Rope-driven robot joint control system with power switching function

Abstract

The invention discloses a rope-driven robot joint control system with a power switching function, and belongs to the technical field of control and adjustment. The system comprises at least one sub-control system, and each sub-control system comprises a driving motor, a power switching mechanism, two rope transmission mechanisms, a differential mechanism and a reduction gearbox. The reduction gearbox is driven to rotate through the rope transmission mechanism, torque amplification and rotating speed reduction are achieved, rope tension is reduced, the load capacity is improved, and the mechanical service life is prolonged. Motion mode switching under different load conditions is achieved through the power switching mechanism. Power of the two motors is combined through the differential mechanism, and therefore synchronism of the multiple motors during cooperative work is guaranteed.

Description

Technical Field

[0001] The present invention relates to robot design and control technology, and in particular discloses a rope-driven robot joint control system with a power switching function, which is suitable for application scenarios such as industrial robots and exoskeleton robots that require high load capacity and high energy efficiency, and belongs to the technical field of control and regulation. Background Art

[0002] The driving methods of robot joints are generally divided into two categories: direct motor drive and rope drive. The advantages of direct drive are simple structure and high control accuracy, but the motor must be installed near the joint, resulting in uneven weight distribution, especially in high-load robots, which will increase the weight and energy consumption of the action parts and affect the efficiency of the system. In order to solve this problem, rope drive has gradually attracted attention. Through rope transmission, the motor can be concentrated on the robot base or other fixed parts, thereby reducing the weight of the action parts.

[0003] However, traditional rope-driven technology still faces some problems. Since the rope is directly connected to the joint, it is difficult to achieve accurate torque amplification and speed control during the transmission process, resulting in excessive rope tension, which not only limits the load capacity but also may cause premature damage to the rope. Secondly, due to the elastic properties of the rope, the rope may stretch or relax when the load changes or is used for a long time, resulting in inaccurate robot motion control. Especially in high-load or complex motion scenarios, it may cause uncoordinated movements of different joints.

[0004] In the prior art, the robot system has limited ability to respond to overload or emergency situations, usually relying on simple current limiting, deceleration or emergency shutdown methods, and cannot fully utilize the idle motor resources in the system. This response method not only limits the overall load capacity of the robot, but also reduces the flexibility and work efficiency of the system. Especially in complex application scenarios, such as industrial robots or exoskeleton robots, it is impossible to dynamically adjust the power output of the motor when the load increases, thus affecting the overall performance.

[0005] Existing robot designs lack an effective power switching mechanism, making it difficult to fully utilize the redundant resources of multi-motor systems under overload conditions. For example, when one motor is overloaded, other idle motors are usually unable to automatically join the work, resulting in a waste of system load capacity. If a power switching mechanism can be designed to enable idle motors to automatically work with the main motor when necessary, the system's load capacity and reliability will be significantly improved.

[0006] Therefore, there is an urgent need for a rope-driven robot joint control system that can achieve torque amplification, synchronous control, and power switching functions, so as to efficiently utilize multi-motor resources under overload or complex working conditions and improve the flexibility, load capacity and energy efficiency of the robot system. Summary of the invention

[0007] The present invention aims to address the technical problems of insufficient load capacity, imprecise coordinated control and lack of effective power switching mechanism in the actual application of existing rope-driven robot joint control systems, and to provide a rope-driven robot joint control system with a power switching function. The purpose of the present invention is to achieve more precise torque amplification and speed control through the system, thereby improving the overall performance and adaptability of the rope-driven robot in complex working environments.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A rope-driven robot joint control system with a power switching function includes at least one sub-control system, each sub-control system has the same structure and drives a joint respectively, wherein a sub-control system includes: a drive motor, a power switching mechanism, two rope transmission mechanisms, a differential and a reduction gearbox, a drive motor provides power to the head end of any one of the rope transmission mechanisms in the rope-driven robot joint control system under the action of the power switching mechanism, the ends of the two rope transmission mechanisms are respectively connected to an input shaft of the differential, the output shaft of the differential combines the torque transmitted to the ends of the two rope transmission mechanisms and transmits it to the input shaft of the reduction gearbox, and the reduction gearbox provides power to the joint connected to its output shaft.

[0010] As a further optimization solution for a rope-driven robot joint control system with a power switching function, the power switching mechanism includes: a spiral pair consisting of a lead screw nut and a lead screw, and a micro motor. The lead screw nut is installed on a drive motor base, and the end of the lead screw is connected to the output shaft of the micro motor through a coupling.

[0011] As a further optimization solution for a rope-driven robot joint control system with a power switching function, a drive motor output shaft is keyed to a drive motor side cylindrical gear.

[0012] As a further optimization scheme of a rope-driven robot joint control system with a power switching function, the two rope transmission mechanisms have the same structure. Each rope transmission mechanism includes: a rope, two rope winding wheels, and a cylindrical gear at the head end of the rope transmission mechanism meshing with the cylindrical gear on the drive motor side, wherein one rope winding wheel is coaxially installed with the cylindrical gear at the head end of the rope transmission mechanism, and the other rope winding wheel is coaxially installed with an input shaft of the differential as the end of the rope transmission mechanism, and the rope is wound around the two rope winding wheels.

[0013] As a further optimization scheme of the rope-driven robot joint control system with power switching function, a rope threading hole is opened on the rope winding wheel body. The rope starts to be wound from one end of the rope winding wheel. When the rope is wound to the rope threading hole, it passes through the rope threading hole and continues to be wound to the other end of the rope winding wheel. The number of rope winding turns satisfies: number of turns>joint stroke×reduction ratio÷2π.

[0014] As a further optimization solution for a joint control system of a rope-driven robot with a power switching function, a bevel gear is fixed on the input shaft of the reduction box, and the output shaft of the differential is meshed with the bevel gear.

[0015] As a further optimization solution for the joint control system of a rope-driven robot with a power switching function, a tension sensor for sensing the load of each joint is installed on the rope in each sub-control system;

[0016] When the tension-free sensor senses that the joint driven by its sub-control system is overloaded, each drive motor provides power to the head end of a rope sensor mechanism in its sub-control system, and the differential input shaft connected to the end of another rope sensor mechanism in each sub-control system is locked, and the rope-driven robot joint control system works in an independent motion mode;

[0017] When a tension sensor senses that the joint driven by its sub-control system is overloaded, the joint driven by the sub-control system to which the idle drive motor belongs is locked, the power switching mechanism of the sub-control system to which the idle drive motor belongs is started, and the idle drive motor and the drive motor in the joint overload sub-control system cooperate to provide power to the head ends of the two rope transmission mechanisms in the joint overload sub-control system, and the rope-driven robot joint control system operates in the enhanced motion mode.

[0018] As a further optimization solution for the rope-driven robot joint control system with power switching function, encoders are installed on the output shaft of the reduction gearbox in each sub-control system. According to the joint positions and rotation angles measured by the encoders, speed control instructions for the drive motors in each control system are generated.

[0019] The present invention adopts the above technical solution and has the following beneficial effects:

[0020] (1) Improved load capacity: Compared with the traditional rope-driven system, the present invention uses a drive motor, a power switching mechanism, two rope transmission mechanisms, a differential and a reduction gearbox to construct a rope-driven robot joint sub-control system with a power switching function. The torque amplification and speed reduction are achieved through the end reduction gearbox, which reduces the rope tension and extends the mechanical life. Through the power switching mechanism, the motor resources are dynamically allocated under overload conditions, thereby improving the overall load capacity of the system and adapting to various working scenarios.

[0021] (2) Enhanced motion coordination: In order to address the problem of unbalanced load distribution caused by motor synchronization in the dual-motor drive system, the present invention ensures the synchronization of multiple motors working together through the design of a differential, avoids motion failure caused by motor incoordination in traditional systems, and improves control accuracy. The system is suitable for robot application scenarios that require high load capacity and lightweight, such as industrial robots and exoskeleton systems.

[0022] (3) Energy consumption optimization: The present invention uses the tension sensor on the rope transmission mechanism to sense the load at the end of the reduction gearbox in real time. When the load is light, a small number of motors can be selected to work, reducing energy consumption and improving the overall energy efficiency ratio, thereby extending the battery life or reducing energy consumption. When the load is heavy, idle motors are selected to cooperate with the main motor to meet the heavy load driving requirements.

[0023] (4) Improved reliability: The present invention combines a harmonic reduction box with precise encoder feedback, and the system can achieve high-precision motion control, solving the problem of inaccurate robot motion control due to rope elongation or relaxation in traditional rope-driven systems, thereby enhancing the stability and reliability of the system.

[0024] (5) Strong flexibility: The present invention uses a power switching mechanism to enable the system to quickly adapt to different load conditions and task requirements. Through the flexible configuration of the power source combination, the robot's work efficiency in complex environments is improved, and the scalability of the system is enhanced.

[0025] (6) Simplified structure: The present invention arranges the motor and the reduction gearbox in a centralized manner, concentrates the motor in the robot body, and transmits power remotely through the flexible material of rope, thereby reducing the weight of the moving parts and facilitating the compactness and lightweight of the overall design. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the winding of the rope wheel in the rope-driven robot joint control system provided in one embodiment of the present invention.

[0027] Figure 2 It is a schematic diagram of an independent motion mode of a cable-driven robot joint control system provided in one embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of a dual-motor cooperative enhanced motion mode of a rope-driven robot joint control system provided in one embodiment of the present invention.

[0029] Figure 4 It is a schematic diagram of an expanded motion mode when more motors are added to a joint control system of a rope-driven robot provided in one embodiment of the present invention.

[0030] Explanation of reference numerals in the figure: 10, first drive motor; 11, second drive motor; 12, third drive motor; 20, first cylindrical gear; 21, second cylindrical gear; 22, third cylindrical gear; 23, fourth cylindrical gear; 24, fifth cylindrical gear; 25, sixth cylindrical gear; 26, seventh cylindrical gear; 27, eighth cylindrical gear; 28, ninth cylindrical gear; 30, first differential; 31, first input shaft of first differential; 32, second input shaft of first differential; 33, second differential; 34, first input shaft of second differential; 35, second input shaft of second differential; 36, third differential; 37, first input shaft of third differential; 38, second input shaft of third differential; 40, first bevel gear; 41, second bevel gear; 42, third bevel gear; 50, The first reducer; 51, the second reducer; 52, the third reducer; 60, the first micro motor; 61, the second micro motor; 62, the third micro motor; 70, the first rope; 71, the second rope; 72, the third rope; 73, the fourth rope; 74, the fifth rope; 75, the sixth rope; 80, the first screw nut; 81, the first screw; 82, the second screw nut; 83, the second screw; 84, the third screw nut; 85, the third screw; 90, the first rope pulley; 91, the second rope pulley; 92, the third rope pulley; 93, the fourth rope pulley; 94, the fifth rope pulley; 95, the sixth rope pulley; 96, the seventh rope pulley; 97, the eighth rope pulley; 98, the ninth rope pulley; 99, the tenth rope pulley; 100, the eleventh rope pulley; 101, the twelfth rope pulley. DETAILED DESCRIPTION

[0031] The technical solution of the invention is described in detail below with reference to the accompanying drawings.

[0032] The rope-driven robot joint control system with power switching function provided by the present invention configures a sub-control system for each joint of the robot, and each sub-control system has the same mechanical structure. A sub-control system includes: a driving motor, a power switching mechanism, two rope transmission mechanisms, a differential and a reduction box. The driving motor provides power to the head end of any rope transmission mechanism in all sub-control systems under the action of the power switching mechanism. The ends of the two rope transmission mechanisms are respectively connected to an input shaft of the differential. The output shaft of the differential combines the torque transmitted to the ends of the two rope transmission mechanisms and transmits it to the input shaft of the reduction box. The reduction box provides power to the joint connected to its output shaft.

[0033] In one embodiment of the present invention, a mechanical structure is provided such as Figure 2 , Figure 3The rope-driven robot joint control system with a power switching function includes two sub-control systems, and the control system includes: a first sub-control system providing power for a first joint and a second sub-control system providing power for a second joint.

[0034] In one embodiment of the present invention, a mechanical structure is provided such as Figure 4 The rope-driven robot joint control system with power switching function shown includes three sub-control systems, and the control system includes: a first sub-control system providing power for the first joint, a second sub-control system providing power for the second joint, and a third sub-control system providing power for the third joint.

[0035] The first subsystem includes: a first drive motor 10, a first cylindrical gear 20, a second cylindrical gear 21, a fourth cylindrical gear 23, a first differential 30, a first bevel gear 40, a first reducer 50, a first micro motor 60, a first rope 70, a second rope 71, a first screw nut 80, a first screw 81 and first to fourth rope reels 90 to 93. The second subsystem includes: a second drive motor 11, a third cylindrical gear 22, a fifth cylindrical gear 24, a sixth cylindrical gear 25, a second differential 33, a second bevel gear 41, a second reducer 51, a second micro motor 61, a third rope 72, a fourth rope 73, a second screw nut 82, a second screw nut 83 and fifth to eighth rope reels 94 to 97. The third subsystem includes: a third drive motor 12, a seventh cylindrical gear 26, an eighth cylindrical gear 27, a ninth cylindrical gear 28, a third differential 36, a third bevel gear 42, a third reducer 52, a third micro motor 62, a fifth rope 74, a sixth rope 75, a third screw nut 84, a third screw 85 and ninth to twelfth rope pulleys 98 to 101.

[0036] The mechanical connection method of the second sub-control system and the third sub-control system is the same as that of the first sub-control system. The mechanical connection method of the first sub-control system is described in detail below, and the mechanical connection method of the second sub-control system and the third sub-control system are not repeated here.

[0037] The power switching mechanism includes: a first screw nut 80, a first screw 81 and a first micro motor 60. The first screw nut 80 is installed on the base of the first drive motor 10 and forms a spiral pair with the first screw 81 to ensure smooth and accurate power switching. The end of the first screw 81 is connected to the output shaft of the first micro motor 60 through a coupling. The rotation of the first micro motor 60 can drive the first drive motor 10 to move horizontally to complete the switching of the motion mode. The working principle of the power switching mechanism is: the tension sensor installed on the rope senses whether the load exceeds the limit. When the system detects an overload, the micro motor automatically activates the power switching mechanism, drives the screw nut to move the drive motor base along the slide rail, and makes the gear keyed to the drive motor output shaft mesh with the gear at the head end of different rope transmission mechanisms to achieve power switching between different motion modes.

[0038] The first rope 70, the first rope pulley 90, the second rope pulley 91 and the second cylindrical gear 21 constitute a first rope transmission mechanism, and the second rope 71, the third rope pulley 92, the fourth rope pulley 93 and the fourth cylindrical gear 23 constitute a second rope transmission mechanism. In the first rope transmission mechanism, the first rope 70 is wound around the first rope pulley 90 and the second rope pulley 91, the second rope pulley 91 is coaxially installed with the second cylindrical gear 21 as the head end of the first rope transmission mechanism through a keyway, and the first rope pulley 90 is coaxially installed with the first input shaft 31 of the first differential as the end of the first rope transmission mechanism. In the second rope transmission mechanism, the second rope 71 is wound around the third rope pulley 92 and the fourth rope pulley 93, the fourth rope pulley 93 is coaxially installed with the fourth cylindrical gear 23 as the head end of the second rope transmission mechanism through a keyway, and the third rope pulley 92 is coaxially installed with the second input shaft 32 of the first differential as the end of the second rope transmission mechanism. The specific way of winding the rope around the two rope pulleys is as follows: Figure 1 As shown, there is a rope threading hole in the middle of the rope reel. The rope starts to wind from one end of the rope reel. When the rope is wound to the rope threading hole, it passes through the rope threading hole and continues to wind to the other end of the rope reel. This can avoid relative slippage between the rope and the rope reel. The number of turns of the rope should meet the movement travel requirements of the joint, that is:

[0039] Number of turns > joint travel × reduction ratio ÷ 2π

[0040] The output shaft of the first differential 30 meshes with the first bevel gear 40, and the first bevel gear 40 is fixed to the input shaft of the first reduction gear box 50, so as to realize the power transmission from the differential to the reduction gear box.

[0041] The reducer is a harmonic reducer, and a high-precision encoder is installed on its output shaft. According to the joint position and rotation angle measured by the high-precision encoder, the speed control command of the drive motor is generated to achieve precise position and speed feedback control of the robot joint system movement.

[0042] Figure 2 The independent motion mode of the key control system of the rope-driven robot of the present invention including two sub-control systems is shown. In this mode, the power of the first drive motor 10 is transmitted to the head end of the first rope transmission mechanism after the first cylindrical gear 20 and the second cylindrical gear 21 are meshed. The power of the head end of the first rope transmission mechanism drives the second rope pulley 91 to rotate coaxially, converting the torque of the first drive motor 10 into a pulling force along the first rope 70, thereby pulling the first rope pulley 90 to rotate. The first rope pulley 90 drives the first input shaft 31 of the first differential to rotate coaxially, and the second input shaft 32 of the first differential is locked. The power transmitted by the first rope transmission mechanism drives the second rope pulley 91 to rotate coaxially. The first differential 30 drives the input shaft of the first reducer 50 to rotate, thereby realizing the long-distance transmission and control of the motor torque. The power of the first reduction box 50 is completely provided by the first drive motor 10; the power of the second drive motor 11 is input into the second input shaft 35 of the second differential via the third cylindrical gear 22, the sixth cylindrical gear 25, the eighth rope pulley 97, the fourth rope 73, and the seventh rope pulley 96. The first input shaft 34 of the second differential is locked, and the power of the second reduction box 51 is completely provided by the second drive motor 11. At this time, each motor independently drives the joints corresponding to each sub-control system, and realizes precise position control and torque amplification through the harmonic reduction box. This design is suitable for normal load conditions, ensuring the flexibility and accuracy of each joint of the robot when moving independently, and meeting diverse operation requirements.

[0043] In one embodiment of the present invention, there is provided Figure 3 The dual motor cooperation enhanced motion mode shown. This mode is used to cope with overload work scenarios. When the robot needs to carry a weight that exceeds the load capacity of a single motor, some joints are locked so that the idle drive motor works in conjunction with the main drive motor. In this scenario, the power of the first drive motor 10 is not enough to drive the load at the end of the first reduction box 50. At this time, the second reduction box 51 is locked, and the power of the second drive motor 11 is released. The second micro motor 61 rotates, driving the second drive motor 11 to translate, and the third cylindrical gear 22 is engaged with the fourth cylindrical gear 23. The power is transmitted to the second input shaft 32 of the first differential via the second rope transmission mechanism of the first sub-control system, and the power of the two drive motors is combined via the first differential 30, and output to the first reduction box 50 via the output shaft of the first differential 30. At this time, the two drive motors share the load, and the maximum torque of the joint can be increased to twice the original, enhancing the motion efficiency and load capacity.

[0044] Correspondingly, the present invention also has another enhanced motion mode, that is, the first drive motor 10 supports the second drive motor 11. Since it is similar to the previous enhanced motion mode, it will not be described in detail here.

[0045] In a traditional dual-motor drive system, even motors of the same model may have inconsistent output characteristics such as torque and speed due to slight differences in manufacturing processes, resulting in energy waste. The present invention solves the problem of unbalanced load distribution when dual motors are input in the following way: the torque of the two drive motors is transmitted to the two input ends of the differential via two rope transmission mechanisms in the same sub-control system, and the torque is combined by the differential and output from the output end. Through this method, the two drive motors can work together, significantly improving the load capacity of the system, ensuring synchronization during the collaboration process, and avoiding control failure problems caused by uneven torque distribution.

[0046] Through the detailed description of the above embodiments and the accompanying drawings, the working principle of the present invention and its advantages in load capacity improvement, coordinated control and power switching are clearly demonstrated. Obviously, the above embodiments are only specific descriptions of the present invention, not limitations. The design of the system has strong scalability and can also include multiple motors and multiple reduction gearboxes to meet more complex motion requirements. In this system, since each set of drive motors and the rope reel system are relatively independent, by adding additional motors and reduction gearboxes, it is possible to achieve control of more joints or more complex motion tasks, such as Figure 4 As shown. Multiple drive motors can work together through the power switching function to improve the load capacity of the system, enhance redundancy and fault tolerance, and ensure continuous operation under high load or complex environments. On this basis, those skilled in the art can make various changes or modifications to the present invention, and any modification, substitution or improvement within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A rope-driven robot joint control system with power switching function, characterized in that: It includes at least one sub-control system, each sub-control system has the same structure and drives a joint respectively, wherein a sub-control system includes: a driving motor, a power switching mechanism, two rope transmission mechanisms, a differential and a reduction gearbox, the driving motor provides power to the head end of any one of the rope transmission mechanisms in the rope-driven robot joint control system under the action of the power switching mechanism, the ends of the two rope transmission mechanisms are respectively connected to an input shaft of the differential, the differential output shaft combines the torque transmitted to the ends of the two rope transmission mechanisms and transmits it to the reduction gearbox input shaft, and the reduction gearbox provides power to the joint connected to its output shaft.

2. A cable-driven robot joint control system with power switching function according to claim 1, characterized in that: The power switching mechanism comprises: a screw pair consisting of a screw nut and a screw and a micro motor, the screw nut is installed on a driving motor base, and the end of the screw is connected to the output shaft of the micro motor through a coupling.

3. A cable-driven robot joint control system with power switching function according to claim 2, characterized in that: The drive motor output shaft is key-connected with a drive motor side cylindrical gear.

4. A cable-driven robot joint control system with power switching function according to claim 3, characterized in that: The two rope transmission mechanisms have the same structure, and each rope transmission mechanism includes: a rope, two rope winding wheels, and a cylindrical gear at the head end of the rope transmission mechanism meshing with the cylindrical gear on the drive motor side, wherein one rope winding wheel is coaxially installed with the cylindrical gear at the head end of the rope transmission mechanism, and the other rope winding wheel is coaxially installed with an input shaft of the differential as the end of the rope transmission mechanism, and the rope is wound around the two rope winding wheels.

5. A cable-driven robot joint control system with power switching function according to claim 4, characterized in that: A rope threading hole is provided on the rope winding wheel body, and the rope is wound from one end of the rope winding wheel. When the rope is wound to the rope threading hole, it passes through the rope threading hole and continues to be wound to the other end of the rope winding wheel. The number of rope winding turns satisfies: number of turns>joint stroke×reduction ratio÷2π.

6. A cable-driven robot joint control system with power switching function according to claim 4 or 5, characterized in that: A bevel gear is fixed on the reduction box input shaft, and the differential output shaft is meshed with the bevel gear.

7. A cable-driven robot joint control system with power switching function according to claim 6, characterized in that: The ropes in each sub-control system are equipped with tension sensors for sensing the load of each joint; When the tension-free sensor senses that the joint driven by its sub-control system is overloaded, each drive motor provides power to the head end of a rope sensor mechanism in its sub-control system, and the differential input shaft connected to the end of another rope sensor mechanism in each sub-control system is locked, and the rope-driven robot joint control system works in an independent motion mode; When a tension sensor senses that the joint driven by the sub-control system to which it belongs is overloaded, the joint driven by the sub-control system to which the idle drive motor belongs is locked, and the power switching mechanism of the sub-control system to which the idle drive motor belongs is started. The idle drive motor and the drive motor in the joint overload sub-control system cooperate to provide power to the head ends of the two rope transmission mechanisms in the joint overload sub-control system, and the rope-driven robot joint control system operates in the enhanced motion mode.

8. A cable-driven robot joint control system with power switching function according to claim 7, characterized in that: An encoder is installed on the output shaft of the reduction box in each sub-control system, and a speed control instruction of the drive motor in each control system is generated according to the position and rotation angle of each joint measured by the encoder.

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