Multi-input second-order sliding-mode hybrid control of constrained manipulators

This paper deals with the hybrid position/force control of constrained mani pulators subjected to uncertainties. A solution is proposed that is based o n sliding-mode control theory, which proved to be highly effective in count eracting uncertainties for some classes of nonlinear systems. Specific prob lems involved in this technique are chattering elimination and the algebrai c coupling between constraint forces and possibly discontinuous control sig nals. Both the problems are addressed in this paper by exploiting the robus tness properties of a second-order sliding-mode control algorithm. This alg orithm, recently proposed by the authors for solving the single-input hybri d control problem, is generalized in this paper to deal with the class of m ulti-input differential algebraic systems describing the behaviour of const rained mechanical systems.