مدلسازي ديناميكي ، طراحي مسير و كنترل يك ربات دوپاي هفت عضوي

چكيده انگليسي :

Dynamic Modeling Trajectory Planning and Control of a Seven Link Biped Robot Amin Fakhari a fakhari@me iut ac ir November 1 2009 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSuperviser Dr Abbas Fattah fattah@cc iut ac irAbstractNowadays biped robots have attracted the attention of many researchers and many studies have been focused onthis subject Biped robots have higher mobility than conventional wheeled robots especially when moving onrough terrain stairs and in environments with obstacles To enable the robot to walk on various surfaces it isnecessary for the robot to adapt its motion with the ground conditions and maintain its stability Most of the essential parameters of the human walking can be captured with a seven link planar biped robot Inthis thesis dynamics modeling dynamic stability trajectory planning control and implementation of a seven link planar biped robot walking on a level ground with a ditch or stairs are studied The biped robot consists ofseven links which represents trunk thigh shin and metatarsal respectively The links are attached together bysix revolute joints two hip joints two knee joints and two ankle joints There is an actuator in each joint and allof the joints are only in the sagittal plane and friction free Each walking step may include two phases the singlesupport phase SSP and the double support phase DSP Dynamic equations of the biped were derived in bothphases The generalized coordinates are chosen so that the final form of dynamic equations could be expressedin a simpler form Zero moment point ZMP which was first introduced by Vukobratovic is used as thecriterion to evaluate the stability of the biped robot To generate smooth hip and foot trajectories and continuousZMP it is necessary that the velocity and acceleration terms of foot and hip joint trajectories be continuous allthe times To this end with having the kinematics constraints for foot and hip joints we can generate smoothtrajectories for foot and hip joints in Cartesian space using polynomials with suitable orders such that the firstand the second time derivatives are continuous all the times The hip and foot trajectories are designed such thatimpact effect of feet with ground eliminated If hip and ankle joints trajectories of each leg are known all otherjoint trajectories will be determined using inverse kinematics The key parameters of the hip joint trajectory inwalking direction of the robot are obtained using boundaries of biped stable region during the walking to satisfydynamic stability of robot Using this method we can also plan trajectories for walking on slope surfaces andstairs Then the highest position of the swing foot ankle joint in sagittal plane is optimized with two differentfitness functions namely optimization for maximum stability and optimization for minimum consumed energy For walking in environments with different obstacles and ditches the robot has to change its step length Hence a novel method for trajectory planning of walking with different step lengths uses for online trajectory planning is proposed The effectiveness of the proposed method is verified by simulation and experimental results Wehave used the proposed method to our small size biped robot to verify the validation of simulation results Experimental results prove the stability of our biped robot during walking on the level ground with different steplengths Finally with adding a joint as trunk joint ZMP of the biped is controlled by trunk compensation toachieve stable walking Key WordsBiped robot dynamic stability zero moment point walking pattern generation ZMP control

فخاري، امين

مدلسازي ديناميكي ، طراحي مسير و كنترل يك ربات دوپاي هفت عضوي

پايداري ديناميكي , نقطه ممان صفر