Design of a continuous controller for contact transition task based on impulsive constraint analysis

Many manipulation tasks involve transition from unconstrained to constrained motion marked by the contact with a constrained surface. This phenomenon divides the task into more than one control strategies plagued with control discontinuity. This paper seeks to design a controller which avoids such discontinuity. The principle is based on the analysis of impulsive constraints. It is shown that, in theory, such discontinuity can be avoided by replacing the force discontinuity of the end-effector by velocity discontinuity of the constraint surface. This velocity discontinuity can then be dealt with using a continuous control strategy. A controller has been designed based on this principle. Input-output linearization has been performed to linearize and decouple the system