Optimization Algorithm for Contact Forces Based on Grasping Stability

Under the condition of fixed-point contact models with friction between the three fingertips and the object surface, a planning algorithm for grasping-force optimization of three-fingered robot hand is established. According to the decomposition of contact force in the friction cone, the effect of internal force on both contact stability and grasping stability is studied. Based on the analysis of the relative location relationships between the intersection point of internal forces and concurrent polygon, the optimization model for the best intersection point of internal forces is constructed. As a result, the grasping stability can reach maximum value when the intersection point of internal forces is the center of maximal incircle of the concurrent polygon. The algorithm integrates the planning of grasp configurations and the distribution of contact force into a unified process, thereby effectively improving the planning efficiency and facilitating online planning of grasping. An example is given to illustrate the validity of the algorithm.