Walk and Kick Motion Generation for a General Purpose Full Sized Humanoid Robot

In this paper, we describe our adoption of the THOR-OP (Tactical Hazardous Operations Robot Open Platform) full sized humanoid robot, originally developed to compete at the DARPA Robotics Challenge, for the RoboCup robotic soccer competition. For full sized general purpose humanoid robots, the zero moment point (ZMP) preview controller is widely used since it provides excellent stability and accepts generic walk patterns as inputs. However, simple reactive walk controllers can be advantageous in robot soccer applications that require limited onboard computation and handling of dynamic environment. We use a hybrid walk controller that dynamically switches between the reactive and preview ZMP controllers in order to leverage the best of both controllers. Reactive controllers are used to move the robot with little latency, and the preview controller is used for double support transition and dynamic kick generation. To make smooth transitions between these two controllers, the preview controller considers the boundary conditions of the center of mass (COM) state based on the analytic solution of the linear inverted pendulum model in its optimization process. The suggested controller is validated using the THOR-OP humanoid platform.