Torque measurement system, torque measurement method and device

Abstract

The application provides a torque measurement system, a torque measurement method and equipment, and the torque measurement system comprises a torque measurement sensor and a target device, wherein: the torque measurement sensor is fixedly connected with a stator of a motor to be measured, the torque measurement sensor is used for measuring torque stress of the stator and outputting a voltage signal corresponding to the torque stress; the target device is connected with the torque measurement sensor, the target device is used for collecting a first voltage signal and determining torque characteristics of the motor to be measured according to the collected first voltage signal, and the first voltage signal is a voltage signal output by the torque measurement sensor under the condition that a rotor of the motor to be measured rotates. The technical scheme can realize torque measurement and improve the accuracy of torque measurement.

Description

Technical Field

[0001] This application relates to the field of motor torque testing, and in particular to torque measurement systems, torque measurement methods and equipment. Background Technology

[0002] Most current motors use a tooth and slot structure. The teeth are used to guide magnetic lines of force and reduce magnetic resistance, while the slots are used to embed the windings and link with the magnetic lines of force in the teeth. The different magnetic permeability of the teeth and slots causes the rotor to have a different number of magnetic lines of force at different positions. When the magnetic poles are aligned with the stator teeth, the ferromagnets attract each other, thus hindering the rotation of the permanent magnet motor rotor. This interaction between the rotor magnets and the stator teeth and slots is called the cogging effect of the motor.

[0003] Measuring and analyzing cogging torque and identifying its characteristics is a key step in optimizing motors. How to measure cogging torque has become a technical problem that urgently needs to be solved. Summary of the Invention

[0004] This application provides a torque measurement system, torque measurement method, and apparatus, with the aim of measuring cogging torque.

[0005] In a first aspect, this application provides a torque measurement system, including a torque measurement sensor and a target device, wherein:

[0006] The torque measurement sensor is fixedly connected to the stator of the motor under test. The torque measurement sensor is used to measure the torque stress of the stator and output the voltage signal corresponding to the torque stress.

[0007] The target device is connected to the torque measurement sensor. The target device is used to acquire a first voltage signal and determine the torque characteristics of the motor under test based on the acquired first voltage signal. The first voltage signal is the voltage signal output by the torque measurement sensor when the rotor of the motor under test is rotating.

[0008] In this technical solution, the torque measurement system includes a torque measurement sensor and a target device. The torque measurement sensor is fixedly connected to the stator of the motor under test. The torque measurement sensor measures the torque stress of the stator and outputs a voltage signal corresponding to the torque stress. The target device is connected to the torque measurement sensor and is used to acquire a first voltage signal and determine the torque characteristics of the torque under test based on the acquired first voltage signal. Since the first voltage signal is the voltage signal output by the torque measurement sensor when the rotor of the motor under test is rotating, the first voltage signal can reflect the torque stress of the stator of the motor when the motor is rotating. The torque stress of the stator when the motor is rotating includes the reaction force of the dynamic torque of the motor rotor on the stator. Therefore, the first voltage signal can indirectly reflect the dynamic torque of the motor rotor. By determining the torque characteristics of the motor under test based on the acquired first voltage signal, the measurement of torque characteristics, including the cogging torque of the motor, can be realized. In addition, since the torque measurement sensor is fixedly connected to the stator of the motor under test, the dynamic torque of the motor rotor is measured by measuring the torque stress of the stator. The torque measurement sensor does not need to be connected to the coupling, and the measurement result is not affected by the concentricity of the coupling, which can improve the accuracy of torque measurement.

[0009] In conjunction with the first aspect, in one possible design, the torque measurement system further includes a signal amplification circuit, wherein: the signal amplification circuit is connected between the target device and the torque measurement sensor; the signal amplification circuit is used to amplify the voltage signal output by the torque measurement sensor.

[0010] By setting a signal amplification circuit between the target device and the torque measurement sensor to amplify the voltage signal output by the torque measurement sensor, the torque characteristics of the motor can be amplified, which is beneficial for torque measurement.

[0011] In conjunction with the first aspect, in one possible design, the torque measurement sensor is a static torque sensor, which includes an elastic body and strain gauges disposed on the elastic body, the strain gauges forming a Wheatstone bridge; the signal amplification circuit includes a differential amplifier, the two input terminals of the differential amplifier being respectively connected to the two output terminals of the Wheatstone bridge, and the output terminal of the differential amplifier being connected to the target device.

[0012] By setting up a static torque sensor containing an elastomer and strain gauges to measure the torque stress of the stator, accurate measurement of the stator torque stress can be achieved, which is beneficial for torque measurement.

[0013] Secondly, this application provides a torque measurement method applied to a target device in the torque measurement system of the first aspect described above, the method comprising:

[0014] Acquire the first voltage signal;

[0015] The first voltage signal is subjected to a fast fourier transform (FFT) to obtain the first spectrum;

[0016] The noise frequencies are filtered out from the first spectrum to obtain the second spectrum, where the noise frequencies are those that do not conform to the torque characteristics to be measured.

[0017] The torque characteristics of the motor under test are obtained by performing an inverse fast fourier transform (IFFT) on the second spectrum.

[0018] In this technical solution, after acquiring the first voltage signal, an FFT is performed on the acquired first voltage signal to obtain the first spectrum. Then, noise frequencies that do not conform to the torque characteristics to be measured are filtered out from the first spectrum to obtain the second spectrum. Finally, an IFFT is performed on the second spectrum to obtain the torque characteristics of the motor under test, thus realizing the measurement of torque characteristics including the cogging torque of the motor. Since the torque measurement sensor is fixedly connected to the stator of the motor under test, the dynamic torque of the motor rotor is measured by measuring the torque stress of the stator. The torque measurement sensor does not need to be connected to the coupling, and the measurement result is not affected by the concentricity of the coupling, which can improve the accuracy of torque measurement.

[0019] In conjunction with the second aspect, in one possible implementation, the torque characteristic to be measured is a cogging torque characteristic; the step of filtering out noise frequencies in the first spectrum to obtain a second spectrum includes: in the first spectrum, setting the amplitude of frequencies other than the first frequency to zero to obtain the second spectrum, wherein the first frequency includes zero, an integer multiple of the number of coggings corresponding to the motor under test, and an integer multiple of the number of magnetic poles corresponding to the motor under test.

[0020] By setting the amplitude of frequencies that are independent of the number of cogging teeth and magnetic poles of the motor under test to zero, the characteristic frequency of the cogging torque can be preserved, which is beneficial for determining the characteristics of the cogging torque.

[0021] In conjunction with the second aspect, in one possible implementation, the torque characteristic to be measured is a cogging torque characteristic; the step of filtering out noise frequencies in the first spectrum to obtain a second spectrum includes: setting the amplitude of a second frequency to zero in the first spectrum to obtain the second spectrum, wherein the first frequency is a frequency with an amplitude less than a preset threshold, and the preset threshold is preset based on the cogging torque characteristic.

[0022] By setting frequencies with smaller amplitudes to zero, non-characteristic frequencies that do not belong to the characteristics of cogging torque can be filtered out, which is helpful in determining the characteristics of cogging torque.

[0023] In conjunction with the second aspect, in one possible implementation, the target device acquires the voltage signal output by the torque measurement sensor through an analog-to-digital conversion (ADC) module; before acquiring the first voltage signal, the device further includes: acquiring a second voltage signal, the second voltage signal being the voltage signal output by the torque measurement sensor when the motor under test is stationary; and calibrating the ADC module based on the acquired second voltage signal.

[0024] Before formally measuring the voltage signal under rotor rotation conditions, calibrating the analog-to-digital converter module can prevent interference from the additional stress generated by the motor's gravity on the torque measurement sensor, thereby improving the accuracy of voltage signal measurement.

[0025] In conjunction with the second aspect, in one possible implementation, calibrating the analog-to-digital converter module based on the acquired second voltage signal includes: calculating the average value of the acquired second voltage signal over a first preset time period to obtain the static bias voltage of the analog-to-digital converter module; and setting the static bias voltage to zero.

[0026] In conjunction with the second aspect, in one possible implementation, the first voltage signal is the voltage signal output by the torque measurement sensor when the rotor of the motor under test rotates at a constant speed, wherein the constant speed is less than a preset speed.

[0027] By detecting the voltage signal output by the rotor of the motor under test when it is rotating at a relatively low constant speed using a torque measurement sensor, the voltage signal can more accurately reflect the dynamic torque of the motor rotor.

[0028] In conjunction with the second aspect, in one possible implementation, the first voltage signal is a voltage signal within a second preset time period, and the duration of the second preset time period is longer than a preset duration.

[0029] By increasing the sampling time of the voltage signal, more data can be collected, increasing the amount of data to be processed subsequently and improving the accuracy of data processing.

[0030] This application can achieve the following technical effects: Since the first voltage signal is the voltage signal output by the torque measurement sensor when the rotor of the motor under test is rotating, the first voltage signal can reflect the torque stress of the stator of the motor when the motor is rotating. The torque stress of the stator when the motor is rotating includes the reaction force of the dynamic torque of the motor rotor on the stator. Therefore, the first voltage signal can indirectly reflect the dynamic torque of the motor rotor. Based on the collected first voltage signal, the torque characteristics of the motor under test can be determined, and the measurement of torque characteristics including the cogging torque of the motor can be realized. In addition, since the torque measurement sensor is fixedly connected to the stator of the motor under test, the dynamic torque of the motor rotor is measured by measuring the torque stress of the stator. The torque measurement sensor does not need to be connected to the coupling, and the measurement result is not affected by the concentricity of the coupling, which can improve the accuracy of torque measurement. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A simplified schematic diagram of a scheme for measuring cogging torque;

[0033] Figure 2 This is a schematic diagram of the composition of the torque measurement system provided in the embodiments of this application;

[0034] Figure 3 A simplified connection diagram of the torque measurement sensor and the motor under test provided in an embodiment of this application;

[0035] Figure 4 A schematic diagram of a static torque sensor provided in an embodiment of this application;

[0036] Figure 5 A schematic diagram of a Wheatstone bridge composed of strain gauges and a differential amplifier provided in the embodiments of this application;

[0037] Figure 6 A schematic flowchart of a torque measurement method provided in an embodiment of this application;

[0038] Figure 7A A schematic diagram of the waveform of the first voltage signal acquired in an embodiment of this application;

[0039] Figure 7B A schematic diagram of the first spectrum provided for an embodiment of this application;

[0040] Figure 7CA schematic diagram of torque characteristics provided for an embodiment of this application;

[0041] Figure 8 This is a schematic diagram of the structure of a torque measuring device provided in an embodiment of this application;

[0042] Figure 9 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0044] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. Moreover, the terms "first," "second," and "third" used in this application do not limit the data or execution order, but only distinguish identical or similar items with substantially the same function and effect.

[0045] The technical solution of this application is used to measure motor torque. Specifically, the technical solution of this application can be used to measure friction torque, oscillation torque of galvanometer motor, constant speed output torque of motor, and cogging torque, etc.

[0046] In one feasible technical solution, a dynamic torque measurement sensor is connected to a coupling to measure the cogging torque of the motor. A simplified schematic diagram of the measurement of cogging torque can be shown as follows: Figure 1 As shown, the dynamic torque measurement sensor is connected to the motor under test and the servo motor via a coupling. The coupling transmits the torque generated by the rotor rotation of the motor under test to the dynamic torque sensor, allowing the sensor to detect and output the torque signal corresponding to the torque. The cogging torque is then determined based on the torque signal output by the dynamic torque sensor. Because a coupling is required to connect the dynamic torque measurement sensor and the motor under test, the concentricity of the coupling installation can significantly affect the measurement results, hindering accurate analysis of the cogging torque.

[0047] In view of this, this application proposes a novel torque measurement scheme. A torque measurement sensor is fixedly connected to the stator of the motor and mounted on a base. The torque measurement sensor measures the torque stress of the stator and outputs a voltage signal corresponding to the torque stress, driving the rotor of the motor to rotate. By detecting the voltage signal output by the torque measurement sensor when the motor rotor rotates, the torque characteristics of the motor are determined. Since the rotation of the motor rotor generates a reaction force on the stator, and this reaction force is part of the torque stress acting on the stator, the voltage signal output by the torque measurement sensor when the motor rotor rotates can indirectly reflect the dynamic torque of the motor rotor. Therefore, detecting the voltage signal output by the torque measurement sensor when the motor rotor rotates allows for the measurement of torque characteristics, including the cogging torque of the motor. Because the torque measurement sensor is fixedly connected to the stator of the motor, it does not need to be connected to a coupling, and the measurement results are not affected by the concentricity of the coupling, thus improving the accuracy of torque measurement.

[0048] The technical solution of this application is described in detail below.

[0049] To achieve the technical solution of this application, a torque measurement system is proposed. See also... Figure 2 , Figure 2 This is a schematic diagram of the composition of the torque measurement system provided in the embodiments of this application, as shown below. Figure 2 As shown, the torque measurement system 10 includes a torque measurement sensor 101 and a target device 102.

[0050] The torque measurement sensor 101 is fixedly connected to the stator of the motor under test. The motor under test refers to the motor whose torque needs to be measured, and it can be any type of motor. A simplified connection diagram of the torque measurement sensor 101 and the motor under test can be shown below. Figure 3 As shown, the torque measurement sensor 101 can be coaxially connected to the stator of the motor under test and fixed on the base via an adapter structure.

[0051] The torque measurement sensor 101 is used to measure the torque stress of the stator of the motor under test and output a voltage signal corresponding to the torque stress of the stator. The torque measurement sensor 101 can be any type of sensor that can be fixedly connected to the stator of the motor under test and detect the torque stress of the stator to output a voltage signal.

[0052] In some possible cases, the torque measurement sensor 101 can be a static torque sensor. A static torque sensor can be as follows: Figure 4As shown, the device includes an elastic body a1 and strain gauges a2 disposed on the elastic body a1. The strain gauges a2 are bonded to the torsion beam of the elastic body a1. Two characteristic points on two sides of one torsion beam of the elastic body a1 can serve as bonding points for the strain gauges a2. In this application, the strain gauges a2 are bonded to two tension points and two compression points of the torsion beam, respectively, forming a Wheatstone bridge with the four strain gauges a2. The Wheatstone bridge formed by the four strain gauges a2 can... Figure 5 As shown in D1, strain gauge a2 corresponds to the resistor in the Wheatstone bridge D1. When the elastic body a1 is subjected to torque stress generated by the stator, the elastic body a1 deforms, and the strain gauge a2 placed on the elastic body a1 deforms accordingly, causing a change in the resistance in the Wheatstone bridge. The resistance in the Wheatstone bridge causes a change in the output voltage of the Wheatstone bridge. By using a static torque sensor containing an elastic body and a strain gauge to measure the torque stress of the stator, accurate measurement of the stator torque stress can be achieved, which is beneficial for torque measurement.

[0053] Optionally, the torque measurement sensor 101 can also be other types of sensors capable of measuring the stator's torque stress and outputting a voltage signal corresponding to the torque stress; this application does not impose any limitations on this. For example, the torque measurement sensor 101 can also be a sensor based on the magnetostrictive principle. The torque stress generated by the stator will cause a change in the permeability of the magnetostrictive material in the magnetostrictive sensor, and the change in the permeability of the magnetostrictive material will cause a change in the sensor's output voltage.

[0054] The target device 102 is connected to the torque measurement sensor 101. The target device 102 is used to acquire a first voltage signal and determine the torque characteristics of the motor under test based on the acquired first voltage signal. The first voltage signal is the voltage signal output by the torque measurement sensor 101 when the rotor of the motor under test is rotating. When the rotor of the motor under test rotates, it will generate a reaction force on the stator of the motor. The reaction force, as the torque stress acting on the stator, is detected by the torque measurement sensor 101 and converted into a voltage signal.

[0055] The target device 102 can acquire the voltage signal output by the torque measurement sensor 101 through an ADC module. The voltage signal output by the torque measurement sensor 101 is an analog signal, and the ADC module converts this analog signal into a digital signal for subsequent processing. The ADC module can sequentially sample, quantize, and encode the voltage signal output by the torque measurement sensor 101, thereby converting continuous analog voltage signal values ​​into discrete digital ADC values. The ADC module can be a functional module independent of the target device 102, or it can be part of the target device 102.

[0056] In one specific implementation, the ADC module can be an oversampling ADC module, which includes a modulator consisting of a difference circuit and an integral summation circuit, as well as a digital filter.

[0057] In some possible situations, such as Figure 2 As shown, the torque measurement system 10 also includes a signal amplification circuit 103, which is connected between the torque measurement sensor 101 and the target device 102. The signal amplification circuit 103 is used to amplify the voltage signal output by the torque measurement sensor 101 and output the amplified voltage signal to the target device 102.

[0058] The signal amplification circuit 103 can be any type of circuit capable of amplifying signals. The signal amplification circuit 103 includes, but is not limited to, common-emitter amplifiers, common-collector amplifiers, common-base amplifiers, and so on.

[0059] The specific circuit structure of the signal amplification circuit 103 can be set based on the torque measurement sensor 101. In the torque measurement sensor 101, such as... Figure 4 and Figure 5 As shown, when the four strain gauges form a Wheatstone bridge, the signal amplification circuit 103 can be a differential amplifier. The two input terminals of the differential amplifier are respectively connected to the two output terminals of the Wheatstone bridge, and the output terminal of the differential amplifier is connected to the target device 103. For example, the differential amplifier can be as follows: Figure 5 As shown in D2 in the diagram. This application does not impose any restrictions on the specific circuit structure of the signal amplifier circuit 103.

[0060] By setting a signal amplification circuit between the target device and the torque measurement sensor to amplify the voltage signal output by the torque measurement sensor, the torque characteristics of the motor can be amplified, which is beneficial for torque measurement.

[0061] In the above Figure 2In the corresponding technical solution, the torque measurement system includes a torque measurement sensor and a target device. The torque measurement sensor is fixedly connected to the stator of the motor under test. The torque measurement sensor measures the torque stress of the stator and outputs a voltage signal corresponding to the torque stress. The target device is connected to the torque measurement sensor and is used to acquire the first voltage signal and determine the torque characteristics of the torque under test based on the acquired first voltage signal. Since the first voltage signal is the voltage signal output by the torque measurement sensor when the rotor of the motor under test is rotating, the first voltage signal can reflect the torque stress of the stator of the motor when the motor is rotating. The torque stress of the stator when the motor is rotating includes the reaction force of the dynamic torque of the motor rotor on the stator. Therefore, the first voltage signal can indirectly reflect the dynamic torque of the motor rotor. By determining the torque characteristics of the motor under test based on the acquired first voltage signal, the measurement of torque characteristics, including the cogging torque of the motor, can be realized. In addition, since the torque measurement sensor is fixedly connected to the stator of the motor under test, the dynamic torque of the motor rotor is measured by measuring the torque stress of the stator. The torque measurement sensor does not need to be connected to the coupling, and the measurement result is not affected by the concentricity of the coupling, which can improve the accuracy of torque measurement.

[0062] Based on the torque measurement system of this application, this application also proposes a torque measurement method. See [link to relevant documentation]. Figure 6 , Figure 6 This is a flowchart illustrating a torque measurement method provided in an embodiment of this application. This torque measurement method can be applied to... Figure 2 The target device 102 in the torque measurement system shown; such as Figure 6 As shown, it includes the following steps:

[0063] S201, acquire the first voltage signal.

[0064] Here, the first voltage signal is the voltage signal output by the torque measurement sensor in the torque measurement system when the rotor of the motor under test is rotating. It is used to reflect the torque stress of the stator of the motor when the motor is rotating. The torque stress of the stator of the motor when the motor is rotating includes the reaction force generated by the rotation of the rotor of the motor on the stator of the motor.

[0065] The target device can acquire a first voltage signal through an ADC module. The first voltage signal acquired by the target device through the ADC module is represented as an ADC value output by the ADC module. This ADC value, after certain calculations and conversions, yields the torque value. The ADC value is obtained by the ADC module sampling, quantizing, and encoding the first voltage signal; the ADC value output by the ADC module is the amplitude of the acquired first voltage signal.

[0066] The sampling rate of the ADC module for acquiring the first voltage signal can be greater than the preset sampling rate. Setting the sampling rate high enough allows for the acquisition of more voltage signals per unit time. It is understandable that, when a signal amplification circuit is connected between the target device and the torque measurement sensor, the first voltage signal acquired by the target device through the ADC module is the amplified voltage signal; that is, the ADC value reflects the signal value of the amplified first voltage signal.

[0067] The device can drive the motor under test to rotate at a constant speed. An ADC module collects the voltage signal output by a torque measurement sensor when the rotor of the motor under test is rotating at a constant speed. This voltage signal serves as the first voltage signal. A constant speed refers to a fixed, unchanging speed, which is less than a preset speed. By detecting the voltage signal output when the rotor of the motor under test is rotating at a relatively low constant speed using a torque measurement sensor, the voltage signal can more accurately reflect the dynamic torque of the motor's rotor.

[0068] During the process of driving the motor under test to rotate at a constant speed, the target device can acquire voltage signals within a second preset time period through the ADC module, which will be used as the first voltage signal. The duration of the second preset time period is longer than a preset duration, such as 10 seconds. By increasing the sampling time of the voltage signal, more data can be acquired, increasing the amount of data processed subsequently and improving the accuracy of data processing.

[0069] For example, the waveform of the acquired first voltage signal can be as follows: Figure 7A As shown, Figure 7A The waveform diagram shows time on the horizontal axis and the amplitude of the first voltage signal on the vertical axis. This waveform diagram reflects how the amplitude of the first voltage signal changes over time.

[0070] S202, perform a fast Fourier transform on the acquired first voltage signal to obtain the first spectrum.

[0071] Here, performing a Fast Fourier Transform on the acquired first voltage signal to obtain the first spectrum means converting the amplitude, which is represented in the time domain, into the amplitude, which is represented in the frequency domain, through the Fast Fourier Transform.

[0072] For example, the first spectrum can be as follows Figure 7B As shown, Figure 7B The horizontal axis of the spectrum diagram shown represents frequency, and the vertical axis represents the amplitude of the first voltage signal acquired. The spectrum diagram can reflect how the amplitude of the first voltage signal acquired changes with frequency.

[0073] S203, filter out noise frequencies from the first spectrum to obtain the second spectrum.

[0074] Here, noise frequency refers to the frequency that does not conform to the characteristics of the torque to be measured. The definition of noise frequency is related to the characteristics of the torque to be measured. Different characteristics of the torque to be measured will result in different definitions of noise frequency.

[0075] Filtering out noise frequencies in the first spectrum to obtain the second spectrum means setting the amplitude of the noise frequencies in the first spectrum to zero. Specifically, an appropriate filtering algorithm can be selected to filter out noise frequencies in the first spectrum based on the characteristic frequency of the torque to be measured.

[0076] When the torque characteristic to be measured is a cogging torque characteristic, if the number of coggings and the number of poles of the motor under test are known quantities, the amplitude of frequencies other than the first frequency can be set to zero in the first spectrum to obtain the second spectrum. The first frequency includes zero, integer multiples of the number of coggings and the number of poles of the motor under test. In this process, frequencies with non-zero amplitude (hereinafter referred to as non-zero amplitude frequencies) can be identified in the first frequency spectrum. These frequencies are added to a target frequency set, which includes at least one non-zero amplitude frequency. The non-zero amplitude frequencies in the target frequency set are traversed as frequencies to be processed. It is determined whether the frequency to be processed is zero, or an integer multiple of the number of tooth slots or magnetic poles corresponding to the motor under test. If the frequency to be processed is non-zero and is not an integer multiple of the number of tooth slots or magnetic poles corresponding to the motor under test, the amplitude of the frequency to be processed is set to zero. If the frequency to be processed is zero, or is an integer multiple of the number of tooth slots or magnetic poles corresponding to the motor under test, the next non-zero amplitude frequency in the target frequency set is traversed as the frequency to be processed, until all non-zero amplitude frequencies in the target frequency set have been traversed. The final processed frequency spectrum is the second frequency spectrum.

[0077] When the torque characteristic to be measured is a cogging torque characteristic, if the number of cogging teeth and the number of magnetic poles of the motor under test are unknown, the amplitude of the second frequency in the first spectrum can be set to zero to obtain the second spectrum. The second frequency is the frequency whose amplitude is less than a preset threshold, which is preset based on the cogging torque characteristic. Specifically, frequencies with non-zero amplitudes (hereinafter referred to as non-zero amplitude frequencies) can be identified in the first spectrum and added to a target frequency set. The target frequency set includes at least one non-zero amplitude frequency. The non-zero amplitude frequencies in the target frequency set are traversed as frequencies to be processed. It is determined whether the amplitude corresponding to the frequency to be processed is less than the preset threshold. If the amplitude corresponding to the frequency to be processed is less than the preset threshold, the amplitude corresponding to the frequency to be processed is set to zero. If the amplitude corresponding to the frequency to be processed is greater than or equal to the preset threshold, the next non-zero amplitude frequency in the target frequency set is traversed as the frequency to be processed, until all non-zero amplitude frequencies in the target frequency set have been traversed. The final processed spectrum is the second spectrum.

[0078] S204 performs an inverse fast Fourier transform on the second spectrum to obtain the torque characteristics of the motor under test.

[0079] Here, performing an inverse fast Fourier transform on the second spectrum to obtain the torque characteristics of the motor under test means converting the amplitude expressed in frequency domain form into the amplitude expressed in angle form through the inverse fast Fourier transform.

[0080] For example, a schematic diagram of the angle waveform obtained by performing an inverse fast Fourier transform on the second spectrum can be shown as follows: Figure 7C As shown, Figure 7C The horizontal axis of the angular waveform diagram shown represents the angle, and the vertical axis represents the amplitude. The angular waveform diagram can reflect the torque characteristics of the motor under test.

[0081] In the technical solution corresponding to 6 above, after acquiring the first voltage signal, an FFT is performed on the acquired first voltage signal to obtain the first spectrum. Then, noise frequencies that do not conform to the torque characteristics to be measured are filtered out from the first spectrum to obtain the second spectrum. Finally, an IFFT is performed on the second spectrum to obtain the torque characteristics of the motor under test, thus realizing the measurement of torque characteristics including the cogging torque of the motor. Since the torque measurement sensor is fixedly connected to the stator of the motor under test, the dynamic torque of the motor rotor is measured by measuring the torque stress of the stator. The torque measurement sensor does not need to be connected to the coupling, and the measurement result is not affected by the concentricity of the coupling, which can improve the accuracy of torque measurement.

[0082] In some possible cases, a second voltage signal can also be acquired before acquiring the first voltage signal. The second voltage signal is the voltage signal output by the torque measurement sensor when the motor under test is stationary. Based on the acquired second voltage signal, the analog-to-digital conversion module corresponding to the target device is calibrated.

[0083] Similar to acquiring the first voltage signal, the target device can acquire the second voltage signal through an ADC module. Before the motor rotor rotates, the motor under test is stationary. The target device can acquire the voltage signal from the torque measurement sensor over a period of time through the ADC module, obtaining the second voltage signal. The second voltage signal acquired by the target through the ADC module is also represented as the ADC value output by the ADC module.

[0084] The average value of the acquired second voltage signal within a first preset time period can be calculated to obtain the static bias voltage of the analog-to-digital converter (ADC); the static bias voltage of the ADC is then set to zero. Here, the average value of the acquired second voltage signal within the first preset time period refers to the average value of the ADC output by the ADC module within the first preset time period.

[0085] Before formally measuring the voltage signal under rotor rotation conditions, calibrating the analog-to-digital converter module can prevent interference from the additional stress generated by the motor's gravity on the torque measurement sensor, thereby improving the accuracy of voltage signal measurement.

[0086] See Figure 8 , Figure 8 This is a schematic diagram of the structure of a torque measuring device provided in an embodiment of this application. This torque measuring device can be applied to... Figure 2 The target device 102 in the torque measurement system shown; such as Figure 8 As shown, the torque measuring device 30 includes:

[0087] Voltage signal acquisition module 301 is used to acquire the first voltage signal;

[0088] Fourier transform module 302 is used to perform fast Fourier transform on the acquired first voltage signal to obtain the first spectrum;

[0089] The noise frequency filtering module 303 is used to filter out noise frequencies from the first spectrum to obtain the second spectrum, wherein the noise frequency refers to the frequency that does not conform to the torque characteristics to be measured;

[0090] The inverse Fourier transform module 304 is used to perform a fast inverse Fourier transform on the second spectrum to obtain the torque characteristics of the motor under test.

[0091] It should be noted that the torque measuring device 30 described above can execute the torque measuring method provided in the embodiments of this application, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in the embodiments of the torque measuring device 30 can be found in the torque measuring method provided in the embodiments of this application.

[0092] See Figure 9, Figure 9 This is a schematic diagram of the structure of a computer device 40 provided in an embodiment of this application. The computer device 40 includes a processor 401 and a memory 402. The memory 402 is connected to the processor 401, for example, via a bus.

[0093] Processor 401 is configured to support the computer device 40 in performing the corresponding functions in the methods described in the above method embodiments. Processor 401 may be a central processing unit (CPU), a network processor (NP), a hardware chip, or any combination thereof. The aforementioned hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The aforementioned PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0094] Memory 402 is used to store program code, etc. Memory 402 may include volatile memory (VM), such as random access memory (RAM); memory 402 may also include non-volatile memory (NVM), such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid-state drive (SSD); memory 402 may also include combinations of the above types of memory.

[0095] The memory 402 is used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the torque measurement method in the embodiments of this application. The processor executes various functional applications and data processing of the torque measurement method by running the non-volatile software programs, instructions, and modules stored in the memory, thereby realizing the function of the torque measurement method provided in the above method embodiments.

[0096] The memory 402 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function. The data storage area may store data created based on the use of the torque measuring device. In some embodiments, the memory may include memory remotely located relative to the processor, which can be connected to the torque measuring device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0097] The one or more modules are stored in the memory. When executed by the one or more processors, they perform the torque measurement method in any of the above method embodiments. For example, they perform the method steps described in the above method embodiments to realize the functions of the modules described in the above device embodiments.

[0098] This application also provides a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a computer, cause the computer to perform the method described in the foregoing embodiments.

[0099] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0100] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A torque measurement system, characterized in that, Includes torque measurement sensors and target devices, wherein: The torque measurement sensor is fixedly connected to the stator of the motor under test. The torque measurement sensor is used to measure the torque stress of the stator and output the voltage signal corresponding to the torque stress. The target device is connected to the torque measurement sensor. The target device is used to acquire a first voltage signal and determine the torque characteristics of the motor under test based on the acquired first voltage signal. The first voltage signal is the voltage signal output by the torque measurement sensor when the rotor of the motor under test is rotating.

2. The torque measurement system according to claim 1, characterized in that, The torque measurement system also includes a signal amplification circuit, wherein: The signal amplification circuit is connected between the target device and the torque measurement sensor; The signal amplification circuit is used to amplify the voltage signal output by the torque measurement sensor.

3. The torque measurement system according to claim 2, characterized in that, The torque measurement sensor is a static torque sensor, which includes an elastic body and strain gauges disposed on the elastic body, the strain gauges forming a Wheatstone bridge; the signal amplification circuit includes a differential amplifier, the two input terminals of the differential amplifier are respectively connected to the two output terminals of the Wheatstone bridge, and the output terminal of the differential amplifier is connected to the target device.

4. A torque measurement method, characterized in that, The method is applied to a target device in the torque measurement system according to any one of claims 1-3; the method includes: Acquire the first voltage signal; The first voltage signal is subjected to a fast Fourier transform to obtain the first spectrum; The noise frequencies are filtered out from the first spectrum to obtain the second spectrum, where the noise frequencies are those that do not conform to the torque characteristics to be measured. Perform an inverse fast Fourier transform on the second spectrum to obtain the torque characteristics of the motor under test.

5. The method according to claim 4, characterized in that, The torque characteristic to be measured is the cogging torque characteristic; The step of filtering out noise frequencies from the first spectrum to obtain the second spectrum includes: In the first spectrum, the amplitude of frequencies other than the first frequency is set to zero to obtain the second spectrum. The first frequency includes zero, an integer multiple of the number of tooth slots corresponding to the motor under test, and an integer multiple of the number of magnetic poles corresponding to the motor under test.

6. The method according to claim 4, characterized in that, The torque characteristic to be measured is the cogging torque characteristic; The step of filtering out noise frequencies from the first spectrum to obtain the second spectrum includes: In the first spectrum, the amplitude of the second frequency is set to zero to obtain the second spectrum. The second frequency is a frequency whose amplitude is less than a preset threshold, which is preset based on the cogging torque characteristics.

7. The method according to any one of claims 4-6, characterized in that, The target device acquires the voltage signal output by the torque measurement sensor through an analog-to-digital conversion module; Before acquiring the first voltage signal, the method further includes: Acquire a second voltage signal, which is the voltage signal output by the torque measurement sensor when the motor under test is stationary; The analog-to-digital converter module is calibrated based on the acquired second voltage signal.

8. The method according to claim 7, characterized in that, The step of calibrating the analog-to-digital conversion module based on the acquired second voltage signal includes: The average value of the acquired second voltage signal within a first preset time period is calculated to obtain the static bias voltage of the analog-to-digital conversion module; Set the static bias voltage to zero.

9. The method according to any one of claims 4-6, characterized in that, The first voltage signal is the voltage signal output by the torque measurement sensor when the rotor of the motor under test rotates at a constant speed, wherein the constant speed is less than a preset speed.

10. The method according to any one of claims 4-6, characterized in that, The first voltage signal is the voltage signal within a second preset time period, and the duration of the second preset time period is longer than the preset duration.

11. A computer device, characterized in that, The device includes a memory and a processor, the memory being connected to the processor, the processor being configured to execute one or more computer programs stored in the memory, the processor causing the computer device to perform the method as described in any one of claims 4-10 when executing the one or more computer programs.

Images