Biped locomotion control via hybrid position control and gravity compensation modes /

Official URL: http://risc01.sabanciuniv.edu/record=b1123086 (Table of Contents)

Past three decades witnessed a growing interest in biped walking robots because of their advantageous use in the human environment. However, their control is challenging because of their many degrees of freedom and non-linearities in their dynamics. Various trajectory generation and walking control approaches ranging from open loop walking to systems with many sensors and feedback loops have been reported in the literature. The tuning of the parameters of reference gait is a common complication encountered. Another important problem of the walking control is the contact transients at the instant of landing. The method presented in this thesis generated position references for the upper body. Optimization techniques are employed to obtain suitable leg joint torques for the supporting leg to track body reference trajectories. Locomotion is achieved by a swinging leg control scheme, which is based on position control on certain directions, and artificial gravity compensation on certain directions. Soft landing and low impedance problem of the legs can easily be handled with this scheme. Another advantage is that limited number of parameters is required for gait generation. 3D dynamics and ground interaction simulation techniques are employed for a 12-DOF biped robot to test the proposed method. The simulations indicate the applicability of the method in real implementations.