超音波モータの高速位置決め手法

抄録

Ultrasonic motors have some features; small size, lightweight, low speed-high torque, silence, and large holding torque. However, due to the friction drive and the need for switching about rotation direction, it is not easy to realize the fast response without overshoot. To overcome these issues, this paper heuristically proposes some practical control methods. At first, P/PI changeover for the position compensator is introduced to realize overshoot-less responses. Next, it is shown that the input shaping filter, which is introduced to improve the shape of positioning waveforms using the conventional input filter, desirably influences the settling time. Moreover, Bang-Bang control is implemented in the position loop to realize the fast positioning. Finally, combined control for the above techniques, i.e. fusion control scheme, is examined under the conditions with and without load torque. As a result, most fast positioning is realized in case that P/PI changeover, Bang-Bang control, and CW/CCW changeover with dead zone are mixed. Then successful positioning waveform is realized.