1脚ロボットの爪先による屈伸動作の姿勢安定化

抄録

Recently, the research of humanoid robotics is very popular. However, few humanoid robots usually have the tiptoe due to complicated mechanism and control, etc. though the degrees of freedom of the joint increase by appending a tiptoe to the robot foot and a leg construction with the high movement ability can be expected. In this paper, an autonomous attitude stabilization control based on a repetitive bending and stretching movement with standing on the tiptoe is proposed. Namely, the control performance is verified under a narrow situation of the stable range by using a tiptoe of one-legged robot. When a one-legged robot moves each joint by using the tiptoe without an attitude stabilization planning, the ZMP (Zero-Moment Point) of robot goes over the boundary of a contact surface often. As the result, the robot falls down due to the occurrence of an unstable situation.
The compensation of ZMP by using a force sensor set up the ankle is a general method in conventional humanoid robots. However, the center of gravity and ZMP are calculated from motion data because providing a force sensor for the verification of movements using a tiptoe is so difficult. The autonomous stabilization is achieved by controlling an imaginary inverted pendulum (IIP) that passes through the center of gravity from the robot tiptoe. In other words, the VSS adaptive control suppresses as much as possible the disturbance concerning a change of the center of gravity caused by the robot movement. The I-PD control system is designed to both joints of an ankle and a knee, and two reference angles of sinusoid wave are given to their joints without inverse kinematics in an experiment. Simultaneously, VSS adaptive control input for the attitude stabilization is given to a tiptoe joint. Finally, the validity of the proposed system is demonstrated through some simulations and experiments.