Application of a second order sliding mode control to constrained manipulators

This paper deals with the hybrid position/force control problem for constrained manipulators subjected to uncertainties and disturbance of various nature. A solution for the uncertain case has been carried out basing 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. This paper presents a solution to these problems in the particular case of a manipulator with n degrees of freedom and n - 1 holonomic constraints, via a new second order sliding mode control algorithm which does not require the availability of the acceleration vector.