Stability Control of Minimalist Bipedal Robot in Single Support Phase

This paper presents the conceptual design of a new four degree-of-freedom minimalist bipedal walking robot and specifically discusses on the physical development of the robot's sagittal balancing mechanism and its control in a single support phase. The proposed mechanism combines a novel method for stability sensing and balancing of the robot during the strides. The sensing mechanism utilizes an additional flexible ankle joint which is able to provide responsive and accurate measurement of the sagittal instability of the bipedal robot. The use of double balancing mass and the developed control algorithm are responsible to maintain the sideway stability of the robot during single support phase. The proposed method enables the walking control algorithms to be decoupled from the robot stability control algorithms and also simplifies the overall robot motion control and reduces the requirements of computing power. Furthermore, the use of two different masses for the balancing helps to improve response time and efficiency of the balancing system. In this paper, the proposed method is tested on the physical prototype and the experimental results are presented.