Mechanism Modeling And Motion Control Of Quadruped Robot Driven By Pneumatic Muscles

As a new type of actuator which has the feature of biological muscle,pneumatic muscle is increasingly being applied to the study of walking robot.In this paper,on the basis of summarizing the existing quadruped robot mechanism and from the perspective of bionics,we designed a quadruped robot driven by pneumatic muscle,meanwhile,studied its motion control.First of all,we chose four mammals as bionic object and simplified the number of joint and freedom appropriately,and selected the ultimate form of joint configuration of the robot.In part of shape parameters of the German shepherd for reference,we designed its leg which has two antagonism type joints driven by pneumatic muscles and completed the assemble of 3D model of the whole machine by Solid Works.By analyzing the relations between the pneumatic muscle advance shrank and joint maximum angular,pneumatic muscle's model was chose.Whole control system of the robot was designed and relevant control elements were selected.For rotary potentiometer,the calibration experiment was conducted and the relationship curve between the output voltage and the angle of rotation was fitted.And then,the Lagrange dynamics models of the single joint and single leg driven by pneumatic muscle were established.PID control algorithm and Sliding Mode Control algorithm were designed for single joint and single leg independently,using MATLAB/Simulink to build simulation platforms for step response and simulation of curve tracking of single joint as well as curve tracking simulation of single leg.C++ program language was used to achieve PID and SMC control algorithms.VC++ interface for single joint and single leg were developed,and the experiments of step response,curve tracking to single joint,as well as to single leg were conducted,and the experiment results were compared.Finally,all-elbow joint configuration was chose to built the quadruped robot,and the walking test platform also was established.Driving function of trot gait given to each joint was designed for the walking experiment.The experiment result showed that the quadruped robot can complete the swing control of four legs and achieved the trot gait,which means it has the ability to walk to some degree.