Research And Design Of A Cable-driven Robot Arm

After more than half a century of development,traditional robot arms have made outstanding contributions in many fields such as industrial production,environmental detection,military activities,medical services and so on,thanks to their advantages of high speed,high precision and strong robustness.As human requirements for robot arms increase,the drawbacks of conventional robot arms are also gradually exposed,such as weak applicability,large joint volume,large structural mass,high moment of inertia,and low payload capacity,low flexibility and high price.Therefore,a novel transmission method is needed to overcome the defects of the traditional robot arm,and the cable-driven technology provides a feasible idea.Based on the cable-driven technology,a six-degree-of-freedom series robot arm with the ability to track visual targets is proposed.First of all,the mechanical design of the cable-driven robot arm was carried out.Since the cables can transmit force and motion from a long distance,the motor and the reducer are moved from the joint to the base so that the joint mass and the moment of inertia are greatly reduced.At the same time,scroll springs and one-way bearings have been innovatively used to design the cable-driven automatic tensioning device,which solves the problem of one-way transmission and automatic tensioning of cables.After that,the experimental prototype was built,and related analysis and visual tracking experiments were carried out.Secondly,the kinematics analysis of the proposed cable-driven robot arm is carried out.Through the establishment of the kinematics of the cable-driven robot arm and the equation of kinematics,the workspace of the cable-driven robot arm is obtained.And through the analysis of the influence coefficient curve of the workspace,the link and joint angles that have the most obvious influence on the workspace are determined,which provides reference for the subsequent optimization work.Then,related research on robot arm navigation based on ROS(Robot Operation System)was carried out,and a circuit control system was designed.Through the construction of the robot arm simulation platform,the task of solving the positive kinematics,inverse kinematics,and visual target tracking of the cable-driven robot arm is completed.In addition,based on STM32,joint angle measurement,robot arm initialization,motor control and other functions are realized.Finally,the performance of the robotic arm prototype was tested in terms of the self-tensioning device tensioning effect,the robotic arm performing the target trajectory,and the robotic arm tracking visual target.The test results show that the self-tensioning device can ensure the tension and service life of the rope drive system well;the target trajectory accuracy can reach 1.1mm;the tracking vision target accuracy can reach 2.6mm.The experimental results show that the proposed cable-driven mechanical arm has good performance and can realize the expected requirements.