Integrated robot design considering feasible motion conditions and dynamical relations between body parameters

Abstract

This paper presents an integrated robot design method considering feasible motion conditions and dynamical relations between body parameters. The robot motion is generated from a vector field which is formed as a result of the interactions between a robot body, an environment and a control system. Therefore, not only the motion pattern, but also the robot body parameters should be simultaneously designed to maximize a motion performance of the robot. The integrated robot design is a method which designs a robot body and a robot motion simultaneously. The design parameters are the motion pattern and the robot body parameters, and these initial values are optimized by a gradient method to maximize (or minimize) a given evaluation function which defines the robot motion performance. Limitations of angle, angular velocity and torque are also considered, and these are utilized as the constraints to obtain the feasible robot motion. To validate the effectiveness of the proposed method, for example, a ball throwing motion performed by a human is transformed to a motion pattern of the 9 degrees of freedom (DOFs) arm robot, and the robot body parameters are designed simultaneously. In this paper, the integrated robot design method is improved, for example, additional feasible motion conditions are introduced in the optimization procedure, and dynamical relations between the robot body parameters are considered. In this case, the new motion conditions contain an orthogonal condition between a throwing direction and a hand opening direction, a static condition of a motion and a self collision avoidance condition. The dynamical relations between body parameters, which contain link length, mass, center of gravity and moment of inertia, are considered. The effectiveness of these improvement are discussed from the calculation results.