A GENERALIZED STIFFNESS MATRIX-METHOD FOR FORCE DISTRIBUTION OF ROBOTIC SYSTEMS WITH INDETERMINACY

Foot forces in walking machines and finger forces in multi-fingered gr ippers are usually indeterminate due to the multi-closed-chain geometr y of the systems. While many methods were proposed to solve the force distribution of such systems, a method called stiffness matrix method [2] was developed based on the concept that the forces must satisfy th e equations of material deformations. However, only leg compliances we re considered in the stiffness matrix method. In this paper, the stiff ness matrix method is generalized to include all the major system comp liances, i.e., those of legs (fingers), actuators and terrain (object to be grasped). Based on the developed generalized stiffness matrix me thod, an example of foot force analysis of a quadruped is presented to demonstrate the effects of different system compliances on the foot f orces.