A stiffness matrix method for foot force distribution of walking vehicles

The authors formulate a compliance model of walking systems and develop a stiffness matrix method for their foot force distribution by considering leg structure, actuators, and terrain as compliant, and incorporating the compatibility condition of deformation into equilibrium equations. To demonstrate the method in an actual machine, the stiffness matrix of a walking machine with pantograph legs is derived analytically, and numerical results for a quadruped walking with different gaits are presented and discussed. Compared with previous approaches, this method is considered to be more realistic, since it satisfies material deformation laws. Moreover, it is computationally very efficient and can be used in real-time control or simulation