Online Center of Mass Detection for Quadruped Robots in Trot Gait Motion Most of the motion control strategies for the quadruped robots are based on the trajectory planning of the center of mass (CoM) and the hypothesis that the CoM locates at the geometrical center of the trunk. In fact, the CoM position offsets will introduce obvious influence to the control performance. This paper presents a method for online CoM detection for quadruped robots running in trot gait. The dynamical model of the robot is built in the inertial coordinate system. Transforming methods for the status variables from the base frame to the inertial frame are also provided. To get more precise results, the step height compensation method for swing feet and comparative ground reaction force calculations are presented. With the proposed method, the analytical solution of the CoM position is obtained. Simulations show the effectiveness of the proposed method.

WholeBody Motion and Landing Force Control for Quadrupedal Stair Climbing In this paper, we present a novel framework for quadrupedal stair climbing, which considers force interaction with stairs. For stable and robust climbing, a key issue is to avoid falling down on the stairs. From this point of view, control to minimize rate of change of angular momentum about Center of Mass (CoM) which is produced by ground reaction force (GRF) at contact of robotxe2x80x98s foot is necessary. Using this approach, direct forcebased Zero Moment Point (ZMP) for motion planning of the CoM and landing force control are implemented. The direct forcebased ZMP method allows the robot to lift its foot with reduced possibility of tilting on the stairs, and the landing force control prevents instant increase of the moment by impact of the GRFs. In addition, terrain recognition to estimate parameters of the stairs and find proper footholds by vision system mounted on the robot is presented. Proposed framework is implemented to quadruped robot, AiDINVI, that has torque sensor at each joint, through experiments, capability of ascending several stairs including 3step stairs which have 21cm height (31% of its maximum leg length) and 26.5xc2xb0 inclination is validated.