Nonlinear control of tendon driven robot manipulators: Elimination of actuator side position measurements

In this study, a partial state feedback controller is proposed for the link position tracking control problem of flexible tendon driven robotic systems. Specifically; a nonlinear model based controller is formulated for tendon driven robot manipulators under the constraint that only the link position and tendon expansion force measurements are available. Despite the lack of link and actuator side velocity and actuator position measurements, the proposed controller ensures exponential link position tracking. To eliminate the need of actuator position and velocity measurements, a model based velocity observer has been utilized. Stability of the closed loop system and boundedness of system states are proven via Lyapunov based arguments. The performance of the purposed observer-controller couple is then verified by a set of numerical simulations.