Adaptive control of a robot carrying a time-varying payload

In this paper, we consider adaptive control of a robot carrying a time-varying payload. The robot dynamic model and its properties are given for time-varying payloads. This dynamic model and its properties are different when compared with a robot dynamic model with constant payload. A compact parameterization of the dynamics is obtained based on the payload being parameterized by a group of known bounded functions and unknown constant parameters. Based on this parameterization, a passivity-type adaptive control law is proposed for the robot with time-varying payload. Stability of the closed-loop system with the proposed adaptive controller is shown. An experimental platform consisting of a two-link robot with a time-varying payload has been developed. The experimental platform mimics pouring/filling operations using a robot. Typical experimental results are shown and discussed.