Research On Dynamic Modeling And Control Of Parallel Legged Hexapod Walking Robot

In this paper,a hexapod walking robot with parallel legs is taken as the research object,which includes two legs,six legs,twelve UPUR leg branches and six auxiliary branches,and each leg is a 6-UPUR+3P parallel mechanism.In the process of movement,the robot moves smoothly and has a large load capacity,which will be helpful to the application research of the robot and lay a theoretical foundation for other new robots with different structures.Firstly,the structure design of the hexapod walking robot with parallel legs is carried out and its degree of freedom is calculated.The coordinate system of fixed platform,moving platform and UPUR hinge point of parallel legs are established,and the transformation matrix of fixed platform coordinate system and moving platform coordinate system is derived.Matlab/Simulink software is used to build the Sim Mechanics physical model of the parallel leg hexapod walking robot.Secondly,the vector method is used for kinematic analysis,and the displacement,velocity and acceleration among components are analyzed,which lays a foundation for various research work such as dynamic modeling,simulation and analysis.Taking the length of each leg branch as the research object,the kinematics mathematical model is established by theoretical formula derivation,and the vector equations of displacement,velocity and acceleration of the branch are established according to the spatial geometric structure relationship of the 6-DOF parallel robot.Finally,according to the established kinematics mathematical model,the simulation is carried out by matlab software,and the simulation curve of corresponding variation is obtained.According to the characteristics of robot structure and dynamic performance,Newton-Euler method is used to build dynamic model of walking leg of parallel legged hexapod walking robot,and the dynamic mathematical model of walking leg of robot is deduced.The dynamic mathematical model program is written in Matlab software to obtain the driving force curve of each leg branch in motion.At last,the physical model of the walking leg of the robot is built in Simulink,and the simulation curve based on the physical model is obtained by establishing a joint simulation model based on Matlab and Simulink.By comparing the two simulation curves,the kinematic mathematical model and the dynamic mathematical model established by Newton-Euler method are verified.Finally,the advantages of PID control and adaptive fuzzy control technology are complementary,and a fuzzy adaptive PID controller with leg branches is designed.The simulation model of fuzzy adaptive PID controller is built in Simulink to verify the effectiveness of the designed fuzzy adaptive PID controller.The gait planning of the parallel leg hexapod walking robot is carried out,and experimental research is carried out based on this gait.The experimental results show that the gait planning of the parallel leg hexapod walking robot is reasonable and meets the planning requirements,and the control effect of the fuzzy adaptive PID controller is obviously better than that of the traditional PID controller.