以陀螺儀與磁力計實現線性多自由度自走式壓電馬達 回授控制系統之設計與開發

Abstract

目前自走式線性壓電馬達已可大幅提升速度表現下，但其移動時的偏移問題也隨之加劇。因此本研究旨在開發一種使用陀螺儀與磁力計進行姿態控制的自走式線性壓電馬達，達到三自由度操控之性能，將原先本團隊的自走式壓電馬達位移偏移進行有效抑制，達到穩定控制前進方向之研究目標。本研究使用四個模態的選擇性疊加達到三個驅動自由度的操控能力，本研究透過在同一結構上同時引入單頻雙模態與整數倍頻兩種不同驅動理論以達成在同一結構上同時實現三個自由度行進波的生成，分別為x方向、y方向的直線移動與相對於z方向的旋轉移動。本研究在此基礎上引入了姿態控制系統，解決自走式壓電馬達因運動表現上升帶來的位移偏移問題。透過系統鑑別得出壓電馬達系統的姿態轉移函數，並透過數值模擬設計姿態控制的控制系統，得出最適合該系統表現的控制系統並以數位控制器實現。經過姿態控制的系統，旋轉運動時姿態控制穩態誤差可達0.001°以下，且累積誤差為0.000038°/min。直線移動時，x方向移動角度偏移量由原先的1.42°~ 44.8°下降至0.44°~ 4.78°，最大誤差修正率達到95.9%。100Vpp下未加入負載開迴路最大速度為44.1mm/s，加入姿態控制後平均速度為11.6 mm/s，最大負載可達140 g。y方向移動角度偏移量由原先的7.91°~ 64.7°下降至1.2°~ 7.17°，最大誤差修正率達到99.2%。100Vpp下未加入負載開迴路最大速度為45.29mm/s，加入姿態控制後平均速度為9.1 mm/s，最大負載可達140g。

In recent years, self-propelled linear piezoelectric motors have much improved in speed performance. But, the offset of its moving trajectories has become an inevitable problem. Therefore, this research aims to develop a self-propelled linear piezoelectric motor that uses gyroscopes and magnetometers for attitude control to achieve three-degree-of-freedom control. We integrate this technology into the self-propelled piezoelectric motor previously reported by our team. To enable three driving degrees of freedom, we selectively superpose two of four chosen bending modes to achieve multi-direction control. Two different driving methods are used, including One-Frequency Two-Mode (OF-TM) and Multi-Integer Frequency Two-Mode (MIF-TM). Then, different traveling waves that can create three degrees of freedom can be activated to propel the linear piezoelectric motor, including x-direction, y-direction and rotational movement with respect to the z-direction. On top of this design, we also introduces an attitude control system to solve the problem of displacement offset of an open-loop self-propelled piezoelectric linear motor. Using the system identification method, the attitude transfer function of the piezoelectric motor system is obtained, and the attitude control system is designed using numerical simulation. Then, the control system that is most suitable for the performance of the system is obtained and implemented with a digital controller. After attitude control of the system, the steady-state error of attitude control during rotation can reach less than 0.001°, and the cumulative error is 0.000038°/min. When moving in a straight line, the angular offset of the x-direction movement dropped from the original 1.42°~44.8° to 0.44°~4.78°, and the maximum error correction rate reached 95.9%. The maximum open-loop speed under 100Vpp without loading is 44.1mm/s. After adding attitude control, the average speed is 11.6 mm/s, and the maximum load can reach 140 g. The y-direction movement angle offset dropped from the original 7.91°~64.7° to 1.2°~7.17°, and the maximum error correction rate reached 99.2%. The maximum open-loop speed under 100Vpp without loading is 45.29mm/s. After adding attitude control, the average speed is 9.1 mm/s, and the maximum load can reach 140g.