Optimization of Stable Grasps by Evolutionary Programming

This paper deals with the problem of synthesis of stable grasp by multi-fingered hands. First, a mathematical description of the problem is formulated. The grasp to be synthesized should satisfy equilibrium conditions and unilateral frictional constraints. It should also be stable against disturbances applied to the object. Two types of stability conditions, contact stability and Lyapunov stability, are taken into consideration. Contact points, contact forces and joint stiffnesses are considered as the problem variables. The objective function maximizes admissible linear and rotational disturbances applied to the object. Since the dimension and the complexity of the resulting optimization problem is high enough, a robust evolutionary programming algorithm with a genetic drift is explored. The feasibility of the algorithm is verified for the synthesis of stable grasp by a three-fingered robotic hand.