A Pace Gait of Quadruped Robot Based on The Control of Walking Cycle Using A Discrete-time Model.

Abstract

A pace gait considering in this study is the walking in which lateral legs form pairs and the members of a pair strike the floor in unison and they leave the floor in unison. In order to realize a stable pace gait, it is very important to control actively a walking cycle. Namely, the proper control of the walking cycle ensures the cooperation of the sagittal motion and the lateral motion. In this study, a control method of the walking cycle based on the motion control in the lateral plane is proposed. A discrete-time model is suitable for the analysis of the walking system in case off adjusting the walking cycle. By using the proposed discrete-time model, several control method of the walking cycle are discussed. At first, a conventional proportional plus integral control is examined by using a maximum absolute value of the closed loop eigenvalues as a performnce index. Secondly, an optimal servo controller and a dead beat controller are discussed. For the sagittal motion control, a trafectory of the leg is designed under the consideration of the algorithm of the lateral motion control. The COLT-3 achieved a smooth pace gait at a speed of 0.25 m/s.