A system theoretical framework to study unilaterally constrained mechanical systems

The aim. of this paper is to study, in a system theoretical framework, the contact problem for mechanical systems subject to unilateral constraints. Contrary to what is usually done in studies on this subject, we first investigate what can be deduced already from the mathematical models of the unconstrained mechanical system and the constraint set. It is only after this analysis that we incorporate the physics of contact in our framework. This sequence of steps leads to important insight in the contact problem itself, and to useful theoretical developments regarding modelling and control of impact.