Inverse Dynamic Models of Closed-Chain Mechanisms With Contact Compliance

A general inverse dynamic model which is applicable to closed-chain mechanisms with contact compliance is presented. This class of mechanism has relatively rigid members and joints, but experiences compliant interactions with objects and the environment; examples include walking machines operating on natural terrain, devices for grasping a compliant object, and wheeled mobile robots. Previous approaches for formulating inverse dynamic models of compliant mechanisms have been approximations or limited to simple configurations and open-chain mechanisms. Inverse dynamic equations for closed-chain mechanisms with contact compliance are shown to be solvable sets of differential/algebraic equtaions (DAEs) which assures that stable and accurate solutions can be calculated; relevant characteristics and solutions of DAE systems are discussed.