AN ANALYSIS OF THE KINEMATICS AND DYNAMICS OF UNDERACTUATED MANIPULATORS

The dynamics and kinematics of manipulators that have fewer actuators than degrees of freedom are studied. These underactuated manipulators arise in a number of important applications such as free-flying space robots, hyperredundant manipulators, manipulators with structural flex ibility, etc. In the analysis such underactuated manipulators are deco mposed into component active and passive arms. This decomposition allo ws techniques previously developed for regular (fully actuated) manipu lators to be applied to underactuated systems. Spatial operator identi ties are used to develop closed-form expressions for the generalized a ccelerations for the system. These expressions form the basis for a re cursive O(N) dynamics algorithm. The structure of this algorithm is a hybrid of known forward and inverse dynamics algorithms for regular ma nipulators. Expressions and computational algorithms are also develope d for the generalized and disturbance Jacobians for underactuated mani pulators. The application of the results in the paper to space manipul ators is also described.