Research On Design And Motion Control Of Closed-loop Cable-driven Segmented Linkage Robot

The cable-driven redundant robot has the advantages of slim body and flexible movement,so it has great application potential in a small space and can be used for equipment monitoring,assembly and maintenance.The dimension of the drive space of the traditional cable-driven redundant robot is 1.5 times that of the joint space,that is,3motors drive 2DOF joint,the hardware cost is high and the motion control is complicated.Based on this,this paper designs a robot system that uses a segmented linkage structure and a closed-loop cable-driven mode to achieve the consistency of the drive space dimension and the joint space dimension,which greatly reduces the cost and simplifies the motion control.In response to the requirements of narrow space operations,a robot system scheme with a segmented linkage structure and a closed-loop cable-drive mode is proposed,which achieves the goal of large-scale joint motion and minimal motor drive.The subjoints in the linked arm section under this structure have the characteristics of equal-angle motion.The cable drive redundant robot system is designed with multiple linked arm sections as the main structure.The designed pulley-guided closed-loop cable-driven form greatly reduces the quality of the drive control box and size.Compared with the existing similar robots,the robot has more flexible joint motion range,lighter overall weight,and better potential for motion in narrow spaces.Based on the structural characteristics of the designed closed-loop cable-driven segmented linkage robot,a multi-layer kinematics model of "drive space-joint spaceoperation space" is derived,and the inverse motion solution and trajectory planning based on the simplified jacobian matrix are proposed.The geometric method is used to solve the problem of the working space boundary of the linkage arm section and the working space of the entire arm is analyzed,which provides guidance for motion control planning.Aiming at the characteristics of the rigid-flexible hybrid segmented linkage of the robot,a simplified equivalent kinematics model based on virtual joints is established,and the traditional Forward and Backward Reaching Inverse Kinematics(FABRIK)and Cyclic Coordinate Descent(CCD)inverse kinematics solving algorithms are improved.Compared with the traditional jacobian pseudo-inverse method,the calculation is high efficiency in speed.According to the state-space mapping,the spatial control hierarchy mapping architecture is designed,and the cable-driven manipulator motion control system is built based on Robot Operating System(ROS).Based on the above research,the system prototype was developed and related test experiments were carried out,including the verification test of the ball rolling joint,the performance test of the linkage arm section and the whole machine test.The experimental results show that the developed robot prototype achieves the required functions and performance indicators.