Dynamic Modeling And Motion Control Of LCS Quadruped Robot

Quadruped animals have so strong ability to move and various forms of motion that they can adapt to a variety of terrain,so they have become a hot research object on bionic robots field.This paper mainly studies foot trajectory optimization,kinematics and dynamics analysis,gait planning and numerical simulation on the LCS-I quadruped robot.1)Based on the early LCS-leg structure designed in the laboratory,the robot's forward and inverse kinematics is solved by using the methods with foot position decoupling and joint data fitting.Based on the cheetah robot's three-stage foot trajectory design,a quintic Bessel curve is designed as second-order continuously differentiable foot trajectory.The optimized foot trajectory curve is obtained by using Matlab and Isight to minimize its acceleration change rate and constrain the known position and speed at the end points of the head and the tail.The validity of the designed foot-end trajectory curve is verified by comparing with other types of foot-end trajectory curve.2)On the basis of Cartesian coordinate system and driving joint angle,Lagrange dynamic equation is established by pseudo inertia matrix and transfer matrix.The correctness is verified of the deduction process by Matlab-SimMechanics.The methods are briefly introduced and analyzed of the stability margin and polygon stability.The numerical calculation methods are described and expanded of diagonal motion stability.At the same time,the calculation methods are extended of improving body stability with biped motion.3)A motion planning method planar is proposed of LCS-I quadruped robot's tripod gait(Walk)and diagonal gait(Trot)on the omnidirectional straight line and in-situ turning motion.Based on the discrete exponential reaching law and the input anti-saturation sliding mode structure,the numerical tracking is realized of discrete and continuous leg joint angle on the LCS-I quadruped robot.The sliding mode structure is used to realize joint angles' dynamic tracking combined nominal model with saturated input under joint moment input.4)Dual simulation platforms are built for models' numerical calculation and motion simulation validation by Matlab-SimMechanics and Matlab-Adams.Using the motion simulation platform,Matlab-Adams with LCS-I quadruped robot,the correctness are verified of static adjustment method to realize the stability of tripod support motion and the rationality of trajectory planning method is proved with diagonal support motion.