Calibration device and calibration method for a torque sensor

Abstract

The present disclosure provides a kind of calibration device and calibration method of torque sensor, belong to sensor calibration field.The device includes: calibration arm, leveling module, force module and control module.The symmetrical center of calibration arm has mounting hole, and the first coupling is located in the mounting hole and is interference fit with calibration arm;Leveling module includes at least two micrometers, at least two micrometers are symmetrically located on the two sides of the symmetrical center of calibration arm, and are connected with the middle part of calibration arm, at least two micrometers are used to determine whether calibration arm is leveled;Force module is connected with the two ends of calibration arm respectively, and is connected with force module;Control module is electrically connected with torque sensor.The torque sensor calibration device in the embodiment of the present disclosure can calibrate the torque sensor without disassembling the torque sensor in the electric drive assembly.

Description

Technical Field

[0001] This disclosure relates to the field of sensor calibration, and in particular to a calibration device and calibration method for a torque sensor. Background Technology

[0002] The electric drive assembly test bench is used to test relevant parameters of a vehicle's electric drive assembly, such as its computational mechanical power and efficiency. When calculating mechanical power and efficiency, the output torque of the electric drive assembly must first be measured. In the electric drive assembly test bench, the input shaft of the torque sensor is connected to the electric drive assembly to measure its output torque. However, during use, the measurement accuracy of the torque sensor gradually decreases, requiring periodic calibration to maintain its accuracy.

[0003] In related technologies, the calibration device for a torque sensor includes: a test bench, a fixing device, a lever arm, and weights. The fixing device is located on the test bench and is used to fix the torque sensor to be calibrated. The lever arm is fixed to the output shaft of the torque sensor, and the torque sensor is calibrated by adding or removing weights from the lever arm.

[0004] However, if the aforementioned calibration device is used to calibrate the torque sensor in the electric drive assembly test bench, the torque sensor needs to be removed from the test bench first, and then calibrated on the test bench. Calibration devices that remove the torque sensor before calibration are removed from the sensor's operating environment, leading to errors in the calibration results, and the measurement accuracy of the torque sensor cannot be guaranteed. Summary of the Invention

[0005] This disclosure provides a calibration device and method for a torque sensor, capable of calibrating a torque sensor located in an electric drive assembly test bench. The technical solution includes at least the following:

[0006] On one hand, an apparatus is provided for calibrating a torque sensor mounted in an electric drive assembly test bench, the test bench including an electric drive assembly connected to the input shaft of the torque sensor via a first coupling. The calibration apparatus for the torque sensor includes: a calibration arm, a leveling module, a force application module, a force measuring module, and a control module. The calibration arm has a mounting hole at its center of symmetry, and the first coupling is located in the mounting hole and is interference-fitted with the calibration arm. The leveling module includes at least two dial indicators symmetrically located on either side of the center of symmetry of the calibration arm and interference-fitted with the input shaft of the torque sensor. The calibration lever arm is connected at its middle section, and the at least two dial indicators are used to determine whether the calibration lever arm is leveled. The force measuring module is connected to both ends of the calibration lever arm and to the force applying module. The force measuring module is used to measure the tension applied by the force applying module to the calibration lever arm. The control module is electrically connected to the torque sensor. The control module is used to calibrate the torque sensor according to a first torque and a target torque. The first torque is the torque output by the torque sensor when the tension applied by the force applying module to the calibration lever arm is the target tension. The target tension is determined according to the target torque and the lever arm of the calibration lever arm.

[0007] Optionally, the line connecting the at least two dial indicators is in the same plane as the calibration arm, and the line connecting the heads of the at least two dial indicators is parallel to the horizontal plane.

[0008] Optionally, the force-applying module includes an electrically controlled force-applying device, the control terminal of which is electrically connected to the control module; the control module is configured to control the electrically controlled force-applying device to apply a pulling force to the calibrated lever arm.

[0009] Optionally, the force-applying module further includes weights and a weight tray, the weight tray being connected to the bottom of the electronically controlled force-applying device.

[0010] Optionally, the calibration device for the torque sensor further includes: a support module, the support module comprising a first bearing, a first bearing housing, a second bearing, and a second bearing housing; the first bearing is coaxially connected to the first coupling and located at one axial end of the first coupling, the first bearing is mounted in the first bearing housing, and the base of the first bearing housing is fixed on the electric drive assembly frame; the second bearing is coaxially connected to the first coupling and located at the other axial end of the first coupling, the second bearing is mounted in the second bearing housing, and the base of the second bearing housing is fixed on the electric drive assembly frame, and the calibration lever arm is located between the first bearing housing and the second bearing housing.

[0011] Optionally, the electric drive assembly test bench further includes a dynamometer, the output shaft of the torque sensor is connected to the dynamometer via a second coupling, and the calibration device for the torque sensor further includes a locking device connected to the second coupling for circumferentially locking the second coupling.

[0012] Optionally, the calibration device for the torque sensor further includes a display module, which is electrically connected to the control module and the force measuring module, respectively. The display module is used to display the target tensile force, the target torque, and the tensile force measured by the force measuring module.

[0013] On the other hand, a calibration method for a torque sensor is provided, which is implemented using the torque sensor calibration device described in the above embodiments. The method includes: leveling the calibration lever arm; applying a target tension to the calibration lever arm, the target tension being determined based on a target torque and the lever arm of the calibration lever arm; obtaining a first torque output by the torque sensor, the first torque being the torque output by the torque sensor when the tension applied to the calibration lever arm by the force application module is the target tension; and calibrating the torque sensor based on the target torque and the first torque.

[0014] Optionally, leveling the calibration arm includes: obtaining the readings of the at least two dial indicators, wherein the line connecting the at least two dial indicators is in the same plane as the calibration arm, and the line connecting the heads of the at least two dial indicators is parallel to the horizontal plane; adjusting the calibration arm until the readings of the at least two dial indicators are the same.

[0015] Optionally, calibrating the torque sensor based on the target torque and the first torque includes: determining an absolute error based on the difference between the target torque and the first torque; determining an actual relative error based on the target torque and the absolute error; determining an indication relative error based on the first torque and the absolute error; and calibrating the torque sensor by compensating its output value based on the absolute error when at least one of the actual relative error, the indication relative error, and the absolute error does not meet the accuracy level requirements of the torque sensor.

[0016] The beneficial effects of the embodiments disclosed herein include at least the following:

[0017] In this embodiment, since the input shaft of the torque sensor located in the electric drive assembly test bench is connected to the electric drive assembly via a first coupling, and the calibration arm is mounted on the first coupling, the torque sensor can be calibrated without removing it from the electric drive assembly when using the torque sensor calibration device. During calibration, the torque sensor and the electric drive assembly are considered as a whole, effectively reducing the possibility of errors in calibration results caused by removing the torque sensor from the electric drive assembly test bench.

[0018] Furthermore, since a leveling module with at least two dial indicators is used to level the calibration lever arm, and dial indicators have high precision, using dial indicators for leveling can improve the leveling accuracy, thereby improving the accuracy of the calibration results. In addition, compared with high-priced horizontal direction sensors, dial indicators have a lower cost, which can effectively reduce calibration costs. Attached Figure Description

[0019] Figure 1 A schematic diagram illustrating an application scenario of a torque sensor calibration device provided in an exemplary embodiment of this disclosure is shown.

[0020] Figure 2 A schematic diagram of the structure of a calibration device for a torque sensor provided in an exemplary embodiment of the present disclosure is shown;

[0021] Figure 3 It shows Figure 2 Cross-sectional view in the AA direction;

[0022] Figure 4 A schematic diagram of the structure of a calibration device for a torque sensor provided in another exemplary embodiment of this disclosure is shown;

[0023] Figure 5 It shows Figure 4 Cross-sectional view in the BB direction;

[0024] Figure 6 A flowchart illustrating a calibration method for a torque sensor provided in an exemplary embodiment of this disclosure is shown. Detailed Implementation

[0025] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0026] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0027] Figure 1 A schematic diagram illustrating an application scenario of the torque sensor calibration apparatus provided in an exemplary embodiment of this disclosure is shown. See also Figure 1 The calibration device for the torque sensor is used to calibrate the torque sensor 101 installed in the electric drive assembly bench 10.

[0028] The electric drive assembly test bench 10 generally includes a measurement module 11 and a test module 12. The measurement module 11 includes a torque sensor 101, a dynamometer 102, a voltage / current sensor, a vibration acceleration sensor, a data acquisition module, and a computer 103. The data output terminals of the voltage / current sensor, vibration acceleration sensor, and torque sensor 101 are electrically connected to the data acquisition module. The data acquisition module is used to convert the output data of the voltage / current sensor, vibration acceleration sensor, and torque sensor 101 and send them to the computer.

[0029] The module under test 12 is an electric drive assembly, which includes a DC power supply, an inverter, a motor, a gearbox, and a motor controller connected in sequence to the inverter. In the measurement module 11, a voltage / current sensor is used to measure the current or voltage between the motor and the inverter. A vibration acceleration sensor is connected to the motor to measure the motor's vibration acceleration. The input shaft of the torque sensor 101 is connected to the gearbox, and the output shaft is connected to a dynamometer to measure the output torque of the electric drive assembly. The dynamometer is used to simulate the actual working environment of the electric drive assembly, acting as a load.

[0030] During the operation of the electric drive assembly test bench 10, the torque sensor 101 may experience a decrease in measurement accuracy due to prolonged use. Therefore, it is necessary to periodically calibrate the torque sensor 101 in the electric drive assembly test bench 10. The common method is to remove the torque sensor 101 from the electric drive assembly test bench 10 for calibration. However, the torque sensor 101 is connected to both the module under test 12 and the dynamometer in the electric drive assembly test bench 10. If it is removed from the electric drive assembly test bench 10 for separate calibration, it is out of the working environment of the torque sensor 101, resulting in inaccurate calibration results (for example, factors such as resistance and friction may exist during separate calibration, leading to errors in the calibration results).

[0031] The calibration device for torque sensor 101 provided in this embodiment can calibrate torque sensor 101 when it is on electric drive assembly stand 10, without having to remove torque sensor 101 for calibration. During calibration, torque sensor 101 and electric drive assembly 12 can be regarded as a whole, thereby improving the calibration accuracy of torque sensor 101.

[0032] Figure 2 A schematic diagram of the structure of a calibration device for a torque sensor provided in an exemplary embodiment of this disclosure is shown. Figure 3 yes Figure 2 For the cross-sectional view in the AA direction, see [reference needed]. Figure 2 and Figure 3 The calibration device for the torque sensor includes: a calibration lever arm 21, a leveling module 22, a force application module 23, a force measurement module 24, and a control module 27.

[0033] The torque sensor 101 is located on the electric drive assembly stand 10, and the input shaft of the torque sensor 101 is connected to the output shaft of the electric drive assembly 12. In this embodiment, the input shaft of the torque sensor 101 and the output shaft of the electric drive assembly 12 are connected by a first coupling 29.

[0034] Optionally, the first coupling 29 can be a flexible coupling, such as a flexible pin coupling, a flexible sleeve pin coupling, a flexible sleeve pin gear coupling, etc.

[0035] Optionally, in the axial direction of the flexible coupling, the first end of the flexible coupling is connected to the output shaft of the electric drive assembly 12, and the second end of the flexible coupling is connected to the input shaft of the torque sensor 101. An elastic medium exists between the first and second ends of the flexible coupling, and the first end, the second end, and the elastic medium are connected by bolts or pins, thereby connecting the first device and the second device. The first and second ends of the flexible coupling are two axially opposite ends of the flexible coupling.

[0036] like Figure 3 As shown, the calibration lever arm 21 has a mounting hole 21b at the center of symmetry 21a, and the first coupling 29 is located in the mounting hole 21b and is interference-fitted with the calibration lever arm 21.

[0037] Alternatively, the calibration lever arm 21 can be as follows: Figure 3 The calibration arm 21 can be a rhomboid lever arm; or, the calibration arm 21 can be a straight lever arm. When a tension force is applied to the rhomboid calibration arm 21 or the straight lever arm 21, the tension force on the calibration arm 21 can be evenly distributed on the lever arm, resulting in a better calibration effect.

[0038] Optionally, the mounting hole 21b is circular, and the inner diameter of the mounting hole 21b is the same as or slightly smaller than the outer diameter of the first coupling 29. In this way, when the first coupling 29 is located in the mounting hole 21b, the calibration lever arm 21 can be interference-fitted with the first coupling 29.

[0039] Optionally, the calibration arm 21 includes an upper part and a lower part, which are connected by bolts. The connection points of the upper and lower parts each have partial mounting holes 21b. When the upper and lower parts are connected by bolts, the mounting holes 21b of the upper and lower parts can be combined to form a complete mounting hole 21b. When the bolts are slightly loosened, the calibration arm 21 and the first coupling 29 become a clearance fit, thus facilitating subsequent leveling of the calibration arm 21.

[0040] Optionally, the calibration arm 21 may include a left and a right portion, which are connected by bolts. The connection points of the left and right portions each have partial mounting holes 21b. When the left and right portions are connected by bolts, the mounting holes 21b of the left and right portions can be combined to form a complete mounting hole 21b. Similarly, when the bolts are slightly loosened, the calibration arm 21 and the first coupling 29 become a clearance fit, thus facilitating subsequent leveling of the calibration arm 21.

[0041] Optionally, the calibration lever 21 is installed on the axial side of the first coupling 29 near the input shaft of the torque sensor 101. This reduces the torque transmission distance when the calibration lever 21 applies torque to the torque sensor 101. With a reduced torque transmission distance, the error that may occur during torque transmission is reduced, thus ensuring that the torque received by the torque sensor 101 is the torque applied to the torque sensor 101 by the calibration lever 21, thereby improving the accuracy of the measurement results.

[0042] Optionally, the calibration lever 21 is mounted axially on one end of the first coupling 29 near the input shaft of the torque sensor.

[0043] For example, when the first coupling 29 is a flexible coupling, the calibration lever arm 21 is installed on the second end of the flexible coupling. Since the second end of the flexible coupling is connected to the torque sensor 101, the calibration lever arm 21 being installed on the second end of the flexible coupling is equivalent to the calibration lever arm 21 being installed on the end of the first coupling 29 near the input shaft of the torque sensor 101.

[0044] In some embodiments, when the first coupling 29 is a flexible coupling, the connection between the first end and the second end of the first coupling 29 can be disconnected before calibration, so that the input shaft of the torque sensor 101 is no longer connected to the electric drive assembly 12. This can be achieved by simply removing the pin or bolt between the first and second ends of the flexible coupling.

[0045] During calibration, when the calibration lever 21 drives the input shaft of the torque sensor 101 to rotate, the presence of the first coupling 29 causes the output shaft of the electric drive assembly 12 to rotate as well. However, there may be resistance when the output shaft of the electric drive assembly 12 rotates (for example, resistance when lubrication fails), which can lead to errors in the torque ultimately applied to the first coupling 29, affecting the accuracy of the calibration results. Disconnecting the first and second ends of the first coupling 29 before calibration can reduce the impact of this situation and further improve the calibration accuracy.

[0046] Leveling module 22 includes at least two dial gauges, for example Figure 3 The first dial indicator 22a and the second dial indicator 22b are located symmetrically on both sides of the center of symmetry 21a of the calibration lever arm 21 and connected to the middle of the calibration lever arm 21. At least two dial indicators are used to determine whether the calibration lever arm 21 is level.

[0047] Optionally, at least two dial indicators are on the same plane as the calibration arm 21, and the line connecting the heads of the at least two dial indicators is parallel to the horizontal plane. The first dial indicator 22a and the second dial indicator 22b are fixed above or below the calibration arm 21, respectively. The leveling module 22 is configured to determine that the calibration arm 21 is level when the readings of at least two dial indicators are the same.

[0048] The following describes the process of leveling the calibration lever arm 21 using the first dial indicator 22a and the second dial indicator 22b.

[0049] Step 1: Fix the dial indicator heads of the first dial indicator 22a and the second dial indicator 22b onto the leveling bracket.

[0050] The leveling bracket includes a first straight rod, a second straight rod, and a third straight rod. The first straight rod is perpendicular to the horizontal plane and coplanar with the axis of the first coupling 29; the second straight rod is perpendicularly connected to the first straight rod and parallel to the axis of the first coupling 29; the third straight rod is perpendicular to the second straight rod and parallel to the horizontal plane. The dial indicators 22a and 22b are respectively fixed to the two ends of the third straight rod of the leveling bracket.

[0051] Optionally, in the leveling bracket, the base of the first straight rod is fixed on the frame of the electric drive assembly frame 10. The second straight rod is connected to the first straight rod by bolts, and the connection position between the second straight rod and the first straight rod can be adjusted axially along the first straight rod, that is, the second straight rod can be moved axially along the first straight rod. For example, the connection position between the second straight rod and the first straight rod can be adjusted axially along the first straight rod by loosening the bolts. Since the second straight rod is connected to the third straight rod, adjusting the connection position between the second straight rod and the first straight rod axially is equivalent to translating the third straight rod axially along the first straight rod.

[0052] The second step is to move the second straight rod axially along the first straight rod until at least one of the first dial indicator 22a and the second dial indicator 22b contacts the middle of the calibration lever arm 21.

[0053] Taking the first dial indicator 22a contacting the left side of the calibration arm 21 as an example, after the first dial indicator 22a contacts the left side of the calibration arm 21, adjust the screw measuring head of the second dial indicator so that the screw measuring head of the second dial indicator contacts the right side of the calibration arm 21. At this time, observe the readings of the first dial indicator 22a and the second dial indicator 22b. If the readings of the first dial indicator 22a and the second dial indicator 22b are not equal, adjust the calibration arm 21, and then repeat the second step until the readings of the first dial indicator 22a and the second dial indicator 22b are the same.

[0054] Since dial indicators have high measurement accuracy, at the 0.001mm level, by setting at least two symmetrically placed dial indicators in the leveling module 22, the calibration lever arm 21 can be accurately leveled, preventing errors in subsequent calibration results caused by unevenness of the calibration lever arm 21.

[0055] In some examples, the leveling module 22 includes four dial indicators, which are symmetrically located on either side of the center of symmetry 21a of the calibration arm 21 and connected to the middle of the calibration arm 21. Among the four dial indicators, the first dial indicator 22a is symmetrical to the second dial indicator 22b, and the third dial indicator is symmetrical to the fourth dial indicator (not shown). In this case, the leveling module 22 is configured to determine that the calibration arm 21 is level when the readings of the first dial indicator 22a and the second dial indicator 22b are the same, and the readings of the third dial indicator and the fourth dial indicator are the same.

[0056] Using four dial indicators to level the calibration lever 21 can further improve the accuracy of leveling, ensure that the calibration lever 21 is in a horizontal state, and thus further improve the accuracy of subsequent calibration results.

[0057] Optionally, the force-applying module 23 includes an electrically controlled force-applying device, the control terminal of which is electrically connected to the control module 27. The control module is configured to control the electrically controlled force-applying device to apply a pulling force to the calibration lever arm 21.

[0058] Optionally, the force-applying module 23 also includes weights and a weight tray, with the weight tray located at the bottom of the electronically controlled force-applying device. The weights are used to increase the tension applied by the electronically controlled force-applying device to the calibration force arm 21 via the weight tray when the tension applied by the electronically controlled force-applying device to the calibration force arm 21 reaches the tension boundary. The tension boundary is used to indicate the maximum tension that the force-applying module can apply.

[0059] By using weights and a weight tray, when the tension of the electronically controlled force-applying device reaches the tension boundary, the tension applied by the force-applying module 23 to the calibration force arm 21 can be further increased, so that the tension applied by the force-applying module 23 to the calibration force arm 21 can be further increased.

[0060] Optionally, the electrically controlled force-applying device can be any one of an electric telescopic rod, a hydraulic cylinder, or a pneumatic telescopic rod. The following description uses a hydraulic cylinder as the electrically controlled force-applying device.

[0061] The top of the hydraulic cylinder is the liquid outlet, and the bottom is the liquid inlet; or, the top of the hydraulic cylinder is the liquid inlet, and the bottom is the liquid outlet. The hydraulic system is connected to the liquid inlet and liquid outlet of the hydraulic cylinder respectively. The control module 27 can control the opening of the corresponding valves in the hydraulic system (e.g., valves that supply liquid to the hydraulic cylinder) through electrical signals, thereby increasing or decreasing the liquid content in the hydraulic cylinder, controlling the pressure on the hydraulic cylinder, and thus controlling the pulling force applied by the hydraulic cylinder to the calibration arm 21.

[0062] like Figure 3 As shown, the force measuring module 24 is connected to both ends of the calibration lever arm 21 and to the force application module 23. The force measuring module 24 is used to measure the tension applied by the force application module 23 to the calibration lever arm 21.

[0063] Optionally, the bottom of the force measuring module 24 is the measuring end of the force measuring module 24, so that the force measuring module 24 can measure the tension applied by the force applying module 23 to the calibration lever arm 21.

[0064] For example, the upper part of the force measuring module 24 can be fixed to the two ends of the calibration lever arm 21 by bolts.

[0065] In this embodiment of the disclosure, when installing the calibration device for the torque sensor, it is necessary to first install the force measuring module 24 on the calibration lever arm 21, and then install the force application module 23 on the lower part of the force measuring module 24.

[0066] Alternatively, the force measuring module 24 can be installed on top of the force-applying module 23 first, and then the force measuring module 24 can be installed on the calibration lever arm 21.

[0067] Optionally, the force measuring module 24 is a tension sensor. In this embodiment, after the calibration arm 21 is leveled and the force application module 23 is installed on the calibration arm 21, the values ​​output by the tension sensors at both ends of the calibration arm 21 should be equal. If the values ​​output by the tension sensors are not equal at this time, the calibration arm 21 needs to be readjusted.

[0068] Optionally, when the values ​​of the tension sensors at both ends of the calibration lever 21 are equal, the two tension sensors can be zeroed so that when the subsequent force application module 23 applies a tension to the calibration lever 21, the value measured by the tension sensor is the value of the tension applied by the force application module 23 to the calibration lever 21.

[0069] Alternatively, instead of zeroing the two force sensors, the initial values ​​of the two force sensors can be recorded. In this way, when the force application module 23 applies a force to the calibration arm 21, the value measured by the force sensor minus the initial value of the force sensor is the value of the force applied by the force application module 23 to the calibration arm 21.

[0070] Optionally, the data output terminal of the force measuring module 24 is electrically connected to the control module 27 to send the measured tension applied by the force applying module 23 to the calibration lever arm 21 to the control module 27.

[0071] In one possible implementation, after leveling the calibration lever arm 21 using the leveling module 22, force measuring modules 24 are then installed at both ends of the calibration lever arm 21. Initially, the two force measuring modules 24 are identical; therefore, installing the force measuring modules 24 on the calibration lever arm 21 after leveling it will not affect the balance of the calibration lever arm 21.

[0072] In another possible implementation, the force measuring module 24 is first connected to the calibration arm 21, and then the calibration arm 21 is leveled by the leveling module 22 to level the calibration arm 21 more accurately.

[0073] The control module 27 is electrically connected to the torque sensor 101. The control module 27 is used to calibrate the torque sensor 101 according to the first torque and the target torque. The first torque is the torque output by the torque sensor 101 when the tension applied by the force application module 23 to the calibration lever arm 21 is the target tension. The target tension is determined according to the target torque and the lever arm of the calibration lever arm 21.

[0074] The target torque can be a user-defined torque value, and the lever arm of the calibration lever arm 21 is the distance between one end of the calibration lever arm 21 and the center of symmetry 21a. Determining the target tension based on the target torque and the lever arm of the calibration lever arm 21 includes dividing the target torque by the lever arm of the calibration lever arm 21 to obtain the target tension.

[0075] Optionally, the control module 27 may include, but is not limited to, a microcontroller unit (MCU), a CPU (Central Processing Unit), or an integrated logic circuit capable of performing control functions.

[0076] Optionally, the control module 27 is also connected to the control terminal of the electronically controlled force-applying device, thereby enabling the electronically controlled force-applying device to apply a target pulling force to the calibration lever arm 21.

[0077] When the electrically controlled force-applying device is a hydraulic cylinder, the control module 27 is connected to the control terminal of the electrically controlled force-applying device, which is connected to the control terminal of the hydraulic system. The control module 27 can control the opening of the valve in the hydraulic system through electrical signals, thereby controlling the electrically controlled force-applying device to output the target pulling force to the calibration arm 21.

[0078] Optionally, the control module 27 can calibrate the torque sensor 101 in the following manner: First, the control module 27 determines the absolute error based on the difference between the target torque and the first torque; then, it determines the actual relative error based on the target torque and the absolute error; it determines the indicated relative error based on the first torque and the absolute error; finally, it determines the range of values ​​for the actual relative error, the indicated relative error, and the absolute error based on the accuracy level of the torque sensor 101. If at least one of the actual relative error, the indicated relative error, and the absolute error does not meet the accuracy level requirements of the torque sensor 101, it indicates that the torque sensor 101 is unusable. When the torque sensor 101 is unusable, the output value of the torque sensor 101 is compensated based on the absolute error to calibrate the torque sensor 101.

[0079] Optionally, if the actual relative error, the indicated relative error, and the absolute error all meet the accuracy class requirements of the torque sensor, then the torque sensor 101 is considered usable. When the torque sensor 101 is usable, there is no need to calibrate it, and it can continue to be used.

[0080] The formulas for calculating the absolute error, the indicated relative error, and the actual relative error are shown in Table 1 below.

[0081] Table 1: Formulas for calculating absolute error, indicated relative error, and actual relative error

[0082]

[0083] Where Δ is the absolute error, γ X γ represents the relative error of the indicated value. A For the actual relative error, A X A0 is the target torque, and A0 is the first torque.

[0084] The accuracy class of the torque sensor 101 is determined based on its actual model; for example, the accuracy can be obtained from the label on the housing of the torque sensor 101. Different accuracy classes correspond to different actual relative errors γ. A and the relative error of the indicated value γ X The accuracy requirements are as follows: 0.1, 0.2, 0.5, 1.0, 1.5, 2.0, 2.5, and 5, etc. For the torque sensor 101 in the electric drive assembly test bench 10, the accuracy requirement is relatively high, generally around 0.2 to 1.0. For example, it can be 0.2 to 0.5.

[0085] The following explanation uses the torque sensor 101 with an accuracy class of 0.2 as an example.

[0086] When the accuracy class is 0.2, the absolute value of the absolute error of the torque sensor 101 should be less than or equal to 0.2% * maximum range U. The maximum range U is the maximum range of the torque sensor 101, which can be obtained from the label on the housing of the torque sensor 101.

[0087] When the accuracy class is 0.2, the relative error γ of the indicated value of torque sensor 101 is required. x The absolute value should be less than or equal to (0.2*U) / A x Actual relative error γ A The absolute value should be less than or equal to (0.2*U) / A0.

[0088] For torque sensors 101 with other accuracy levels, simply replace 0.2 in the aforementioned range with the corresponding accuracy level to determine the requirements for the absolute error, indicated relative error, and actual relative error of the torque sensor 101 at that accuracy level.

[0089] Optionally, calibrating the torque sensor 101 based on the output value of the torque sensor 101 with absolute error compensation includes: modifying the correspondence between the electrical signal output by the torque sensor 101 and the torque value, so that the torque value corresponding to the electrical signal output by the torque sensor 101 under the target torque is compensated from the first torque to the first torque plus the absolute error, thereby calibrating the torque sensor 101.

[0090] The torque value corresponding to the electrical signal output by the torque sensor 101 under the target torque is compensated from the first torque to the first torque plus the absolute error. At this time, the output value of the torque sensor 101 is equal to the target torque, which is the torque actually applied to the torque sensor 101, so that the unusable torque sensor 101 can be accurately calibrated.

[0091] Optionally, N different target tensions can be applied sequentially to the torque sensor 101 to obtain multiple different target torques and multiple different first torques. Here, N is a positive integer, and the value of N can range from 2 to 20, etc.

[0092] Optionally, when applying N different target tensions, the N different target tensions gradually increase. Alternatively, N different target torques can be calculated by applying N different target tensions, and these N target torques are taken at equal intervals within the range of the torque sensor 101.

[0093] For example, when N equals 5, that is, five different target tensions are applied to the torque sensor 101, and the target torques calculated from these five different target tensions are taken at equal intervals within the range of the torque sensor 101. Assuming the range of the torque sensor 101 is 0 to 2000 N*m, and the lever arm of the calibration lever arm 21 is 1 m, then the target tensions are 400 N, 800 N, 1200 N, 1600 N, and 2000 N, respectively, and the corresponding calculated target torques are 400 N*m, 800 N*m, 1200 N*m, 1600 N*m, and 2000 N*m, respectively.

[0094] Then, calculate the absolute error, indicated relative error, and actual relative error between the target torque and the first torque under each target tension, and take the average of each absolute error, indicated relative error, and actual relative error.

[0095] Finally, based on the average of the actual relative error, the average of the indicated relative error, the average of the absolute error, and the accuracy class of the torque sensor 101, it is determined whether the torque sensor 101 is usable; and if the torque sensor 101 is unusable, the average of the absolute error is used to calibrate the torque sensor 101. In this way, by taking the average of multiple measurements, the influence of random errors on the calibration results can be avoided, further improving the accuracy of the calibration results.

[0096] Optionally, the control module 27 is also used to calculate the sensitivity of the torque sensor 101 based on the target torque and the first torque.

[0097] For example, the sensitivity of torque sensor 101 is calculated using formula (1).

[0098]

[0099] Where Δy is the output change and Δx is the input change, the input being the target torque A. x The output is the first torque A0, and the output change is the difference between two adjacent first torques A0 output by the torque sensor 101. The input change is the difference between two adjacent target torques A0 corresponding to these two first torques A0. x The difference between them.

[0100] Optionally, such as Figure 3 As shown, the electric drive assembly test bench 10 also includes a base plate 13, and the various components in the electric drive assembly test bench 10 (including the measurement module 11 and the electric drive assembly 12) are fixed to the base plate 13 of the electric drive assembly test bench 10 through T-slots.

[0101] In this configuration, the electric drive assembly stand 10 also includes a first fixed bracket and a second fixed bracket. The electric drive assembly 12 is mounted on the first fixed bracket, and the torque sensor 101 is mounted on the second fixed bracket. The base of the first and second fixed brackets includes a protrusion with a T-shaped cross-section in the AA direction, and the base plate 13 has a T-shaped groove corresponding to the T-shaped protrusion at the mounting positions of the first and second fixed brackets, respectively.

[0102] The T-slots allow for the fixing of each module onto the base plate 13 of the electric drive assembly stand 10, providing a good fixing effect and facilitating easy assembly and disassembly.

[0103] In this embodiment, since the input shaft of the torque sensor 101 located in the electric drive assembly test bench 10 is connected to the electric drive assembly 12 via a first coupling 29, and the calibration arm 21 is mounted on the first coupling 29, the torque sensor 101 can be calibrated without removing it from the electric drive assembly when using the torque sensor calibration device. By treating the torque sensor 101 and the electric drive assembly 12 as a single unit during calibration, errors in the calibration results caused by removing the torque sensor 101 from the electric drive assembly test bench 10 are effectively reduced.

[0104] Furthermore, a leveling module 22 with at least two dial indicators is used to level the calibration arm 21. Since dial indicators have high precision, using dial indicators for leveling can improve the leveling accuracy and thus improve the accuracy of the calibration results. In addition, compared with high-priced horizontal direction sensors, dial indicators have a lower cost, which can effectively reduce calibration costs.

[0105] Figure 4 A schematic diagram of the structure of a calibration device for a torque sensor provided in another exemplary embodiment of this disclosure is shown. Figure 5 for Figure 4 Cross-sectional view in the BB direction. See also Figure 4 The calibration device for the torque sensor includes a calibration lever 21, a leveling module 22, a force application module 23, a force measuring module 24, a support module 25, a locking device 26, a control module 27, and a display module 28.

[0106] In this embodiment of the disclosure, the input shaft of the torque sensor 101 is connected to the electric drive assembly 12 via a first coupling 29; the output shaft of the torque sensor 101 is connected to the dynamometer 102 via a second coupling 210.

[0107] Figure 4 In the middle, the support module 25 includes: a first bearing, a first bearing housing 25a, a second bearing and a second bearing housing 25b.

[0108] Optionally, the first bearing and the second bearing can be ball bearings.

[0109] The first bearing is coaxially connected to the first coupling 29 and located at one axial end of the first coupling 29. The first bearing is installed in the first bearing housing 25a, and the base of the first bearing housing 25a is fixed on the electric drive assembly frame 10. The second bearing is coaxially connected to the first coupling 29 and located at the other axial end of the first coupling 29. The second bearing is installed in the second bearing housing 25b, and the base of the second bearing housing 25b is fixed on the electric drive assembly frame 10. The calibration lever arm 21 is located between the first bearing housing 25a and the second bearing housing 25b.

[0110] Optionally, such as Figure 5 As shown, the base of the first bearing housing 25a and the second bearing housing 25b includes a protrusion with a T-shaped cross-section in the BB direction, and the base plate 13 has a T-shaped groove corresponding to the T-shaped protrusion at the mounting position of the first bearing housing 25a and the second bearing housing 25b, respectively.

[0111] In this way, the bases of the first bearing housing 25a and the second bearing housing 25b can be fixed to the base plate 13 of the electric drive assembly frame 10 through the T-slot, which has a good fixing effect and is easy to disassemble and assemble.

[0112] The support module 25 can support the first coupling 29 during calibration, effectively reducing the phenomenon that the output shaft of the electric drive assembly 12 and the input shaft of the torque sensor 101 are not on the same straight line due to the force applied to the first coupling 29 by the calibration lever 21 during the calibration process, thereby improving the accuracy of the calibration results.

[0113] Optionally, the calibration device for the torque sensor also includes a locking device 26. The locking device 26 is connected to the second coupling 210 and is used to circumferentially lock the second coupling 210.

[0114] Optionally, such as Figure 5 As shown, the base of the locking device 26 includes a protrusion with a T-shaped cross-section in the BB direction, and the base plate 13 has a T-shaped groove corresponding to the T-shaped protrusion at the mounting position of the locking device 26.

[0115] In this way, the locking device 26 can be fixed to the base plate of the electric drive assembly frame via the T-slot.

[0116] Optionally, the locking device 26 can be connected to the second coupling 210 via a key or spline to achieve circumferential locking of the second coupling 210. Circumferential locking of the second coupling 210 via a key or spline provides a good locking effect.

[0117] For example, such as Figure 5 As shown, the locking device 26 is connected to the second coupling 210 via a spline.

[0118] Alternatively, the locking device 26 can be press-fitted with the second coupling 210 to achieve circumferential locking of the second coupling 210. The locking device 26 can also effectively secure the second coupling 210 by press-fitting and circumferentially locking the second coupling 210.

[0119] Alternatively, the locking device 26 and the second coupling 210 can be connected by a flat key with an interference fit to achieve circumferential locking of the second coupling 210. By combining the flat key with the interference fit, the locking device 26 can achieve circumferential locking of the second coupling 210, thereby further enhancing the locking effect.

[0120] By locking the second coupling 210 circumferentially with the locking device 26, the output shaft of the torque sensor 101 is fixed, which can effectively avoid measurement errors caused by relative sliding between the input shaft and the output shaft of the torque sensor 101, and further improve the accuracy of the calibration results.

[0121] Optionally, a display module 28 is also included. The display module 28 is electrically connected to the control module 27 and the force measuring module 24, respectively, and is used to display the target tension, the first torque, and the actual tension measured by the force measuring module 24.

[0122] For example, the display module 28 may be a display, such as a computer screen or a mobile phone screen, or other devices with display functions.

[0123] Optionally, the display module 28 can be integrated with the control module 27 in a single device, for example, integrated into a... Figure 1 The computer 103 in the electric drive assembly bench 10 shown saves on the implementation cost of the torque sensor calibration device.

[0124] The following are method embodiments of this application. For details not described in detail in the method embodiments, please refer to the above device embodiments.

[0125] Figure 6 A flowchart illustrating a calibration method for a torque sensor provided in an exemplary embodiment of this disclosure is shown. This calibration method is implemented based on the aforementioned torque sensor calibration apparatus. See also... Figure 6 The method includes:

[0126] In step 601, the calibrated lever arm is obtained.

[0127] The lever arm of the calibration lever arm is the distance between one end of the calibration lever arm and the center of symmetry.

[0128] In step 602, the calibration lever arm is leveled.

[0129] Optionally, step 602 includes the following two steps:

[0130] The first step is to obtain the readings of at least two dial indicators.

[0131] Optionally, the line connecting at least two dial indicators is in the same plane as the calibration lever arm and parallel to the horizontal plane.

[0132] For example, at least two dial gauges include a first dial gauge and a second dial gauge, and obtaining the readings of at least two dial gauges can be done by obtaining the readings of the first dial gauge and the second dial gauge, respectively.

[0133] The second step is to adjust the calibration lever arm until at least two micrometer readings are the same.

[0134] In step 603, a target tension is applied to the calibration lever arm.

[0135] The target tensile force is determined based on the lever arm of the calibrated lever arm and the target torque.

[0136] Optionally, the target torque is equal to the tension multiplied by the standard lever arm.

[0137] In step 604, the first torque output by the torque sensor is obtained.

[0138] The first torque is the torque output by the torque sensor when the force applied by the force-applying module to the calibration lever arm is the target force.

[0139] In step 605, the torque sensor is calibrated based on the target torque and the first torque.

[0140] Optionally, step 605 includes the following four steps:

[0141] The first step is to determine the absolute error based on the difference between the target torque and the first torque.

[0142] The second step is to determine the actual relative error based on the target torque and the absolute error.

[0143] The third step is to determine the relative error of the indicated value based on the first torque and the absolute error.

[0144] Fourth step: When at least one of the actual relative error, indicated relative error, and absolute error does not meet the accuracy level requirements of the torque sensor, compensate the output value of the torque sensor according to the absolute error to calibrate the torque sensor.

[0145] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A device for calibrating a torque sensor, characterized in that This is used to calibrate a torque sensor mounted on an electric drive assembly test bench, which includes an electric drive assembly and a dynamometer. The electric drive assembly is connected to the input shaft of the torque sensor via a first coupling, and the output shaft of the torque sensor is connected to the dynamometer via a second coupling. The calibration device for the torque sensor includes: a calibration lever arm, a leveling module, a force application module, a force measuring module, a locking device, and a control module; The calibration lever arm has a mounting hole at its center of symmetry, and the first coupling is located in the mounting hole and is interference-fitted with the calibration lever arm. The leveling module includes at least two dial indicators, which are symmetrically located on both sides of the center of symmetry of the calibration lever arm and connected to the middle of the calibration lever arm. The at least two dial indicators are used to determine whether the calibration lever arm is level. The force-applying module includes an electronically controlled force-applying device, weights, and a weight tray, wherein the weight tray is connected to the bottom of the electronically controlled force-applying device; The force measuring module is connected to both ends of the calibration lever arm and to the force applying module. The force measuring module is used to measure the tension applied by the force applying module to the calibration lever arm. The locking device is connected to the second coupling and is used to circumferentially lock the second coupling. The control module is electrically connected to the control terminal of the electronically controlled force-applying device and the torque sensor, respectively. The control module is used to control the electronically controlled force-applying device to apply a pulling force to the calibration lever arm, and to calibrate the torque sensor according to a first torque and a target torque. The first torque is the torque output by the torque sensor when the pulling force applied by the force-applying module to the calibration lever arm is the target pulling force. The target pulling force is determined according to the target torque and the lever arm of the calibration lever arm.

2. The device for calibrating a torque sensor according to claim 1, characterized in that The line connecting the at least two dial indicators is in the same plane as the calibration arm, and the line connecting the heads of the at least two dial indicators is parallel to the horizontal plane.

3. The device for calibrating a torque sensor according to claim 1 or 2, characterized in that The calibration device for the torque sensor further includes a support module, which comprises a first bearing, a first bearing housing, a second bearing, and a second bearing housing. The first bearing is coaxially connected to the first coupling and is located at one axial end of the first coupling. The first bearing is installed in the first bearing housing, and the base of the first bearing housing is fixed on the electric drive assembly frame. The second bearing is coaxially connected to the first coupling and is located at the other end of the first coupling in the axial direction. The second bearing is installed in the second bearing housing, and the base of the second bearing housing is fixed on the electric drive assembly frame. The calibration lever arm is located between the first bearing housing and the second bearing housing.

4. The device for calibrating a torque sensor according to claim 1 or 2, characterized in that The calibration device for the torque sensor also includes: a display module. The display module is electrically connected to the control module and the force measuring module respectively. The display module is used to display the target tensile force, the target torque and the tensile force measured by the force measuring module.

5. A method of calibrating a torque sensor, characterized by, The calibration device for the torque sensor according to any one of claims 1 to 4 is used, and the method includes: Adjust the calibrated lever arm; A target tension is applied to the calibrated lever arm, the target tension being determined based on the target torque and the lever arm of the calibrated lever arm; The first torque output by the torque sensor is obtained, wherein the first torque is the torque output by the torque sensor when the pulling force applied by the force application module to the calibration lever arm is the target pulling force; The torque sensor is calibrated based on the target torque and the first torque.

6. The method of claim 5, wherein, The leveling of the calibration lever arm includes: Obtain the readings of the at least two dial indicators, wherein the line connecting the at least two dial indicators is in the same plane as the calibration lever arm, and the line connecting the heads of the at least two dial indicators is parallel to the horizontal plane; Adjust the calibration lever arm until the at least two per mille readings are the same.

7. The method of claim 5, wherein, The step of calibrating the torque sensor based on the target torque and the first torque includes: The absolute error is determined based on the difference between the target torque and the first torque; The actual relative error is determined based on the target torque and the absolute error; The relative error of the indicated value is determined based on the first torque and the absolute error; When at least one of the actual relative error, the indicated relative error, and the absolute error fails to meet the accuracy level requirements of the torque sensor, the output value of the torque sensor is compensated according to the absolute error to calibrate the torque sensor.

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