Compact motor-clutch coupled magnetorheological compliant joint and coupling working method thereof

Abstract

The application discloses a compact motor-clutch coupling type magneto-rheological compliant joint and a coupling working method thereof, comprising a control driving module, a hollow brushless motor module, a magneto-rheological clutch module, an input shaft and an output shaft. The hollow brushless motor module and the magneto-rheological clutch module are coaxially integrated, the input shaft penetrates through a hollow rotor and is connected with a driving force transmission component of the magneto-rheological clutch, and compact continuous force transmission is realized. The control driving module calls a non-linear calibration relationship between excitation current and transmission torque according to a target torque, and combines temperature, slip, hysteresis state or output torque error to carry out compensation correction; meanwhile, impact, unlocking and overload are recognized according to an operating state, and compliant protection is implemented by reducing excitation current and limiting motor output. The application can realize active motion output, adjustable transmission torque and safe slip protection.

Description

Technical Field

[0001] This invention belongs to the field of robot compliant actuators and magnetorheological transmission control technology, specifically relating to a compact motor-clutch coupled magnetorheological compliant joint, and a motor-magnetorheological clutch coupling working method applied to the compliant joint. Background Technology

[0002] As robots and electromechanical actuators develop towards higher integration, higher power density, and safer interaction, joint actuators, in addition to achieving basic motion outputs such as position, speed, and torque, also need to possess a certain degree of compliant response and transmission protection under external impacts, sudden load changes, or overload conditions. Traditional rigid transmission joints typically have a motor directly driving the load through a transmission mechanism. When subjected to transient impacts, the impact load can easily be transmitted along the transmission chain to the motor and internal components, which is detrimental to the safe operation of the system.

[0003] Existing compliant joints typically improve compliance by placing elastic elements, damping elements, or controllable clutches between the active drive unit and the load. However, when the active drive unit and the compliant force transmission unit are set up independently, it can easily lead to an increase in axial dimensions, a longer force transmission chain, and a more complex structure, which is not conducive to compact joint design and also increases the difficulty of coordinating motion output and compliant torque adjustment.

[0004] Magnetorheological force transmission elements can adjust the shear force transmission capability of magnetorheological materials by changing the excitation current, featuring fast response and adjustable transmitted torque. However, the transmitted torque and excitation current typically have a nonlinear relationship, and are affected by factors such as temperature, input / output slip, hysteresis, and deviation from the actual output torque. Existing control methods struggle to simultaneously achieve active motion output, precise torque regulation, and safety protection under impact, unlocking, and overload conditions. Therefore, it is necessary to design a compliant joint with a compact structure, short force transmission path, and the ability to achieve coordinated control of motor drive and magnetorheological compliant force transmission. Summary of the Invention

[0005] The purpose of this invention is to provide a compact motor-clutch coupled magnetorheological compliant joint to solve the problems of large structural size, long force transmission chain, and difficulty in coordinating motion output and compliant torque adjustment caused by the independent arrangement of existing active drive units and compliant force transmission units. This invention coaxially integrates a hollow brushless motor module and a magnetorheological clutch module, allowing the input shaft to pass through the hollow rotor and extend directly into the magnetorheological clutch, forming a continuous coaxial force transmission path. Simultaneously, it utilizes the shear interface of the magnetorheological medium to controllably transmit the motor output torque, thereby achieving active motion output, adjustable torque transmission, and compliant protection under impact or overload conditions within a compact structure.

[0006] The technical solution for realizing the present invention is as follows: a compact motor-clutch coupled magnetorheological compliant joint, comprising a control drive module, a control drive module housing, a hollow brushless motor module, a motor-clutch composite housing, a magnetorheological clutch module, an input shaft, an output shaft, and a compliant joint lead interface.

[0007] The control drive module housing is fixed to the front end of the motor-clutch composite housing, and the control drive module is housed inside the control drive module housing. The hollow brushless motor module and the magnetorheological clutch module are sequentially arranged along the same axis within the motor-clutch composite housing. The input shaft passes through the hollow rotor of the hollow brushless motor module and is circumferentially fixedly connected to the hollow rotor. The clutch connection section of the input shaft extends directly into the interior of the magnetorheological clutch module and is circumferentially fixedly connected to the active force transmission component of the magnetorheological clutch module. The output shaft is connected to the driven force transmission component of the magnetorheological clutch module. The output torque of the hollow brushless motor module is sequentially transmitted to the output shaft via the input shaft, the active force transmission component, the magnetorheological medium shear interface, and the driven force transmission component.

[0008] The control drive module is used to generate motor drive commands for the hollow brushless motor module and excitation current commands for the magnetorheological clutch module; the hollow brushless motor module is used to generate active motion output; the magnetorheological clutch module is used to adjust the transmittable torque between the input shaft and the output shaft according to the excitation current; the compliant joint lead interface is located on the front face of the control drive module housing and is used to lead out power lines, communication lines, motor phase lines, sensor signal lines or magnetorheological clutch excitation lines.

[0009] The present invention also provides a coupling operation method for the above-mentioned compact motor-clutch coupled magnetorheological compliant joint, comprising the following steps:

[0010] Step 1: The control drive module receives the target motion command and the target torque command. And collect data from the hollow brushless motor module during the current control cycle. Motor current and input speed at that time Output speed of the output shaft and output torque Proceed to step 2.

[0011] Step 2: Control the drive module according to and Calculate input-output slip:

[0012] ,

[0013] in, Indicates the current control cycle The input-output slip between the input and output shafts at that time.

[0014] And based on the joint output torque of the current control cycle Joint output torque in the previous control cycle Calculate the change in output torque:

[0015] ,

[0016] in, This indicates the change in output torque between adjacent control cycles, then proceed to step 3.

[0017] Step 3: Control the drive module to adjust the input / output slip. Output torque variation and joint output torque Compare with the safety threshold respectively:

[0018] When the output torque changes When the corresponding safety threshold is reached or exceeded, the joint is determined to be in an impact state;

[0019] When input and output slip When the corresponding safety threshold is reached or exceeded, the joint is determined to be in an unlocked state;

[0020] When motor current, output torque When at least one of the following conditions reaches or exceeds the corresponding safety threshold, the joint is determined to be in an overload state.

[0021] When at least one of the impact state, disengagement state or overload state is detected, the control drive module enters the protection mode, reduces the excitation current of the magnetorheological clutch module, and limits the output torque of the hollow brushless motor module. Then it returns to step 1, collects the safety status again and performs protection judgment.

[0022] When no impact, unlocking, or overload condition is detected, or when all status parameters in the protection mode return to the preset safe range, proceed to step 4.

[0023] Step 4: The control drive module controls the target torque command input from the outside. and output torque Calculate the current control cycle Output torque error :

[0024] ,

[0025] The control drive module determines the motion direction of the hollow brushless motor module based on the target motion command, and determines the motion direction based on the output torque error. Adjust the motor drive commands of the hollow brushless motor module.

[0026] The hollow rotor of the hollow brushless motor module moves according to the above motor drive command, and drives the active disc of the magnetorheological clutch module to move through the input shaft which is circumferentially fixed to the hollow rotor.

[0027] At the same time, the target torque command will be sent. The amplitude is determined as the target transmitted torque of the magnetorheological clutch module. :

[0028] ,

[0029] Proceed to step 5.

[0030] Step 5: The control drive module transmits torque according to the target determined in Step 4. By calling the nonlinear calibration relationship between excitation current and transmitted torque, the initial excitation current of the magnetorheological clutch module can be obtained by reverse lookup:

[0031] ,

[0032] Where F represents the nonlinear calibration relationship between excitation current and transmitted torque. This indicates the initial excitation current before operational state compensation is performed in the current control cycle.

[0033] The control drive module will use the initial excitation current The excitation coil, sent to the magnetorheological clutch module, generates a magnetic field that passes through the gap between the discs.

[0034] The magnetorheological powder in the gap between the discs generates controllable shear resistance under the action of the magnetic field, which enables the active disc to transmit the motion and torque of the input shaft to the driven disc. The driven disc drives the output shaft to move through the force transmission sleeve, thereby establishing a controllable force transmission relationship between the hollow brushless motor module and the output shaft; proceed to step 6.

[0035] Step 6: Initial excitation current As the reference excitation current, the magnetorheological clutch module uses the initial excitation current. After operation, the control drive module collects the operating temperature of the magnetorheological clutch module and re-collects the input speed and output shaft speed to update the input and output slip, then proceeds to step 7.

[0036] Step 7: Repeat steps 1 to 6 to compensate and correct the initial excitation current, and determine the amount of excitation current correction. The control drive module will obtain the initial excitation current. With excitation current correction By superimposing these values, the final excitation current command for the current control cycle is obtained. :

[0037] ,

[0038] When the operating temperature of the magnetorheological clutch module reaches or exceeds the preset temperature threshold, the control drive module reduces the maximum allowable excitation current of the magnetorheological clutch module and limits the final excitation current command according to the reduced maximum allowable excitation current.

[0039] The final excitation current command Send to the magnetorheological clutch module and proceed to step 8.

[0040] Step 8: The magnetorheological clutch module executes the final excitation current command as described above. Adjust the transmittable torque between the driving disc and the driven disc, and output motion and torque through the driven disc, the force transmission sleeve and the output shaft.

[0041] After completing the current work cycle, return to step 1, receive the target instructions again, obtain the joint running status, and execute the next work cycle.

[0042] When an impact, disengagement, or overload condition is detected in the next working cycle, the protection mode is entered according to step 3; after the joint operating parameters are restored to the preset safe range, the motion output of the hollow brushless motor module and the transmittable torque of the magnetorheological clutch module are restored.

[0043] Compared with the prior art, the advantages of this invention are as follows:

[0044] (1) The hollow brushless motor module and the magnetorheological clutch module are coaxially integrated. The input shaft passes through the hollow rotor and is directly connected to the clutch active force transmission component, which can shorten the force transmission chain and improve the compactness and integration of the joint structure.

[0045] (2) By using a multi-disc magnetorheological shear force transmission structure and a closed magnetic circuit design, the effective shear area is increased in a limited space, and the continuous adjustment of the transmittable torque is realized.

[0046] (3) By identifying impact, disengagement and overload conditions, the clutch excitation current is reduced and the motor output is limited, so that the input shaft and output shaft can generate controllable slip, thereby achieving smooth torque limiting and safety protection.

[0047] (4) It can switch between rigid transmission, precision torque and safe slip mode, taking into account the needs of motion output, torque adjustment and safety and smoothness. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the overall shape of the compact magnetorheological compliant joint of the present invention.

[0049] Figure 2This is a schematic diagram of the overall cross-section of the magnetorheological compliant joint and the cross-sectional structure of the magnetorheological clutch module of the present invention.

[0050] Figure 3 This is an exploded structural diagram of the magnetorheological clutch module of the present invention.

[0051] Figure 4 This is a schematic diagram of the impact / unlocking protection mechanism of the present invention.

[0052] Figure 5 This is a schematic diagram of the excitation current-torque nonlinear calibration curve of the present invention.

[0053] Figure 6 This is a flowchart of the motor-magnetorheological clutch cooperative working method of the present invention.

[0054] In the diagram: 1. Control drive module; 2. Control drive module housing; 3. Hollow brushless motor module; 4. Motor-clutch composite housing; 5. Magnetorheological clutch module; 6. Input shaft; 7. Output shaft; 8. Compliant joint lead wire interface; 9. Magnetic clutch housing; 10. Clutch rear end cover; 11. Driving disc; 12. Driven disc; 13. Coil support; 14. Force transmission sleeve; 15. Magnetic connecting ring; 16. Disc gap; 17. Outer separator ring; 18. Inner separator ring; 19. Clutch front end cover; 20. Excitation coil. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0056] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0057] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; "connection" can mean a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible to those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0059] The following section will further introduce the specific implementation method, as well as the technical difficulties and inventive points of this invention, using this design example as an example.

[0060] Combination Figures 1-6 The compact motor-clutch coupled magnetorheological compliant joint of the present invention includes a control drive module 1, a control drive module housing 2, a hollow brushless motor module 3, a motor-clutch composite housing 4, a magnetorheological clutch module 5, an input shaft 6, an output shaft 7, and a compliant joint lead interface 8.

[0061] To address the issues of large structural size, long transmission chains, and difficulty in coordinating motion output and compliant torque adjustment caused by the independent setup of existing active drive units and compliant force transmission units, this invention adopts a coaxial integrated design. In the overall assembly, the control drive module housing 2 is fixed to the front end face of the motor-clutch composite housing 4, and the control drive module 1 is housed within the control drive module housing 2. The hollow brushless motor module 3 and the magnetorheological clutch module 5 are sequentially arranged along the same axis within the motor-clutch composite housing 4. The input shaft 6 passes through the hollow rotor of the hollow brushless motor module 3 and is circumferentially fixedly connected to the hollow rotor. The clutch connection section of the input shaft 6 extends directly into the interior of the magnetorheological clutch module 5 and is circumferentially fixedly connected to the active force transmission component of the magnetorheological clutch module 5. This coaxial direct connection structure allows the output torque of the hollow brushless motor module 3 to be transmitted sequentially through the input shaft 6, the active force transmission component, the magnetorheological medium shear interface, and the driven force transmission component to the output shaft 7, significantly shortening the transmission chain length and eliminating backlash and inertia accumulation in intermediate transmission links.

[0062] The control drive module 1 generates motor drive commands for the hollow brushless motor module 3 and excitation current commands for the magnetorheological clutch module 5, achieving coordinated control of the motor's active motion output and the clutch's controllable force transmission. The hollow brushless motor module 3 generates active motion output. The magnetorheological clutch module 5 adjusts the transmittable torque between the input shaft 6 and the output shaft 7 according to the excitation current, utilizing the shear yielding effect of magnetorheological powder under a magnetic field to achieve precise adjustment of the output torque. The compliant joint lead interface 8 is located on the front end of the control drive module housing 2, used to lead out power lines, communication lines, motor phase lines, sensor signal lines, or magnetorheological clutch excitation lines, realizing centralized interconnection between external systems and various electrical modules inside the joint.

[0063] The motor-clutch composite housing 4 includes a non-magnetic housing and a magnetic clutch housing 9 connected sequentially from front to back. The non-magnetic housing is used to house the hollow brushless motor module 3 and reduce the impact of magnetic leakage. It is made of non-magnetic material to prevent magnetic field leakage from the motor's permanent magnets from interfering with the magnetorheological clutch module 5. The magnetic clutch housing 9 is made of magnetic material and, together with the magnetic circuit components in the magnetorheological clutch module 5, forms a closed magnetic flux path, ensuring that the magnetic flux generated by the excitation coil 20 passes through the disc gap 16 efficiently, maximizing magnetic field utilization.

[0064] The magnetorheological clutch module 5 includes a clutch rear end cover 10, a coil support 13, a force transmission sleeve 14, a magnetically conductive connecting ring 15, a disc clearance 16, a clutch front end cover 19, an excitation coil 20, several driving discs 11, several driven discs 12, several outer separator rings 17, and several inner separator rings 18. The clutch front end cover 19 and the clutch rear end cover 10 are respectively fixed to the front and rear ends of the magnetically conductive clutch housing 9. The magnetically conductive connecting ring 15 is disposed between the clutch rear end cover 10 and the magnetically conductive clutch housing 9. The clutch front end cover 19, the clutch rear end cover 10, the magnetically conductive connecting ring 15, and the magnetically conductive clutch housing 9 together form a closed cavity. This closed cavity uses a high-temperature resistant sealing component to seal the magnetorheological powder, preventing powder leakage that could lead to a decline in force transmission performance.

[0065] The input shaft 6 extends into the enclosed cavity as the central shaft. The driving disc 11 and driven disc 12 are alternately arranged along the input shaft 6, with the driving disc 11 circumferentially fixed to the input shaft 6 via a key connection. A force transmission sleeve 14 is fitted over the driving disc 11 and driven disc 12, with the driven disc 12 connected to the force transmission sleeve 14. The force transmission sleeve 14 is linked to the output shaft 7, thereby outputting the torque transmitted by the magnetorheological clutch module 5 to the output shaft 7. This multi-disc alternating arrangement structure multiplies the effective shear area within a limited axial space, significantly improving the torque density of the joint.

[0066] The coil support 13 is disposed between the force transmission sleeve 14 and the magnetic clutch housing 9, and the excitation coil 20 is wound on the coil support 13. The coil support 13 is made of insulating and heat-resistant material to ensure electrical isolation and thermal stability between the excitation coil 20 and the surrounding magnetic components.

[0067] The input shaft 6 and the output shaft 7 are coaxial and independently arranged. This structure allows the motor side and the load side to rotate relative to each other physically, providing a structural basis for controllable slippage under overload conditions. Torque transmission between the input shaft 6 and the output shaft 7 is accomplished through the driving disc 11, the magnetorheological powder in the disc gap 16, the driven disc 12, and the force transmission sleeve 14.

[0068] The compliant joint also includes several outer partition rings 17 and several inner partition rings 18 for maintaining the stability of the disk gap 16. When the driving disk 11 and driven disk 12 are arranged alternately along the input shaft 6, a disk gap 16 is formed between the driving disk 11 and the driven disk 12, and the disk gap 16 is filled with magnetorheological powder. The outer partition rings 17 are used to limit the axial spacing of the driven disk 12, and the inner partition rings 18 are used to limit the axial spacing of the driving disk 11. By limiting the axial positions of the driving and driven disks by the outer partition rings 17 and the inner partition rings 18 respectively, the axial dimensional uniformity of the disk gap 16 is maintained, ensuring that the magnetic field strength distribution in each layer of the gap is uniform, thereby obtaining a consistent shear stress output.

[0069] The coil support 13 supports the excitation coil 20. The magnetically conductive clutch housing 9, the magnetically conductive connecting ring 15, the force transmission sleeve 14, the driving disc 11, and the driven disc 12 together form a closed magnetic circuit passing through the disc gap 16. When the excitation coil 20 is energized, the generated magnetic flux sequentially forms a closed loop along the path of the magnetically conductive clutch housing 9, the magnetically conductive connecting ring 15, the force transmission sleeve 14, the driving disc 11, the disc gap 16, the driven disc 12, and the magnetically conductive clutch housing 9. The magnetorheological powder in the disc gap 16 forms a chain-like or columnar structure under the action of the magnetic field, generating controllable shear resistance between the driving disc 11 and the driven disc 12, thereby adjusting the transmittable torque between the input shaft 6 and the output shaft 7.

[0070] The control drive module 1 stores a nonlinear calibration relationship between excitation current and transmitted torque. This nonlinear calibration relationship is established by interpolation or fitting based on the steady-state transmitted torque data of the magnetorheological clutch module 5 collected under different excitation currents. The control drive module 1 calls upon this nonlinear calibration relationship based on the target transmitted torque to retrieve the initial excitation current of the magnetorheological clutch module 5. Since the BH curve of the magnetorheological powder has nonlinear characteristics and exhibits hysteresis, establishing an accurate mapping relationship through pre-calibration is fundamental to achieving fast open-loop response.

[0071] The control drive module 1 compensates and corrects the initial excitation current based on temperature, slip between input shaft 6 and output shaft 7, hysteresis state of magnetorheological powder, or output torque error, to obtain the final excitation current command. The compensation and correction include at least one of temperature rise compensation, hysteresis compensation, slip compensation, and torque error closed-loop correction. Temperature rise compensation overcomes the decrease in shear yield stress of the magnetorheological powder due to temperature increase; hysteresis compensation corrects the excitation current based on the historical excitation state of the magnetorheological powder, effectively compensating for the nonlinear hysteresis error caused by the historical magnetization state of the magnetorheological material; slip compensation corrects the transmission torque deviation caused by changes in the relative rotational speed between the driving and driven disks; and torque error closed-loop correction dynamically adjusts the output torque by real-time feedback of the deviation from the target torque, achieving high-precision torque control.

[0072] The coupling operation method of the compact motor-clutch coupled magnetorheological compliant joint described in this invention includes the following steps:

[0073] Step 1: Control drive module 1 receives target motion command and target torque command. And collect data from the hollow brushless motor module 3 during the current control cycle. Motor current and input speed at that time Output speed of output shaft 7 and output torque .

[0074] In this embodiment, the output torque can be acquired by a torque sensor.

[0075] Proceed to step 2.

[0076] Step 2, control drive module 1 according to and Calculate input-output slip:

[0077] ,

[0078] in, Indicates the current control cycle The input / output slip between input shaft 6 and output shaft 7 at that time.

[0079] And based on the joint output torque of the current control cycle Joint output torque in the previous control cycle Calculate the change in output torque:

[0080] ,

[0081] in, This indicates the change in output torque between adjacent control cycles, then proceed to step 3.

[0082] Step 3: Control drive module 1 to adjust the input / output slip. Output torque variation and joint output torque Compare with the safety threshold respectively:

[0083] When the output torque changes When the corresponding safety threshold is reached or exceeded, the joint is determined to be in an impact state;

[0084] When input and output slip When the corresponding safety threshold is reached or exceeded, the joint is determined to be in an unlocked state;

[0085] When motor current, output torque When at least one of the following conditions reaches or exceeds the corresponding safety threshold, the joint is determined to be in an overload state.

[0086] Each safety threshold can be preset based on the rated current of the hollow brushless motor module, the allowable transmission torque of the magnetorheological clutch module, the allowable input-output slip of the joint, and the fluctuation range of the sensor signal; the preset temperature threshold can be determined based on the allowable operating temperature of the excitation coil and the magnetorheological powder.

[0087] When at least one of the following conditions is detected: impact, disengagement, or overload, the control drive module 1 enters protection mode, rapidly reduces the excitation current of the magnetorheological clutch module 5, and limits the output torque of the hollow brushless motor module 3. Then, it returns to step 1 to collect the safety status again and perform protection judgment.

[0088] When no impact, unlocking, or overload condition is detected, or when all status parameters in the protection mode return to the preset safe range, proceed to step 4.

[0089] Step 4: Control drive module 1 according to the target torque command input from the outside. and output torque Calculate the current control cycle Output torque error :

[0090] ,

[0091] The control drive module 1 determines the motion direction of the hollow brushless motor module 3 according to the target motion command, and determines the motion direction according to the output torque error. Combining the field-oriented control logic, the target quadrature-axis current command is output through the closed-loop PID regulator, thereby adjusting the motor drive command of the hollow brushless motor module 3 and regulating the output torque of the motor.

[0092] The hollow rotor of the hollow brushless motor module 3 moves according to the above motor drive command, and drives the active disc 11 of the magnetorheological clutch module 5 to move through the input shaft 6 which is circumferentially fixedly connected to the hollow rotor.

[0093] At the same time, the target torque command will be sent. The amplitude is determined as the target transmitted torque of the magnetorheological clutch module 5. :

[0094] ,

[0095] Proceed to step 5.

[0096] Step 5: Control drive module 1 to transmit torque according to the target determined in step 4. By calling the nonlinear calibration relationship between excitation current and transmitted torque, the initial excitation current of the magnetorheological clutch module 5 can be obtained by reverse lookup:

[0097] ,

[0098] Where F represents the nonlinear calibration relationship between excitation current and transmitted torque. This indicates the initial excitation current before operational state compensation is performed in the current control cycle.

[0099] Control drive module 1 will control the initial excitation current The excitation coil 20 is sent to the magnetorheological clutch module 5, causing the excitation coil 20 to generate a magnetic field that passes through the disc gap 16.

[0100] Under the action of the magnetic field, the magnetorheological powder in the disc gap 16 is polarized along the direction of the magnetic field lines and aggregates into chain or columnar structures to generate controllable shear resistance, so that the active disc 11 transmits the motion and torque of the input shaft 6 to the driven disc 12. The driven disc 12 drives the output shaft 7 to move through the force transmission sleeve 14, thereby establishing a controllable force transmission relationship between the hollow brushless motor module 3 and the output shaft 7.

[0101] Proceed to step 6.

[0102] Step 6: Initial excitation current As the reference excitation current, the magnetorheological clutch module 5 uses the initial excitation current. After operation, the control drive module 1 collects the operating temperature of the magnetorheological clutch module 5 to monitor the temperature rise of the magnetorheological powder and the excitation coil, and provides a basis for subsequent temperature rise compensation and excitation current limiting. It also re-collects the input speed and the output speed of the output shaft 7 to update the input and output slip, and then proceeds to step 7.

[0103] Step 7: Repeat steps 1 to 6 to compensate and correct the initial excitation current, and determine the amount of excitation current correction. The control drive module 1 will obtain the initial excitation current. With excitation current correction By superimposing these values, the final excitation current command for the current control cycle is obtained. :

[0104] ,

[0105] When the operating temperature of the magnetorheological clutch module 5 reaches or exceeds the preset temperature threshold, the control drive module 1 reduces the maximum allowable excitation current of the magnetorheological clutch module 5 to reduce the risk of overheating, and limits the final excitation current command according to the reduced maximum allowable excitation current.

[0106] The final excitation current command Send to magnetorheological clutch module 5, proceed to step 8.

[0107] Step 8: The magnetorheological clutch module 5 executes the final excitation current command as described above. Adjust the transmittable torque between the active disc 11 and the driven disc 12, and output motion and torque through the driven disc 12, the force transmission sleeve 14 and the output shaft 7.

[0108] After completing the current work cycle, return to step 1, receive the target instruction again, obtain the joint running status, and execute the next work cycle;

[0109] When an impact state, a disengagement state, or an overload state is detected in the next working cycle, the protection mode is entered according to step 3. After the joint operating parameters are restored to the preset safe range, the control drive module 1 smoothly restores the motion output of the hollow brushless motor module 3 and the transmittable torque of the magnetorheological clutch module 5 according to the predetermined slope, so as to avoid the secondary impact caused by the sudden output.

[0110] The control drive module 1 switches between rigid transmission mode, precision torque mode and safe slip mode according to the target motion command, target torque command and joint state.

[0111] In rigid transmission mode, the target motion command may include the target position command or the target speed command. The hollow brushless motor module 3 performs corresponding position or speed servo control according to the target motion command, and at the same time corrects or limits the motor drive command according to the output torque error. The magnetorheological clutch module 5 provides transmittable torque, so that the input shaft 6 and the output shaft 7 establish a corresponding force transmission relationship.

[0112] In precision torque mode, the hollow brushless motor module 3 provides motion input, and the magnetorheological clutch module 5 adjusts the actual transmittable torque of the output shaft 7 according to the target transmittable torque. Through closed-loop adjustment, high-precision control of the output torque is achieved to meet the needs of compliant force control application scenarios.

[0113] In safe slip mode, the control drive module 1 reduces the excitation current of the magnetorheological clutch module 5 and limits the output of the hollow brushless motor module 3, creating a controllable slip between the input shaft 6 and the output shaft 7. Under controllable slip, the driving disc 11 and the driven disc 12 slide relative to each other through the shear layer of the magnetorheological powder, converting transient impact mechanical energy into shear friction heat energy and dissipating it, thus achieving compliant torque limiting protection for the transmission components.

[0114] Before operation, the control drive module 1 is powered on and completes the self-test of various sensors and the reading and initialization of nonlinear calibration relationships. During operation, the hollow brushless motor module 3 generates active drive, and the output torque is transmitted sequentially through the input shaft 6, the active disk 11, the magnetorheological powder shear interface, the driven disk 12, and the force transmission sleeve 14 to the output shaft 7. Whether under normal drive or impact overload conditions, it can achieve safe and smooth force transmission with high torque density by relying on the above structure and cooperative working logic.

[0115] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of the present invention and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A compact motor-clutch coupled magnetorheological compliant joint, comprising a control drive module (1), a control drive module housing (2), a hollow brushless motor module (3), a motor-clutch composite housing (4), a magnetorheological clutch module (5), an input shaft (6), an output shaft (7), and a compliant joint lead interface (8). The control drive module housing (2) is fixed to the front end of the motor-clutch composite housing (4), and the control drive module (1) is located inside the control drive module housing (2). The hollow brushless motor module (3) and the magnetorheological clutch module (5) are arranged sequentially along the same axis inside the motor-clutch composite housing (4). The input shaft (6) passes through the hollow rotor of the hollow brushless motor module (3) and is circumferentially fixedly connected to the hollow rotor. The clutch connection section of the input shaft (6) extends directly into the interior of the magnetorheological clutch module (5) and is circumferentially fixedly connected to the active force transmission component of the magnetorheological clutch module (5). The output shaft (7) is connected to the driven force transmission component of the magnetorheological clutch module (5). The output torque of the hollow brushless motor module (3) is transmitted to the output shaft (7) sequentially through the input shaft (6), the active force transmission component, the magnetorheological medium shear interface, and the driven force transmission component. The control drive module (1) is used to generate motor drive commands for the hollow brushless motor module (3) and excitation current commands for the magnetorheological clutch module (5); the hollow brushless motor module (3) is used to generate active motion output; the magnetorheological clutch module (5) is used to adjust the transmittable torque between the input shaft (6) and the output shaft (7) according to the excitation current; the compliant joint lead wire interface (8) is set on the front end face of the housing (2) of the control drive module and is used to lead out power lines, communication lines, motor phase lines, sensor signal lines or magnetorheological clutch excitation lines.

2. The compact motor-clutch coupled magnetorheological compliant joint according to claim 1, characterized in that: The motor-clutch composite housing (4) includes a non-magnetic housing and a magnetic clutch housing (9) connected sequentially from front to back. The non-magnetic housing is used to accommodate the hollow brushless motor module (3) and reduce the influence of magnetic leakage. The magnetic clutch housing (9) is made of magnetic material and together with the magnetic circuit components in the magnetorheological clutch module (5) forms a closed magnetic flux path.

3. A compact motor-clutch coupled magnetorheological compliant joint according to claim 2, characterized in that: The magnetorheological clutch module (5) includes a clutch rear end cover (10), a coil support (13), a force transmission sleeve (14), a magnetic connecting ring (15), a disc clearance (16), a clutch front end cover (19), an excitation coil (20), several driving discs (11), several driven discs (12), several outer separator rings (17), and several inner separator rings (18). The clutch front end cover (19) and the clutch rear end cover (10) are respectively fixed at the front and rear ends of the magnetically conductive clutch housing (9). The magnetic connecting ring (15) is disposed between the clutch rear end cover (10) and the magnetically conductive clutch housing (9). The clutch front end cover (19), the clutch rear end cover (10), the magnetic connecting ring (15), and the magnetically conductive clutch housing (9) together form a closed cavity. The input shaft (6) extends into the closed cavity as the central shaft. The driving discs (11) and The driven discs (12) are arranged alternately along the input shaft (6). The driving disc (11) is connected to the input shaft (6) by a key. The force transmission sleeve (14) is sleeved on the outside of the driving disc (11) and the driven disc (12). The driven disc (12) is connected to the force transmission sleeve (14). The force transmission sleeve (14) is linked with the output shaft (7), thereby outputting the torque transmitted by the magnetorheological clutch module (5) to the output shaft (7). The coil support (13) is set between the force transmission sleeve (14) and the magnetic clutch housing (9). The excitation coil (20) is wound on the coil support (13). The input shaft (6) and the output shaft (7) are coaxial and set independently. The torque transmission between the input shaft (6) and the output shaft (7) is completed through the driving disc (11), the magnetorheological powder in the disc gap (16), the driven disc (12) and the force transmission sleeve (14).

4. A compact motor-clutch coupled magnetorheological compliant joint according to claim 3, characterized in that: It also includes several outer partition rings (17) and several inner partition rings (18) for maintaining the stability of the disk gap (16). When the active disk (11) and the driven disk (12) are arranged alternately along the input shaft (6), a disk gap (16) is formed between the active disk (11) and the driven disk (12). The disk gap (16) is filled with magnetorheological powder. The outer partition rings (17) are used to limit the axial spacing of the driven disk (12), and the inner partition rings (18) are used to limit the axial spacing of the active disk (11).

5. A compact motor-clutch coupled magnetorheological compliant joint according to claim 4, characterized in that: The coil support (13) is used to support the excitation coil (20). The magnetic clutch housing (9), magnetic connecting ring (15), force transmission sleeve (14), driving disc (11) and driven disc (12) together form a closed magnetic circuit passing through the disc gap (16). When the excitation coil is energized, the magnetorheological powder in the disc gap (16) forms a chain or column structure under the action of the magnetic field, so that a controllable shear resistance is generated between the driving disc (11) and the driven disc (12), thereby adjusting the transmittable torque between the input shaft (6) and the output shaft (7).

6. A compact motor-clutch coupled magnetorheological compliant joint according to claim 5, characterized in that: The control drive module (1) stores the nonlinear calibration relationship between excitation current and transmission torque. The nonlinear calibration relationship is established by interpolation or fitting based on the steady-state transmission torque data of the magnetorheological clutch module (5) collected under different excitation currents. The control drive module (1) calls the nonlinear calibration relationship according to the target transmission torque and retrieves the initial excitation current of the magnetorheological clutch module (5).

7. A compact motor-clutch coupled magnetorheological compliant joint according to claim 6, characterized in that: The control drive module (1) compensates and corrects the initial excitation current based on the temperature, the slip between the input shaft (6) and the output shaft (7), the hysteresis state of the magnetorheological powder, or the output torque error, to obtain the final excitation current command; wherein, the compensation correction includes at least one of temperature rise compensation, hysteresis compensation, slip compensation and torque error closed-loop correction.

8. A coupling operation method applied to the compact motor-clutch coupled magnetorheological compliant joint according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: The control drive module (1) receives the target motion command and the target torque command. And collect data from the hollow brushless motor module (3) during the current control cycle. Motor current and input speed at that time Output speed of output shaft (7) and output torque Proceed to step 2; Step 2, Control drive module (1) According to and Calculate input-output slip: ， in, Indicates the current control cycle The input-output slip between the input shaft (6) and the output shaft (7) at that time; And based on the joint output torque of the current control cycle Joint output torque in the previous control cycle Calculate the change in output torque: ， in, This indicates the change in output torque between adjacent control cycles; proceed to step 3. Step 3: Control the drive module (1) to control the input and output slip. Output torque variation and joint output torque Compare each with a safety threshold; When the output torque changes When the corresponding safety threshold is reached or exceeded, the joint is determined to be in an impact state; When input and output slip When the corresponding safety threshold is reached or exceeded, the joint is determined to be in an unlocked state; When motor current, output torque When at least one of the following conditions reaches or exceeds the corresponding safety threshold, the joint is determined to be in an overload state. When at least one of the impact state, unlocking state or overload state is detected, the control drive module (1) enters the protection mode, reduces the excitation current of the magnetorheological clutch module (5), and limits the output torque of the hollow brushless motor module (3), and then returns to step 1 to collect the safety status again and perform protection judgment. When no impact state, unlocking state, or overload state is detected, or when all state parameters in the protection mode return to the preset safe range, proceed to step 4. Step 4: Control drive module (1) according to the target torque command input from the outside. and output torque Calculate the current control cycle Output torque error : ， The control drive module (1) determines the motion direction of the hollow brushless motor module (3) according to the target motion command, and determines the motion direction according to the output torque error. Adjust the motor drive command of the hollow brushless motor module (3); The hollow rotor of the hollow brushless motor module (3) moves according to the above motor drive command, and drives the active disc (11) of the magnetorheological clutch module (5) to move through the input shaft (6) which is circumferentially fixed to the hollow rotor. At the same time, the target torque command will be sent. The amplitude is determined as the target transmitted torque of the magnetorheological clutch module (5). : ， Proceed to step 5; Step 5: Control drive module (1) transmits torque according to the target determined in step 4. By calling the nonlinear calibration relationship between excitation current and transmitted torque, the initial excitation current of the magnetorheological clutch module (5) can be obtained by reverse lookup: ， Where F represents the nonlinear calibration relationship between excitation current and transmitted torque. This indicates the initial excitation current before operational state compensation is performed in the current control cycle; The control drive module (1) will control the initial excitation current. The excitation coil (20) sent to the magnetorheological clutch module (5) generates a magnetic field that passes through the disc gap (16); The magnetorheological powder in the gap (16) generates controllable shear resistance under the action of the magnetic field, so that the active disk (11) transmits the motion and torque of the input shaft (6) to the driven disk (12). The driven disk (12) drives the output shaft (7) to move through the force transmission sleeve (14), thereby establishing a controllable force transmission relationship between the hollow brushless motor module (3) and the output shaft (7). Proceed to step 6; Step 6: Initial excitation current As the reference excitation current, the magnetorheological clutch module (5) uses the initial excitation current. After the operation, the control drive module (1) collects the working temperature of the magnetorheological clutch module (5) and re-collects the input speed and the output speed of the output shaft (7) to update the input and output slip, and then proceeds to step 7. Step 7: Repeat steps 1 to 6 to compensate and correct the initial excitation current, and determine the amount of excitation current correction. The control drive module (1) will obtain the initial excitation current. With excitation current correction By superimposing these values, the final excitation current command for the current control cycle is obtained. : ， When the operating temperature of the magnetorheological clutch module (5) reaches or exceeds the preset temperature threshold, the control drive module (1) reduces the maximum allowable excitation current of the magnetorheological clutch module (5) and limits the final excitation current command according to the reduced maximum allowable excitation current. The final excitation current command Send to magnetorheological clutch module (5), proceed to step 8; Step 8: The magnetorheological clutch module (5) executes the final excitation current command as described above. Adjust the transmittable torque between the active disc (11) and the driven disc (12), and output motion and torque through the driven disc (12), the force transmission sleeve (14) and the output shaft (7); After completing the current work cycle, return to step 1, receive the target instruction again, obtain the joint running status, and execute the next work cycle; When an impact state, a disengagement state, or an overload state is detected in the next working cycle, the protection mode is entered according to step 3; when the joint operating parameters are restored to the preset safe range, the motion output of the hollow brushless motor module (3) and the transmittable torque of the magnetorheological clutch module (5) are restored.

9. The coupling operation method of the compact motor-clutch coupled magnetorheological compliant joint according to claim 8, characterized in that: The control drive module (1) switches between rigid transmission mode, precision torque mode and safe slip mode according to the target motion command, target torque command and joint state; in rigid transmission mode, the hollow brushless motor module (3) runs according to the target position or target speed, and the magnetorheological clutch module (5) provides the transmittable torque; in precision torque mode, the hollow brushless motor module (3) provides motion input, and the magnetorheological clutch module (5) adjusts the actual transmittable torque of the output shaft (7) according to the target transmittable torque; in safe slip mode, the control drive module (1) reduces the excitation current of the magnetorheological clutch module (5) and limits the output of the hollow brushless motor module (3), so that a controllable slip is generated between the input shaft (6) and the output shaft (7).

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