Dexterous Whole-boby Manipulation of Humanoid robot

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In this fiscal year, our goal is to realize a motion of lifting a heavy object dynamically with the humanoid robot. Key issue of lifting motion is how to reduce the load on humanoid arms in which lowed power actuators are implemented. The use of singular postures of arms is well-known to avoid actuator saturation of the arms. We firstly develop the method of selecting initial and final statically stable states of the motion. Both states are obtained by taking singular posture for low powered limbs, and high-manipulability posture for high powered ones. We thus address how to move the object from initial sate to final one passing through the unstable area in which the robot cannot hold the object statically due to saturation of the actuators. To generate the dynamic lifting motion, we propose a motion planner based on an optimization method with making better use of actuator's characteristics. In the optimization, the energy consumption of the actuators is minimized under constraints of the output limit of actuators, and stability based on the zero moment point(ZMP). By combining two different kinds of humanoid's motions such as accelerating an object upward and sliding the body into under the object, we show that the method enables to transit one singular posture of arms to another while lifting the object. We verify the effectiveness of the proposed method for reducing the load on the arms through simulation and experiments using the humanoid robot HRP-2 developed by Kawada Industries Inc. We confirm that a heavy object whose weight is more than forty percents of that of the robot can be lifted above the head of the robot within five seconds. A part of the results are presented in the National conference, and the International conference.