Gait Research And Implementation Of Biped Robot Based On Variable Length Inverted Pendulum

Gait control of biped robot has always been a hot area of intelligent control,and it has become one of the most difficult problems in the field of intelligent control because of its high degree of freedom and high coupling.The research of biped robot is a combination of many kinds of subjects,such as mechanical manufacturing technology,intelligent control technology,information technology,software control technology,and so on.Armed at the problem of the stability of biped robot is poor,when in a non horizontal environment,such as the slope and up the stairs.In this paper,the smooth function fitting control algorithm is applied,it's better than the three spline interpolation,avoiding the mutation of speed and acceleration,ensuring the stability of the biped robot,and NAO robot is used to the experimental platform,the up stairs gait simulation experiment is completed.This paper is devoted to the following work:Firstly,the model of variable length inverted pendulum is studied.Combined with the inherent parameters of the NAO robot,the thigh,leg,feet and hip torso is equivalent to the seven link model,According to the change characteristics of the centroid and the joint angle of the up stairs gait,a variable length inverted pendulum model is established,achieving the goal of equivalent physical process and simplified calculation.Then,aiming at the problem that the three spline interpolation algorithm can cause the acceleration mutation,this paper,the method of smooth function fitting is proposed.The method is applied to the trajectory planning of the ankle joint,and then combined with the principle of kinematics and inverse kinematics,to get the different joint angles of the lower limb during the upper step process.Thirdly,the ZMP stability of the NAO robot walking is verified.Through experiments,we show that the use of smooth function and the three spline interpolation algorithms to plan the differences in the stability of the motion of the ankle,The smooth function fitting method improves the stability margin of ZMP and the stability of walking.Finally,the deep development environment of NAO robot is built,and the step gait experiment of NAO robot is completed.In this paper,Matlab,VS2010,Cmake compiler,Webots PRO,Choregraphe and other related software are used to build the development environment of the biped robot,NAO robot console program is used to complete the gait control on the simulation and prototype robot.