| Abstract: | Adaptive controllers applied to high-speed and high-precision robot manipulators give excellent tracking performances because they take into account the full dynamics of the robot. Recent publications have shown that on-line estimation of the dynamic constant parameters can be obtained by the joint tracking error (direct adaptive control) or by the torque prediction error (indirect adaptive control). In direct adaptive controllers the estimation law is derived from Lyapunov stability or Popov hyperstability methods. These controllers are simple and their real-time implementation is easy; however, the estimation is not so accurate. In indirect adaptive controllers the estimation law is based on a least squares algorithm. These controllers give accurate estimates of the manipulator parameters; however, they involve much more computation than the direct approach. Therefore no real-time implementations of indirect adaptive tracking controllers for robots have been reported in the literature until now. This paper describes a real-time implementation of an indirect adaptive scheme applied to a two-degree-of-freedom (2DOF) direct-drive SCAM robot. the controller is implemented at low cost by the use of a single-chip digital signal processor (DSP). |
