Swing-up control of an Acrobot having a limited range of joint angle of two links

In this paper, a nonlinear control scheme to swing up an Acrobot (acrobat robot) is proposed. The scheme is based on an idea to model a horizontal bar gymnast by the robot. The difference between the robot and the model of a human body is in the second link of the robot which rotates 360/spl deg/, whereas the lower half of human body does not rotate 360/spl deg/. To make the robot more humanlike mechanics, rotation of the second link angle of the robot is constrained mechanically. By using this robot, a control scheme to perform a swing-up motion of the Acrobot is proposed. A numerical simulation shows the effectiveness of the proposed scheme in this paper.