Cable Physical Property Research And Robot Joint Stability Analysis In Space Environment

Soft cables exist widely in the space robot body,and bear important functions such as information transmission and power transmission.The shielded carrying cable will become extremely hard and heavy under the coupling of multiple physical fields such as space and moon,high and low temperature,strong radiation,and gravity,but the space robot joint will be very weak under strict environmental constraints.During the movement of the space robot,the soft cable bends and deforms as the robot body moves,which causes strong nonlinear interference to the weak and small robot joints,causing the robot joints to vibrate.Therefore,studying the physical characteristics of the space cable during the robot's motion and the interference torque produced by the robot's joints is of great significance for improving the accuracy and stability of the space robot's end operations.In this paper,a nonlinear static model for space cables and a complex environment constraint model are established.A new optimization algorithm is proposed to solve the model effectively.Based on this,the interference torque generated by the space cable to the robot joint is analyzed and solved,and the stability of the space robot joint is studied,which provides theoretical support for the design and development of the space exploration moon robot.The main research contents of this article are as follows:(1)Study on the establishment and solution of nonlinear static model of cable.This paper studies the basic physical characteristics of space cables from the aspects of cable curvature,torsion and torsion angle,and establishes a nonlinear static model of space cables.The differential quadrature method is used to discretize the equation,and a new optimization algorithm is proposed to solve the model effectively.In addition,this paper proposes an iterative initial value search strategy to quickly find a suitable initial value for the iteration.(2)Study on the establishment and solution of nonlinear static model of cable under complex space constraints.Limited by environmental resources,space robot cables are constrained by obstacles such as points,planes,and curved surfaces in the operating environment.Considering the gravity,friction,and environmental constraints of the space cable in the space environment,this paper establishes a complex environmental constraint mechanical model of the space cable,and proposes an optimization algorithm with constraints to solve the model.(3)Research on robot joint stability.The mechanical model of the space robot joint was established,the nonlinear interference torque generated by the space cable to the robot joint was studied,and the variation law of the interference torque at different speeds of the robot joint was analyzed.(4)Experimental verification.A space robot joint test platform was set up,and the theoretical calculation results and actual measurement results of the interference force of the space cable on the robot were compared for different environmental constraints.The calculation errors of the cable shape were compared to verify the correctness of the proposed model.