超声电机驱动温漂特性的优化补偿方法研究

发布时间：2019-05-07 11:37

【摘要】：超声电机自问世至今已获得广泛关注。它的工作原理与传统电机不同。运行时,定子在压电陶瓷的带动下高频振动,转子在与定子的摩擦力带动下转动,而压电陶瓷的振动是外加输入电压的结果。超声电机特点鲜明,在很多方面比电磁电机更有优势。它运行速度远低于电磁电机,单位体积输出转矩更大,响应时间更短,断电后存在保持转矩。由于上述优点,超声电机已经成为科技界的一个研究热点。超声电机运行时将产生大量损耗,损耗一方面来源于压电陶瓷内部,另一方面来源于定转子的接触摩擦。损耗的积累使电机运行时温度上升,导纳特性发生变化。补偿电机的温漂特性需要从源头入手,因此需要研究如何减小系统损耗。针对行波旋转型超声电机运行时的温漂特性,本文提出一种基于频率跟踪原理的温漂补偿方法,最终实现了一套有温漂补偿功能的最优频率跟踪系统。主要研究内容如下:本文首先构建了一个可以反映温漂特性的超声电机数学模型。建模过程从超声电机内部的能量转化过程出发,对超声电机内部的损耗进行定量计算,指出了损耗对压电陶瓷参数的影响,最终建立了包含温度特性的超声电机等效电路模型。通过对模型仿真,研究发现损耗导致超声电机导纳频谱和相位频谱向左偏移,同时发现超声电机存在最小导纳相位点。本文设计了一种用于温漂补偿的超声电机最优频率跟踪原理。最优频率跟踪原理以机械品质因数为性能指标,通过调整驱动频率,保证超声电机运行在机械品质因数最大的状态。可以证明,机械品质因数最大的频率近似等于导纳相位最小的频率,最优频率跟踪原理的核心问题从对最大机械品质因数的跟踪转化为对最小导纳相位的跟踪。最优频率跟踪系统是基于最优频率跟踪原理实现的一套软硬件系统。该系统包含超声电机驱动器和软件系统两部分,本文对该系统的实现做了介绍,实现后的最优频率跟踪系统具备了对超声电机温漂特性的补偿功能。
[Abstract]:Ultrasonic motor has been paid more and more attention since it came out. Its working principle is different from the traditional motor. When the stator is driven by piezoelectric ceramics, the stator vibrates at high frequency and the rotor rotates with the friction between the stator and the stator. The vibration of the piezoelectric ceramic is the result of the applied input voltage. Ultrasonic motor has distinct characteristics and has more advantages than electromagnetic motor in many aspects. Its running speed is much lower than that of electromagnetic motor, the output torque per unit volume is larger, the response time is shorter, and the holding torque exists after power loss. As a result of the above advantages, ultrasonic motor has become a research hotspot in the field of science and technology. Ultrasonic motor will produce a lot of loss when it is running. On the one hand, the loss comes from piezoelectric ceramic, on the other hand, it comes from the contact friction between stator and rotor. The accumulation of loss causes the temperature to rise and the admittance characteristic to change when the motor is running. The temperature drift characteristics of the compensated motor need to start from the source, so it is necessary to study how to reduce the loss of the system. Aiming at the temperature drift characteristics of traveling wave rotary ultrasonic motor, a temperature drift compensation method based on frequency tracking principle is proposed in this paper. Finally, an optimal frequency tracking system with temperature drift compensation function is realized. The main contents are as follows: firstly, a mathematical model of ultrasonic motor, which can reflect the temperature drift characteristics, is constructed in this paper. Based on the internal energy conversion process of ultrasonic motor, the loss of ultrasonic motor is calculated quantitatively, and the influence of loss on piezoelectric ceramic parameters is pointed out. Finally, the equivalent circuit model of ultrasonic motor including temperature characteristics is established. Through the simulation of the model, it is found that the loss leads to the shift to the left of the admittance spectrum and phase spectrum of the ultrasonic motor, and the minimum admittance phase point of the ultrasonic motor is found at the same time. In this paper, an optimal frequency tracking principle of ultrasonic motor for temperature drift compensation is designed. The optimal frequency tracking principle takes the mechanical quality factor as the performance index. By adjusting the driving frequency, the ultrasonic motor is guaranteed to run in the state of the maximum mechanical quality factor. It can be proved that the maximum frequency of the mechanical quality factor is approximately equal to the minimum frequency of admittance phase. The core problem of the optimal frequency tracking principle is transformed from the tracking of the maximum mechanical quality factor to the tracking of the minimum admittance phase. The optimal frequency tracking system is a set of hardware and software system based on the optimal frequency tracking principle. The system consists of two parts: ultrasonic motor driver and software system. The realization of the system is introduced in this paper. The optimal frequency tracking system can compensate the temperature drift characteristics of ultrasonic motor.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM359.9

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