Robot manipulator adaptive control using disturbance estimator

In this paper, adaptive control of a robotic manipulator and a parameter estimation method are discussed. This paper considers the circumstance that a five-bar linkage manipulator is position controlled and unknown external disturbance is exist. In this case, conventional position based and/or prediction error based parameter estimation methods do not guarantee asymptotic stability due to the unknown disturbance. To overcome this problem, this paper presents a prediction error based adaptation with the disturbance estimator (DE). By using a characteristic that the estimation result of the DE contains informations about the estimated model error and the external disturbance, asymptotically stable parameter estimation is achieved under the ideal condition of the DE. In addition, by using the DE feedback control, both the tracking error and the parameter estimation error are converged to zero. Performance of the proposed adaptive control method is demonstrated by simulations.