Study On The Dynamics Of A Novel Quadruped Walking Robot With Serial-Parallel Hybrid Structure

A novel quadruped robot with hybrid leg structure was proposed in this paper.An reverse coordinate equation of the robot base on generalized input was established by introducing the tensor analysis theory and the screw theory.The dynamic load was coordinated by using genetic algorithm based on the anti-slip performance of the robot.The dynamics of the robot was analyzed by this method.A new method to analyze kinematics was presented by using the screw theory and Lie groups and Lie Algebras combined with tensor analysis.This method provides a new way to analyze the kinematics of the mechanism,and has certain theoretical value and guiding significance.Firstly,the kinematics analysis of the hybrid leg mechanism was carried out,and the inverse kinematics model and the forward solution method are obtained.By using the coordinate transformation rule the kinematics problem of the robot is transformed into the kinematics problem of a single leg to solve the kinematics of the whole robot,and the kinematics of the robot was simplified in this way.The utilization rate of driving force of the leg mechanism was presented in this paper.The key structural parameters of single leg mechanism were optimized by using genetic algorithm based on this rate.Aiming at the problem of single objective optimization the composition of the parameters was changed and the further multi objective optimization based on genetic algorithm was carried out by introducing weighted index.The results show that more comprehensive capability could abtained by this improved algorithm.Two methods were used to analyze the dynamics of leg mechanism,including the Lagrangian dynamics method and the method combined New-Euler equations with the influence coefficient method.The kinematics and dynamics of the leg mechanism were calculated by using MATLAB.The kinematics and dynamics simulation of the mechanism were carried out based on ADAMS and the result agreed well with the calculated results,which showed the validity of the prototype model built in the environment of ADAMS.And the accuracy of the kinematics and dynamics model was verified in the same way.It lays the foundation for further kinematic and dynamic control of the robot.Finally,by regarding the force of each supporting foot of robot as the generalized input,the inverse coordination equation of the robot was established by introducing the antisymmetric tensor.The virtual load of the robot was defined and the angles between the force on each supporting foot and the normal direction of the ground were taken as the index to evaluate the anti-slip performance,and the dynamic load coordination optimization was carried out based on genetic algorithm.The dynamic load of the robot was calculated based on New-Euler equations and the theory of relative motion in theoretical mechanics.The dynamic problem of the robot was solved by using New-Euler equations and the coordination method above.The varying curve of the angle between the support force of each end of the foot and the normal direction of the ground was obtained,and the phenomena in the movement of the robot were analyzed combined with the gait of the robot.The research in this paper laid a foundation for the kinematic and dynamic control of this novel quadruped robot,and it also had a certain reference value for the kinematics and dynamics research of hybrid mechanism and quadruped robot with hybrid leg structure.