Design And Verification Of Planar Cable-Driven Multi-Body Robot

Based on the current research results of cable driven robot,this paper designs a planar cable driven multi-body robot,which can form a planar multi-link mechanism in series,using the advantages of low manufacturing cost,large workspace,small inertia and easy assembly and reconstruction of the rope traction robot.The cable distribution mode of cable driven multi-body system is deduced,and the deduced relationship is applied to the two-link and three-link mechanism of planar cable driven multi-body robot designed in this paper,and the optimized cable driven mode is calculated.The planar cable driven multi-body robot designed in this paper includes structure module,hardware module and software module(optimization module).The structure module can also be divided into rod module,limit module,joint module and rope module.The hardware module is divided into rope driving module,motion control module and data acquisition module,which is used to control the motor so as to control the collection and release of the cable and collect the pull data at the same time.In this paper,the null space method is used to solve the system workspace,and the analytical solution of the boundary of wrench closed workspace is deduced.Also the wrench feasible workspace is solved.On the basis of solving the workspace,an optimization method is proposed to optimize the motor position of plane cable driven multi-body system and the traction position of cable on the connecting rod.Under the premise of ensuring that the planned trajectory is within the wrench feasible workspace,the wrench feasible workspace is maximized.This optimization method is the optimization module of this paper.Optical three-dimensional motion capture system is used to measure the size and range of upper limbs,and the trajectory of three-link mechanism is planned according to the measured data.The configuration is optimized by optimization method.The D-H method is used to analyze the kinematics of the three-link mechanism,and the kinematics equation is deduced.The change of the length of the rope in the whole period is calculated,and the rope speed and acceleration are also calculated.The dynamic analysis is carried out by using Lagrange equation method,then the joint moment and the cable tension are calculated.Finally,according to the design of the cable driven multi-body robot in this paper,two-link mechanism and three-link mechanism are built to carry out experiments.The actual trajectory of the mechanism is measured and compared with the theoretical trajectory.The actual pulling force of the rope is measured and compared with the theoretical pulling force,which verifies the correctness of the kinematics dynamics analysis and optimization method mentioned above.