Improving Human Positioning Control of Oscillatory Systems

Flexible systems are difficult to control because they deflect in response to any applied force and they tend to oscillate around the desired path or set point. Human operators driving such systems are challenged by the deflection and vibration that makes the system difficult to move and accurately position. Such systems can be augmented with an intelligent control scheme that aids the human operator. Numerous types of controllers can be used for such applications; however, it is challenging to balance the control authority of the human operator and the augmenting controller. Input shaping is a control technique that reduces unwanted flexible system responses by modifying the human-operator command in real-time. This paper investigates the use of input shaping as an augmenting controller to aid in the accurate positioning of highly-oscillatory systems. Results from operator testing verify some of the key advantages of this controller.