Principal base parameters of open and closed kinematic chains

A general and systematic method to find the dynamic parameters, known as the base parameters, that directly contribute to joint torques for both open and closed kinematic chains is presented. The principal base parameters are defined as a set of the base parameters with their order of sensitivity. The principal base parameters are obtained by taking into account the nonlinearity. It is also shown that for a closed kinematic chain a set of base parameters are invariant to the location and the number of the actuated joints if they can sufficiently activate the mechanism