A combined first and second order sliding mode approach for hybrid control of constrained manipulators

This paper deals with the hybrid position/force control of constrained manipulators subject to uncertainties and disturbances of various nature. A solution is proposed based on the sliding mode control theory, which revealed to be highly effective in counteracting uncertainties and disturbances for some class of uncertain nonlinear systems. Specific problems connected to this technique are the chattering elimination and the algebraic coupling between constraint forces and possibly discontinuous control signals. The solution proposed in this paper overcomes these problems by applying a new second order sliding mode control algorithm.