The paper addresses control of variable mass and configuration mechanical systems subjected to holonomic or nonholonomic constraints, which are imposed due to systems desired performance, tracking specified motions or other control needs. The control design is model-based and an analytical dynamics modeling framework underlying controller design is presented. The framework novelty is that constraints, including nonholonomic ones and these on variable mass, can be merged into variable mass system dynamics and final motion equations are free of the constraint reaction forces so they can be used directly to control design. Many mechanical systems change their mass or configuration when they move, e.g. inertia-based propelled underwater vehicles, mobile robots and manipulators transporting loads or space vehicles flying their space missions.
The dynamics modeling framework presented in the paper can be applied to all variable mass system examples mentioned above. An underwater inertia-based propelled vehicle model dynamics and control performance illustrate the theoretical development presented in the paper. The paper contribution is two folded. It presents a unified approach to constrained variable mass or configuration systems modeling and introduces analytical dynamics methods to the nonlinear control domain.