Design And Experiment Of Bionic Flexible Manipulator For Aerospace Demand

With the continuous development of science and technology and aerospace demand,the requirements for the operation and maintenance of spacecraft's autonomous tasks are increasing.Combining aerospace intelligent robots with spacecraft can replace astronauts to complete space construction,on-orbit assembly,target detection and pollutant treatment in spacecraft,greatly reducing the astronauts' on-orbit tasks and safety hazards,and has become an important development direction of technology.Space robots are also becoming the core equipment for onorbit services.This paper is based on the actual spacecraft's narrow space operation requirements,and uses the elephant trunk as a biomimetic object to design and manufacture a bionic flexible manipulator for aerospace applications.According to the structural characteristics of the inner part of the elephant trunk,a flexible joint with the function of “two turns and one shift” is proposed.According to the abstract function of the proposed flexible joint,a UCR parallel configuration joint with three degrees of freedom is designed.The characteristics of the branch are analyzed,and the motion law and constraints of the flexible joint moving platform are obtained.According to the configuration scheme of the flexible joint,two prototypes are designed and developed,and the configuration scheme is compared and selected.Based on the selected configuration scheme,the kinematics model is established.Based on the driving equation and the constraint equation,the description method of the flexible joint attitude is analyzed,and the velocity equation is established.The mapping relationship between the flexible joint driving space velocity and the effective control space velocity is obtained.Using Catia to complete the modeling and assembly of the parts,the DMU visual motion simulation platform was established to intuitively reflect the motion characteristics of the bionic flexible mechanical arm.The finite element analysis of the flexible joint was performed using Abaqus software,and the flexible joints were subjected to different types of load critical conditions.Combined with the motion subspace and interference conditions of the flexible joint,the constraints of the search space are analyzed and the workspace simulation platform based on Matlab-Simmechanics is established.The proposed search algorithm is used to solve the numerical joint space of the flexible joint.Based on the Monte Carlo method,the evaluation model of the flexible joint working space is proposed.The influence of the dimension of the evaluation matrix on the evaluation of the workspace is analyzed,and the evaluation effect of each evaluation dimension interval on the workspace is obtained.A series model of flexible joints is proposed to propose a achievable method for the workspace of bionic flexible manipulators composed of multiple flexible joints.Design a control system for the bionic flexible manipulator.The modular design of the control system based on the hierarchical and progressive relationship,including the hardware and software level of the microcontroller module,the drive module,the host computer design and the embedded system design,etc.,to achieve the specific operation of the space environment for the realization of the bionic flexible mechanical arm The task provides the basis for control.The imitation gravity experiment platform was designed and built.The planning operation of the bionic flexible manipulator was completed based on the microgravity experiment platform.According to the experimental data and theoretical analysis,and referring to the actual motion characteristics of the elephant trunk,the motion planning strategy of the bionic flexible manipulator swing was completed.The multi-obstacle structure of space is constructed,and the short-space obstacle avoidance strategy of bionic flexible manipulator is proposed.The obstacle avoidance experiment in narrow space is completed,and the end effector which can realize soft grip is designed.The surface can be fragile and the curvature is better.The large surface achieves a smooth grip.It is thus verified that the bionic flexible manipulator designed and developed can meet the mission operation requirements for aerospace environments.