Torque in-situ calibration device and method for comprehensive test system of indexing mechanism

Abstract

The invention discloses an indexing mechanism comprehensive test system torque in-situ calibration device, which comprises a calibration tool module, a measurement unit, a loading mechanism and an upper computer, and is characterized in that the calibration tool module comprises a loading arm, a spring mechanism and an adjusting mechanism, and the measurement unit comprises a torque measurement unit and a torque measurement unit; the loading mechanism is connected with the loading arm, the spring mechanism and the upper computer, the loading arm and the spring mechanism are connected with the torque measuring unit, the torque measuring unit is connected with the adjusting mechanism and the upper computer, the adjusting mechanism is connected with the torque measuring unit, and the torque measuring unit is connected with the upper computer. The invention further discloses an indexing mechanism comprehensive test system torque in-situ calibration method, standard torque is applied to the torque sensor through the loading mechanism, and according to the function relation between the output value of the torque sensor of the calibrated unit and the standard torque sensor, in-situ calibration of the indexing torque parameters of the test system is completed.

Description

Technical Field

[0001] The invention relates to the technical field of metrology and calibration, and in particular to a torque in-situ calibration device and method for a comprehensive test system of a transfer mechanism. Background Art

[0002] The space station transfer mechanism comprehensive test system is a key test equipment used to simulate the rotation angle and torque, positioning accuracy and full-time state of the space station transfer and re-docking process on the ground during the development phase of the transfer mechanism.

[0003] The rotation of the rotating arm of the transposition mechanism is realized by the torque loading system of the test system. The torque parameter value of the transposition mechanism during the transposition process is obtained by the torque sensor in the torque loading system, and fed back to the loading system. The loading controller outputs a control signal, which is amplified and drives the torque motor to load to complete the closed-loop control of the entire control system. Therefore, the accuracy of the transposition torque measured by the torque sensor will directly affect the authenticity and reliability of the ground test data of the transposition mechanism, and then affect the control of the real transposition torque of the transposition mechanism during the transposition on the space station. Therefore, during the transposition mechanism test, the transposition torque parameter will affect the correctness of the test data during the rotation of the cabin during the movement of the rotating arm. It is necessary to measure the transposition torque parameter in real time to ensure the accuracy of the test conditions. Due to the complex structure and shape of the comprehensive test system of the transposition mechanism of the space station, the data results of the transposition torque parameter are measured in real time by the torque sensor, which is a key equipment installed in the test system. The installation and positioning accuracy of the torque sensor is very high. Once the sensor is installed, it cannot be directly disassembled, and it is difficult to use conventional measurement methods to perform on-site in-situ calibration.

[0004] At present, for the value traceability of the indexing torque parameter of the indexing mechanism comprehensive test system, the method of adding weights to a lever is used to apply a torque to the end of the shaft system where the torque sensor to be calibrated is installed. Due to the limitation of the on-site space, it can only be calibrated to 400N·m, which cannot cover the sensor's operating range (3000N·m). There are certain limitations, and a set of systematic on-site in-situ calibration methods has not been formed, and there is a prominent problem of incomplete measurement. Therefore, in order to ensure the accuracy and reliability of the measurement data of the indexing mechanism comprehensive test system and improve the efficiency of on-site in-situ calibration, it is urgent to carry out on-site in-situ calibration of the indexing torque parameter according to the structural characteristics of the test system. Summary of the invention

[0005] In order to solve the above problems, the present invention provides an in-situ calibration device for torque of a comprehensive test system of an indexing mechanism, which is used for performing on-site in-situ calibration of a wide range of indexing torques of the comprehensive test system of the indexing mechanism.

[0006] The torque in-situ calibration device of the transfer mechanism comprehensive test system comprises a loading mechanism, a calibration fixture module, a measuring unit, and a host computer, wherein the calibration fixture module comprises a loading arm and a spring mechanism (32), and an adjustment mechanism, and the measuring unit comprises a torque measuring unit and a moment measuring unit;

[0007] The loading mechanism is connected to the loading arm and the spring mechanism (32) and the host computer, the loading arm and the spring mechanism (32) are connected to the torque measuring unit, the torque measuring unit is connected to the adjustment mechanism and the host computer, the adjustment mechanism is connected to the torque measuring unit, and the torque measuring unit is connected to the host computer;

[0008] The loading mechanism is used to generate torque and apply torque to the torque sensor;

[0009] The calibration fixture module is used to install the loading mechanism to ensure that the standard torque can be correctly applied around the torque rotation axis of the measuring unit;

[0010] The measuring unit is used to measure the value of the standard torque applied to the calibrated torque sensor;

[0011] The host computer is used for loading control of the loading mechanism and analysis and processing of collected data;

[0012] The loading mechanism comprises a driver, a torque motor (11), a cam transmission mechanism (12), an angle measuring unit, and a controller;

[0013] The loading mechanism has the characteristics of stable force application, light structure, easy installation, convenient operation, safety and reliability;

[0014] The driver is connected to the torque motor (11), the torque motor (11) is connected to the cam transmission mechanism (12), the cam transmission mechanism (12) is connected to the angle measuring unit, the angle measuring unit is connected to the controller, and the controller is connected to the driver;

[0015] The driver is used to drive the torque motor to perform torque loading;

[0016] The torque motor (11) is used to realize torque loading and has the characteristics of small size, compact structure, smooth transmission, good rigidity and small deformation;

[0017] The cam transmission mechanism (12) is a disc-shaped component with a curved profile and adopts an involute design to ensure that the cam transmission mechanism (12) moves smoothly, the pressure direction is constant, and the pressure is stable, so as to realize precise torque loading control;

[0018] The angle measuring unit is used to obtain the angle change during the torque loading process and feed it back to the controller;

[0019] The controller is used to achieve accurate control of the loading speed and torque, thereby achieving safe and stable load application to the torque sensor;

[0020] The torque motor (11) drives the cam transmission mechanism (12) to rotate, and through the radial drive of the cam transmission mechanism (12), the spring mechanism (32) on the loading arm is compressed to achieve the application of driving force;

[0021] The angle measuring unit comprises a circular grating encoder, a connecting tool (133), and a reading head adjustment bracket (134);

[0022] The circular grating encoder comprises a grating (131) and a grating reading head (132);

[0023] The grating (131) is connected to the loading mechanism via the connecting fixture (133); the grating reading head is mounted on a reading head adjustment bracket (134); the reading head is aligned with the grating measurement surface by adjusting the bracket to ensure that the gap and radial jump between the reading head and the grating meet the calibration requirements;

[0024] The circular grating encoder adopts a circular grating encoder with a built-in stator coupling;

[0025] The circular grating encoder with built-in stator coupling has good dynamic performance and is suitable for in-situ calibration of index angle and index angular velocity parameters;

[0026] When the cam transmission mechanism (12) rotates, the stator coupling of the circular grating encoder with a built-in stator coupling absorbs the friction torque caused by bearing friction;

[0027] Encoding and subdividing the grating encoder to obtain high-precision and high-resolution position information;

[0028] The coding subdivision uses a grating encoder subdivision method based on FPGA, and burns part of the peripheral circuit into the FPGA based on FPGA hardware logic programming to achieve the purpose of simplifying the circuit; the programmability of FPGA makes it easy to modify, and it can be adjusted according to the on-site conditions while achieving high resolution; the FPGA is used to adjust the decimal places of the data to achieve higher accuracy;

[0029] The specific principle of the coding subdivision is as follows:

[0030] The dual reading heads of the grating encoder output Moiré fringe signals A and B with a phase difference of 90°. The Moiré fringe signal obtained by processing the above two differential signals is expressed as:

[0031] U A =Usinθ

[0032] U B =Usin(θ+π / 2)=Ucosθ (1)

[0033] Where U is the signal amplitude, and θ is the phase angle of the moiré fringe signal. The present invention is based on the above two-phase signal, and obtains the required real-time mechanical angle through n-frequency multiplication and precise code subdivision. The calculation formula is:

[0034]

[0035] Where λ is the final real-time mechanical angle, N is the number of physical lines of the encoder, n is the frequency multiplication number, Z is the number of cycles of the periodic signal after frequency multiplication, and β is the fractional part of less than one cycle; in order to obtain a more accurate mechanical angle, β needs to be subdivided to obtain higher resolution and accuracy;

[0036] According to the positive and negative signs of the product of the A and B signals, the phase angles of the three quadrants except the first quadrant are corrected so that their phase angle changes are the same as those of the first quadrant. Then, the correction module and algorithm module are built using FPGA to obtain the real-time electrical angle. The high-speed data processing and high-bit width of FPGA are used to achieve high-resolution and high-precision signal segmentation. After the two sine and cosine signals are corrected, the algorithm inverse tangent is used to calculate the real-time electrical angle. The correction result is:

[0037]

[0038] The torque measurement unit is used to accurately measure the applied standard torque and perform in-situ calibration data processing;

[0039] The torque measurement unit is used to measure the torque applied to the torque sensor by the standard torque sensor for accurate measurement;

[0040] The torque measurement unit includes a standard torque sensor and a signal conditioning module A;

[0041] The torque measurement unit includes a torque sensor and a signal conditioning module B;

[0042] The standard torque sensor is connected to the torque sensor through the adjustment mechanism; the standard torque sensor is connected to the signal conditioning module A, and the signal conditioning module A is connected to the host computer; the torque sensor is connected to the signal conditioning module B, and the signal conditioning module B is connected to the host computer;

[0043] Preferably, in order to cover the entire measurement torque range of the torque loading unit of the indexing mechanism comprehensive test system and obtain the real torque measurement result, the standard torque sensor adopts a 3000Nm cylindrical strain gauge standard torque sensor with a smaller measurement lower limit and an accuracy level of 0.05;

[0044] The strain gauge standard torque sensor has high accuracy, and the output signal is a weak voltage signal of 2mV / V;

[0045] The sensor sensitivity is calibrated for the two measuring ranges of 10% to 100% and 1% to 10% respectively to ensure the accuracy of the torque sensor measurement value;

[0046] Preferably, for weak signal collection, a special signal conditioning and collection module of direct bridge type is used;

[0047] The direct bridge type special signal conditioning acquisition module has a full-scale measurement accuracy of 1 / 200000, which is suitable for accurate measurement of sensors;

[0048] The loading arm comprises a connecting rod (21), an upper connecting flange (22), and a lower connecting flange (23);

[0049] The spring mechanism (32) comprises a threaded rod (321), a fixed pressure plate (322), a top rod (323), a jacket (324), a bottom plate (325), a spring (326), a nut (327), and a screw (328), and is used to achieve stable loading of torque;

[0050] The lower end surface of the lower connecting flange (23) is connected to the upper end surface of the sensor to be calibrated by bolts;

[0051] The upper end surface of the lower connecting flange (23) is connected to the lower end surface of the standard torque sensor in the measuring unit by bolts;

[0052] The lower end surface of the upper connecting flange (22) in the loading arm is connected to the upper end surface of the standard torque sensor by bolts;

[0053] The upper end surface of the lower connecting flange (23) is connected to the connecting rod (21) in the measuring unit via a positioning pin;

[0054] The spring mechanism (32) is installed at the end of the connecting rod (21);

[0055] The spring mechanism (32) is subjected to a force applied by the cam transmission mechanism (12);

[0056] The fixed pressure plate (322) and the bottom plate (325) form a frame structure through the nut (327), the screw (328) and the threaded rod (321), which is fixed to the end of the connecting rod (21) of the loading arm. The spring (326) is placed in the outer sleeve (324), and the top end is extended by the top rod (323) to serve as the loading point of the torque;

[0057] The adjustment mechanism is fixed on the mounting platform via the lower connecting flange (23);

[0058] The adjusting mechanism adjusts the height and levelness of the upper connecting flange (22) plate by locking the nut (327), and achieves radial adjustment of the loading mechanism by fine-tuning the screw (328), thereby finally achieving correct connection between the loading mechanism and the test system table;

[0059] The host computer includes an industrial computer, a data acquisition analysis and display module, a data acquisition module, a measurement loading software, and a control software;

[0060] The data acquisition, analysis and display module of the host computer displays the torque applied by the loading mechanism to the standard torque sensor;

[0061] The host computer is used to carry out in-situ torque measurement of the indexing mechanism comprehensive test system, and can read the force value of the torque sensor;

[0062] The host computer can read the angle value of the circular grating encoder in real time, and carry out closed-loop control on the torque motor (11) according to the grating angle value;

[0063] The host computer can control the enabling state of the torque motor (11), including two states: enabled and disabled. In the enabled state, the torque motor (11) is used to rotate to a target position. In the disabled state, the voltage of the torque motor (11) is not given, and the loading mechanism is manually rotated, and the grating reads the current angle value.

[0064] The host computer control system has a torque protection mode and is provided with an enabling button for controlling whether this mode is effective. When the torque motor (11) moves to a certain position, the torque value reaches a target value, the torque motor (11) stops, and the torque motor (11) is locked; the rotation of the torque motor has an angle control mode, and the indexing angle is adjusted in real time by giving an absolute angle position or a relative angle position value and a given angular velocity (or a default angular velocity) motion value target value;

[0065] The host computer has emergency stop and alarm functions when the measurement range is exceeded;

[0066] The industrial computer performs unified control and display on the torque in-situ calibration device of the indexing mechanism comprehensive test system;

[0067] The industrial computer is used as a client to write a host computer to input parameters, thereby controlling the motion control card to send control instructions to the driver, and the driver controls the torque motor (11). At the same time, during the motion process, the circular grating encoder, the torque sensor and the sensor data acquisition card are used to complete the measurement and reading of the angle value and the torque value, and the read value is transmitted to the host computer to complete display and recording;

[0068] Preferably, the host computer uses a PCI chassis with a high-precision digital acquisition card, a communication card, and a controller component to achieve synchronous acquisition of torque and angle;

[0069] The measurement loading software is developed based on LabView open software under Windows operating system;

[0070] The measurement loading software includes position mode, speed mode, and jog mode, and also has data acquisition and recording, torque protection, and static acquisition and recording functions;

[0071] The measurement loading software interface is required to be friendly and clear, simple and intuitive to operate, able to accurately implement various functions, and have an open framework structure. According to the actual use of the software, the program modules can be changed, added and improved in subsequent work;

[0072] The host computer is divided into a motor drive control system and a data acquisition system according to the functions and objectives of the hardware system;

[0073] The motor drive control system mainly sends pulses to the driver through the PCI-1245L board, and the driver amplifies and outputs pulses to the torque motor (11). At the same time, the driver receives position information from the circular grating encoder and feeds it back to the PCI-1245L board to obtain detailed position information of the torque motor (11);

[0074] The data acquisition system mainly includes a torque acquisition system, which directly connects the torque sensor to the PCI-9524 board to obtain torque value information, and uses the position information acquisition function of the PCI-1245L board to obtain the position information of the circular grating encoder for position data acquisition;

[0075] The control software also has a torque protection function for preventing excessive torque from damaging the system; when the torque protection button is clicked, the torque protection function is turned on; under the torque protection function, when the torque measured by the torque sensor exceeds a certain value, the torque motor (11) stops moving and is locked, thereby effectively protecting the system;

[0076] The torque protection function is realized based on the data acquisition module;

[0077] The realization of the torque protection function requires pressing the torque protection button and the start acquisition button at the same time;

[0078] In order to avoid forgetting to turn on the torque protection function in the indexing torque calibration mode, the control software is designed with a self-locking function to prevent misoperation and missed operation in the experiment. That is, in the indexing torque calibration mode, only when the torque protection and start acquisition buttons are pressed at the same time, the system can move in different motion modes, otherwise the system will report an error and will not move.

[0079] A torque field calibration device adopts an in-situ calibration method. A standard torque is directly applied to the torque sensor of a test system through a loading mechanism designed and developed in the device, so that the sensor has the same loading conditions during calibration and testing, avoiding the use of the characteristic indicators of the torque sensor as indicators of the measurement unit, and ensuring the authenticity of the test bench measurement data.

[0080] A method for in-situ calibration of torque of a comprehensive test system for an indexing mechanism, using the in-situ calibration device for torque of a comprehensive test system for an indexing mechanism, the method applies a standard torque to the torque sensor in a certain loading manner through a specially developed loading mechanism without changing the installation state of the torque sensor of the unit to be calibrated of the test system, and completes the in-situ calibration of the indexing torque parameter of the test system according to the functional relationship between the output value of the torque sensor of the unit to be calibrated and the standard torque sensor;

[0081] During calibration, the torque generated by the loading mechanism is applied to the torque sensor through a standard torque sensor, and the output value of the standard torque sensor is used as the standard torque value. After signal conditioning, it is displayed on the data display instrument, and the accuracy of the torque measurement data of the torque sensor of the indexing mechanism comprehensive test system is determined by comparing it with the output value of the torque sensor; when performing the indexing torque in-situ calibration, a standard torque sensor is installed at the front end of the loading mechanism, and it needs to be connected to the torque loading unit shaft system of the test system with a coupling; the loading mechanism loads the shaft system end of the torque loading unit point by point in a certain way, and after signal conditioning and data processing, the output value of the torque sensor of the torque loading unit is recorded from the display instrument until all the set calibration points are calibrated, and then data processing is performed to give the calibration results;

[0082] The method comprises the following steps:

[0083] S1. Correctly install the loading mechanism, tooling and standard torque sensor

[0084] The loading mechanism is installed at the designated position. The upper end of the loading mechanism is connected to the standard torque sensor and the sensor to be tested through the calibration fixture to ensure that the rotation axis of the loading mechanism coincides with the axis of the torque sensor, so as to reduce the influence of the parasitic components of the bending moment and lateral force.

[0085] Without connecting the load, the torque motor under the indexing mechanism is controlled to move, and the torque values ​​of the two torque sensors at different points such as A, B, and C are collected;

[0086] S2. Select several calibration points according to the range of the sensor being measured.

[0087] According to the range of the sensor to be measured, 100Nm is used as the initial calibration point, and a calibration point is taken for each additional 100Nm. The calibration range is 3% to 100%, ensuring that each point is evenly distributed;

[0088] S3, device preheating and preloading

[0089] Correctly connect the standard torque sensor, signal conditioning module A and data acquisition and analysis module (host computer), power on and preheat, and ensure that all parts of the instrument operate stably. Before in-situ calibration, turn on the torque protection switch to prevent excessive torque from damaging the test bench. Then the host computer first controls the loading mechanism to preload according to the maximum range of the torque sensor being tested. Load twice, keep it for 2 minutes each time, and then unload to zero;

[0090] S4, zero correction

[0091] After completing the preloading and unloading to zero, turn on the loading mechanism controller and start collecting to obtain the standard value displayed by the loading mechanism; if the standard value is not zero, perform zero position correction in the measurement software, and record the zero position of the measured sensor at the same time, and record it in the measurement software;

[0092] S5. Calibration process

[0093] In the measurement software, set the torque motor rotation speed of the loading mechanism, determine the rotation direction, torque loading peak, torque loading and unloading calibration points, and click the acquisition button of the measurement software to start acquisition; the host computer measurement software controls the torque motor of the loading mechanism to rotate continuously at the selected speed, stops loading whenever the calibration point is reached, and continues loading after a period of time until the torque reaches the determined peak value, and maintains at the peak value for a period of time; then control the torque motor to reverse and unload, stop unloading whenever the unloading gradient is reached, and continue unloading after a period of time until the torque value is cleared, and end this calibration after a period of time; after the acquisition is completed, save and record the torque values ​​of the standard torque sensor and the torque sensor under test;

[0094] After completing the calibration of all calibration points, perform data processing and give the calibration results. The indication error of the indexing torque calibration is calculated according to formula (4):

[0095]

[0096] Where:

[0097] EMi M is the indication error of the indexing torque; 1i M is the average indication of the indexing torque at the ith calibration point; 0i is the standard value of the indexing torque at the ith calibration point.

[0098] Compared with the prior art, the present invention has the following beneficial effects:

[0099] (1) The torque in-situ calibration device realizes the on-site in-situ calibration of the indexing torque of the indexing mechanism comprehensive test system.

[0100] (2) A loading mechanism is developed using a servo-controlled torque motor. The loading mechanism has a small size, compact structure, smooth transmission, good rigidity, and small deformation. It can easily realize torque loading and meet the requirements of in-situ calibration of the transfer torque under the special structure of the torque loading unit of the space station transfer mechanism comprehensive test system.

[0101] (3) The transmission mechanism of the cam structure used for deceleration and force amplification transmission is designed with an involute configuration to ensure that the output inclination angle of the radial loading force output by the loading mechanism remains unchanged and that the indexing torque transmitted by the loading force to the shaft system of the test system can be increased smoothly.

[0102] (4) PCI bus-based synchronous loading control and data acquisition technology is used to synchronously control and collect data on the loading mechanism, standard torque sensor, and grating encoder to achieve precise torque loading under real-time closed-loop control.

[0103] (5) The developed spring mechanism transmits the loading force transmitted by the cam transmission mechanism to the loading arm, and stores energy through spring compression, so that the spring mechanism further ensures the smooth loading of the torque and realizes the precise loading of the torque sensor.

[0104] (6) Develop an adjustment mechanism with positioning and adjustment functions that is compatible with the comprehensive test system to achieve the problem of benchmark uniformity in the in-situ torque calibration of the comprehensive test system. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] In order to more clearly illustrate the technical solutions disclosed in the present invention, the following briefly introduces the drawings required to be used in some embodiments disclosed in the present invention. Obviously, the drawings described below are only drawings of some embodiments disclosed in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the products involved in the embodiments disclosed in the present invention, the actual process of the method, etc.

[0106] Figure 1 It is a schematic diagram of a torque in-situ calibration device of a comprehensive test system for an indexing mechanism provided by the present invention;

[0107] Figure 2 It is a schematic diagram of the torque in-situ calibration provided by the present invention;

[0108] Figure 3 is a schematic diagram of a torque loading mechanism provided by the present invention;

[0109] Figure 4 It is a schematic diagram of the internal structure of the loading mechanism provided by the present invention;

[0110] Figure 5 is a top view of the cam transmission mechanism provided by the present invention;

[0111] Figure 6 It is a schematic diagram of a circular grating encoder measurement system provided by the present invention;

[0112] Figure 7 is a schematic diagram of a torque measurement unit provided by the present invention;

[0113] Figure 8 It is a front view of the loading arm structure provided by the present invention;

[0114] Fig. 9 is a top view of the loading arm structure provided by the present invention;

[0115] Fig.10 It is a schematic diagram of the spring mechanism structure provided by the present invention;

[0116] Fig.11 It is the wiring diagram of the host computer system provided by the present invention;

[0117] Fig.12 It is the wiring diagram of the torque sensor and grating encoder provided by the present invention;

[0118] Fig.13 It is the rear panel program of the self-locking function part of the upper computer provided by the present invention;

[0119] Fig.14 The present invention provides a flow chart for the in-situ calibration of the indexing torque of the test system. DETAILED DESCRIPTION

[0120] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0121] The torque in-situ calibration device of the transfer mechanism comprehensive test system is as follows: Figure 1As shown, it includes a loading mechanism, a calibration fixture module, a measuring unit, and a host computer, wherein the calibration fixture module includes a loading arm, a spring mechanism 32, and an adjustment mechanism, and the measuring unit includes a torque measuring unit and a moment measuring unit;

[0122] The loading mechanism is connected to the loading arm and spring mechanism 32 and the host computer, the loading arm and spring mechanism 32 are connected to the torque measuring unit, the torque measuring unit is connected to the adjustment mechanism and the host computer, the adjustment mechanism is connected to the torque measuring unit, and the torque measuring unit is connected to the host computer;

[0123] The loading mechanism is used to generate torque and apply torque to the sensor to be calibrated;

[0124] The calibration fixture module is used to install the loading mechanism to ensure that the standard torque can be correctly applied around the torque rotation axis of the measuring unit;

[0125] The measuring unit is used to measure the value of the standard torque applied to the calibrated torque sensor 24;

[0126] The host computer is used for loading control of the loading mechanism and analysis and processing of collected data;

[0127] The loading mechanism includes a driver, a torque motor 11, a cam transmission mechanism 12, an angle measuring unit, and a controller. Figure 4 As shown;

[0128] The loading mechanism has the characteristics of stable force application, light structure, easy installation, convenient operation, safety and reliability;

[0129] The driver is connected to the torque motor 11, the torque motor 11 is connected to the cam transmission mechanism 12, the cam transmission mechanism 12 is connected to the angle measuring unit, the angle measuring unit is connected to the controller, and the controller is connected to the driver. Figure 4 As shown;

[0130] The driver is used to drive the torque motor to perform torque loading;

[0131] The torque motor 11 is used to realize torque loading, and has the characteristics of small size, compact structure, smooth transmission, good rigidity and small deformation;

[0132] The cam transmission mechanism 12 is a disc-shaped component with a curved profile, and adopts an involute design to ensure that the cam transmission mechanism 12 moves smoothly, the pressure direction is constant, and the pressure is stable, so as to achieve precise torque loading control. Figure 5 As shown;

[0133] The angle measuring unit is used to obtain the angle change during the torque loading process and feed it back to the controller;

[0134] The controller is used to achieve accurate control of the loading speed and torque, thereby achieving safe and stable application of load to the torque sensor 24;

[0135] The torque motor 11 drives the cam transmission mechanism 12 to rotate, and through the radial drive of the cam transmission mechanism 12, the spring mechanism 32 on the loading arm is compressed to achieve the application of driving force;

[0136] The angle measuring unit includes a circular grating encoder, a connecting tool 133, and a reading head adjustment bracket 134;

[0137] The circular grating encoder includes a grating 131 and a grating reading head 132;

[0138] The grating 131 is connected to the loading mechanism through the connecting fixture 133; the grating reading head is installed on the reading head adjustment bracket 134, and the reading head is aligned with the grating measurement surface by adjusting the bracket to ensure that the gap and radial jump between the reading head and the grating meet the calibration requirements;

[0139] The circular grating encoder adopts a circular grating encoder with a built-in stator coupling;

[0140] The circular grating encoder with built-in stator coupling has good dynamic performance and is suitable for in-situ calibration of index angle and index angular velocity parameters;

[0141] When the cam transmission mechanism 12 rotates, the stator coupling of the circular grating encoder with built-in stator coupling absorbs the friction torque caused by bearing friction;

[0142] Encoding and subdividing the grating encoder to obtain high-precision and high-resolution position information;

[0143] The coding subdivision uses a grating encoder subdivision method based on FPGA, and burns part of the peripheral circuit into the FPGA based on FPGA hardware logic programming to achieve the purpose of simplifying the circuit; the programmability of FPGA makes it easy to modify, and it can be adjusted according to the on-site conditions while achieving high resolution; the FPGA is used to adjust the decimal places of the data to achieve higher accuracy;

[0144] The specific principle of the coding subdivision is as follows:

[0145] The dual reading heads of the grating encoder output Moiré fringe signals A and B with a phase difference of 90°. The Moiré fringe signal obtained by processing the above two differential signals is expressed as:

[0146] U A =Usinθ

[0147] U B =Usin(θ+π / 2)=Ucosθ (1)

[0148] Where U is the signal amplitude, and θ is the phase angle of the moiré fringe signal. The present invention is based on the above two-phase signal, and obtains the required real-time mechanical angle through n-frequency multiplication and precise code subdivision. The calculation formula is:

[0149]

[0150] Where λ is the final real-time mechanical angle, N is the number of physical lines of the encoder, n is the frequency multiplication number, Z is the number of cycles of the periodic signal after frequency multiplication, and β is the fractional part of less than one cycle; in order to obtain a more accurate mechanical angle, β needs to be subdivided to obtain higher resolution and accuracy;

[0151] According to the positive and negative signs of the product of the A and B signals, the phase angles of the three quadrants except the first quadrant are corrected so that their phase angle changes are the same as those of the first quadrant. Then, the correction module and algorithm module are built using FPGA to obtain the real-time electrical angle. The high-speed data processing and high-bit width of FPGA are used to achieve high-resolution and high-precision signal segmentation. After the two sine and cosine signals are corrected, the algorithm inverse tangent is used to calculate the real-time electrical angle. The correction result is:

[0152]

[0153] The torque measurement unit is used to accurately measure the applied standard torque and perform in-situ calibration data processing;

[0154] The torque measurement unit is used to measure the torque applied to the torque sensor 24 by the standard torque sensor 24 for accurate measurement;

[0155] The torque measurement unit includes a standard torque sensor 24, a signal conditioning module A, such as Figure 7 As shown;

[0156] The torque measurement unit includes a torque sensor 24 and a signal conditioning module B;

[0157] The standard torque sensor 24 is connected to the torque sensor 24 through the adjustment mechanism; the standard torque sensor 24 is connected to the signal conditioning module A, and the signal conditioning module A is connected to the host computer; the torque sensor 24 is connected to the signal conditioning module B, and the signal conditioning module B is connected to the host computer;

[0158] Preferably, in order to cover the entire measurement torque range of the torque loading unit of the indexing mechanism comprehensive test system and obtain the real torque measurement result, the standard torque sensor 24 adopts a 3000Nm cylindrical strain standard torque sensor 24 with a smaller measurement lower limit and an accuracy level of 0.05;

[0159] The strain gauge standard torque sensor 24 has a high accuracy, and the output signal is a weak voltage signal of 2mV / V;

[0160] The sensor sensitivity is calibrated for the two measuring ranges of 10% to 100% and 1% to 10% respectively to ensure the accuracy of the measured value of the torque sensor 24;

[0161] Preferably, for weak signal collection, a special signal conditioning and collection module of direct bridge type is used;

[0162] The direct bridge type special signal conditioning acquisition module has a full-scale measurement accuracy of 1 / 200000, which is suitable for accurate measurement of sensors;

[0163] The loading arm includes a connecting rod 21, an upper connecting flange 22, and a lower connecting flange 23. Figure 8 As shown;

[0164] The spring mechanism 32 includes a threaded rod 321, a fixed pressure plate 322, a top rod 323, a jacket 324, a bottom plate 325, a spring 326, a nut 327, and a screw 328, and is used to achieve a stable loading of the torque. Fig.10 As shown;

[0165] The lower end surface of the lower connecting flange 23 is connected to the upper end surface of the sensor to be calibrated by bolts;

[0166] The upper end surface of the lower connecting flange 23 is connected to the lower end surface of the standard torque sensor 24 in the measuring unit by bolts;

[0167] The lower end surface of the upper connecting flange 22 in the loading arm is connected to the upper end surface of the standard torque sensor 24 by bolts. Figure 8 As shown;

[0168] The upper end surface of the lower connecting flange 23 is connected to the connecting rod 21 in the measuring unit via a positioning pin;

[0169] The spring mechanism 32 is mounted at the end of the connecting rod 21;

[0170] The spring mechanism 32 is subjected to the force applied by the cam transmission mechanism 12;

[0171] The fixed pressure plate 322 and the bottom plate 325 form a frame structure through the nut 327, the screw 328 and the threaded rod 321, which is fixed to the end of the connecting rod 21 of the loading arm. The spring 326 is placed in the outer sleeve 324, and the top end is extended by the top rod 323, which serves as the loading point of the torque.

[0172] The adjustment mechanism is fixed on the mounting platform through the lower connecting flange 23;

[0173] The adjusting mechanism adjusts the height and levelness of the upper connecting flange 22 by locking the nut 327, and realizes radial adjustment of the loading mechanism by fine-tuning the screw 328, and finally realizes the correct connection between the loading mechanism and the test system table;

[0174] The host computer includes an industrial computer, a data acquisition analysis and display module, a data acquisition module, a measurement loading software, and a control software;

[0175] The data acquisition analysis and display module of the host computer displays the torque applied by the loading mechanism to the standard torque sensor 24;

[0176] The host computer is used to carry out in-situ torque measurement of the indexing mechanism comprehensive test system, and can read the force value of the torque sensor 24;

[0177] The host computer can read the angle value of the circular grating encoder in real time, and carry out closed-loop control of the torque motor 11 according to the grating angle value;

[0178] The host computer can control the enabling state of the torque motor 11, including enabling and disabling states. In the enabling state, the torque motor 11 is used to rotate to the target position. In the disabling state, the voltage of the torque motor 11 is not given, and the loading mechanism is manually rotated, and the grating reads the current angle value;

[0179] The host computer control system has a torque protection mode and an enable button is set to control whether this mode is effective. When the torque motor 11 moves to a certain position, the torque value reaches the target value, the torque motor 11 stops, and the torque motor 11 is locked; the torque motor rotation has an angle control mode, by giving an absolute angle position or a relative angle position value, with a given angular velocity or a default angular velocity motion value target value, the indexing angle is adjusted in real time;

[0180] The host computer has emergency stop and alarm functions when the measurement range is exceeded;

[0181] The industrial computer performs unified control and display on the torque in-situ calibration device of the indexing mechanism comprehensive test system;

[0182] The industrial computer is used as the client written by the host computer to input parameters, so as to control the motion control card to send control instructions to the driver, and the driver controls the torque motor 11. At the same time, during the motion process, the circular grating encoder, the torque sensor 24 and the sensor data acquisition module are used to complete the measurement and reading of the angle value and the torque value, and the read value is transmitted to the host computer for display and recording;

[0183] Preferably, the host computer uses a PCI chassis with a high-precision digital acquisition card, a communication card, and a controller component to achieve synchronous acquisition of torque and angle;

[0184] The measurement loading software is developed based on LabView open software under Windows operating system;

[0185] The measurement loading software includes position mode, speed mode, and jog mode, and also has data acquisition and recording, torque protection, and static acquisition and recording functions;

[0186] The measurement loading software interface is required to be friendly and clear, simple and intuitive to operate, able to accurately implement various functions, and have an open framework structure. According to the actual use of the software, the program modules can be changed, added and improved in subsequent work;

[0187] The host computer is divided into a motor drive control system and a data acquisition system according to the functions and objectives of the hardware system;

[0188] The motor drive control system mainly sends pulses to the driver through the PCI-1245L board, and the driver amplifies and outputs them to the torque motor 11. At the same time, the driver receives the position information from the circular grating encoder and feeds it back to the PCI-1245L board to obtain detailed position information of the torque motor 11, such as Fig.11 As shown;

[0189] The data acquisition system mainly includes a torque acquisition system, which directly connects the torque sensor 24 to the PCI-9524 board to obtain torque value information, and uses the position information acquisition function of the PCI-1245L board to obtain the position information of the circular grating encoder for position data acquisition, such as Fig.12 As shown;

[0190] The control software also has a torque protection function, which is used to prevent excessive torque from damaging the system. When the torque protection button is clicked, the torque protection function is turned on. Under the torque protection function, when the torque measured by the torque sensor 24 exceeds a certain value, the torque motor 11 stops moving and is locked, effectively protecting the system.

[0191] The torque protection function is realized based on the data acquisition module;

[0192] The realization of the torque protection function requires pressing the torque protection button and the start acquisition button at the same time;

[0193] In order to avoid forgetting to turn on the torque protection function in the indexing torque calibration mode, the control software is designed with a self-locking function to prevent misoperation and missed operation in the experiment. That is, in the indexing torque calibration mode, only when the torque protection and start acquisition buttons are pressed at the same time, the system can move in different motion modes. Otherwise, the system will report an error and will not move. Fig.13 shown.

[0194] A torque field calibration device adopts an in-situ calibration method. A standard torque is directly applied to the torque sensor 24 of the test system through a loading mechanism designed and developed in the device, so that the sensor has the same loading conditions during calibration and testing, avoiding the use of the characteristic indicators of the torque sensor 24 as indicators of the measurement unit, and ensuring the authenticity of the test bench measurement data.

[0195] A method for in-situ calibration of torque of an indexing mechanism comprehensive test system, using the in-situ calibration device for torque of an indexing mechanism comprehensive test system, the method applies a standard torque to the torque sensor 24 in a certain loading manner through a specially developed loading mechanism without changing the installation state of the torque sensor 24 of the calibrated unit of the test system, and completes the in-situ calibration of the indexing torque parameter of the test system according to the functional relationship between the output value of the torque sensor 24 of the calibrated unit and the standard torque sensor 24;

[0196] like Figure 2 As shown, during calibration, the torque generated by the loading mechanism is applied to the torque sensor 24 through the standard torque sensor 24, and the value output by the standard torque sensor 24 is used as the standard torque value. After signal conditioning, it is displayed on the data display instrument, and the accuracy of the torque measurement data of the torque sensor 24 of the indexing mechanism comprehensive test system is determined by comparing it with the output value of the torque sensor 24; when performing the indexing torque in-situ calibration, the standard torque sensor 24 is installed at the front end of the loading mechanism, and it needs to be connected to the torque loading unit shaft system of the test system with a coupling; the loading mechanism loads the shaft system end of the torque loading unit point by point in a certain way, and after signal conditioning and data processing, the output value of the torque sensor 24 of the torque loading unit is recorded from the display instrument until all the set calibration points are calibrated, and then data processing is performed to give the calibration result;

[0197] The method comprises the following steps: Fig.14 As shown:

[0198] S1. Correctly install the loading mechanism, tooling and standard torque sensor 24

[0199] The loading mechanism is installed at a designated position, and the upper end of the loading mechanism is connected to the standard torque sensor 24 and the sensor to be tested through a calibration fixture, ensuring that the rotation axis of the loading mechanism coincides with the axis of the torque sensor 24, so as to reduce the influence of the parasitic components of the bending moment and the lateral force;

[0200] Without connecting the load, the torque motor under the indexing mechanism is controlled to move, and the torque values ​​of the two torque sensors 24 at different points such as A, B, and C are collected;

[0201] S2. Select several calibration points according to the range of the sensor being measured.

[0202] According to the range of the sensor to be measured, 100Nm is used as the initial calibration point, and a calibration point is taken for each additional 100Nm. The calibration range is 3% to 100%, ensuring that each point is evenly distributed;

[0203] S3, device preheating and preloading

[0204] Correctly connect the standard torque sensor 24, signal conditioning module and data acquisition and analysis module host computer, power on and preheat, and ensure that all parts of the instrument operate stably. Before in-situ calibration, turn on the torque protection switch to prevent excessive torque from damaging the test bench. Then the host computer first controls the loading mechanism to preload according to the maximum range of the torque sensor 24 to be tested. Load twice, keep it for 2 minutes each time, and then unload to zero;

[0205] S4, zero correction

[0206] After completing the preloading and unloading to zero, turn on the loading mechanism controller and start collecting to obtain the standard value displayed by the loading mechanism; if the standard value is not zero, perform zero position correction in the measurement software, and record the zero position of the measured sensor at the same time, and record it in the measurement software;

[0207] S5. Calibration process

[0208] In the measurement software, set the rotation speed of the torque motor of the loading mechanism, determine the rotation direction, torque loading peak value, and various calibration points of torque loading and unloading, and click the acquisition button of the measurement software to start acquisition; the upper computer measurement software controls the torque motor of the loading mechanism to rotate continuously at the selected speed, and stops loading whenever the calibration point is reached, and continues loading after a period of time until the torque reaches a determined peak value, and maintains at the peak value for a period of time; then control the torque motor to reverse and unload, and stop unloading whenever the unloading gradient is reached, and continue unloading after a period of time until the torque value is cleared, and end this calibration after a period of time; after the acquisition is completed, save and record the torque values ​​of the standard torque sensor 24 and the torque sensor 24 to be measured;

[0209] After completing the calibration of all calibration points, perform data processing and give the calibration results. The indication error of the indexing torque calibration is calculated according to formula (4):

[0210]

[0211] Where:

[0212] E Mi M is the indication error of the indexing torque; 1i M is the average indication of the indexing torque at the ith calibration point; 0i is the standard value of the indexing torque at the ith calibration point.

[0213] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention using the above disclosed contents without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the contents of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A torque in-situ calibration device for a comprehensive test system of an indexing mechanism, characterized in that: The calibration device includes a calibration tooling module, a measuring unit, a loading mechanism, and a host computer, wherein: The calibration fixture module comprises a loading arm, a spring mechanism (32), and an adjustment mechanism, which is used to install the loading mechanism to ensure that the standard torque can be correctly applied around the torque rotation axis of the measuring unit; The measuring unit includes a torque measuring unit and a moment measuring unit, which are used to measure the value of the standard torque applied to the calibrated torque sensor; The loading mechanism is used to generate torque and apply torque to the torque sensor; The host computer is used to control the loading mechanism and analyze and process the collected data; The loading mechanism is connected to the loading arm, the spring mechanism (32) and the host computer; the loading arm and the spring mechanism (32) are connected to the torque measuring unit; the torque measuring unit is connected to the adjusting mechanism and the host computer; the adjusting mechanism is connected to the torque measuring unit; and the torque measuring unit is connected to the host computer.

2. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 is characterized in that: The loading mechanism comprises a driver, a torque motor (11), a cam transmission mechanism (12), an angle measuring unit, and a controller, wherein the driver is connected to the torque motor (11), the torque motor (11) is connected to the cam transmission mechanism (12), the cam transmission mechanism (12) is connected to the angle measuring unit, the angle measuring unit is connected to the controller, and the controller is connected to the driver, wherein: The driver is used to drive the torque motor (11) to load torque; The torque motor (11) is used to achieve torque loading; The cam transmission mechanism (12) compresses the spring mechanism (32) on the loading arm to achieve precise loading control of the torque; The angle measuring unit is used to obtain the angle change during the torque loading process and feed it back to the controller; The controller is used to accurately control the loading speed and torque, so as to safely and smoothly apply the load to the torque sensor; The torque motor (11) drives the cam transmission mechanism (12) to rotate, and through the radial drive of the cam transmission mechanism (12), the spring mechanism (32) on the loading arm is compressed to achieve the application of driving force.

3. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 2 is characterized in that: The angle measuring unit comprises a circular grating encoder, a connecting tool (133), and a reading head adjustment bracket (134); The circular grating encoder comprises a grating (131) and a grating reading head (132); The grating (131) is connected to the shaft of the loading mechanism through the connecting fixture (133); the grating reading head is mounted on a reading head adjustment bracket (134); the reading head is aligned with the grating measurement surface by adjusting the reading head adjustment bracket (134) to ensure that the gap and radial jump between the reading head and the grating meet the calibration requirements; The circular grating encoder adopts a circular grating encoder with a built-in stator coupling, which ensures dynamic performance by absorbing the friction torque caused by motion friction.

4. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 3 is characterized in that: Encoding and subdividing the circular grating encoder to obtain high-precision and high-resolution position information; The coding subdivision uses a grating encoder subdivision method based on FPGA, and the specific method is as follows: The dual reading heads of the grating encoder output Moiré fringe signals A and B with a phase difference of 90°; the Moiré fringe signal obtained by processing the above two differential signals is expressed as: U A =Usinθ U B =Usin(θ+π / 2)=Ucosθ (1) Where U is the signal amplitude, θ is the phase angle of the moiré fringe signal; Based on the above two-phase signal, the required real-time mechanical angle is obtained through n-frequency multiplication and fine code subdivision. The calculation formula is: Where λ is the final real-time mechanical angle, N is the number of physical lines of the encoder, n is the frequency multiplication number, Z is the number of cycles of the periodic signal after frequency multiplication, and β is the fractional part that is less than one cycle; According to the positive and negative signs of the product of the A and B signals, the phase angles of the three quadrants except the first quadrant are corrected so that their phase angle changes are the same as those of the first quadrant. Then, the correction module and algorithm module are built using FPGA to obtain the real-time electrical angle. The high-speed data processing and high-bit width of FPGA are used to achieve high-resolution and high-precision signal segmentation. After the two sine and cosine signals are corrected, the algorithm inverse tangent is used to calculate the real-time electrical angle. The correction result is:

5. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 is characterized in that: The torque measurement unit includes a standard torque sensor and a signal conditioning module A, which are used to accurately measure the applied standard torque and perform in-situ calibration data processing; The torque measurement unit includes a torque sensor and a signal conditioning module B, which is used to measure the torque applied to the torque sensor by the standard torque sensor for accurate measurement; The standard torque sensor is connected to the torque sensor through the adjustment mechanism; the standard torque sensor is connected to the signal conditioning module A, and the signal conditioning module A is connected to the host computer; the torque sensor is connected to the signal conditioning module B, and the signal conditioning module B is connected to the host computer.

6. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 is characterized in that: The loading arm comprises a connecting rod (21), an upper connecting flange (22), and a lower connecting flange (23); The lower end surface of the lower connecting flange (23) is connected to the upper end surface of the sensor to be calibrated by bolts; The upper end surface of the lower connecting flange (23) is connected to the lower end surface of the standard torque sensor in the measuring unit by bolts; The lower end surface of the upper connecting flange (22) in the loading arm is connected to the upper end surface of the standard torque sensor by bolts; The upper end surface of the lower connecting flange (23) is connected to the connecting rod (21) in the measuring unit via a positioning pin.

7. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 is characterized in that: The spring mechanism (32) comprises a threaded rod (321), a fixed pressure plate (322), a top rod (323), a jacket (324), a bottom plate (325), a spring (326), a nut (327), and a screw (328), and is used to achieve stable loading of torque; The spring mechanism (32) is installed at the end of the connecting rod (21); The spring mechanism (32) is subjected to a force applied by the cam transmission mechanism (12); The fixed pressure plate (322) and the base plate (325) form a frame structure through the nut (327), the screw (328) and the threaded rod (321), which is fixed to the end of the connecting rod (21) of the loading arm. The spring (326) is placed in the outer sleeve (324), and the top end is extended by the top rod (323) to serve as the loading point of the torque.

8. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 is characterized in that: The adjusting mechanism is fixed on the mounting platform via the lower connecting flange (23); The adjusting mechanism adjusts the height and levelness of the upper connecting flange (22) plate by locking the nut (327), and achieves radial adjustment of the loading mechanism by fine-tuning the screw (328), thereby achieving correct connection between the loading mechanism and the test system table.

9. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 is characterized in that: The host computer includes an industrial computer, a data acquisition analysis and display module, a data acquisition module, a measurement loading software, and a control software; The data acquisition, analysis and display module of the host computer displays the torque applied by the loading mechanism to the standard torque sensor; The host computer is used to carry out in-situ torque measurement of the indexing mechanism comprehensive test system, and can read the force value of the torque sensor; The host computer can read the angle value of the circular grating encoder in real time, and carry out closed-loop control on the torque motor (11) according to the grating angle value; The host computer can control the enabling state of the torque motor (11), including two states: enabled and disabled. In the enabled state, the torque motor (11) is used to rotate to a target position. In the disabled state, the voltage of the torque motor (11) is not given, and the grating reads the current angle value by manually rotating the loading mechanism.

10. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 or 9, characterized in that: The host computer control system has a torque protection mode and is provided with an enabling button. When the torque motor (11) moves to a certain position and the torque value reaches a target value, the torque motor (11) stops and is locked.

11. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 or 9, characterized in that: The host computer has emergency stop and alarm functions when the measurement range is exceeded.

12. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 9 is characterized in that: The industrial computer performs unified control and display on the torque in-situ calibration device of the indexing mechanism comprehensive test system; The industrial computer, as a client programmed by the host computer, implements parameter input and controls the motion control card to send control instructions to the driver, and the driver controls the torque motor (11). Meanwhile, during the motion process, the circular grating encoder, the torque sensor and the sensor data acquisition card are used to measure and read the angle value and the torque value, and the read values ​​are transmitted to the host computer for display and recording.

13. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 1 or 9, characterized in that: The host computer adopts a PCI chassis with a high-precision digital acquisition card, a communication card, and a controller component to realize the synchronous acquisition of torque and angle.

14. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 9 is characterized in that: The measurement loading software is developed based on LabView open software under Windows operating system; The measurement loading software includes position mode, speed mode, and jog mode, and also has data acquisition and recording, torque protection, and static acquisition and recording functions.

15. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 9, characterized in that: The control software has a torque protection function to prevent excessive torque from damaging the system.

16. The torque in-situ calibration device of the indexing mechanism comprehensive test system according to claim 15, characterized in that: The torque protection function is realized based on the data acquisition module; The realization of the torque protection function requires pressing the torque protection button and the start acquisition button at the same time; In order to avoid forgetting to turn on the torque protection function in the indexing torque calibration mode, the control software is designed with a self-locking function to prevent misoperation and missed operation in the experiment. That is, in the indexing torque calibration mode, only when the torque protection and start acquisition buttons are pressed at the same time, the system can move in different motion modes, otherwise the system will report an error and will not move.

17. A method for in-situ calibration of torque in a comprehensive test system for an indexing mechanism, characterized in that: The in-situ calibration method comprises the following steps: S1. Correctly install the loading mechanism, tooling and standard torque sensor The loading mechanism is installed at the designated position. The upper end of the loading mechanism is connected to the standard torque sensor and the sensor to be tested through the calibration fixture to ensure that the rotation axis of the loading mechanism coincides with the axis of the torque sensor, so as to reduce the influence of the parasitic components of the bending moment and lateral force. Without connecting the load, the torque motor under the indexing mechanism is controlled to move, and the torque values ​​of the two torque sensors at different points A, B, and C are collected; S2. Select several calibration points according to the range of the sensor being measured. According to the range of the sensor to be measured, start from the initial torque calibration point of 3% of the sensor range, and take a calibration point for each additional fixed torque value. The calibration range is only 100% of the sensor range to ensure that each point is evenly distributed; S3, device preheating and preloading Correctly connect the standard torque sensor, signal conditioning module and data acquisition and analysis module, power on and preheat them, and ensure that all parts of the instrument operate stably; Before the in-situ calibration, turn on the torque protection switch to prevent the test bench from being damaged by excessive torque. Then the host computer controls the loading mechanism to preload according to the maximum range of the torque sensor to be tested. The loading is performed twice, each time for 2 minutes, and then unloaded to zero. S4, zero correction After completing the preloading and unloading to zero, turn on the loading mechanism controller and start collecting to obtain the standard value displayed by the loading mechanism; if the standard value is not zero, perform zero position correction in the measurement software, and record the zero position of the measured sensor at the same time, and record it in the measurement software; S5. Calibration process In the measurement software, set the torque motor rotation speed of the loading mechanism, determine the rotation direction, torque loading peak, torque loading and unloading calibration points, and click the acquisition button of the measurement software to start acquisition; the host computer measurement software controls the torque motor of the loading mechanism to rotate continuously at the selected speed, stops loading whenever the calibration point is reached, and continues loading after a period of time until the torque reaches the determined peak value, and maintains at the peak value for a period of time; then control the torque motor to reverse and unload, stop unloading whenever the unloading gradient is reached, and continue unloading after a period of time until the torque value is cleared, and end this calibration after a period of time; after the acquisition is completed, save and record the torque values ​​of the standard torque sensor and the torque sensor under test; The indication error of the indexing torque calibration is calculated according to formula (4): Where: E Mi is the indication error of the indexing torque, M 1i is the average indication of the indexing torque at the ith calibration point, M 0i is the standard value of the indexing torque at the ith calibration point.

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