Research On The Gait Planning For Bipedal Robot Climbing Stairs

Biped robots have better mobility than conventional wheeled robots,especially for moving on rough terrain,steep stairs and obstacle environments.The study of biped robots has aroused the interest of a number of researchers.The stair gait planning and feedback control algorithm are mainly focused in this dissertation.The model for dynamic-walking is established and the robot can walk in all directions.A walking pattern generator can be considered as a ZMP(zero-moment-point)tracking control system.The preview controller with ZMP feedback is used to improve the dynamic-stability of robot.The robot kinetics model is expressed as exponent product using screw theory.The coordinates are set neatly with less parameters compared with the conventional D-H method.The analytical solution of the inverse kinematics is presented according to the geometric features of human legs.Considering the contact between the supporting foot and the ground,the ZMP criterion for dynamic-stability is introduced.The principle of gait planning is studied by the linear inverted pendulum model.The kinematics simulation analysis is given and can be used for online calculation of ZMP.A set of time series of joint angles for desired walking is called a walking pattern.The linear inverted pendulum is extended to 3D and a 3D walking pattern generation is described.Walking pattern can be figured out by numerical solution of ZMP equation.For obstacle avoidance,a method of biped robots walking in all directions is proposed.Moreover,a preview controller with feedback-loop is designed to improve the tracking effect of ZMP.The gait planning and study on stability of biped robot climbing sta irs are the foundation and key to solve biped robots walking in complex environment.An algorithm for calculating position compensation for ankle joint is used in order to improve walking efficiency.The effectiveness of the proposed method is verified by simulation examples.Simulation experiments of flat ground walking and stair climbing are carried out respectively,which lays a foundation for physical prototype experiments in the future.