Motor with torque self-detection function and design method thereof

Abstract

The invention belongs to the technical field of motor design, and particularly relates to a motor with a torque self-detection function and a design method thereof, a motor shell is fixedly connected with a motor stator, and a motor rotor is connected with the motor stator through a bearing. The motor rotor comprises a rotating shaft, an iron core and other structures. The angle measurement sensor is composed of a fixed part and a rotating part, the fixed part is fixedly connected with the motor shell, and the rotating part is fixedly connected with a motor rotor rotating shaft. And the two angle measurement sensors are respectively arranged on two sides of the motor rotor iron core. The angle difference of the rotating shaft of the motor rotor is measured in real time through the angle measuring sensors on the two sides of the motor rotor iron core, and real-time monitoring of the motor torque is achieved. When the motor operates normally, the output torque of the motor can be monitored in real time, the rotating speed of the motor can be monitored at the same time through the two angle measurement sensors, and the testability, the control performance, the safety and the reliability of the motor are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor design, and specifically relates to a motor with a torque self-detection function and a design method thereof, and specifically to a mechanical connection device with an automatic positioning function and a design method thereof. Background Art

[0002] Motors are widely used in many fields, such as industry, automobiles, aviation, etc. The torque of a motor is an important parameter for evaluating its performance. Accurately measuring the torque of a motor is of great significance for improving the motor control performance, improving the motor working efficiency and extending the motor service life. However, traditional motor torque testing methods usually require additional measurement equipment and steps, which increases the complexity of the measurement process, affects the real-time and accuracy of the measurement, and increases the test cost. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] The technical problem to be solved by the present invention is: how to provide a motor with a torque self-detection function, wherein angle measurement sensors are installed on both sides of the rotor core of the motor to calculate the torque of the motor by measuring the angle difference between the two sides of the motor rotor core.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a motor with a torque self-detection function, the motor comprising: a motor housing (1), a motor stator (2), a motor rotor core (3), two bearings (4), two angle measurement sensors (5), and a motor rotor main shaft (6);

[0007] The motor rotor core (3) and the motor rotor main shaft (6) are assembled into a motor rotor; the motor housing (1) is fixedly connected to the motor stator (2), and the motor rotor (3) is connected to the motor stator (2) via a bearing (4);

[0008] The angle measurement sensor (5) comprises a rotor and a stator, the angle measurement sensor stator is fixedly connected to the motor housing (1), and the angle measurement sensor rotor is fixedly connected to the motor rotor main shaft (6);

[0009] Two angle measurement sensors (5) are respectively installed on both sides of the motor rotor core (3).

[0010] The angle measurement sensor (5) is an optical encoder, a magnetic encoder or a rotary transformer.

[0011] The two angle measurement sensors (5) are respectively installed on both sides of the motor rotor core (3) and are located inside or outside the two bearings (4).

[0012] The angle and rotation speed of the output end and the non-force-bearing end of the rotating main shaft of the motor rotor are measured by two angle measurement sensors (5), and the angle difference is calculated, and then the output torque of the motor is calculated by the angle difference.

[0013] In addition, the present invention also provides a motor with a torque self-detection function, comprising a motor stator, a motor rotor and an angle measurement sensor;

[0014] The motor rotor is installed inside the motor stator, and the motor rotor is connected to the motor stator through two bearings; angle measurement sensors are installed on both sides of the rotor core and on the outside or inside of the bearings.

[0015] The angle measurement sensor is used to measure the rotation angle and rotation speed of the motor rotor main shaft output end and the non-stress end, and calculate the angle difference;

[0016] The functional relationship between the rotation angle difference between the output end and the non-stressed end of the rotor main shaft and the torque is obtained through calibration;

[0017] When the application is in progress, the real-time output torque of the motor is obtained by measuring the rotation angle difference between the output end and the non-stressed end of the motor rotor main shaft.

[0018] In addition, the present invention also provides a design method for the motor with torque self-detection function, the method comprising:

[0019] Step 1: Design simulation; Based on the conventional design of the motor, add angle measurement design and torque calibration clamping design on both sides of the motor rotor; the angle measurement sensor is located on both sides of the motor rotor core, on the inside or outside of the motor rotor mounting bearing;

[0020] By simulating and analyzing the torque characteristics of the motor rotor, the changing law of the rotation angle of the motor rotor at the installation position of the angle measurement sensor under different torques is determined to ensure that the structural changes of the motor rotor caused by the installation of the angle measurement sensor do not affect the design indicators of the motor rotor and to ensure the testability of the angle measurement;

[0021] Step 2: Manufacturing of motor parts: According to the design requirements, the motor housing, motor stator, and motor rotor are manufactured, and the bearing and angle measurement sensor rotor are installed on the motor rotor main shaft;

[0022] Step 3: Torque test system design; The torque test system includes an angle signal collector, a signal processor, and a data storage device; The angle signal collector is used to collect signals from the angle measurement sensor and should have at least two channels; The signal processor is used to process the data from the angle signal collector and can calculate the rotation angle difference between the output end and the non-stress end of the motor rotor main shaft, the motor rotor speed, and the motor torque, and the obtained data is stored in the data storage device;

[0023] Step 4: Calibration; obtain the functional relationship between the torque and the angle difference between the two sides of the rotor. According to the functional relationship, the angle difference between the two sides of the rotor can be converted into torque in real time;

[0024] Step 5: Motor assembly: Assemble the motor components into a finished motor according to the design requirements;

[0025] Step 6: Application: When the motor is working normally, the measurement values ​​of the two angle sensors are collected to calculate the corresponding motor rotor rotation angle difference, and the real-time torque value of the motor is calculated based on the functional relationship between the torque and the angle difference obtained in step 4.

[0026] The angle measurement sensor adopts an optical encoder, a magnetic encoder or a rotary transformer.

[0027] In the step 4, calibration is performed; the purpose of the calibration is to obtain a functional relationship between the torque and the angle difference between the two sides of the rotor, and the angle difference between the two sides of the rotor can be converted into torque in real time according to the functional relationship;

[0028] The specific process is as follows:

[0029] ① Install the motor rotor made in step 2 on the torque calibration equipment, connect the output end of the motor rotor main shaft to the loading interface of the torque calibration equipment, connect the non-stress end of the motor rotor main shaft to the fixed end of the loading equipment, and install the angle measurement sensor stator according to the use requirements of the angle measurement sensor;

[0030] ② Apply a set of torque loads to the motor rotor through the torque loading device, measure the angle data of the angle sensors on both sides of the motor rotor through the acquisition device, obtain and record the rotation angle difference between the output end and the non-stressed end of the corresponding motor rotor through data processing, and establish the corresponding functional relationship between the torque and the angle difference; each torque loading is performed at least three times;

[0031] ③ Calibration data processing: With torque as the output value and the rotation angle difference between the output end and the non-stressed end of the motor rotor as the input value, the mean value of multiple sets of calibration data is calculated to eliminate the systematic error and random error caused by processing, assembly, operation, etc.; the mean value calculation result is fitted by the least squares method to obtain the torque-angle difference function;

[0032] ④ Test error calibration: input the torque-angle difference function into the torque test system as the torque correction function. At this time, the torque test system indicates the torque physical quantity; use the torque loading device to apply several torque loads to the output end of the motor rotor, record the torque loading device and the torque test system indications respectively, and obtain several sets of test data;

[0033] The following formula is used to calculate the test accuracy of the test system:

[0034]

[0035] Several accuracy values ​​are calculated, and the maximum value is considered to be the full-scale test accuracy of this torque test.

[0036] (III) Beneficial effects

[0037] Compared with the prior art, the motor with torque self-detection function and the design method thereof proposed in the present invention realize real-time monitoring of the torque of the motor by installing angle measurement sensors on both sides of the motor rotor core. This method does not require additional measuring equipment and calibration steps, simplifies the measurement process, improves the real-time and accuracy of the measurement, and reduces the cost of motor torque testing. At the same time, the motor of the present invention can monitor the torque of the motor in real time while achieving normal operation, and can back up the motor speed measurement through two angle measurement sensors, thereby increasing the redundancy of the motor speed measurement and improving the working efficiency, safety and reliability of the motor. In addition, the present invention also combines traditional motor design and modern sensor technology, so that the motor has a wider application prospect and higher market value. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of a motor with torque detection function.

[0039] Figure 2 Develop a flow chart for a motor with torque self-detection function.

[0040] Figure 3 It is a schematic diagram of the torque value and the motor rotor rotation angle difference curve. DETAILED DESCRIPTION

[0041] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0042] In order to solve the above technical problems, the present invention provides a motor with a torque self-detection function, the motor comprising: a motor housing (1), a motor stator (2), a motor rotor core (3), two bearings (4), two angle measurement sensors (5), and a motor rotor main shaft (6);

[0043] The motor rotor core (3) and the motor rotor main shaft (6) are assembled into a motor rotor; the motor housing (1) is fixedly connected to the motor stator (2), and the motor rotor (3) is connected to the motor stator (2) via a bearing (4);

[0044] The angle measurement sensor (5) comprises a rotor and a stator, the angle measurement sensor stator is fixedly connected to the motor housing (1), and the angle measurement sensor rotor is fixedly connected to the motor rotor main shaft (6);

[0045] Two angle measurement sensors (5) are respectively installed on both sides of the motor rotor core (3).

[0046] The angle measurement sensor (5) is an optical encoder, a magnetic encoder or a rotary transformer.

[0047] The two angle measurement sensors (5) are respectively installed on both sides of the motor rotor core (3) and are located inside or outside the two bearings (4).

[0048] The angle and rotation speed of the output end and the non-force-bearing end of the rotating main shaft of the motor rotor are measured by two angle measurement sensors (5), and the angle difference is calculated, and then the output torque of the motor is calculated by the angle difference.

[0049] In addition, the present invention also provides a motor with a torque self-detection function, comprising a motor stator, a motor rotor and an angle measurement sensor;

[0050] The motor rotor is installed inside the motor stator, and the motor rotor is connected to the motor stator through two bearings; angle measurement sensors are installed on both sides of the rotor core and on the outside or inside of the bearings.

[0051] The angle measurement sensor is used to measure the rotation angle and rotation speed of the motor rotor main shaft output end and the non-stress end, and calculate the angle difference;

[0052] The functional relationship between the rotation angle difference between the output end and the non-stressed end of the rotor main shaft and the torque is obtained through calibration;

[0053] When the application is in progress, the real-time output torque of the motor is obtained by measuring the rotation angle difference between the output end and the non-stressed end of the motor rotor main shaft.

[0054] In addition, the present invention also provides a design method for the motor with torque self-detection function, the method comprising:

[0055] Step 1: Design simulation; Based on the conventional design of the motor, add angle measurement design and torque calibration clamping design on both sides of the motor rotor; the angle measurement sensor is located on both sides of the motor rotor core, on the inside or outside of the motor rotor mounting bearing;

[0056] By simulating and analyzing the torque characteristics of the motor rotor, the changing law of the rotation angle of the motor rotor at the installation position of the angle measurement sensor under different torques is determined to ensure that the structural changes of the motor rotor caused by the installation of the angle measurement sensor do not affect the design indicators of the motor rotor and to ensure the testability of the angle measurement;

[0057] Step 2: Manufacturing of motor parts: According to the design requirements, the motor housing, motor stator, and motor rotor are manufactured, and the bearing and angle measurement sensor rotor are installed on the motor rotor main shaft;

[0058] Step 3: Torque test system design; The torque test system includes an angle signal collector, a signal processor, and a data storage device; The angle signal collector is used to collect signals from the angle measurement sensor and should have at least two channels; The signal processor is used to process the data from the angle signal collector and can calculate the rotation angle difference between the output end and the non-stress end of the motor rotor main shaft, the motor rotor speed, and the motor torque, and the obtained data is stored in the data storage device;

[0059] Step 4: Calibration; obtain the functional relationship between the torque and the angle difference between the two sides of the rotor. According to the functional relationship, the angle difference between the two sides of the rotor can be converted into torque in real time;

[0060] Step 5: Motor assembly: Assemble the motor components into a finished motor according to the design requirements;

[0061] Step 6: Application: When the motor is working normally, the measurement values ​​of the two angle sensors are collected to calculate the corresponding motor rotor rotation angle difference, and the real-time torque value of the motor is calculated based on the functional relationship between the torque and the angle difference obtained in step 4.

[0062] The angle measurement sensor adopts an optical encoder, a magnetic encoder or a rotary transformer.

[0063] In the step 4, calibration is performed; the purpose of the calibration is to obtain a functional relationship between the torque and the angle difference between the two sides of the rotor, and the angle difference between the two sides of the rotor can be converted into torque in real time according to the functional relationship;

[0064] The specific process is as follows:

[0065] ① Install the motor rotor made in step 2 on the torque calibration equipment, connect the output end of the motor rotor main shaft to the loading interface of the torque calibration equipment, connect the non-stress end of the motor rotor main shaft to the fixed end of the loading equipment, and install the angle measurement sensor stator according to the use requirements of the angle measurement sensor;

[0066] ② Apply a set of torque loads to the motor rotor through the torque loading device, measure the angle data of the angle sensors on both sides of the motor rotor through the acquisition device, obtain and record the rotation angle difference between the output end and the non-stressed end of the corresponding motor rotor through data processing, and establish the corresponding functional relationship between the torque and the angle difference; each torque loading is performed at least three times;

[0067] ③ Calibration data processing: With torque as the output value and the rotation angle difference between the output end and the non-stressed end of the motor rotor as the input value, the mean value of multiple sets of calibration data is calculated to eliminate the systematic error and random error caused by processing, assembly, operation, etc.; the mean value calculation result is fitted by the least squares method to obtain the torque-angle difference function;

[0068] ④ Test error calibration: input the torque-angle difference function into the torque test system as the torque correction function. At this time, the torque test system indicates the torque physical quantity; use the torque loading device to apply several torque loads to the output end of the motor rotor, record the torque loading device and the torque test system indications respectively, and obtain several sets of test data;

[0069] The following formula is used to calculate the test accuracy of the test system:

[0070]

[0071] Several accuracy values ​​are calculated, and the maximum value is considered to be the full-scale test accuracy of this torque test.

[0072] Example 1

[0073] A permanent magnet synchronous motor is taken as an example to illustrate the specific implementation of the present invention.

[0074] Step 1: First design the motor structure

[0075] The difference between the conventional motor structure and the conventional motor structure is that the conventional motor has only one angle measurement sensor, while the motor of the present invention has two angle measurement sensors. The two angle measurement sensors of the present invention are installed on both sides of the motor rotor core. Figure 1 similar.

[0076] Step 2: Simulation analysis

[0077] Through simulation analysis, the variation law of the angle difference between two angle measurement positions of the motor rotor main shaft under different torques is determined. The non-stressed end of the motor rotor main shaft is fixed, and a set of torque is applied to the output end of the motor rotor. The simulation results are as follows: Figure 3 shown.

[0078] The simulation results show that the difference in rotation angle between the non-stressed end and the output end of the motor rotor has a strong linear relationship with the loading torque. The method of measuring the motor torque by measuring the difference in rotation angle between the non-stressed end and the output end of the motor rotor is feasible.

[0079] Step 3: Motor parts manufacturing

[0080] According to the design requirements, the motor housing, motor stator, and motor rotor are manufactured, and the bearing and the angle measurement sensor rotor are installed on the motor rotor main shaft. In this example, the angle measurement sensor uses a rotary transformer, and non-contact angle measurement sensors such as optical encoders or magnetic encoders can also be used.

[0081] Step 4: Calibration

[0082] Calibration fixture design. The calibration fixture includes a fixed clamping fixture and a rotating clamping fixture. The fixed clamping fixture connects the non-stressed end of the motor rotor to the fixed interface of the torque calibration equipment, and the rotating clamping fixture connects the output end of the motor rotor to the torque loading actuator of the torque calibration equipment.

[0083] The calibration test requires the participation of the entire test system, including: torque loading equipment, motor rotor, calibration fixture and torque test system. The torque loading equipment applies standard torque to the motor rotor, and the test system collects and displays the rotation angle of the motor rotor under the torque load. The accuracy and stability of the torque applied by the torque loading equipment should be 2 levels higher than the test accuracy of the test system.

[0084] The calibration method is divided into three parts: Part 1, perform torque loading test on the motor rotor; Part 2, calculate the torque-angle difference function relationship based on the torque loading test results; Part 3, calibrate the test accuracy of the torque test system to obtain the torque test accuracy.

[0085] Content 1: The steps for the torque loading test of the motor rotor are as follows:

[0086] (1) Debug the torque loading device, assemble the motor rotor onto the torque loading device, and adjust the torque loading value to zero.

[0087] (2) Select several equally spaced torque values ​​for the full torque range (measurement range) to be measured;

[0088] (3) Apply torque load to the motor rotor point by point from small to large (process), and record the torque loading value and the angle difference between the non-stress end of the motor rotor and the output end of the motor rotor displayed by the torque test system.

[0089] (4) Apply torque load to the motor rotor point by point from large to small (return stroke), and record the torque loading value and the angle difference between the non-stressed end of the motor rotor and the output end of the motor rotor displayed by the torque test system.

[0090] (5) Repeat steps (3) and (4) three times to obtain three sets of data.

[0091] Content 2, obtain the torque-angle difference function relationship:

[0092] (1) Confirm the validity of the data. Calculate the standard deviation of the three angle differences obtained under the same torque load. If the ratio of the standard deviation of the angle difference corresponding to each torque value to the full torque range is not greater than the accuracy required by the torque test, the data is considered valid.

[0093] (2) Elimination and supplementation of data. If the calculated standard deviation is greater than the required accuracy of the torque test, the variance of each group of numbers is calculated, the group with the largest variance is eliminated, and new experimental data is used to fill it. Repeat step (1) until it meets the requirements.

[0094] (3) Calculation of correction curve. The three angle differences under the same torque load are averaged. The result is that each torque load value corresponds to an angle difference. The least squares method is used for linear fitting to obtain the torque-angle difference function expression and its characteristic indicators: linearity, sensitivity, hysteresis and repeatability, etc.

[0095] (4) Input the torque-angle difference function expression into the data correction function module of the torque test system. The data correction module converts the angle difference value collected in real time into torque in real time according to the torque-angle difference expression, so as to achieve the purpose of correcting the test results.

[0096] Content 3, Torque test system test accuracy calibration steps:

[0097] (1) Five torque loads of random magnitude are applied to the motor rotor in a torque loading device, and the torque indication of the torque loading device and the torque indication of the test system are recorded to obtain a set of test data.

[0098] (2) The test accuracy of the test system is calculated using the following formula:

[0099]

[0100] The calculation result is the full-scale test accuracy of this thrust test.

[0101] Step 5: Motor assembly

[0102] According to the design requirements, the various components of the motor are assembled into a complete motor.

[0103] Step 6. Application

[0104] When the motor is working normally, the measurement values ​​of the rotary transformers on both sides are collected to calculate the relative rotation angle difference. Then, according to the torque-angle difference function established during the calibration process, the real-time torque value of the motor can be obtained.

[0105] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A motor with torque self-detection function, characterized in that: The motor comprises: a motor housing (1), a motor stator (2), a motor rotor core (3), two bearings (4), two angle measurement sensors (5), and a motor rotor main shaft (6); The motor rotor core (3) and the motor rotor main shaft (6) are assembled into a motor rotor; the motor housing (1) is fixedly connected to the motor stator (2), and the motor rotor (3) is connected to the motor stator (2) via a bearing (4); The angle measurement sensor (5) comprises a rotor and a stator, the angle measurement sensor stator is fixedly connected to the motor housing (1), and the angle measurement sensor rotor is fixedly connected to the motor rotor main shaft (6); Two angle measurement sensors (5) are respectively installed on both sides of the motor rotor iron core (3).

2. The motor with torque self-detection function according to claim 1, characterized in that: The angle measurement sensor (5) is an optical encoder, a magnetic encoder or a rotary transformer.

3. The motor with torque self-detection function according to claim 1, characterized in that: The two angle measurement sensors (5) are respectively installed on both sides of the motor rotor core (3) and are located inside or outside the two bearings (4).

4. The motor with torque self-detection function according to claim 1, characterized in that: The angle and rotation speed of the output end and the non-force-bearing end of the rotating main shaft of the motor rotor are measured by two angle measurement sensors (5), and the angle difference is calculated, and then the output torque of the motor is calculated by the angle difference.

5. A motor with torque self-detection function, characterized in that: It includes a motor stator, a motor rotor and an angle measurement sensor; The motor rotor is installed inside the motor stator, and the motor rotor is connected to the motor stator through two bearings; angle measurement sensors are installed on both sides of the rotor core and on the outside or inside of the bearings.

6. The motor with torque self-detection function as claimed in claim 5, characterized in that: The angle measurement sensor is used to measure the rotation angle and rotation speed of the motor rotor main shaft output end and the non-stress end, and calculate the angle difference; The functional relationship between the rotation angle difference between the output end and the non-stressed end of the rotor main shaft and the torque is obtained through calibration; When the application is in progress, the real-time output torque of the motor is obtained by measuring the rotation angle difference between the output end and the non-stressed end of the motor rotor main shaft.

7. A method for designing a motor with a torque self-detection function as claimed in claim 1 or 5, characterized in that: The method comprises: Step 1: Design simulation; add angle measurement design and torque calibration clamping design on both sides of the motor rotor; the angle measurement sensor is located on both sides of the motor rotor core, inside or outside the motor rotor mounting bearing; By simulating and analyzing the torque characteristics of the motor rotor, the changing law of the rotation angle of the motor rotor at the installation position of the angle measurement sensor under different torques is determined to ensure that the structural changes of the motor rotor caused by the installation of the angle measurement sensor do not affect the design indicators of the motor rotor and ensure the testability of the angle measurement; Step 2: Manufacturing of motor parts: According to the design requirements, the motor housing, motor stator, and motor rotor are manufactured, and the bearing and angle measurement sensor rotor are installed on the motor rotor main shaft; Step 3: Torque test system design; The torque test system includes an angle signal collector, a signal processor, and a data storage device; The angle signal collector is used to collect signals from the angle measurement sensor and should have at least two channels; The signal processor is used to process the data from the angle signal collector and can calculate the rotation angle difference between the output end and the non-stress end of the motor rotor main shaft, the motor rotor speed, and the motor torque, and the obtained data is stored in the data storage device; Step 4: Calibration; obtain the functional relationship between the torque and the angle difference between the two sides of the rotor. According to the functional relationship, the angle difference between the two sides of the rotor can be converted into torque in real time; Step 5: Motor assembly: Assemble the motor components into a finished motor according to the design requirements; Step 6: Application: When the motor is working normally, the measurement values ​​of the two angle sensors are collected to calculate the corresponding motor rotor rotation angle difference, and the real-time torque value of the motor is calculated based on the functional relationship between the torque and the angle difference obtained in step 4.

8. The design method of a motor with a torque self-detection function as claimed in claim 7, characterized in that: The angle measurement sensor adopts an optical encoder, a magnetic encoder or a rotary transformer.

9. The design method of a motor with a torque self-detection function as claimed in claim 8, characterized in that: In the step 4, calibration is performed; the purpose of the calibration is to obtain a functional relationship between the torque and the angle difference between the two sides of the rotor, and the angle difference between the two sides of the rotor can be converted into torque in real time according to the functional relationship; The specific process is as follows: ① Install the motor rotor made in step 2 on the torque calibration equipment, connect the output end of the motor rotor main shaft to the loading interface of the torque calibration equipment, connect the non-stress end of the motor rotor main shaft to the fixed end of the loading equipment, and install the angle measurement sensor stator according to the use requirements of the angle measurement sensor; ② Apply a set of torque loads to the motor rotor through the torque loading device, measure the angle data of the angle sensors on both sides of the motor rotor through the acquisition device, obtain and record the rotation angle difference between the output end and the non-stressed end of the corresponding motor rotor through data processing, and establish the corresponding functional relationship between the torque and the angle difference; each torque loading is performed at least three times; ③ Calibration data processing: With torque as the output value and the rotation angle difference between the output end and the non-stressed end of the motor rotor as the input value, the mean value of multiple sets of calibration data is calculated to eliminate the systematic error and random error caused by processing, assembly, operation, etc.; The mean calculation results are fitted using the least square method to obtain the torque-angle difference function; ④ Test error calibration: input the torque-angle difference function into the torque test system as the torque correction function. At this time, the torque test system indicates the torque physical quantity; Use a torque loading device to apply several torque loads to the output end of the motor rotor, record the indications of the torque loading device and the torque test system respectively, and obtain several groups of test data; Several accuracy values ​​are calculated, and the maximum value is considered to be the full-scale test accuracy of this torque test.

10. The design method of a motor with a torque self-detection function as claimed in claim 9, characterized in that: In step 4, the test accuracy of the test system is calculated according to the following formula:

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