Kinetostatic analysis for compliant legged robots with ground contact forces evaluation

This paper presents a systematic proposal for the kinetostatic analysis in compliant legged robots. The proposal applies the screw theory, Assur virtual chains, and Davies method as an integrated approach, including kinematics and statics during the quasi-static movement of n-legged robots. The general proposed procedure applies to robots with any number of legs and any degree of stiffness to evaluate the ground contact forces that emerge from the addition of compliant elements. The external forces on the torso and feet on the ground are analyzed, including the compliant effects. Numerical simulations validate the proposal, comparing the performance of planar legged robots during quasi-static movements, including two-legged robots without compliant elements (rigid robots) and composed of compliant elements on every joint. The analysis yields an index that features the kinetostatic performance and indicates a path to developing compensation strategies.