the same connecting axis detect the same deformation. That is, by measuring each connecting axis separately with a full-bridge, the measurement impact caused by machining errors of different axes is reduced, thereby improving measurement accuracy and the reliability of measurement data of the disc claw power meter. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic structural diagram of a claw-type power meter with independent full-bridge detection provided by an embodiment of the present invention from a first perspective;

[0020] Figure 2 A schematic structural diagram of a claw-type power meter with independent full-bridge detection from a second perspective provided by an embodiment of the present invention;

[0021] Figure 3 A circuit diagram of a full-bridge circuit composed of a connecting shaft provided by an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of the connection relationship of a claw-type power meter with independent full-bridge detection provided by an embodiment of the present invention;

[0023] Figure 5 A schematic diagram of a torque curve provided by an embodiment of the present invention;

[0024] Figure 6 A schematic diagram of a torque comparison curve after temperature compensation provided by an embodiment of the present invention;

[0025] Figure 7 A schematic diagram of the components of a mainboard according to an embodiment of the present invention;

[0026] Figure 8 A schematic diagram of a portion of the circuit corresponding to the four connecting axes provided in an embodiment of the present invention;

[0027] Reference numerals:

[0028] 100-claw-type power meter; 10-claw body; 101-connecting shaft; 20-detection unit; 201-strain gauge; 30-mainboard; 301-op amp module; 302-analog-to-digital conversion module; 303-processing chip. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The existing structure of a disc-claw power meter is as follows: a strain gauge is placed on each of the four connecting shafts, and the resistors of the four strain gauges are connected in series to form a full bridge. When the rider applies force, the connecting shaft is deformed by torque, which in turn causes the strain gauge to deform, resulting in a change in resistance. This change in resistance causes a change in the current or voltage passing through the resistor. The electrical signal from the strain gauge is converted to digital form, ultimately outputting power data.

[0031] However, research has found that there will be processing consistency issues in the production of the disc-claw structure. That is, there will be slight differences in the various connecting axes of some disc-claw structures during the production process. The current connection method connects the strain gauge resistors of each connecting axis in series to form a full bridge, which is easily affected by process errors during the processing of different connecting axes, thereby affecting the measurement accuracy and reducing the reliability of the measurement data.

[0032] In view of the above problems, this application provides the following embodiments to solve them:

[0033] See also Figures 1 to 4 An embodiment of the present application provides a claw-type power meter 100 with independent full-bridge detection, including: a claw body 10, N detection units 20 and a main board 30.

[0034] The claw body 10 includes N connecting shafts 101 .

[0035] Each detection unit 20 includes two strain gauges 201. Each strain gauge 201 includes two resistors.

[0036] The two resistors of each strain gauge 201 are connected in series. Each detection unit 20 is respectively arranged on a connecting shaft 101 , and a strain gauge 201 is respectively arranged on the opposite surface of each connecting shaft 101 .

[0037] That is, each detection unit 20 corresponds to one connecting shaft 101 . The number of the detection units 20 is equal to the number of the connecting shafts 101 .

[0038] Specifically, such as Figure 1~Figure 2 As shown, Figure 1 This is the first side of the claw-type power meter 100. Figure 2 The second surface of the disc claw power meter 100 is opposite to the second surface. For any connecting shaft 101, a strain gauge 201 is provided on its first surface and a strain gauge 201 is provided on its second surface. The first surface of the connecting shaft 101 corresponds to the first surface of the disc claw power meter 100, and the second surface of the connecting shaft 101 corresponds to the second surface of the disc claw power meter 100.

[0039] It can be understood that a strain gauge 201 is attached to both the front and back surfaces of each connecting shaft 101 , and the two strain gauges 201 on each connecting shaft 101 serve as a detection unit 20 .

[0040] In the embodiments of the present application, N is a positive integer, such as 3, 4, 5, etc.

[0041] In one embodiment, N may be a positive integer greater than or equal to 4.

[0042] Specifically, when N is 4, the claw body 10 includes four connecting shafts 101. The claw-type power meter 100 includes four detection units 20.

[0043] Each detection unit 20 includes two strain gauges 201 connected so that the four resistors of each detection unit 20 form a full-bridge circuit. The full-bridge circuit formed by each detection unit 20 can independently measure the deformation of the connecting shaft 101 in which it is located.

[0044] like Figure 3 As shown, Figure 3 A schematic diagram of a full-bridge circuit formed by arranging a strain gauge on both the positive and negative sides of any connecting shaft is presented.

[0045] The full-bridge circuit is composed of resistors R1, R2, R3, and R4. Resistors R1 and R2 are two resistors in a strain gauge on the front side of the connecting shaft. Resistors R3 and R4 are two resistors in a strain gauge on the back side of the connecting shaft.

[0046] In terms of connection relationship, the first end of the resistor R1 is connected to the first end of the resistor R3, and the first end of the resistor R1 and the first end of the resistor R3 are also connected to the power supply terminal (VCC), the second end of the resistor R1 is connected to the first end of the resistor R2, and the second end of the resistor R3 is connected to the first end of the resistor R4; the second end of the resistor R2 is connected to the second end of the resistor R4; the second end of the resistor R2 and the second end of the resistor R4 are commonly grounded (GND); the first output terminal is connected between the second end of the resistor R1 and the first end of the resistor R2, and the second output terminal is connected between the second end of the resistor R3 and the first end of the resistor R4.

[0047] Below Figure 3 As an example, the detection principle of the full-bridge circuit in a single connecting shaft is explained. Assuming that the current connecting shaft is in the state where the user is stepping on the pedal and the connecting shaft rotates clockwise, the resistor R1 on the front of the connecting shaft is stretched, the resistor R1 becomes longer, and the value of the resistor R1 increases. At the same time, the resistor R2 is compressed, the resistor R2 becomes shorter, and the value of the resistor R2 decreases. The resistor R3 on the back of the connecting shaft changes in the same way as the resistor R1, and the resistor R4 on the back of the connecting shaft changes in the same way as the resistor R2. Since the resistance value of the full-bridge circuit changes, the corresponding electrical signal changes can be obtained according to the first output terminal and the second output terminal to determine the torque value of the connecting shaft.

[0048] In other words, as the user cyclically pedals, one of the two resistors on the same side experiences tension, while the other experiences compression. The resistors expand and contract at the micron level during this process. When stretched, they become longer and thinner, increasing their resistance value; when compressed, they become shorter and thicker, decreasing their resistance value. The full-bridge circuit accurately captures these tiny changes and outputs different electrical signals based on them.

[0049] Please refer to Figure 4 The main board 30 is connected to the output terminals of N full-bridge circuits. Each full-bridge circuit is used to detect the torque value of its respective connected shaft. The main board 30 is used to determine the total torque value based on the N torque values ​​and calculate the power based on the total torque value.

[0050] In summary, considering that current claw structures can exhibit processing variations between each connecting shaft during machining, particularly for aluminum alloy claws, connecting the strain gauges on each connecting shaft in series to form a full bridge is susceptible to process errors during machining of the different connecting shafts, thereby affecting measurement accuracy and reducing the reliability of the measured data. Therefore, an embodiment of the present application provides a claw-type power meter 100 with independent full-bridge detection. The power meter 100 includes corresponding detection units 20 according to the number of connecting shafts 101. Each detection unit 20 includes two strain gauges 201, each of which includes two resistors. The four resistors in each detection unit are then connected in series to form a full-bridge circuit. In other words, a full-bridge circuit is provided for each connecting shaft 101 for detection, and each full-bridge circuit is capable of measuring the deformation (corresponding to the torque value) of the connecting shaft 101 to which it belongs. In other words, each connecting shaft 101 can independently perform a full-bridge measurement. After performing a full-bridge measurement on each connecting shaft 101, the total torque value is calculated, and the power is then calculated. This method, firstly, can realize independent detection of each connecting shaft 101, which is helpful for fine-grained evaluation of the user's riding performance (the existing method can only calculate the total torque). Secondly, the full-bridge circuit is constructed by connecting resistors in series on the same connecting shaft 101, and the strain gauges 201 on the same connecting shaft 101 detect the same deformation. That is, through the form of separate full-bridge measurement of each connecting shaft 101, the measurement influence caused by the machining errors of different axes is reduced, thereby improving the measurement accuracy and the reliability of the measurement data of the disc claw power meter.

[0051] In one embodiment, the claw-type power meter 100 includes four connecting shafts 101 .

[0052] The angle between two adjacent connection axes 101 among the four connection axes is 90 degrees, thereby achieving spatial symmetry of the four connection axes 101 and improving measurement accuracy.

[0053] Furthermore, the research revealed that the forces acting on the four connecting shafts 101 are non-uniform (some larger, some smaller), and that different users exert different forces at different points during riding. This results in nonlinear coupling of the forces acting on the four connecting shafts 101, and the overall output cannot be accurately represented by a simple linear combination. Therefore, the following formula is designed in this embodiment to determine the total torque value. The formula specifically includes:

[0054] ;

[0055] in, Indicates the total torque value; Indicates the Torque value of the connecting shaft; Indicates the Torque value of the connecting shaft; Indicates the Sensitivity coefficient of each connecting axis; Indicates the The first connecting shaft and the Nonlinear coupling coefficient of the connected axes; Represents the bias term, which is used to compensate for zero drift.

[0056] It should be noted that during calibration, a known step torque is applied, and the values ​​of the four connecting shafts under each step are recorded. The recorded experimental data are substituted into the above equation, and the optimal linear term, quadratic term coefficients and constant term are obtained through least squares fitting to obtain the optimal solution and obtain the above coefficients.

[0057] It can be seen that in this embodiment, by assigning sensitivity weights to the four groups of full-bridge signals and performing linear weighting, the independent contribution of each connected axis is accurately expressed. At the same time, the signal cross product and coupling weight are introduced to construct nonlinear terms, and the mechanical coupling relationship between the axis arms is comprehensively modeled. Combined with the bias term obtained by regression fitting, structural errors such as system zero-point drift are effectively compensated to achieve high-precision estimation of torque output.

[0058] Optionally, the main board 30 is also used to obtain a first torque curve and a second torque curve, and determine the alternating state of the user's left and right feet during riding based on the peak changes of the first torque curve and the second torque curve; wherein the first torque curve corresponds to the first connecting axis, and the second torque curve corresponds to the second connecting axis; the first connecting axis and the second connecting axis are two connecting axes arranged opposite to each other.

[0059] That is, the embodiment of the present application provides a method for detecting the force status of the user's left and right feet by detecting the peak changes of the torque curves of two oppositely arranged connecting shafts.

[0060] The specific determination method is to install a disc claw power meter on the cycling device and locate it on the right side of the chainring, with the first connecting axis closer to the right crank of the cycling device than the second connecting axis; then the main board is also used to determine that the current user's right foot is exerting force when the peak of the first torque curve is higher than the peak of the second torque curve, and to determine that the current user's left foot is exerting force when the peak of the second torque curve is higher than the peak of the first torque curve.

[0061] See also Figure 5 ,like Figure 5 As shown, the first torque curve and the second torque curve are torque change diagrams of two diagonally connected axes, the horizontal axis represents time, and the vertical axis represents torque. When the peak of the first torque curve is higher than that of the second torque curve, it represents the force exerted by the right foot, and when the peak of the second torque curve is higher than that of the first torque curve, it represents the force exerted by the left foot.

[0062] The aforementioned cycling device may be a bicycle, a cycling trainer, etc. Of course, in other embodiments, the crankshaft-type power meter may be mounted on the left side of the crankset, and the first connecting shaft may be closer to the left crank of the cycling device than the second connecting shaft for calibration to detect the force exerted by the user's left and right feet, without limitation.

[0063] Optionally, the mainboard is further used to determine a waveform period based on the peaks of the first torque curve and / or the second torque curve; determine the user's pedaling frequency based on the waveform period; and calculate the angular velocity based on the user's pedaling frequency.

[0064] It should be noted that when riding, the user's left and right feet pedal alternately to form a sinusoidal force waveform, that is, the above-mentioned first torque curve and second torque curve constitute a waveform period T (of course, the waveform period T can also be determined based on only the first torque curve or the second torque curve).

[0065] Then the user's cadence RPM can be calculated based on the waveform period T. The specific calculation formula is: After determining the cadence RPM, use the formula: The angular velocity can be calculated .

[0066] Correspondingly, the mainboard is also used to calculate the power P based on the angular velocity and the total torque value.

[0067] The power P calculation formula is: P .

[0068] It should be noted that the existing method requires the combination of angular velocity sensors to calculate power, while in this embodiment, the cadence can be calculated through the torque curve of two relatively set connecting shafts, and the angular velocity can be calculated based on the cadence. There is no need to set up other sensors, which can save product costs.

[0069] In summary, this embodiment provides left and right foot and cadence detection. By comparing the detection data waveforms of different full-bridges, it can determine the force exerted by the left and right feet, thereby analyzing left and right foot balance (an important indicator of riding posture and training), quickly obtain the pedaling cycle (or frequency), and quickly detect actual power.

[0070] Optionally, the mainboard 30 is further configured to determine the current ambient temperature; compensate the total torque value based on the current ambient temperature and a temperature compensation curve; and calculate the power based on the compensated total torque value.

[0071] The temperature compensation curve is determined by placing the disc claw type power meter in a temperature box and setting different temperature values ​​to detect the disc claw type power meter.

[0072] If you place a claw-type power meter in a temperature chamber with a temperature range of -20°C to 50°C and record the output value and the corresponding temperature, you can get the temperature change curve of each claw. By compensating the data at different temperatures, you can get the final torque data.

[0073] For example, the operating temperature of the equipment can be monitored in real time by a temperature sensor in a controllable temperature environment of -20°C to 50°C; the total torque value is calculated at each preset temperature; the total torque values ​​at different temperatures are compared with the corresponding temperatures, and a temperature weight factor is obtained using a fitting method; the standard operating temperature is subtracted from the current actual temperature, and the temperature difference is multiplied by the temperature weight factor and then a constant of one is added to obtain a temperature adjustment factor; the total torque value at the current temperature is multiplied by the temperature adjustment factor to obtain a torque compensation value; the torque compensation value obtained at each temperature point and its corresponding temperature are recorded, and the changes in the output total torque value at different temperatures are analyzed to obtain a temperature change curve to analyze the impact of temperature on torque.

[0074] The torque compensation value (corresponding to the temperature compensation curve) is determined by the following formula:

[0075] ;

[0076] Where, Indicates the torque compensation value at temperature T; Indicates the total torque value calculated at temperature T; Indicates the current actual temperature, which can be set between -20 degrees Celsius and 50 degrees Celsius; Indicates that the standard operating temperature is 25 degrees Celsius; The temperature weighting factor is obtained by measuring the error of known torque at multiple temperature points and performing a linear regression fit on the relative deviation versus the temperature difference. It ranges from 0.001 to 0.005.

[0077] See also Figure 6 , Figure 6 The original torque value and the torque value curve after compensation at different temperatures are shown. Figure 6 The horizontal axis is temperature and the vertical axis is torque value.

[0078] In summary, in this embodiment, by monitoring the operating temperature of the equipment in real time and collecting torque data in the temperature range of -20℃~50℃, combining the fitted temperature weight factor, a temperature compensation curve is constructed to dynamically compensate for the torque error caused by temperature changes, which significantly improves the adaptability and measurement accuracy of the system under multiple environmental conditions.

[0079] Optionally, the mainboard 30 is further configured to, when it is detected that the riding device is in a stationary state, use the torque values ​​of N full-bridge circuits as zero point values ​​if the torque values ​​of N full-bridge circuits are collected.

[0080] Considering the existing claw-type power meters, none of them can cope with the plastic deformation of the connecting shaft. For example, when the claw-type power meter is over-pedaled, impacted, or falls, it may cause the connecting shaft to undergo plastic deformation within a certain range. If this plastic deformation does not affect the use of the product (bicycle or cycling platform), the rider will usually continue to use the product (bicycle or cycling platform). However, the occurrence of plastic deformation at this time will cause a basic reading to appear in the power calculation, resulting in an error between the measurement result and the actual data. Therefore, in this embodiment, through timed detection, the strain data output under static conditions is detected, and the static detection data (torque value under static conditions) read is output as a 0-point check, and the power calculation process is re-adapted, so that the claw-type power meter can still accurately output accurate power even after plastic deformation occurs.

[0081] Of course, you can also set a static detection time, such as 5 minutes or 10 minutes. Specifically, through timed detection, the strain data output under static conditions (such as no data change for more than 10 minutes) is detected, and the static detection data (torque value under static conditions) read is output as the zero-point calibration.

[0082] Optionally, the output end of each full-bridge circuit is connected to the mainboard via a twisted pair cable.

[0083] Considering the spatially disparate locations of the multiple connecting arms in current claw-type power meters, the long wires that form the full-bridge circuit are susceptible to electromagnetic interference, which can lead to uncontrollable interference signals. Therefore, in this embodiment, the outputs of the multiple strain gauges are transmitted using twisted-pair cables. Since the multiple strain gauges are located on the same connecting arm and are therefore essentially spatially co-located, the individual wire lengths (the untwisted portions of the twisted pair) are very short when transmitting signals via the twisted-pair cables, significantly reducing the impact of external electromagnetic interference.

[0084] Optionally, see Figure 7 The main board 30 includes: N operational amplifier modules 301 , an analog-to-digital conversion module 302 and a processing chip 303 .

[0085] The N full-bridge circuits are respectively connected to an operational amplifier module 301 , and each operational amplifier module 301 is used to amplify and filter the measurement value of the full-bridge circuit to which it is connected.

[0086] The analog-to-digital conversion module 302 is connected to the N operational amplifier modules 301 and is used to perform analog-to-digital conversion of the signal to obtain N torque values.

[0087] The processing chip 303 is connected to the analog-to-digital conversion module, and is configured to determine a total torque value according to the N torque values, and calculate power according to the total torque value.

[0088] N full-bridge circuits can share a common power supply and ground ground. Signal lines within the same full-bridge circuit are connected to a mainboard 30 via twisted-pair cables. Mainboard 30 houses N operational amplifier modules 301. The measured values ​​of the N full-bridge circuits are amplified and filtered by these modules. The amplified signals are then input into an analog-to-digital conversion module 302 for conversion into a final digital signal. Finally, a processing chip 303 uses an algorithm to combine these N processed digital signals into a total effective value, i.e., the total torque value, and calculate the power.

[0089] See also Figure 8 As an example, Figure 8 The figure shows a partial connection relationship when four connecting shafts 101 are included. The detection unit 20 corresponding to the first connecting shaft 101 includes resistors R1, R2, R3, and R4, and the first connecting shaft 101 corresponds to the first operational amplifier module 301 on the mainboard 30. The detection unit 20 corresponding to the second connecting shaft 101 includes resistors R5, R6, R7, and R8, and the second connecting shaft 101 corresponds to the second operational amplifier module 301 on the mainboard 30. The detection unit 20 corresponding to the third connecting shaft 101 includes resistors R9, R10, R11, and R12, and the third connecting shaft 101 corresponds to the third operational amplifier module 301 on the mainboard 30. The detection unit 20 corresponding to the fourth connecting shaft 101 includes resistors R13, R14, R15, and R16, and the fourth connecting shaft 101 corresponds to the fourth operational amplifier module 301 on the mainboard 30.

[0090] In summary, in the embodiments of the present application, a complete solution from signal acquisition, torque calculation, temperature compensation to power output is provided, which ensures high-quality acquisition and stable conversion of strain signals, overcomes the influence of inconsistent errors of different connecting shafts, and realizes accurate torque and power estimation; the temperature compensation strategy can dynamically correct the measurement offset caused by ambient temperature difference, ensuring the reliability of the system under complex working conditions; at the same time, it also provides real-time analysis of pedaling rhythm and left and right foot recognition, and accurately calculates the final power by inverting angular velocity and torque compensation value, providing users with intelligent and refined riding feedback and training evaluation, and overall improving the comprehensive performance of the system in measurement accuracy, environmental adaptability and interactive intelligence.

[0091] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0092] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0093] In the description of the embodiments of the present invention, it needs to be understood that terms such as "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "center", "top", "bottom", "top", "bottom", "inside", "outside", "inside", and "outside" indicate directions or positional relationships.

[0094] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "install," "connect," "connect," and "assemble" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0095] In the description of the embodiments of the present invention, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0096] In describing the embodiments of the present invention, it should be understood that "-" and "~" represent a range between two values, and the range includes the endpoints. For example, "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0097] In describing the embodiments of the present invention, the term "and / or" is used herein to describe a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " is generally used herein to indicate that the associated objects are in an "or" relationship.

[0098] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A claw-type power meter with independent full-bridge detection, characterized in that: include: The claw body includes N connecting shafts; N is a positive integer; N detection units; each detection unit includes two strain gauges; each strain gauge includes two resistors; each detection unit is respectively arranged on a connecting shaft, and a strain gauge is respectively arranged on the opposite surface of each connecting shaft; wherein the two strain gauges in each detection unit are connected so that the four resistors of each detection unit form a full-bridge circuit; a mainboard connected to the output ends of N full-bridge circuits; wherein each full-bridge circuit is used to detect the torque value of the connected shaft; the mainboard is used to determine the total torque value based on the N torque values ​​and calculate the power based on the total torque value; Wherein, N is four; the angle between two adjacent connecting axes among the four connecting axes is 90 degrees; The mainboard is also used to obtain a first torque curve and a second torque curve, and determine the alternating state of the user's left and right feet during riding based on the peak changes of the first torque curve and the second torque curve; wherein the first torque curve corresponds to the first connecting axis, and the second torque curve corresponds to the second connecting axis; the first connecting axis and the second connecting axis are two connecting axes arranged opposite to each other.

2. The claw-type power meter with independent full-bridge detection according to claim 1, characterized in that: The mainboard is further specifically configured to determine the total torque value using the following formula, including: ； in, Indicates the total torque value; Indicates the Torque value of the connecting shaft; Indicates the Torque value of the connecting shaft; Indicates the Sensitivity coefficient of each connecting axis; Indicates the The first connecting shaft and the Nonlinear coupling coefficient of the connected axes; Represents the bias term, which is used to compensate for zero drift.

3. The claw-type power meter with independent full-bridge detection according to claim 1, characterized in that: The spider-type power meter is installed on the cycling device and is located on the right side of the chainring, and the first connecting shaft is closer to the right crank of the cycling device than the second connecting shaft; The main board is also used to determine that the user's right foot is currently exerting force when the peak of the first torque curve is higher than the peak of the second torque curve, and to determine that the user's left foot is currently exerting force when the peak of the second torque curve is higher than the peak of the first torque curve.

4. The claw-type power meter with independent full-bridge detection according to claim 1, characterized in that: The mainboard is further configured to determine a waveform period based on a peak of the first torque curve and / or the second torque curve; determine a cadence of the user based on the waveform period; and calculate an angular velocity based on the cadence of the user; Correspondingly, the mainboard is also used to calculate power based on the angular velocity and the total torque value.

5. The claw-type power meter with independent full-bridge detection according to claim 1, characterized in that: The mainboard is further configured to determine a current ambient temperature; compensate a total torque value based on the current ambient temperature and a temperature compensation curve; and calculate power based on the compensated total torque value; The temperature compensation curve is determined by placing the disk claw type power meter in a temperature box and setting different temperature values ​​to detect the disk claw type power meter.

6. The claw-type power meter with independent full-bridge detection according to claim 1, characterized in that: The mainboard is further configured to use the torque values ​​of the N full-bridge circuits as zero point values ​​if the torque values ​​of the N full-bridge circuits are collected when the riding device is detected to be in a stationary state.

7. The claw-type power meter with independent full-bridge detection according to claim 1, characterized in that: The output end of each full-bridge circuit is connected to the main board via a twisted pair cable.

8. The claw-type power meter with independent full-bridge detection according to claim 1, characterized in that: The mainboard includes: N operational amplifier modules, an analog-to-digital conversion module and a processing chip; Wherein, each of the N full-bridge circuits is connected to an operational amplifier module, and each operational amplifier module is used to amplify and filter the measurement value of the full-bridge circuit to which it is connected; The analog-to-digital conversion module is connected to the N operational amplifier modules and is used to perform analog-to-digital conversion of the signal to obtain N torque values; The processing chip is connected to the analog-to-digital conversion module and is configured to determine a total torque value according to the N torque values ​​and calculate power according to the total torque value.

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