Design And Mobility Analysis Of A Mobile Robot Based On Planar 6R Single-loop Kinematic Chain

Closed-chain link mobile robots are a kind of ground mobile robots with large-scale deformation ability and high obstacle surmounting ability.At present,the research on closed-chain link mobile robots mainly focuses on the feasibility of mobile,but there are few studies on its locomotivity and evaluation system.Based on the theoretical research of the planar 6R single-loop kinematic chain,this paper proposes a mathematical model for the movement of a closed link robot based on the planar 6R single-loop kinematic chain.Kinematics analysis,dynamics analysis and gait planning are carried out.The mobility theory of the 6R robot is put forward.The new theory obtains the general gait solution of the continuous movement and obstacle surmounting process of this kinematic chain.In addition,the performance of fast gait and stable gait is improved compared with the theoretical analysis of the contrast gait,which is analyzed and demonstrated in detail.First of all,it is clear that the application scope of the theory is the closed-chain link mobile robot whose motion plane can be equivalent to planar 6R single-loop kinematic chain in the process of motion.The kinematics model of planar 6R singleloop kinematic chain is established,and the mathematical relationship between the input driving angle and the output centroid position is obtained.The single-step kinematics of planar 6R single-loop kinematic chain is analyzed.According to this strategy,a unified gait expression form,namely gait periodic table,and a unified evaluation index are proposed.Through the analysis of the control gait,the parameters of velocity and centroid fluctuation are obtained,and the faster gait and the more stable gait with less centroid fluctuation are obtained through optimization.The analysis results are consistent with the simulation results.The multi-step kinematics of planar 6R single-loop kinematic chain is analyzed.A unified obstacle crossing strategy for different kinds of obstacle is proposed,that is,the normalized obstacle crossing strategy.For the same kind of obstacle with different parameters,the general solution of gait is present.The continuity of the kinematic chain is analyzed,and the position of the center of mass in the global coordinate system are obtained.The analysis results are consistent with the simulation results.The dynamics of planar 6R single-loop kinematic chain is analyzed.Based on Lagrange's dynamic equation and D'Alembert's principle,the dynamic model of the kinematic chain is established.Taking the input angle of fast gait as an example,the torque-time curve is obtained.The analysis results are consistent with the simulation results,and two dynamic optimization schemes are proposed.Taking the spatial steering function of planar 6R single-loop kinematic chain as an example,its spatial structure is discussed.The planar 6R single-loop kinematic chain is spatially extended from two directions,and the spatial mechanism is constructed to make it have spatial steering ability.According to the theory,a prototype with spatial steering function is designed,and3 D model,virtual prototype experiments and prototype experiments are carried out to verify the correctness of the theory.This paper proposes a research method and evaluation system for the structure and performance optimization of the closed-chain link mobile robot.