Discrete-time learning control for robotic manipulators based on 2-delay input method

A learning control based on repetitive operations of robotic manipulators is one of the most promising methods to realize high speed and high precision control for robotic manipulators. For implementation the learning algorithm should be represented in the discrete-time domain. When the sampling period is small, the joint servo system will have an unstable zero. This leads to unstable learning. In this paper, the authors propose a new learning algorithm based on so-called 2-delay input method. By using the 2-delay input method, the authors can stabilize the unstable zero, and realize the stable learning even if the sampling period is small. Also, the authors show some simulation results to verify the effectiveness of their proposed method