Experimental Investigation of Human Two-Arm Manipulation

We address the trajectory planning problem for a task which requires positioning and orienting an object firmly grasped by two hands at a visually specified goal configuration in the horizontal plane. The motor task involves three degrees of freedom (two translational and one rotational), and the motions of the arms are constrained by the physical coupling through the held object. Experimentally measured trajectories are presented and they are compared with those obtained by minimizing the integral of the rate of change of actuator torques over the trajectory. Good match is shown for a class of manipulation tasks in which the person-to-person variability is small. INTRODUCTION This paper is primarily concerned with the coordination and cooperation of two physically coupled arms in a task which requires positioning and orienting an object firmly grasped by two hands. Although many previous works have investigated the mechanisms that might underlie the generation of single arm trajecto..