Adaptive sliding mode control of switched constrained robotic manipulators

In this paper, we address the control problem of a constrained robotic manipulators with their constraints continuously switched from one to another. Such a switching in the constraints causes a switching function to be inserted in the equation of the robot dynamics which may cause transient instability for the overall system. Two robust control strategies are presented in this paper to handle such switched robotic systems. In the first strategy, we assume that the bounds of the constraints are known. A sliding mode stabilizing controller is developed that can guarantee global stable performance of the given robotic system. In the second one, we relax the assumption of knowing the constraints bounds through deriving update laws for those bounds and new control actions that can guarantee global stable performance under such switching constraints. Simulation is performed for a two link robotic system having two switching constraints. The results obtained from the simulation verify the efficacy of the suggested control strategy.