CN-121989251-A - Multi-degree-of-freedom mechanical arm based on spherical configuration and decoupling driving and control method thereof

CN121989251ACN 121989251 ACN121989251 ACN 121989251ACN-121989251-A

Abstract

The invention discloses a multi-degree-of-freedom mechanical arm based on spherical configuration and decoupling driving and a control method thereof, wherein the mechanical arm comprises a master arm mechanism, a slave arm mechanism, a control system, a communication module and an upper computer algorithm interface, a mechanical body of the mechanical body adopts a six-degree-of-freedom serial joint configuration, a wrist adopts a space offset design to optimize singular point distribution and expand effective working space, a connecting rod type clamping jaw driving mechanism is arranged at the tail end, each joint integrates a high-precision brushless direct current motor and a moment sensor, the control system adopts a CAN bus distributed motor control architecture, a multi-control mode is supported, a gravity compensation algorithm is built in the control system, the master-slave teleoperation mechanism realizes low-delay action synchronization and bidirectional force feedback, and the upper computer is compatible with ROS2 and multi-language SDK and integrates a body-building intelligent training frame in advance. The invention has the characteristics of high precision, low cost and easy deployment, and is suitable for scenes such as scientific research education, intelligent algorithm training with body, man-machine cooperation, remote operation and the like.

Inventors

ZHAO MINGBO
WANG YANDONG
LIU FUTENG
SUN DIANKAI
Huang Jiacui
ZHANG HONGTAO

Assignees

东华大学

Dates

Publication Date: 20260508
Application Date: 20260327

Claims (10)

1. The multi-degree-of-freedom mechanical arm based on spatial series configuration and algorithm decoupling is characterized by comprising a master arm mechanism, a slave arm mechanism, a control system, a communication module and an upper computer algorithm interface, wherein the master arm mechanism is used for capturing the action of an operator, the slave arm mechanism realizes synchronous motion according to the motion data of the master arm mechanism, the communication module realizes the information interaction of the master arm mechanism, the slave arm mechanism and the control system, the upper computer algorithm interface is used for algorithm deployment and self intelligent data acquisition; The arm of the mechanical arm body is 680mm, the rated load is 2.5kg, the first joint movement range is-180 degrees to +180 degrees, and the repeated positioning precision is +/-0.1 mm.
2. The multi-degree-of-freedom mechanical arm according to claim 1, wherein each joint of the mechanical arm body is provided with a high-precision brushless direct current motor and a torque sensor, the motor and the speed reducer are connected in a modularized mode through a mounting seat, the mechanical arm body adopts an aluminum alloy and carbon fiber mixed structure, and a standard mounting flange is arranged on a base to support the installation of a tabletop fixing or moving platform.
3. The multiple degree of freedom mechanical arm of claim 1 wherein the linkage jaw drive mechanism incorporates a force control feedback mechanism to effect over force protection based on motor current signals and the system automatically stops jaw closing when current is detected to exceed a preset threshold.
4. The multi-degree-of-freedom mechanical arm according to claim 1, wherein the control system adopts a distributed motor control architecture based on a CAN bus, the transmission rate is 1Mbps, each joint motor node has a unique ID address, synchronous instruction broadcasting and state readback are realized, the control period of the control system is 400Hz, the overall control delay is lower than 4ms, the power supply voltage is 24V, and the overall power is about 200W.
5. The multi-degree of freedom mechanical arm of claim 1, wherein the control system supports MIT moment mode, position control mode and hybrid control mode, built-in gravity compensation algorithm and joint space trajectory planning, end effector operation space control function, the control system further integrates limit detection and scram protection mechanism, and the control panel is provided with an overcurrent, overtemperature and short circuit protection module.
6. The multi-degree-of-freedom mechanical arm according to claim 1, wherein the main arm mechanism is provided with six high-precision servo motors for collecting joint position, speed, acceleration and motor state information of an operator in real time, the master-slave teleoperation mechanism transmits motion data through a high-speed communication module, the slave arm controller generates a target joint command through real-time calculation according to the state of the main arm, the motion synchronization is realized through a regulation algorithm, and a force feedback channel is supported, so that the slave arm can return external force contacting with the main arm to the main arm through a current loop estimated moment.
7. The multi-degree-of-freedom mechanical arm according to claim 1, wherein the upper computer algorithm interface is connected with ROS2 and a custom SDK to provide Python and C++ programming interfaces, and the upper computer pre-integrates a body intelligent training framework to collect position, speed, moment and visual data of main arm operation for simulating learning and reinforcement learning training.
8. A control method of a multi-degree-of-freedom mechanical arm based on spherical configuration and decoupling driving, which is applied to the multi-degree-of-freedom mechanical arm according to any one of claims 1 to 7, and is characterized by comprising the following steps: S1, initializing a system, completing zero calibration of each joint of the mechanical arm, and configuring a control mode, threshold parameters and transmission parameters of a communication module of a control system; S2, the upper computer receives a target track or task instruction input by a user, and if the target track or task instruction is in a master-slave teleoperation mode, the master arm mechanism acquires joint motion data of an operator in real time and transmits the joint motion data to the control system; s3, the control system calculates a target track, a task instruction or main arm motion data based on the PoE kinematic model to obtain a desired pose of the mechanical arm and a corresponding inverse joint resolution angle; S4, the control system sends control instructions to the joint motor nodes through the CAN bus, performs track interpolation control, drives the joints of the slave arm mechanism to move in a coordinated manner, and realizes pose adjustment of the end execution unit or grabbing action of the clamping jaw; S5, the torque sensor and the encoder of each joint acquire motor current and joint position feedback information in real time and transmit the motor current and the joint position feedback information back to a control system through a CAN bus; And S6, the control system updates the control loop according to the feedback information, calculates a control instruction of the next period by combining the gravity compensation model and the PD control algorithm, and returns to the step S4 to continuously execute until the target track or the task instruction is completed.
9. The control method according to claim 8, wherein in the PoE kinematic model calculation in step S3, dynamic compensation is synchronously completed, gravity moment of each joint is calculated based on the model and is counteracted in real time, and inertial disturbance caused by the dead weight of the arm body is reduced.
10. The control method according to claim 8, wherein in step S4, when the jaw motion is performed, force control feedback is performed by a motor current signal, if the current exceeds a preset threshold, the jaw closing motion is stopped immediately, and the control system is controlled by an upper computer to realize position control, speed control and switching of a gravity compensation mode, so as to prevent control conflict.

Description

Multi-degree-of-freedom mechanical arm based on spherical configuration and decoupling driving and control method thereof Technical Field The invention belongs to the technical field of intelligent robots, and particularly relates to a multi-degree-of-freedom mechanical arm based on spatial series configuration and algorithm decoupling and a control method thereof, which are suitable for application fields of scientific research education, intelligent algorithm training with bodies, man-machine cooperation, remote operation and the like. Background The cooperative mechanical arm is used as a core component of the intelligent robot and is widely applied to the fields of assembly, carrying, grabbing, scientific research experiments and the like. The existing typical products comprise a UR5 cooperative mechanical arm and a ark X5 mechanical arm, but the UR5 cooperative mechanical arm and the ark X5 mechanical arm have a plurality of defects in application facing scientific education and body intelligent scenes. The UR5 cooperative mechanical arm adopts a six-degree-of-freedom space series offset configuration, and has longer arm extension and high repeated positioning precision. However, the physical structure of the aspheric wrist leads to extremely complex kinematic solution, and the aspheric wrist has a selling price as high as 22 Yuan people's coins, is difficult to be deployed in a large scale in the field of scientific research and education, and in addition, only provides a basic control SDK interface, the system is relatively closed, the integration of a front-edge AI framework is lacking, the complex algorithm or the custom model is integrated, a user is required to complete complex bottom engineering deployment by himself, and the operation difficulty and the development threshold are high. Although the square boat X5 mechanical arm has lower detection on price, the flexibility of the spatial configuration is limited, the arm expansion is only 620mm, the first joint movement range is-120 DEG to +180 DEG, the movement range is limited, the rated load is 2kg, the load requirement of part of scientific research scenes cannot be met, the tail end clamping jaw adopts a rack driving structure, the cost is high, the damage is easy to consume, the maintenance cost is high, meanwhile, the SDK of the mechanical arm only provides a basic interface, a user needs to develop and integrate a complex algorithm by himself, the engineering complexity is high, the whole selling price still reaches 5 ten thousand primordial notes, and the popularization threshold is still high. In summary, the existing cooperative mechanical arm has the problems of high cost, limited arm expansion and joint movement range, low load capacity, defective clamping jaw driving structure, complicated algorithm deployment and the like, and cannot adapt to the application requirements of low cost, easy deployment and high expansibility in the field of scientific research and education, so that a multi-degree-of-freedom mechanical arm solution with high precision, low cost, easy operation and rapid algorithm deployment is needed. Disclosure of Invention Aiming at the technical problems of high cost, limited arm expansion, insufficient joint movement range, complex and easy loss of a clamping jaw structure, difficult algorithm deployment, limited load capacity and the like of the traditional cooperative mechanical arm, the invention provides a multi-degree-of-freedom mechanical arm based on spherical configuration and decoupling driving and a control method thereof, and aims to provide a set of master-slave teleoperation mechanical arm system which is low in cost, easy to deploy, high in precision and supports integration of intelligent algorithms of a tool body, so that the movement stability and repeated positioning precision of the mechanical arm are improved, and meanwhile, high-precision action acquisition and real-time mapping are realized through a master-slave teleoperation control framework, so that an ideal experiment and application platform is provided for training, verification and interactive control of the intelligent model of the tool body. In order to achieve the above purpose, the present invention adopts the following technical scheme: A multi-freedom-degree mechanical arm based on space series configuration and algorithm decoupling consists of a master arm mechanism, a slave arm mechanism, a control system, a communication module and an upper computer algorithm interface, and the functions and the structural design of each part are as follows: The master arm mechanism is provided with six high-precision servo motors, and the core function is to capture the action of an operator in real time, collect the motion data such as joint position, speed, acceleration, motor state and the like, and provide a data base for the synchronous motion of the slave arm mechanism. The slave arm mechanism is a mechanical arm body with six-degree-