Abstract
In this paper, a swing-up controller for the Pendubot which is a typical example of nonlinear underactuated systems is proposed. The proposed method consists in three steps, Step 1: a swing-up control of a first link, Step 2: a swing-up control of a second link with stabilizing the first link at upright position, and Step3: a stabilization control of both links at its unstable equilibrium state. As the controller of Step1, a sliding-mode type partial linearization method, which has the robustness for input disturbances, is applied to swing-up and stabilize of the first link. The controller of Step2 is consisted of an energy based swing-up controller for the second link and stabilization controller for the first link designed in Step1. A control input of Step2 is computed by adding inputs of two controllers, and the input of other controller is regarded as a input disturbances,respectively. Using this idea, the swinging-up of the second link with stabilizing the first link is achieved. And sliding-mode controller to stabilize both links is used as the controller of Step3. Finally, numerical simulation and experiment results are given to show an effectiveness of the proposed method.
