Abstract. A novel approach to analyzing instability in permanent-magnet stepper motors is presented. It is shown that there are two kinds of unstable phenomena in this kind ofmotor: mid-frequency oscillation and high-frequency instability. Nonlinear bifurcation theory is used to illustrate the relationship between local instability and midfrequency
oscillatory motion. A novel analysis is presented to analyze the loss of synchronism phenomenon, which is identified as high-frequency instability. The concepts of separatrices and attractors in phase-space are used to derive a quantity to eva luate the high-frequency instability. By using this quantity one can easily estimate the stability for high supply frequencies. Furthermore, a stabilization method is presented. A generalized approach to analyze the stabilization problem based on feedback theory is given. It is shown that the mid-frequency stability
and the high-frequency stability can be improved by state feedback. Keywords: Stepper motors, instability, nonlinearity, state feedback.
1. Introduction
Stepper motors are electromagnetic incremental-motion devices which convert digital pulse inputs to analog angle outputs. Their inherent stepping ability allows for accurate position control without feedback. That is, they can track any step position in open-loop mode, consequently no feedback is needed to implement position control. Stepper motors deliver higher peak torque per unit weight than DC motors; in addition, they are brushless machines and therefore require less maintenance. All of these properties have made stepper motors a very attractive selection in many position and speed control systems, such as in computer hard disk drivers and printers, XY-tables, robot manipulators, etc.



摘要：本文介紹了一種分析永磁步進(jìn)電機(jī)不穩(wěn)定性的新穎方法。結(jié)果表明，該種電機(jī)有兩種類(lèi)型的不穩(wěn)定現(xiàn)象：中頻振蕩和高頻不穩(wěn)定性。非線(xiàn)性分叉理論是用來(lái)說(shuō)明局部不穩(wěn)定和中頻振蕩運(yùn)動(dòng)之間的關(guān)系。一種新型的分析介紹了被確定為高頻不穩(wěn)定性的同步損耗現(xiàn)象。在相間分界線(xiàn)和吸引子的概念被用于導(dǎo)出數(shù)量來(lái)評(píng)估高頻不穩(wěn)定性。通過(guò)使用這個(gè)數(shù)量就可以很容易地估計(jì)高頻供應(yīng)的穩(wěn)定性。此外，還介紹了穩(wěn)定性理論。廣義的方法給出了基于反饋理論的穩(wěn)定問(wèn)題的分析。結(jié)果表明，中頻穩(wěn)定度和高頻穩(wěn)定度可以提高狀態(tài)反饋。
關(guān)鍵詞：步進(jìn)電機(jī)，不穩(wěn)定，非線(xiàn)性，狀態(tài)反饋。
1. 介紹
步進(jìn)電機(jī)是將數(shù)字脈沖輸入轉(zhuǎn)換為模擬角度輸出的電磁增量運(yùn)動(dòng)裝置。其內(nèi)在的步進(jìn)能力允許沒(méi)有反饋的精確位置控制。 也就是說(shuō)，他們可以在開(kāi)環(huán)模式下跟蹤任何步階位置，因此執(zhí)行位置控制是不需要任何反饋的。步進(jìn)電機(jī)提供比直流電機(jī)每單位更高的峰值扭矩;此外，它們是無(wú)電刷電機(jī)，因此需要較少的維護(hù)。所有這些特性使得步進(jìn)電機(jī)在許多位置和速度控制系統(tǒng)的選擇中非常具有吸引力，例如如在計(jì)算機(jī)硬盤(pán)驅(qū)動(dòng)器和打印機(jī)，代理表，機(jī)器人中的應(yīng)用等.