Research On Kinematics And Motion Planning Of Cable Driven Continuum Manipulator

The space robotic arm plays an increasingly important role in the exploration of human space.However,with the diversification of space-on-orbit tasks and the complexity of the working environment,there are more and more tasks in the narrow space environment,and the traditional space manipulators are difficult to perform these tasks due to their own structural constraints.Therefore,a continuous manipulator with excellent bending properties and adaptability to complex environmental features has become an important choice.In this paper,the research work on the cable-driven continuum manipulator is carried out in the context of the operation in a small space environment.Firstly,based on the detailed analysis of the functional requirements of the working manipulator in a narrow space environment,the mechanical system of the cable-driven continuum manipulator is designed and the physical prototype is developed,modeled on the structural characteristics and movement mechanism of the octopus tentacle.In order to realize the grasping function of the robot arm to the target object,an end flexible grabbing mechanism that is immune to the characteristics of the target object is studied,and its mechanical structure is designed.Secondly,according to the motion characteristics of the cable-driven continuum manipulator,the kinematic assumptions are proposed.On this basis,the relationship between the driving space,joint space and operating space of the manipulator is analyzed in detail.The analysis of these three spatial mapping relations is the forward and inverse kinematics analysis of the manipulator.In the analysis of the forward and reverse kinematics of the multi-joint section of the manipulator,the decoupling algorithm of multi-joint section kinematics and the numerical algorithm for obtaining inverse kinematics are proposed respectively.The simulation experiment is carried out in MATLAB environment.The experimental results verify the effectiveness and feasibility of the proposed algorithm.Then,an improved Monte Carlo method is proposed for the traditional Monte Carlo method to solve the problem that the robot is not accurate enough when it reaches the workspace.Aiming at the workspace obtained by the improved Monte Carlo method,a voxelization algorithm is proposed to obtain the volume of the workspace.In order to verify the validity and practicability of the proposed algorithm,a nine-degree-of-freedom redundant redundant manipulator is taken as an example to carry out simulation analysis.The results show that when the number of sampling points is the same,the improved Monte Carlo method has a smooth workspace boundary and “noise”;when the precise workspace is obtained,the number of sampling points required for the improved method is only 4.67% of the traditional method;The volumetric algorithm is more efficient and the relative error is less than 1%.Then,the normalized operability index is used to analyze the flexibility of the robot movement.The relationship between the maximum operability value and the joint angle number is obtained by numerical simulation method,and the maximum operability value is obtained.The evaluation index of the overall flexibility of the robot is analyzed,and the method of expressing flexible workspace is obtained.The algorithm for obtaining flexible working space is proposed.On this basis,the reachable workspace and flexible workspace of the cable-driven continuum manipulator are simulated and analyzed,and the maneuvering ability of the manipulator is evaluated.Finally,based on the principle of related algorithms in the Snake game,a motion planning algorithm based on the idea of "head traction" is proposed.The effectiveness and feasibility of the proposed algorithm are verified by the simulation experiments of plane path and space path.In order to verify the ability of the cable-driven continuum manipulator to work in a narrow space environment,a small space environment simulation experiment platform was built.Based on the workspace analysis,the narrow space environment was divided into regions,and a path planning algorithm based on regional travel strategy was proposed..The effectiveness and feasibility of the proposed algorithm are verified by simulation experiments.Experimental results show that the cable-driven continuum manipulator has the ability to work in a small space environment.