Feedforward Calculation in Tracking Control of Flexible Robots

A family of asymptotically stabilizing tracking control laws was introduced by the author (1991) for a class of nonlinear Hamiltonian systems. These control laws all have the structure of a sum of a feedback design based on the passivity consideration and a feedforward obtained via a procedure that is closely related to plant inversion. In this paper calculation of the feedforward is considered in detail for both flexible joint robots and a single planar flexible link. The latter also leads to a general result relating inverse dynamics to model reference control in the case of linear systems.<>