【作者】 李岩；

【导师】 王大志；

【作者基本信息】 大连理工大学 ， 机械电子工程， 2023， 硕士

【摘要】 直线式超声电机具有结构简单、输出力大、响应速度快、低噪音等优点,在航空航天、医疗器械、消费电子等领域得到了广泛的应用。随着MEMS技术的发展,消费电子、工业自动化以及物联网等领域的需求牵引下,微型化、低压驱动、大驱动力成为当下直线超声电机的主要发展趋势。定子作为直线超声电机的核心部件,其微型化程度直接决定着直线超声电机的微型化程度,因此研制毫米级尺寸、低压大驱动力的微型直线超声电机定子具有重大的应用价值。本文设计了尺寸为9mm×1.2mm×0.7mm的微型直线超声电机定子。通过有限元法求解定子的振动特性,分析定子结构参数对工作模态特征频率的影响。采用电流体喷射打印技术沉积PZT厚膜,完成定子制备。对PZT厚膜进行性能表征,测试定子的阻抗、振动特性和机械输出特性。具体内容如下:首先进行微型直线超声电机定子结构设计和仿真分析。介绍了微型直线超声电机的结构和驱动原理。根据驱动原理确定定子驱动足位置、设计PZT厚膜八分区上电极。采用COMSOL Multiphysics仿真软件对定子进行有限元仿真分析,求解定子工作模态振型、特征频率和稳态响应振幅,同时研究了定子弹性体和驱动足尺寸对特征频率的影响,确定定子的最终尺寸。其次进行微型直线超声电机定子的制备。搭建电流体喷射打印装置,加工弹性体和上电极掩膜版,并对弹性体进行研磨清洗预处理。配置PP复合悬浮液并通过电流体喷射打印技术在弹性体表面沉积PZT厚膜,退火结晶后通过磁控溅射技术在PZT厚膜表面制备上电极,同步极化使PZT厚膜获得压电性能,完成定子的制备。最后进行微型直线超声电机定子的表征和性能测试。通过XRD分析、扫描电子显微镜观察定子的物相结构、表面和截面形貌,测量PZT厚膜不同分区的极化方向和压电应变常数d₃₃,平均值为153.75pC/N;进行阻抗分析测试定子的特征频率,与仿真数据对比相对误差分别为3.82%和2.01%。对定子进行振动性能测试,结果显示定子工作模态振型正确,20V激励电压时振幅分别为209.8nm和104.3nm。对定子进行机械输出性能测试,结果显示在激励电压幅值为20V时空载速度为23.22mm/s,最大负载为21.56mN,推重比为110。通过对比分析,基于PZT厚膜的微型直线超声电机定子在较低电压下具有良好的机械输出性能,实现微型直线超声电机的毫米级尺寸、低压大驱动力的应用需求。更多还原

【Abstract】 Linear ultrasonic motors have the advantages of simple structure,high output force,fast response,low noise,and have been widely used in fields such as aerospace,medical devices,and consumer electronics.With the development of MEMS technology and the demand from industries such as consumer electronics,industrial automation,and the Internet of Things,miniaturization,low-voltage driving,and high driving force have become the main development trend of linear ultrasonic motors.As the core component of linear ultrasonic motors,the miniaturization of the stator directly determines the miniaturization degree of the entire linear ultrasonic motor.Therefore,developing a millimeter-sized stator with low voltage and high output force has significant application value.In this paper,a micro stator for a linear ultrasonic motor with dimensions of 9mm×1.2mm×0.7mm was designed.The vibration characteristics of the stator were solved by the finite element method,and the stator structural parameters were optimized.PZT thick film was deposited using the electrohydrodynamic jet printing technology to prepare the stator.The performance of the PZT thick film was characterized,and the impedance,vibration characteristics,and mechanical output characteristics of the stator were tested.Firstly,the structure design and simulation analysis optimization of the micro stator for the linear ultrasonic motor were carried out.The structure and driving principle of the micro linear ultrasonic motor were analyzed.The stator driving foot position was determined based on the driving principle,and the PZT thick film was designed with eight electrode segments.The stator was simulated and analyzed by COMSOL Multiphysics finite element simulation software to solve the working mode vibration mode,resonance frequency,and steady-state response amplitude of the stator.The influence of the stator elastic material and driving foot size on the resonance frequency was also studied,and the dimensions were optimized.Secondly,the preparation of the miniaturized stator for the linear ultrasonic motor was carried out.An electrohydrodynamic jet printing device was built,elastomer and upper electrode mask plate was Processed.The elastic material was polished,cleaned,and pre-treated.PP composite suspension was configured and deposited on the surface of the elastic material by the electrohydrodynamic jet printing.After annealing and crystallization,the upper electrode was prepared on the surface of the PZT thick film by magnetron sputtering technology,and the PZT thick film was polarized synchronously to obtain piezoelectric performance,completing the preparation of the stator.Finally,the characterization and performance tests of the miniature linear ultrasonic motor stator was carried out.The phase structure,surface and cross-sectional morphology of the stator were observed by XRD analysis and scanning electron microscopy.The polarization direction and piezoelectric strain constant d₃₃ of the PZT thick film zones were measured,with an average value of 153.75 pC/N.The impedance analysis was performed to test the stator’s resonant frequency,with relative errors of 3.82%and 2.01%compared with simulation data.Vibration performance testing of the stator showed that the working mode and vibration mode were correct,with amplitudes of 209.8 nm and 104.3 nm respectively when the excitation voltage amplitude was 20V.Mechanical output performance testing of the stator showed that the unloaded speed was 23.22 mm/s,the maximum load was 21.56 mN,and the thrust-to-weight ratio was 110 when the excitation voltage amplitude was 20V.By comparison and analysis,the micro linear ultrasonic motor stator based on the piezoelectric thick film exhibited good mechanical output performance at lower voltages,achieving millimeter-scale size and low voltage driving force requirements for micro linear ultrasonic motors.更多还原