Synthesis of humanoid whole-body motion with smooth transition

In planning specific sequential motions of a humanoid, it is desired to transfer from one motion to another motion without stopping between motions. The problem of achieving continuous performance by connecting motions is referred to as motion synthesis in the robotic fields. To solve this problem, it is important to assign an appropriate transition motion that connects a prior motion to a posterior motion. In this research, we propose a new method of generating smooth transition motions under various constraints such as maintaining balance and collision avoidance. Our algorithm comprises two sequential processes based on optimization techniques. First, we assign transition instants of the motions with the formulation of a minimax problem. Second, we connect the transition instants smoothly to satisfy various constraints throughout the transition. Our method is applied to synthesize the walking and kicking motions of the humanoid robot HOAP-3. We confirm that the robot achieves a given task by connecting motions continuously. Furthermore, the motion performance is improved with the planning of transition motion using our method. In particular, the robot kicks a ball quickly under a more stable condition for maintaining balance. These results show that the proposed method achieves effective motion planning by solving the motion synthesis problem.