Rope-driven flexible mechanical arm for force-position fusion measurement

Abstract

The invention discloses a force-position fusion measurement rope-driven flexible mechanical arm, and relates to the field of robot mechanical system design. The invention provides an improved technical scheme for solving the problems that an existing rope-driven multi-joint flexible robot is high in measuring unit cost, complex in wiring, large in power supply consumption, insufficient in control stability and low in measuring precision in force and position sensing. The mechanical arm is composed of a plurality of hollow cone arm sections connected in series and rotating joints connected through spherical hinges, and flexible movement is achieved through rope driving. And the rope is led out from the driving base and is wired through a guide groove in the arm section. The force-position fusion measuring device comprises a gear motor, a ball screw, a pulley, a rope and an extension spring. Reflective mark points are arranged at the two ends of the extension spring, the deformation quantity and the displacement of the two ends of the spring are measured in real time through a visual camera, and high-precision force and position measurement is achieved. The mechanical arm is suitable for industrial automation, complex environment operation, intelligent medical treatment and other scenes needing high-precision force position control.

Description

Technical Field

[0001] The invention relates to the field of robot mechanical system design, and specifically to the force and position fusion measurement technology of a rope-driven multi-joint flexible robot. Background Art

[0002] With the rapid development of robotics technology, flexible robots are increasingly used in industrial automation, medical health, service robots and other fields. In particular, rope-driven multi-joint flexible robots have shown great advantages in spacecraft maintenance, complex environment operations, precision medical surgery and human-machine interaction due to their high degree of freedom, strong movement flexibility and large workspace. This type of robot uses a flexible joint structure, which can achieve efficient operation in complex environments, and is more gentle in grasping and operating targets, so it has attracted much attention.

[0003] In the existing technology, the perception and control of rope-driven multi-joint flexible robots rely on the design and deployment of sensor systems. For example, multiple tension sensors, motor encoders and other devices are usually installed at the drive end to measure the force of the rope and the position of the joints. Although these methods have been implemented in some robots, they still face many technical bottlenecks:

[0004] The problem of sensor quantity and cost: Each joint usually needs to be equipped with a separate force sensor and position sensor. For multi-degree-of-freedom flexible robots, this design means that a large number of sensors are required, resulting in high equipment costs.

[0005] Complex mechanical structure and wiring: The installation of sensors requires special mechanical design, and a large amount of wiring is required. Especially in multi-joint and multi-degree-of-freedom scenarios, the complexity of wiring is significantly increased, which is not conducive to the miniaturization and integration of the system.

[0006] Increased power supply demand: The increase in sensors not only increases the power supply demand, but also increases power consumption, affecting the robot's endurance and practicality in complex environments.

[0007] Control system complexity: High-density deployment of sensors will increase the complexity of signal processing and control, resulting in reduced system reliability.

[0008] Limited measurement accuracy: Traditional methods have difficulty meeting the requirements of real-time measurement while ensuring high accuracy, especially in highly dynamic environments where sensor data may be delayed or have accumulated errors.

[0009] For example, some flexible robots currently use independent joint torque sensor solutions to deduce the system state by directly measuring the torque of each joint. However, this solution requires the integration of torque sensors and corresponding electronic equipment on each joint, which increases the complexity and overall size of the robot mechanism. At the same time, under complex multi-joint structures, due to the limited accuracy of torque sensors, it still cannot meet the needs of some high-precision and high-dynamic applications.

[0010] Other technical solutions attempt to measure the system status through optical sensors or inertial sensors installed at the end, but such methods are often limited by the sensor's viewing angle or ambient light interference, resulting in reduced system performance. In addition, the power supply, maintenance and reliability issues of existing flexible robot measurement and control systems are still difficult to solve technical pain points in the case of high-density sensor layout.

[0011] In summary, the existing technology has significant deficiencies in the force and position perception of rope-driven multi-joint flexible robots: high cost of measurement units, complex wiring, high power consumption, insufficient control system stability, and low measurement accuracy. These problems are particularly prominent when facing scenarios with multiple degrees of freedom and multi-joint structures. Therefore, there is an urgent need for a low-cost, miniaturized, integrated force-position fusion measurement device that can achieve high-precision torque and angle measurement of the entire system while reducing the number of sensors to meet the application requirements of flexible robots in complex scenarios. Summary of the invention

[0012] In order to solve the technical defects in the prior art, such as high cost of measurement unit, complex wiring, large power consumption, insufficient control system stability and low measurement accuracy in the force and position perception of the existing rope-driven multi-joint flexible robot, the technical solution provided by the present invention is as follows:

[0013] A rope-driven flexible mechanical arm for force-position fusion measurement, the mechanical arm is in a slender curved shape as a whole, comprising:

[0014] A plurality of arm sections and rotating joints connected in series, wherein the arm sections are driven by ropes to achieve flexible movement;

[0015] Features:

[0016] The arm section is a hollow cone structure, and a rope guide groove is provided on the inner surface for accommodating and guiding the rope wiring;

[0017] The revolute joint realizes rotation with multiple degrees of freedom through a spherical hinge;

[0018] The rope is led out from the driving base of the mechanical arm and is routed along the inside of the arm section through the rope guide groove;

[0019] It also includes a force-position fusion measurement device, including:

[0020] A reduction motor is connected to the pulley and the rope through a ball screw to drive the rope to move;

[0021] a rope, one end of which is connected to the ball screw and the other end of which is extended by a tension spring;

[0022] The first and second reflective marking points are respectively arranged at the head and tail ends of the tension spring;

[0023] Vision camera is used to identify the spring deformation and the real-time displacement of the spring ends.

[0024] Furthermore, a preferred embodiment is provided, which also includes a plane mirror, which is fixed in the measuring device by a bracket and arranged at an angle of 45 degrees to the spring plane, and is used to reflect the virtual image of the reflective marking point.

[0025] Furthermore, a preferred embodiment is provided, wherein the reflective marking point one and the reflective marking point two are fixedly connected to the spring via a slide seat.

[0026] Furthermore, a preferred embodiment is provided, wherein the visual camera is a monocular camera.

[0027] Furthermore, a preferred embodiment is provided, wherein the surface of the reflective marking point is coated with a high reflectivity material.

[0028] Based on the same inventive concept, the present invention also provides a measurement method of a rope-driven flexible manipulator based on force-position fusion measurement, the method is implemented based on the manipulator, and includes:

[0029] The step of collecting real-time position information of reflective marking points at both ends of the extension spring;

[0030] The step of determining the deformation of the spring according to the displacement of the reflective marking point;

[0031] The step of obtaining the tension value of the rope according to the spring deformation and the spring stiffness parameter;

[0032] The step of obtaining the real-time torque information of each rotating joint in combination with the rope tension value;

[0033] Based on the displacement of the reflective mark point at the tail end of the spring and the rope length model, the step of obtaining the real-time rotation angle of each rotation joint;

[0034] Based on the displacement of the reflective mark point at the head end of the spring and the geometric relationship of the ball screw, the real-time rotation angle of the motor is obtained.

[0035] Based on the same inventive concept, the present invention also provides a measurement device of a rope-driven flexible manipulator based on force-position fusion measurement, and the device is implemented based on the manipulator, and includes:

[0036] A module for collecting real-time position information of reflective marking points at both ends of the extension spring;

[0037] A module for determining the deformation of the spring according to the displacement of the reflective marking point;

[0038] A module for obtaining the tension value of the rope according to the spring deformation and spring stiffness parameters;

[0039] A module that combines the rope tension value to obtain the real-time torque information of each rotating joint;

[0040] A module that obtains the real-time rotation angle of each rotation joint based on the displacement of the reflective mark point at the tail end of the spring and the rope length model;

[0041] A module that obtains the real-time rotation angle of the motor based on the displacement of the reflective mark point at the head end of the spring and the geometric relationship of the ball screw.

[0042] Based on the same inventive concept, the present invention also provides a computer storage medium for storing a computer program. When the computer program is read by a computer, the computer executes the described method.

[0043] Based on the same inventive concept, the present invention also provides a computer, including a processor and a storage medium. When the processor reads a computer program stored in the storage medium, the computer executes the method described.

[0044] Based on the same inventive concept, the present invention also provides a computer program product, which is a computer program. When the computer program is executed, the method described above is implemented.

[0045] Compared with the prior art, the technical solution provided by the present invention is beneficial in that:

[0046] This solution replaces the traditional solution that requires multiple tension sensors and motor encoders by introducing a tension spring and a visual measurement component (including a combination of a camera and a plane mirror) in the drive base, greatly reducing the number of sensors required by the system. This approach effectively reduces the manufacturing cost of the robot, simplifies the structural design of the equipment, and improves the integration of the system. Compared with traditional solutions, it can significantly reduce the complexity of mechanical design.

[0047] By observing the spring deformation and the displacement of the marking point with a visual measurement camera, the torque and angle of multiple joints were successfully measured simultaneously. This method avoids the need for complex wiring and power supply for traditional sensors, effectively reduces the power consumption and wiring difficulty of the system, and improves the applicability of the system in miniaturized design and the overall reliability of the robot.

[0048] This solution uses a plane mirror to measure the reflected image of the spring deformation, ensuring the accurate capture of the spring deformation. This method based on optical principles significantly improves the accuracy of the measurement data, while avoiding the measurement error problem caused by dynamic environmental interference in traditional sensor solutions. Compared with existing optical or inertial sensor solutions, it significantly enhances the measurement stability of the system in complex dynamic environments.

[0049] By simultaneously observing the reflective marking points of multiple tension springs with a camera, the synchronous measurement of joint torque and angle information is achieved. Compared with the traditional sensor-by-sensor measurement solution, this method greatly improves the measurement efficiency of the system, while reducing the complexity of signal processing and response delay, enabling the system to meet the real-time requirements in high-dynamic scenes.

[0050] This solution uses a special arrangement design of a monocular camera combined with a plane mirror array, so that the field of view of the entire system can cover the tension springs of all joints. This design not only further simplifies the hardware cost, but also realizes the centralized measurement of multiple degrees of freedom by reducing the number of visual units. Compared with the traditional multi-sensor solution, it has significant advantages in cost, space occupation and installation convenience.

[0051] The high stiffness parameter of the tension spring enables the system to directly convert the spring deformation into the force on the rope, thereby accurately calculating the joint torque. Compared with the traditional solution that requires an independent torque sensor, this method effectively reduces the complexity of the equipment and the loss of components while maintaining high-precision measurement, laying the foundation for the application of robots in high-precision, high-load tasks.

[0052] This solution realizes the systematic calculation of joint angles, motor rotation angles, and joint torques by combining formulated kinematic and mechanical models with visual measurement methods. Compared with the existing method of relying on multi-model distributed calculation, this solution not only reduces the complexity of data processing, but also improves the uniformity and stability of calculation results, providing a more reliable foundation for the intelligent control of the system.

[0053] It is suitable for applications in industrial automation, complex environment operations, smart medical care and other scenarios that require high-precision force and position control. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is the overall diagram of the rope-driven multi-joint flexible robot, including the actuator and the drive-measurement unit;

[0055] Figure 2 It is a schematic diagram of a single drive-measurement unit module;

[0056] Figure 3 Schematic diagram of the camera and measurement unit arrangement;

[0057] Figure 4 Schematic diagram of a plane mirror combination array.

[0058] Among them, 1 represents an actuator, 2 represents a measuring unit array, 3 represents a reduction motor, 4 represents a ball screw, 5 represents a pulley, 6 represents a rope, 7 represents a tension spring, 8 represents a slide seat, 9 represents a reflective marking point 1, 10 represents a reflective marking point 2, 11 represents a plane mirror, 12 represents a bracket, 13 represents a visual camera, and 14 represents a measuring module. DETAILED DESCRIPTION

[0059] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically:

[0060] Embodiment 1: This embodiment provides a rope-driven flexible manipulator for force-position fusion measurement, wherein the manipulator is in an elongated curved shape as a whole, and includes:

[0061] A plurality of arm sections and rotating joints connected in series, wherein the arm sections are driven by ropes 6 to achieve flexible movement;

[0062] Features:

[0063] The arm section is a hollow cone structure, and a rope 6 guide groove is provided on the inner surface for accommodating and guiding the rope 6 wiring;

[0064] The revolute joint realizes rotation with multiple degrees of freedom through a spherical hinge;

[0065] The rope 6 is led out from the driving base of the robot arm and is routed along the inside of the arm section through the rope 6 guide groove;

[0066] It also includes a force-position fusion measurement device, including:

[0067] The reduction motor 3 is connected to the pulley 5 and the rope 6 through the ball screw 4, and is used to drive the rope 6 to move;

[0068] A rope 6, one end of which is connected to the ball screw 4 and the other end of which is extended by a tension spring 7;

[0069] The first and second reflective marking points 9 and 10 are respectively provided at the head and tail ends of the tension spring 7;

[0070] The visual camera 13 is used to identify the spring deformation and the real-time displacement of the spring ends.

[0071] Specifically, they include:

[0072] Drive unit

[0073] The driving unit includes a reduction motor 3, a ball screw 4 and a pulley 5. The reduction motor 3 drives the movement of the traction rope through the ball screw 4, and the pulley 5 is used to guide and change the direction of the rope 6. The ball screw 4 is fixed in the module frame and is coaxially connected with the reduction motor 3, and the pulley 5 is located at the edge of the frame to ensure that the rope 6 can run smoothly.

[0074] The reduction motor 3 is cylindrical, the ball screw 4 is a linear rod, and the pulley 5 is a small circular component fixed on the bracket 12.

[0075] Rope 6 and tension spring 7

[0076] The rope 6 and the tension spring 7 are connected in series and form the core part of the measurement system. One end of the rope 6 is connected to the ball screw 4, and the other end is connected to the tension spring 7. The other end of the spring is fixed on the slide 8. Reflective marking points (9, 10) are installed at both ends of the tension spring 7 for visual measurement. The springs are arranged in a straight line in the frame to ensure that they are evenly stressed.

[0077] The rope 6 is made of a slender flexible material, and the tension spring 7 is a spiral structure with good elasticity and deformation.

[0078] Reflective marking points

[0079] The reflective marking points are respectively fixed at the head end and the end of the tension spring 7. The surface of the marking point is coated with a highly reflective material, which can clearly reflect light for the visual camera 13 to capture its position change.

[0080] The reflective marking point is a small round dot or square patch, which is fixedly connected to the spring and the slide seat 8.

[0081] Plane mirror 11 and bracket 12

[0082] The plane mirror 11 is fixed in the measuring module 14 through the bracket 12 and is placed at a 45 degree angle. The reflecting surface of the plane mirror 11 is parallel to the spring, and its function is to form a virtual image of the displacement of the spring and the reflective mark point and reflect it vertically to the visual camera 13.

[0083] Shape characteristics: The plane mirror 11 is a rectangular thin sheet, and the bracket 12 is a fixed structure made of metal material, and the mirror surface and the frame remain stable.

[0084] Vision Camera 13

[0085] The visual camera 13 is installed at a fixed position on the module frame, with the lens direction vertically aligned with the plane mirror 11, and is used to capture the virtual image of the reflective marking point in the plane mirror 11. The camera field of view covers all plane mirrors 11 and the spring array.

[0086] The visual camera 13 is a small rectangular box-shaped structure with a built-in monocular lens, supporting high-resolution image acquisition.

[0087] Framework

[0088] The frame structure is modular in design and is used to support and fix the drive unit, tension spring 7, plane mirror 11, camera and other components. The frame is made of lightweight metal or high-strength composite material and can withstand the dynamic load during the operation of the device.

[0089] The frame is rectangular in shape as a whole, and the interior is divided into multiple areas by multiple groups of support rods for arranging various components.

[0090] Measurement unit array

[0091] The measurement unit is composed of a plurality of drive-measurement modules 14 arranged in an array. Each module includes the above core components and can independently realize the force and position measurement of the corresponding joint.

[0092] A single module is in the shape of a cuboid, and the array structure is arranged according to the number of joints of the flexible robotic arm. The overall layout is compact and efficient.

[0093] Composition of actuator 1

[0094] The actuator 1 is composed of a plurality of cones and revolute joints, which are connected in series to form the whole arm body of the robot arm. Each cone is responsible for supporting and connecting adjacent joints, while the revolute joint is driven by a rope 6 to realize rotation in a specific direction.

[0095] Flexible design

[0096] The actuator 1 is made of lightweight and high-strength materials, such as carbon fiber or aluminum alloy, to reduce the weight of the robot arm while ensuring that it has sufficient rigidity to bear the load. The revolute joint adopts a flexible connection design, allowing it to move flexibly within a high degree of freedom.

[0097] Movement Mechanics

[0098] By connecting the measuring unit array 2 with the rope 6, the actuator 1 can realize multi-joint coordinated motion according to the tension and direction of the rope 6 to meet the needs of complex operation tasks. For example, it can realize actions such as grasping, rotating, and stretching.

[0099] Measurement cell array 2

[0100] The measurement unit array 2 is a key component for realizing synchronous measurement of joint torque and position, and its specific implementation is as follows:

[0101] Modular design

[0102] The measurement unit array 2 is composed of multiple drive-measurement modules 14, each of which works independently, including a reduction motor 3, a ball screw 4, a tension spring 7, a plane mirror 11 and a visual measurement component. The modular design facilitates maintenance, replacement and expansion to meet the requirements of different robot arm configurations.

[0103] Arrangement

[0104] The modules are arranged in an array inside the drive base. The arrangement is optimized based on the number and layout of the flexible robotic arm joints to ensure that each module can independently control and measure the torque and angle of a joint.

[0105] Measuring principle

[0106] Each module captures the displacement of the two ends of the tension spring 7 through the visual camera 13 and the plane mirror 11, and calculates the force and deformation of the rope 6 in combination with the tension model. Through the kinematic and mechanical relationship between the spring and the rope 6, the synchronous measurement of multi-joint parameters is achieved.

[0107] Compact layout

[0108] The compact layout of the measurement unit array 2 saves a lot of space, and the design of the plane mirror 11 array enables a single camera to measure multiple modules, which greatly reduces the hardware cost and complexity.

[0109] Gear motor 3

[0110] Motor Selection

[0111] The reduction motor 3 uses a high-torque, low-power servo motor to ensure that it has sufficient power output during the driving process and meets the needs of precise control.

[0112] Structural Configuration

[0113] The reduction motor 3 is connected to the ball screw 4 through a coupling, which converts the rotational motion of the motor into the linear motion of the screw. The motor adopts a compact design and is installed in a modular frame for easy fixing and maintenance.

[0114] Transmission ratio optimization

[0115] The reduction motor 3 provides precise motion control through a high reduction ratio design, ensuring that both speed and precision are taken into account in the process of driving the rope 6. At the same time, the control precision of the linear motion is further improved through the ball screw 4.

[0116] Control method

[0117] The reduction motor 3 receives real-time instructions through the communication interface with the control module, and its position, speed and acceleration are precisely controlled by the algorithm. Combined with visual measurement data, multi-joint coordinated motion is achieved.

[0118] Embodiment 2. This embodiment is a further limitation of a rope-driven flexible robotic arm for force-position fusion measurement provided in embodiment 1, and also includes a plane mirror 11, which is fixed in the measuring device by a bracket 12 and arranged at an angle of 45 degrees to the spring plane, and is used to reflect the virtual image of the reflective marking point.

[0119] Embodiment 3: This embodiment further limits the rope-driven flexible robotic arm for force-position fusion measurement provided in embodiment 1. The reflective marking point 1 9 and the reflective marking point 2 10 are fixedly connected to the spring via the slide 8 .

[0120] Embodiment 4: This embodiment further limits the rope-driven flexible manipulator for force-position fusion measurement provided in embodiment 1, and the visual camera 13 is a monocular camera.

[0121] Embodiment 5: This embodiment further limits the rope-driven flexible robotic arm for force-position fusion measurement provided in embodiment 1, and the surface of the reflective marking point is coated with a high-reflectivity material.

[0122] Embodiment 6: This embodiment provides a measurement method of a rope-driven flexible manipulator based on force-position fusion measurement. The method is implemented based on the manipulator provided in embodiment 1, and includes:

[0123] The step of collecting real-time position information of reflective marking points at both ends of the extension spring;

[0124] The step of determining the deformation of the spring according to the displacement of the reflective marking point;

[0125] The step of obtaining the tension value of the rope 6 according to the spring deformation and the spring stiffness parameter;

[0126] The step of obtaining the real-time torque information of each rotating joint in combination with the tension value of the rope 6;

[0127] Based on the displacement of the reflective mark point at the tail end of the spring and the rope 6 length model, the step of obtaining the real-time rotation angle of each rotation joint;

[0128] Based on the displacement of the reflective mark point at the head end of the spring and the geometric relationship between the ball screw 4, the real-time rotation angle of the motor is obtained.

[0129] Specifically, this embodiment aims to achieve high-precision measurement of the joint position and torque of each joint of a rope-driven multi-joint flexible robot through a force-position fusion measurement device. The device mainly includes a reduction motor 3, a ball screw 4, a pulley 5, a rope 6, a tension spring 7, a slide 8, a reflective marking point, a plane mirror 11 and a visual camera 13. By measuring the displacement of the spring deformation and the reflective marking point, the joint angle, the motor rotation angle and the joint torque are calculated. This embodiment adopts a centralized measurement method based on vision, which effectively reduces the hardware cost and simplifies the mechanism design, including:

[0130] Step 1: System initialization

[0131] Initialize the system to ensure that the rope 6 and the spring are in the initial state, and record the initial positions of the reflective marking points at both ends of the spring through a visual device (such as a camera) as reference points for subsequent measurements.

[0132] Detailed Description

[0133] First, the reduction motor 3 in the device pulls the rope 6 through the ball screw 4 and the pulley 5, driving the tension spring 7 to reset to its initial undeformed state. The visual camera 13 takes pictures of the reflective marking points at the head and tail ends of the spring and records their positions relative to the world coordinate system. At this time, the spring length and the positions of the two ends obtained by the camera are used as the initial reference data.

[0134] Step 2: Joint Angle Measurement

[0135] By measuring the change in the position of the tail end of the spring and combining it with the length model of the rope 6, the rotation angle of the joint is calculated.

[0136] Detailed Description

[0137] When the joint of the rope-driven flexible manipulator rotates, the traction rope pulls the tail end of the spring to move, and the visual camera 13 captures the new position of the reflective mark at the tail end. Since the total length of the rope 6 remains fixed, the rotation angle of the joint can be derived by calculating the remaining length of the rope 6 in the arm body. In other words, the displacement of the tail end mark and the change in the remaining length of the rope 6 jointly determine the rotation angle of the joint.

[0138] Step 3: Motor rotation angle measurement

[0139] By measuring the change in the position of the first end of the spring, the rotation angle of the ball screw 4 and the motor is calculated.

[0140] Detailed Description

[0141] The reduction motor 3 drives the rope 6 and the head end of the spring to move through the ball screw 4. The visual camera 13 measures the displacement of the reflective mark point at the head end of the spring, moving from the initial position to the new position. According to the distance moved by each rotation of the ball screw 4 and the reduction ratio of the motor, the actual rotation angle of the motor can be calculated by the displacement of the head end of the spring. This process directly converts the displacement data of the head end of the spring into the angle change value of the motor.

[0142] Step 4: Joint torque measurement

[0143] By measuring the spring deformation, combining the spring stiffness coefficient and the mechanical model, the torque of the joint is calculated.

[0144] Detailed Description

[0145] The visual camera 13 calculates the deformation of the spring by capturing the displacement changes of the reflective marking points at both ends of the spring. Combined with the stiffness parameters of the spring, the tension value of the spring is further calculated. Since the spring is directly connected to the traction rope, the tension it receives is equal to the tension of the traction rope. Through the known relationship between the rope 6 force and the joint torque, the actual torque value of each joint can be derived. This process ensures the measurement accuracy of the joint torque and can reflect the force condition of the joint in real time.

[0146] Step 5: Multi-joint synchronous measurement

[0147] By arranging the visual camera 13, the plane mirror 11 and the spring array, the synchronous measurement of the torque and angle of multiple joints can be achieved.

[0148] Detailed Description

[0149] The plane mirror 11 is fixed in the measuring module 14 at a specific angle to ensure that the reflective marking points at both ends of the spring form a clear virtual image in the mirror. The field of view of the visual camera 13 has been optimized to simultaneously observe the reflective marking points of multiple plane mirrors 11 and spring arrays, and obtain the deformation and position data of both ends of all springs. Combining the kinematic model and the mechanical model, the torque and angle information of all joints of the flexible robotic arm can be calculated synchronously. This design significantly improves the measurement efficiency, reduces the hardware complexity, and enhances the real-time response capability of the system.

[0150] Embodiment 7: This embodiment provides a measurement device of a rope-driven flexible manipulator based on force-position fusion measurement. The device is implemented based on the manipulator provided in embodiment 1, and includes:

[0151] A module for collecting real-time position information of reflective marking points at both ends of the extension spring;

[0152] A module for determining the deformation of the spring according to the displacement of the reflective marking point;

[0153] A module for obtaining the tension value of the rope 6 according to the spring deformation and spring stiffness parameters;

[0154] A module that obtains real-time torque information of each rotating joint in combination with the tension value of rope 6;

[0155] A module that obtains the real-time rotation angle of each rotation joint based on the displacement of the reflective mark point at the tail end of the spring and the rope 6 length model;

[0156] Based on the displacement of the reflective mark point at the head end of the spring and the geometric relationship between the ball screw 4, a module is used to obtain the real-time rotation angle of the motor.

[0157] Embodiment 8: This embodiment provides a computer storage medium for storing a computer program. When the computer program is read by a computer, the computer executes the method provided in embodiment 6.

[0158] Embodiment 9: This embodiment provides a computer, including a processor and a storage medium. When the processor reads a computer program stored in the storage medium, the computer executes the method provided in embodiment 6.

[0159] Embodiment 10: This embodiment provides a computer program product, which is a computer program. When the computer program is executed, the method provided in embodiment 6 is implemented.

[0160] Implementation Method XI: Combination Figure 1-4 This embodiment is described in detail by using specific examples to further describe the technical solution provided above. Specifically:

[0161] In order to solve the problems of high cost of measurement unit, large space occupied, increased power consumption, reduced control stability and low measurement accuracy in the force and position perception link of the traditional rope-driven multi-joint flexible robot, this embodiment proposes a rope-driven multi-joint flexible robot device with force-position fusion measurement.

[0162] The measuring device proposed in this embodiment is composed of a reduction motor 3, a ball screw 4, a pulley 5, a rope 6, a tension spring 7, a slide 8, a reflective marking point 1 9, a reflective marking point 2 10, a plane mirror 11 and a visual camera 13. The reflective marking point 1 9 and the reflective marking point 2 10 are respectively connected to the spring ends through the slide 8, so that the influence of the original length of the spring on the measuring mechanism can be ignored. The reduction motor 3 is installed to drive the traction rope through the screw, so that the spring ends move, that is, the two reflective marking points 1 9 and the reflective marking point 2 10 are displaced. The plane mirror 11 is fixed to the measuring module 14 through the bracket 12 and is placed at 45 degrees to the spring plane, so that the virtual images of the marking points at both ends of the spring in the plane mirror 11 will be perpendicular to the spring plane and parallel to the camera lens. Due to the unique optical principle of the plane mirror 11, the deformation of the spring is equal to the displacement of the virtual image in the plane mirror 11. The camera can directly observe the virtual image of the marking point in the plane mirror 11 to obtain the deformation of the spring and the displacement of the spring ends.

[0163] The steps to measure joint angles are as follows:

[0164] Step 1: The end of the spring connected to the traction rope is recorded as the tail end of the spring. At the initial time t0, the position x0 of the tail end of the spring relative to the world coordinate system can be measured by a visual device (such as a camera);

[0165] Step 2: After the joint rotates by angle q, at time t1, a visual device (such as a camera) can be used to measure the position x1 of the spring tail relative to the world coordinate system;

[0166] Step 3: Since the traction rope (whose length is fixed) is connected to the tail end of the spring, the distance the tail end of the spring moves is the distance the traction rope moves. When the total length of each traction rope is known, the length of the traction rope remaining in the arm body can be determined, recorded as the rope 6 length, and the corresponding rope 6 vector is obtained. In the rope-driven multi-joint flexible robot, the relationship between the rope 6 vector and each joint angle is:

[0167]

[0168] In the above equation, q represents the joint angle vector, that is, the angle of each joint in the rope-driven flexible manipulator. represents the joint angular velocity vector, that is, the rate of change of each joint angle of the rope-driven flexible manipulator over time, represents the joint angular acceleration vector, i.e., the rate of change of the angular velocity of each joint of the rope-driven flexible manipulator over time; l represents the rope 6 length vector, i.e., the length of the traction rope in the rope-driven flexible manipulator; i represents the rope 6 velocity vector, i.e., the rate of change of the rope 6 length over time; represents the acceleration vector of rope 6, that is, the rate of change of the velocity of rope 6 with time, represents the difference between the rope 6 acceleration vector and the rope 6 velocity derived from the joint angular velocity, It means that the difference between the acceleration of rope 6 and the joint angular velocity is converted into the joint angular acceleration vector through the pseudo-inverse Jacobian matrix. is the inverse function of the rope length function, is the pseudo-inverse of the Jacobian matrix of rope 6 length.

[0169] The steps to measure the motor rotation angle (equivalent to providing the function of the motor encoder) are as follows:

[0170] Step 1: The end of the spring connected to the ball screw 4 by the rope 6 is recorded as the head end of the spring. At the initial time t0, the position y0 of the head end of the spring relative to the world coordinate system can be measured by a visual device (such as a camera);

[0171] Step 2: After the joint rotates by an angle θ, at time t1, a visual device (such as a camera) can be used to measure the position y1 of the spring head relative to the world coordinate system;

[0172] Step 3: Since the ball screw 4 is connected to the head end of the spring, the distance the head end of the spring moves is the distance the screw moves. The distance the head end of the spring moves during the process of t0 to t1 is y1-y0. It is known that the stroke of the ball screw 4 is l for one turn, and the reduction ratio of the motor is n:1, then the motor rotation angle φ can be deduced to be

[0173]

[0174] The steps to measure joint torque (equivalent to providing the function of joint torque sensor) are as follows:

[0175] Step 1: A tension spring 7 is installed at one end of the traction rope, and the elongation ΔL of the tension spring 7 is observed visually (such as with a camera);

[0176] Step 2: The stiffness k of the tension spring 7 is a known quantity. Since the tension spring 7 is connected to the traction rope, the force F exerted on the tension spring 7 is k The pulling force F on the traction rope l Equal, the calculation formula is as follows:

[0177] F l =F k =k·ΔL (3)

[0178] Step 3: The traction rope is subjected to tension F l When , the universal joint of the rope-driven multi-joint flexible robot will rotate. When the Jacobian matrix of the rope 6 tension is known, according to the principle of virtual work, the relationship between the joint torque and the rope 6 force vector can be obtained as follows:

[0179] τ=Jt F l (4)

[0180] In the formula, J t is the Jacobian matrix of rope 6 tension, which is equal to the transpose of the Jacobian matrix of rope 6 length.

[0181] This embodiment introduces a tension spring 7 and a visual measurement component (including a combination of a camera and a plane mirror 11) into the driving base of the rope-driven multi-joint flexible robot, replacing the measurement scheme of the traditional flexible robot that requires the use of 24 tension sensors and motor encoders, thereby greatly saving the robot manufacturing cost and the difficulty of electrical wiring, and reducing the size of the mechanism.

[0182] Specific:

[0183] The 16-DOF flexible robot is composed of 24 drive-measurement modules 14 and an arm body (8 cone sections and 16 rotational freedom joints).

[0184] The torque information of 16 joints of the rope-driven multi-joint flexible robot can be measured by the camera-measured spring deformation and the mechanical model (Formulas 3 and 4) proposed in this embodiment;

[0185] The 16 joint angle information of the rope-driven multi-joint flexible robot can be measured by the camera proposed in this embodiment to measure the displacement of the reflective mark point at the end of the spring and the kinematic model (Formula 1);

[0186] The rotation angles of the 24 motors of the rope-driven multi-joint flexible robot can be obtained by measuring the displacement of the reflective marking point at the head end of the spring using the camera proposed in this embodiment and formula 2.

[0187] The technical solution provided by the present invention is further described in detail above through several specific implementation modes in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific implementation modes described above are not intended to be used as limitations on the present invention. Any reasonable modification and improvement of the present invention, combination of implementation modes and equivalent substitution within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rope-driven flexible manipulator for force-position fusion measurement, the manipulator being in an elongated curved shape as a whole, comprising: A plurality of arm sections and rotating joints connected in series, wherein the arm sections are driven by ropes to achieve flexible movement; Features: The arm section is a hollow cone structure, and a rope guide groove is provided on the inner surface for accommodating and guiding the rope wiring; The revolute joint realizes rotation with multiple degrees of freedom through a spherical hinge; The rope is led out from the driving base of the mechanical arm and is routed along the inside of the arm section through the rope guide groove; It also includes a force-position fusion measurement device, including: A reduction motor is connected to the pulley and the rope through a ball screw to drive the rope to move; a rope, one end of which is connected to the ball screw and the other end of which is extended by a tension spring; The first and second reflective marking points are respectively arranged at the head and tail ends of the tension spring; Vision camera is used to identify the spring deformation and the real-time displacement of the spring ends.

2. The rope-driven flexible manipulator for force-position fusion measurement according to claim 1 is characterized in that: It also includes a plane mirror, which is fixed in the measuring device through a bracket and arranged at an angle of 45 degrees with the spring plane and is used to reflect the virtual image of the reflective marking point.

3. The rope-driven flexible manipulator for force-position fusion measurement according to claim 1 is characterized in that: The first reflective marking point and the second reflective marking point are fixedly connected to the spring via a sliding seat.

4. The rope-driven flexible manipulator for force-position fusion measurement according to claim 1 is characterized in that: The visual camera is a monocular camera.

5. The rope-driven flexible manipulator for force-position fusion measurement according to claim 1 is characterized in that: The surface of the reflective marking point is coated with a high reflectivity material.

6. A measurement method for a rope-driven flexible manipulator based on force-position fusion measurement, characterized in that: The method is implemented based on the robotic arm of claim 1, comprising: The step of collecting real-time position information of reflective marking points at both ends of the extension spring; The step of determining the deformation of the spring according to the displacement of the reflective marking point; The step of obtaining the tension value of the rope according to the spring deformation and the spring stiffness parameter; The step of obtaining the real-time torque information of each rotating joint in combination with the rope tension value; Based on the displacement of the reflective mark point at the tail end of the spring and the rope length model, the step of obtaining the real-time rotation angle of each rotation joint; Based on the displacement of the reflective mark point at the head end of the spring and the geometric relationship of the ball screw, the real-time rotation angle of the motor is obtained.

7. A measurement device for a rope-driven flexible manipulator based on force-position fusion measurement, characterized in that: The device is implemented based on the mechanical arm according to claim 1, comprising: A module for collecting real-time position information of reflective marking points at both ends of the extension spring; A module for determining the deformation of the spring according to the displacement of the reflective marking point; A module for obtaining the tension value of the rope according to the spring deformation and spring stiffness parameters; A module that combines the rope tension value to obtain the real-time torque information of each rotating joint; A module that obtains the real-time rotation angle of each rotation joint based on the displacement of the reflective mark point at the tail end of the spring and the rope length model; A module that obtains the real-time rotation angle of the motor based on the displacement of the reflective mark point at the head end of the spring and the geometric relationship of the ball screw.

8. A computer storage medium for storing a computing program, characterized in that: When the computer program is read by a computer, the computer executes the method according to claim 6.

9. A computer, comprising a processor and a storage medium, characterized in that: When the processor reads the computer program stored in the storage medium, the computer executes the method of claim 6 .

10. A computer program product, being a computer program, characterized in that When the computer program is executed, the method according to claim 6 is implemented.

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