Study On Obstacle Performance Mechanism Of Closed Five-bow-shaped-bar Linkage

This paper is proposed for Closed Five-bow-shaped-bar in unstructured environment.Closed Five-bow-shaped-bar consists of five identical bow rod end module series.The weight of each member is equal to the module and the center of mass is at the midpoint of the joint of the adjacent modules.When the five joint angle is 108 o,the outer contour of the connecting rod is closed five arch shape,CG and CG coincidence.When a single rod touches the ground,the planar quasi-Static Rolling can be realized by the gravity moment mechanism generated by the offset of CG.In order to facilitate the analysis and expression,the terrain of obstacles is usually simplified as the terrain with typical characteristics,such as slope,step,continuous step,convex platform and channel.This paper uses the step and slope obstacles to examine motion performance of Five-bow-shaped-bar.Firstly,Closed Five-bow-shaped-bar was researched by quasi static bow tumbling process,and conducted by quasi static kinematic analysis;kinematic and geometric constraints was analyzed in the process of obstacle analysis,the biggest obstacle analysis model of Closed Five-bow-shaped-bar was set up,and the curve affected by the maximum obstacle height curve with contact angle and joint circle radius was obtained using numerical algorithm.Then,ding to the characteristics of the CG of the boundary of the feasible region of concave curve,the motion of CG system obstacle process path was planned in accordance with the shortest route strategy and tangent method,and then the inverse solution of active joint trajectory is obtained by kinematics,and the curves of quasi static frictional coefficient of maximum static obstacle was calculated through the stress relationship.Secondly,climbing force analysis model was established and gradient expression was calculated in the active joint angle constraints,the maximum slope and roll angle of the curve was obtained using numerical algorithm,the maximum static friction coefficient was calculated through the curve of force.Motion planning of constant CG offset speed climbing was made for calculating the active joint trajectory.Finally,the correctness of the analysis results was verified by the obstacle climbing process of the prototype experiment.Establishment and solution of CG kinematics model of Closed Five-bow-shaped-bar provides a theoretical basis for the study of quasi static obstacle and constant CG climbing process.