Fast Online Gait Transition For Biped Robots And Its Experiments

Biped robot not only has many potential applications in occasions like health care,security monitoring,home service and entertainment and so on due to their flexible mobility and superior adaptability,but also supports the development of several disciplines for interdisciplinary combinations.Hence it has been a research hotspot in recent decades.Previous studies on biped robot are mainly focused on the dynamic modeling,the gait planning and the stability control,of which the gait planning plays a significant role in bipedal research and is directly related to the performance of stable walking and energy efficiency.Till now,most studies on gait planning are still limited to the combination of simple gaits without smooth transitions.Here,a gait planning method with online gait transitions is developed.Simulations and experiments are also conducted to verify this method.The main contents of this thesis are as follows.1.Based on the D-H principle,an eleven-link mathematical model and its reference coordinate system are established according to the real structure of our physical prototype.Then the forward and inverse kinematic problems are figured out based on the quasi-decoupled sagittal and lateral planar motions;2.A fast gait planning method capable of gait transitions is proposed by fitting the joint angle trajectory functions.The relations between the gait parameters and several other key parameters are established ’from the geometrical analysis and geometric constraints adjunctions,and some simple harmonic functions are used to fit the joint trajectories.Then,the gait transitions between different step lengths or walking cycles are developed based on this method;3.A walking stability control method is developed by the parameter optimization.After the stability analysis on the single mass and multi-mass point models,the effects of the trunk posture on the walking stability are discussed in some detail,and the pattern search method is employed to optimize the ZMP stability margin so as to improve the performance of stable walking of the biped robot;4.The ADAMS Simulations and experiments on the gait transitions are conducted to verify the present online gait transition method.The results show that the method is feasible for the stable bipedal walking.