2012 Volume 132 Issue 11 Pages 1024-1032
There are many studies on underactuated systems that control input number is less than output one. That system leads cost reduction and space-saving. Previously, an observer was used widely to control an underactuated system; moreover, time delay occurs because of a low-pass filter. Generally, we use a low-pass filter to obtain the derivative. Recently, Levant suggested a sliding mode differentiator that can estimate the derivative of a input signal, and its time delay is low. Therefore, a new construction of a observer using sliding mode differentiator is proposed, and we investigate how to design the gain of the differentiator. The proposed method was evaluated via a crane experiment. Furthermore, the result showed that the proposed method is effective for controlling an underactuated system.