Bidirectional different torque friction brake testing equipment and method

Abstract

The present invention discloses bidirectional, variable-torque friction brake testing equipment and methods, comprising: a reverse drive assembly, a fixture for a test piece, a test assembly, and a forward drive assembly, all mounted axially in sequence on a base plate. The product under test is mounted within the fixture for the test piece via a bearing, the input shaft of the test piece is spline-connected to the input shaft of the fixture for the test piece, and the output shaft of the test piece is spline-connected to the output shaft of the fixture for the test piece. The present invention can be used to test the dynamic and static transmission characteristics and slip torque of the friction brake product under test at room temperature and pressure, as well as the transmission performance and slip torque of the friction brake product under test in thermal or vacuum environments. It can also be used for life testing of the friction brake product under test, among other applications.

Description

Technical Field

[0001] The present invention relates to a testing device and method for a friction brake product, which can be used for slip torque testing of a friction brake product with a slip function. A bidirectional different torque friction brake testing device is specially designed. Background Art

[0002] Brakes, similar to switches, are placed within the transmission chain of mechanical products. They disconnect and connect the drive system between the driver and actuator, ensuring smooth startup and operation of the transmission chain. They also prevent damage to transmission chain components caused by overload during operation. Based on their operating principle, brakes can be divided into various types, including electromagnetic brakes, magnetic powder brakes, friction brakes, hydraulic brakes, and hysteresis brakes.

[0003] With the rapid development of China's aerospace industry, the number of missions for manned spacecraft, cargo spacecraft, space stations, and various satellites continues to increase. Space exploration and testing require the long-term on-orbit operation of space mechanism products. Typical space mechanism products include docking mechanisms, solar panels, and antenna drive mechanisms. Space mechanism products are all precision transmission systems, and the requirements for actuators include: 1. High-precision positioning; 2. Precise control of end-operating force; 3. Long-term adaptability to the thermal vacuum environment of space; 4. Long-term stable and reliable operation; and 5. Reduced energy demand.

[0004] Friction brakes and hysteresis brakes are passive mechanical brakes ideally suited for space applications. They ensure smooth operation, provide overload protection for transmission chains, and precisely control end-of-load force. Therefore, accurate testing of friction and hysteresis brakes in thermal vacuum environments is crucial. Summary of the Invention

[0005] This invention addresses the transmission characteristics of existing friction brakes and the needs of aerospace development by providing bidirectional, variable-torque friction brake testing equipment and methods. These devices can test friction brake products under both normal temperature and pressure conditions, as well as under thermal vacuum conditions. They can be used to test both dynamic transmission characteristics and slip torque, as well as static transmission characteristics and slip torque. This ensures that the brake can precisely control the end-operation force or output torque of a space actuator.

[0006] The technical solution of the present invention is:

[0007] A bidirectional different torque friction brake test device, comprising: a reversing motor, a reversing reducer, a fixing bracket, a mechanical brake, a test piece fixing fixture, a speed torque sensor, a friction clutch, a forward reducer, a forward motor, a base plate, a mounting bracket, a transition bracket, and a sensor bracket;

[0008] The reversing motor, the reversing reducer and the mechanical brake are connected in sequence;

[0009] The housing of the reversing reducer and the housing of the mechanical brake are mounted on a fixed bracket, and the fixed bracket is mounted on the bottom plate;

[0010] The forward motor, the forward reducer and the friction clutch are connected in sequence;

[0011] The housing of the forward speed reducer and the housing of the friction clutch are mounted on a mounting bracket, and the mounting bracket is mounted on a base plate;

[0012] The housing of the speed and torque sensor is mounted on the sensor bracket, and the sensor bracket is mounted on the base plate;

[0013] The rotating shaft at one end of the speed and torque sensor is connected to the output shaft of the fixed fixture of the measured object; the rotating shaft at the other end of the speed and torque sensor is installed on the transition bracket through a bearing and is rigidly connected to the output shaft of the friction clutch, and the transition bracket is installed on the base plate;

[0014] The product under test is installed inside the test piece fixed fixture through a bearing, the input shaft of the test piece is connected to the input shaft of the test piece fixed fixture, and the output shaft of the test piece is connected to the output shaft of the test piece fixed fixture.

[0015] Preferably, it further comprises: a coupling;

[0016] The input shaft of the fixture for fixing the test piece and the output shaft of the mechanical brake are rigidly connected through a coupling;

[0017] The output shaft of the fixture for fixing the workpiece to be tested is rigidly connected to the rotating shaft at one end of the speed and torque sensor through a coupling;

[0018] The rotating shaft at the other end of the speed torque sensor is rigidly connected to the output shaft of the friction clutch through a coupling.

[0019] Preferably, it also includes: an armrest;

[0020] A plurality of handrails are installed on the bottom plate.

[0021] Preferably, the mechanical brake is in a disengaged state when the power is off, which is equivalent to a coupling, transmitting the speed and torque output by the reverse reducer to the fixture of the test piece;

[0022] The mechanical brake is in a braking state when powered on, realizing the disconnection of transmission between the reverse reducer and the fixed fixture of the test piece.

[0023] Preferably, the friction clutch is powered on and in a connected state, which is equivalent to a coupling, transmitting the speed and torque output by the forward reducer to the fixture of the test piece;

[0024] The friction clutch is in a disengaged state when the power is off, realizing the transmission disconnection between the forward reducer and the fixed fixture of the measured part.

[0025] Preferably, the output power of the reverse rotation motor and the forward rotation motor is different.

[0026] A method for testing static transmission characteristics / slip torque:

[0027] The friction clutch remains stationary, and the reverse motor is powered on to output torque, which synchronously drives the reverse reducer, mechanical brake and the DUT fixture to rotate, so that the input shaft of the DUT fixture drives the input shaft of the DUT to rotate;

[0028] The output shaft on the right side of the fixed fixture of the tested part is kept stationary by the friction clutch, so that the output shaft of the tested product is also kept stationary; the relative rotation between the input shaft and the output shaft of the tested part realizes the reverse slip state, and the slip torque is transmitted to the speed torque sensor through the output shaft of the tested part fixture to obtain the actual measured value of the slip torque.

[0029] A method for testing static transmission characteristics / slip torque:

[0030] The reversing motor is in the power-off state, the mechanical brake is in the brake-on state, and the input shaft of the DUT fixing fixture is connected through a coupling to keep the input shaft of the DUT in the brake state;

[0031] The transmission between the speed torque sensor and the forward reducer is disconnected, the forward motor is powered on and rotates, driving the forward reducer to rotate;

[0032] After the forward reducer runs smoothly, the friction clutch is electrically engaged and in the connected state. The output shaft of the DUT is driven to rotate through the speed torque sensor and the output shaft of the DUT fixed fixture. The relative rotation between the input shaft and the output shaft of the DUT achieves a forward slip state. The slip torque is transmitted to the speed torque sensor through the output shaft of the DUT fixture to obtain the actual measured value of the slip torque.

[0033] A method for dynamic transmission characteristics / slip torque testing:

[0034] The forward motor is powered on and kept in braking state; the friction clutch is in disconnected state, isolating the transmission between the speed torque sensor and the forward motor;

[0035] The mechanical brake is in the power-off disengaged state, which is equivalent to the transmission shaft;

[0036] Reverse the motor and turn it on to rotate, and drive the fixed fixture of the tested part and the speed and torque sensor to rotate through the reverse reducer and mechanical brake;

[0037] When the speed stabilizes, the friction clutch is powered on and in the connected state, which is equivalent to the transmission shaft. The braking torque of the forward motor is transmitted to the output shaft of the DUT through the forward reducer, friction clutch, speed torque sensor and the output shaft of the DUT fixed fixture, so that the output shaft of the DUT is in the braking state.

[0038] The input shaft of the test piece is in a rotating state driven by the reversing motor, and the input shaft and output shaft of the test piece are in a slipping state. The slip torque is transmitted to the speed torque sensor through the output shaft of the test piece tooling to obtain the measured value of the slip torque.

[0039] The advantages of the present invention compared with the prior art are:

[0040] The equipment of the present invention can be used for testing both high-speed and low-speed friction brake products. The bidirectional, variable-torque friction brake testing equipment and method of the present invention can test the transmission characteristics and slip torque of various types of friction brake products under both thermal vacuum and normal temperature and pressure environments. It features versatility, diverse functions, high integration, simple structure, high testing accuracy, and stable and reliable system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the structure of a bidirectional different torque friction brake test device of the present invention;

[0042] Figure 2 This is a schematic diagram of a positive slip state of a product under test in one embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of the reverse slipping state of the product under test in one embodiment of the present invention. DETAILED DESCRIPTION

[0044] The structural composition of a bidirectional different torque friction brake testing device of the present invention will be further described below with reference to the accompanying drawings.

[0045] Figure 1 This is a schematic diagram of the structure of a bidirectional, differential-torque friction brake test device according to the present invention, comprising: a reverse motor 1, a reverse reducer 2, a fixing bracket 3, a mechanical brake 4, a coupling 5, a DUT fixing fixture 6, a speed and torque sensor 7, a friction clutch 8, a forward reducer 9, a forward motor 10, a base plate 11, a mounting bracket 12, a transition bracket 13, a sensor bracket 14, and a handrail 15. The friction brake, i.e., the product under test, is mounted in the DUT fixing fixture 6.

[0046] The reversing motor 1, reversing reducer 2, and mechanical brake 4 are connected in sequence and mounted on a fixed bracket 3 to form a reversing drive assembly. The output shaft of the reversing motor 1 is connected to the input shaft of the reversing reducer 2 via a flat key, and the output shaft of the reversing reducer 2 is connected to the input shaft of the mechanical brake 4 via a flat key. The housings of the reversing reducer 2 and the mechanical brake 4 are mounted on the fixed bracket 3, which is mounted on the base plate 11.

[0047] The forward motor 10, forward reducer 9, and friction clutch 8 are connected and mounted on a mounting bracket 12 to form a forward drive assembly. The output shaft of the forward motor 10 is connected to the input shaft of the forward reducer 9 via a flat key. The output shaft of the forward reducer 9 is also connected to the input shaft of the friction clutch 8 via a flat key. The housings of the forward reducer 9 and the friction clutch 8 are mounted on the mounting bracket 12, which is mounted on the base plate 11.

[0048] The speed and torque sensor 7, sensor bracket 14, and transition bracket 13 form the test assembly. The housing of the speed and torque sensor 7 is mounted on the sensor bracket 14, which is in turn mounted on the base plate 11. The rotating shaft at one end of the speed and torque sensor 7 is connected to the output shaft of the test piece fixture 6 via a coupling 5. The rotating shaft at the other end of the speed and torque sensor 7 is mounted on the transition bracket 13 via a bearing and rigidly connected to the output shaft of the friction clutch 8 via the coupling 5. The transition bracket 13 is mounted on the base plate 11.

[0049] The reverse drive assembly, the test piece fixing fixture 6, the test assembly and the forward drive assembly are sequentially mounted on the base plate 11 along the axial direction. The product under test is mounted inside the test piece fixing fixture 6 via a bearing. The input shaft of the test piece is spline-connected to the input shaft of the test piece fixing fixture 6, and the output shaft of the test piece is spline-connected to the output shaft of the test piece fixing fixture 6. The input shaft of the test piece fixing fixture 6 is rigidly connected to the output shaft of the mechanical brake 4 in the reverse drive assembly via a coupling 5, and the output shaft of the test piece fixing fixture 6 is rigidly connected to the rotating shaft at one end of the speed torque sensor 7 in the test assembly via a coupling 5. A total of three couplings 5 ​​are installed in the friction brake test equipment of the embodiment of the present invention. In addition, four armrests 15 are also installed on the base plate 11. The entire set of test equipment of the present invention and the test piece are placed in a thermal environment or a vacuum environment through the four armrests to complete the transmission characteristics and slip torque test of the forward and reverse rotation of the test piece in the thermal environment or thermal vacuum environment.

[0050] When powered off, mechanical brake 4 is disengaged, acting like a coupling. Its input and output shafts remain connected, transmitting the speed and torque of the reverse drive assembly through coupling 5 to the DUT fixture 6. When powered on, mechanical brake 4 is in a braking state, disconnecting the transmission between reverse reducer 2 and DUT fixture 6.

[0051] The reversing motor 1, reversing reducer 2, mechanical brake 4, speed torque sensor 7, friction clutch 8, forward reducer 9 and forward motor 10 selected in the bidirectional different torque friction brake testing equipment of the present invention are all heat-resistant to vacuum environment, and can test the slip torque of the dynamic or static transmission characteristics of the torque friction brake product in a vacuum environment of -50℃ to 80℃.

[0052] When the testing equipment of the present invention is used for static transmission characteristics / slip torque testing of friction brake product testing equipment, Figure 3 The friction clutch 8 in the reverse motor 1 remains stationary, and the reverse motor 1 is powered on to output torque, which synchronously drives the reverse reducer 2, mechanical brake 4 and the fixed fixture 6 of the test piece to rotate. Figure 3 The input shaft on the left side of the DUT fixture 6 drives the input shaft of the DUT to rotate. At this time, the output shaft on the right side of the DUT fixture 6 remains stationary under the action of the friction clutch 8, so that the output shaft of the DUT also remains stationary. The relative rotation between the input and output shafts of the DUT achieves a reverse slip state, thereby completing the static transmission characteristics and slip torque test of the DUT. In the reverse slip state, the DUT Figure 3 The part marked by the arrow on the left is the actuating part, and the other parts of the test equipment are the braking parts.

[0053] When the test equipment of the present invention is used for the static transmission characteristics / slip torque test of the friction brake product, the reverse motor 1 of the reverse drive assembly is in the power-off state, the mechanical brake 4 is in the brake power-on state, and the input shaft of the test piece fixing fixture 6 is connected through the coupling 5 to keep the input shaft of the test piece in the brake state. The transmission of the speed torque sensor 7 and the forward reducer 9 in the forward drive assembly is in the disconnected state, the forward motor 10 is powered on and rotates, and drives the forward reducer 9 to rotate. After the forward reducer 9 runs smoothly, as shown in FIG. Figure 2 As shown, the friction clutch 8 is electrically engaged and in a connected state (the friction clutch 8 is equivalent to a transmission shaft at this time), and the output shaft of the test piece is driven to rotate by the transition bracket 13, the speed torque sensor 7 and the output shaft of the test piece fixing fixture 6, and the relative rotation between the input shaft and the output shaft of the test piece realizes a positive slip state ( Figure 2 The right side of the tested part is the output shaft rotating, and the left side is the input shaft remaining stationary (when it is positive slip), the slip torque is transmitted to the speed torque sensor 7 of the test component through the output shaft of the tested part fixture 6, and the measured value of the slip torque is obtained. Figure 2 The area marked by the arrow on the right is the actuating section, while the rest of the test equipment is the braking section. Under this operating condition, the friction brake's input shaft remains in a braking state, while the output shaft rotates driven by the forward drive assembly. This test involves static transmission characteristics and slip torque.

[0054] The product under test is a friction brake with different torques in both directions, and it slips in the reverse direction ( Figure 3 The left side of the test piece is the input shaft, which rotates, while the right side, the output shaft, which remains stationary, is characterized by reverse slip (low speed and high torque). Forward slip is characterized by high speed and low torque. Therefore, to accommodate slip torque tests in different directions for the tested product, the present invention uses different output powers for reverse motor 1 and forward motor 10. The forward motor 10 in the bidirectional, differential-torque friction brake test equipment of the present invention can function as either a drive device or a brake device, with switching performed by the device controller.

[0055] When the test equipment of the present invention is used to test the dynamic transmission characteristics / slip torque of a friction brake product, the forward motor 10 of the forward drive assembly is powered on and maintained in the braking state (serving as a brake), and the friction clutch 8 is in the disconnected state, isolating the transmission between the speed torque sensor 7 and the forward motor 10. The mechanical brake 4 of the reverse drive assembly is in the powered off and disengaged state (the mechanical brake 4 is equivalent to the transmission shaft), as shown in FIG. Figure 3 As shown, the reverse motor 1 is powered on and rotated, and the DUT fixture 6 and the test assembly are driven to rotate through the reverse reducer 2 and the mechanical brake 4. When the test assembly detects that the speed is stable, the friction clutch 8 of the forward drive assembly is powered on and connected (the friction clutch 8 is equivalent to the transmission shaft at this time), and the braking torque of the forward motor 10 is transmitted to the output shaft of the DUT through the forward reducer 9, the friction clutch 8, the test assembly and the output shaft of the DUT fixture 6, so that the output shaft of the DUT is in a braking state, and the DUT is switched from dynamic to static, and the DUT slips in the reverse direction. At this time, the corresponding Figure 2 The area to the side of the middle arrow line is braked and stationary. The input shaft of the DUT is rotated by the reverse drive assembly, and the input and output shafts of the DUT are slipping. The slip torque is transmitted through the output shaft of the DUT fixture 6 to the speed and torque sensor 7 of the test assembly, resulting in the actual measured value of the DUT slip torque. Figure 3 The middle arrow marks the actuating portion for dynamic transmission performance and slip torque testing, while the remaining portion is the braking portion. Under this operating condition, during steady operation, the output shaft of the DUT is momentarily braked to achieve dynamic transmission performance and slip torque testing.

[0056] When the tested piece is subjected to reverse slip torque test, Figure 3 In the test, the reverse drive component acts as a driving component to drive the input shaft of the test piece to rotate, and the forward drive component acts as a braking component to keep the output shaft of the test piece in a braking state. The test component is used to test the slip torque and provide the holding torque and output speed at the output shaft of the test piece. This working condition is the dynamic transmission characteristics and slip torque test of the friction brake product.

[0057] When testing the forward slip torque of the tested piece, Figure 2 In the test, the forward drive component acts as a driving component to drive the output shaft of the test piece to rotate, and the reverse drive component acts as a braking component to keep the input shaft of the test piece in a braking state. The test component is used to test the slip torque and provide the holding torque and output speed at the output shaft of the test piece. This working condition is the static transmission characteristics and slip torque test of the friction brake product.

[0058] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above 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 content of the technical solutions of the present invention are within the scope of protection of the technical solutions of the present invention. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0059] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A bidirectional different torque friction brake test equipment, characterized in that: include: Reverse motor (1), reverse reducer (2), fixed bracket (3), mechanical brake (4), test piece fixing fixture (6), speed torque sensor (7), friction clutch (8), forward reducer (9), forward motor (10), bottom plate (11), mounting bracket (12), transition bracket (13) and sensor bracket (14); The reversing motor (1), the reversing reducer (2) and the mechanical brake (4) are connected in sequence; The housing of the reversing speed reducer (2) and the housing of the mechanical brake (4) are mounted on a fixed bracket (3), and the fixed bracket (3) is mounted on a base plate (11); The forward motor (10), the forward speed reducer (9) and the friction clutch (8) are connected in sequence; The housing of the forward speed reducer (9) and the housing of the friction clutch (8) are mounted on a mounting bracket (12), and the mounting bracket (12) is mounted on a base plate (11); The housing of the speed torque sensor (7) is mounted on a sensor bracket (14), and the sensor bracket (14) is mounted on a base plate (11); The rotating shaft at one end of the speed torque sensor (7) is connected to the output shaft of the test piece fixing fixture (6); the rotating shaft at the other end of the speed torque sensor (7) is mounted on a transition bracket (13) through a bearing and is rigidly connected to the output shaft of the friction clutch (8); the transition bracket (13) is mounted on the base plate (11); The product under test is installed inside the test piece fixing fixture (6) through a bearing, the input shaft of the test piece is connected to the input shaft of the test piece fixing fixture (6), and the output shaft of the test piece is connected to the output shaft of the test piece fixing fixture (6).

2. The bidirectional different torque friction brake test equipment according to claim 1, characterized in that: Also includes: Coupling (5); The input shaft of the test piece fixing fixture (6) and the output shaft of the mechanical brake (4) are rigidly connected via a coupling (5); The output shaft of the test piece fixing fixture (6) is rigidly connected to the rotating shaft at one end of the speed torque sensor (7) via a coupling (5); The rotating shaft at the other end of the speed torque sensor (7) is rigidly connected to the output shaft of the friction clutch (8) through a coupling (5).

3. The bidirectional different torque friction brake test equipment according to claim 1, characterized in that: Also includes: Handrails (15); A plurality of handrails (15) are installed on the bottom plate (11).

4. A bidirectional different torque friction brake test device according to any one of claims 2 or 3, characterized in that: The mechanical brake (4) is in a disengaged state when the power is off, which is equivalent to a coupling, transmitting the speed and torque output by the reverse reducer (2) to the fixed fixture (6) of the test piece; The mechanical brake (4) is in a braking state when powered on, realizing the disconnection of transmission between the reversing reducer (2) and the test piece fixing fixture (6).

5. The bidirectional different torque friction brake test equipment according to claim 4, characterized in that: The friction clutch (8) is powered on and in a connected state, which is equivalent to a coupling, transmitting the speed and torque output by the forward reducer (9) to the fixed fixture (6) of the test piece; The friction clutch (8) is in a disengaged state when the power is turned off, so that the transmission between the forward speed reducer (9) and the test piece fixing fixture (6) is disconnected.

6. The bidirectional different torque friction brake testing device according to claim 5, characterized in that: The output power of the reverse rotation motor (1) and the forward rotation motor (10) is different.

7. A method for implementing static transmission characteristics / slip torque testing using the bidirectional different torque friction brake testing device according to claim 5, characterized in that: The friction clutch (8) remains stationary, and the reverse motor (1) is powered on to output torque, thereby synchronously driving the reverse reducer (2), the mechanical brake (4) and the test piece fixing fixture (6) to rotate, so that the input shaft of the test piece fixing fixture (6) drives the input shaft of the test product to rotate; The output shaft on the right side of the test piece fixing fixture (6) is kept stationary under the action of the friction clutch (8), so that the output shaft of the test product is kept stationary at the same time; the relative rotation between the input shaft and the output shaft of the test piece realizes a reverse slip state, and the slip torque is transmitted to the speed torque sensor (7) through the output shaft of the test piece fixing fixture (6), thereby obtaining the actual measured value of the slip torque.

8. A method for implementing static transmission characteristics / slip torque testing using the bidirectional different torque friction brake testing device according to claim 5, characterized in that: The reversing motor (1) is in a power-off state, the mechanical brake (4) is in a brake-on state, and the input shaft of the test piece fixing fixture (6) is connected via a coupling (5) to keep the input shaft of the test piece in a brake state; The transmission between the speed torque sensor (7) and the forward speed reducer (9) is in a disconnected state, the forward speed motor (10) is powered on and rotates, and drives the forward speed reducer (9) to rotate; After the forward speed reducer (9) runs smoothly, the friction clutch (8) is electrically engaged and in a connected state, and the output shaft of the measured part is driven to rotate through the speed torque sensor (7) and the output shaft of the measured part fixing fixture (6). The relative rotation between the input shaft and the output shaft of the measured part realizes a forward slip state, and the slip torque is transmitted to the speed torque sensor (7) through the output shaft of the measured part fixing fixture (6), thereby obtaining a measured value of the slip torque.

9. A method for implementing dynamic transmission characteristics / slip torque testing using the bidirectional different torque friction brake testing device according to claim 5, characterized in that: The forward motor (10) is powered on and maintained in a braking state; the friction clutch (8) is in a disconnected state, isolating the transmission between the speed torque sensor (7) and the forward motor (10); The mechanical brake (4) is in a power-off disengaged state, which is equivalent to a transmission shaft; The reversing motor (1) is powered on and rotated, and the reversing reducer (2) and the mechanical brake (4) drive the test piece fixing fixture (6) and the speed torque sensor (7) to rotate; When the speed stabilizes, the friction clutch (8) is powered on and in a connected state, which is equivalent to a transmission shaft, and transmits the braking torque of the forward motor (10) to the output shaft of the test piece through the forward speed reducer (9), the friction clutch (8), the speed torque sensor (7) and the output shaft of the test piece fixing fixture (6), so that the output shaft of the test piece is in a braking state; The input shaft of the tested part is in a rotating state driven by the reversing motor (1), and the input shaft and output shaft of the tested part are in a slipping state. The slipping torque is transmitted to the speed torque sensor (7) through the output shaft of the tested part fixing fixture (6), and the actual measured value of the slipping torque is obtained.

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