A finite-time convergent sliding mode control for rigid underactuated robotic manipulator

Robotic manipulators are widely used in space endeavors nowadays. For space applications, usually lightweight robotic manipulators are preferred. Hence, the system can be made underactuated intentionally. Also, one or more actuators may fail in space. Therefore, the system is highly uncertain and less actuated. The sliding mode control strategy does not depend on exact knowledge of the system model but chattering in states and control is observed. The present work showcases two different control techniques for achieving finite-time convergence and continuous control. The first technique is to choose a zero-error sliding function with a higher order sliding mode control and the second technique is to use a terminal sliding function with appropriate higher order sliding mode control for tracking control of an underactuated manipulator. A comparison is presented for the same.