Papers by Keyword: Ultrasonic Motor

Abstract: In this paper, the working frequency band gap of ultrasonic motor (USM) was investigated under finite element model and experimental prototype. The findings indicate that the discrepancy between theoretical analysis and experimental test is mainly related to the fixation conditions of stator. This work proposes a new geometrical symmetrical stator for standing-wave-type linear USM to reduce the discrepancy. The first longitudinal and the second bending modes of stator are combined to drive the USM. Parameterized finite element model with actual boundary is developed to analyze and optimize the stator performance. The results show that the gap between working frequencies can be substantial reduced compared to the initial design.

Abstract: The ultrasonic motor is a complex dynamic system, which be divided into an electro-mechanical coupling system and a drive and control system. The core of the electro-mechanical coupling system lies in excitation of elliptical movement of the mass points on the surface of the stator and frictional transfer of the power and the movement. Modeling of the electro-mechanical coupling dynamic system of the ultrasonic motor substantially comprises two aspects. First, the dynamic system is viewed as an integral transfer function, and an intuitive relationship between input of the electric energy and output of the power is established. Second, geometric parameters and material parameters of mechanisms are closely correlated with dynamics of the mechanisms.

Abstract: It has difficulty in nonlinear modeling of performance characteristic of ultrasonic motor for its complex micro-structure. Through matching three sets of V_pp-I_m data measured near the resonance frequencies of five ultrasonic motors, we run PSIM 6.0 to extract a new model in which nonlinear resistance and micro capacitance are tuned till touching the minimum relative errors between model V_pp (mean)-I1 data and measured V_pp-I_m data. The experimental results show that five key parameters of this model match for actual driving data of ultrasonic motors with diameter of 45mm and their waveforms show well too. This work will provide both compact ideas for future nonlinear modeling and applied simulation basis for its ASIC design.

Abstract: Ccording to the running speed of ultrasonic motor instability, design a motor testing system, the closed-loop controller embedded improved neural networkalgorithm, to suppress chaos. In open-loop state, input constant parameters to the motor, the motor rotating speed detection, the test data is chaotic analysis,found the speed has chaotic characteristics; in the closed-loop state, the feedback signal through the controller for processing, effectively inhibited theultrasonic motor speed jitter phenomenon, so as to improve the smoothness of motion motor. Experimental results show that, the neural network controller design not only significantly inhibited motor chaotic jitter phenomenon, but also has good anti-interference ability.

Abstract: A visual tracking system based on ultrasonic motors is designed in view of shortcoming of traditional video surveillance system, which has a large volume, complicated structure. The pan-tilt can rotate in horizontal and vertical directions by using two ultrasonic motors served as the driving units. The image from video camera is processed and the target is identified and real-time tracked by rotating the pan-tilt which is controlled by ultrasonic motor. Compared with electromagnetic motor, the ultrasonic motor has advantages of high torque at low speed, quick response, high precision and self-locked, which makes the structure simpler and control more convenient. Experimental results show that the system can be stably tracking the selected target with fast response speed and relatively high tracking accuracy.

Abstract: This paper presents a rotary standing wave ultrasonic motor using single flexural vibration ring transducer. The motor consists of three main components, the stator, rotor and housing unit. The stator is a piezoelectric transducer ring. The rotor is designed of a compact driving wheel and shaft. The housing unit is made of a transparent thermoplastic Perspex material and is part of the motor working mechanism. The motor design, structure, working principles and modelling using finite element analysis is discussed and presented in this paper. A prototype of the motor was fabricated and its characteristics measured. Experimental tests showed that the motor electrical working parameters are: Current: 100 m-amps, Voltage: 100 volts, Frequency: 41.7 kHz, typical speed of 32 revolutions per minute, a resolution of less than 50μm and maximum load of 1.5 Newton.

Abstract: Linear ultrasonic motor has a wide range of applications in the aerospace field, which requires not only high accuracy of the control, but also the need for a stable running speed. For broadening its application, it is necessary to keep the linear ultrasonic motor having a stable speed. This paper first proposes AR module method for linear ultrasonic motor. The speed of the linear ultrasonic motor is measured by the driving and controlling system. By minimizing the targeted speed value and the actual speed value, we can keep the linear ultrasonic motor stable. This text also compares this method with the traditional PID method. The average deviation of AR is 24%.

Abstract: In order to reveal the Intermixture of Different Modals of Ultrasonic motor, a complete analysis about the modal types and excitation responses were analyzed by finite element analysis. The intermixture of different modals of the stator and its performance under shock excitation are found while doing modal analysis. Through the sensitivity analysis of modal frequency to structural parameters, the separation technique of stator modes is found, which can solve the intermixture problem and provide basis for accessing the structural design

Abstract: Comparedwith traditional electromagnetic motor, the ultrasonic motor (USM) exhibits unique performance advantages. To speed up the research and development of thedriving ASIC for a rotary travelingwave type ultrasonic motor in diameter of 45mm, it is necessaryto obtain its motor model. The modeling of USM which is composed of two parameters (resistance andcapacitance) is presentedand explained. Both the modeling and simulation are based on our real tested motor-drivercharacteristic data by PSIM software. The testeddata can be reproducedby adjusting the unknown two parameters in our model. Some preliminary simulation resultsindicate that this method used to define two parameters of 45mm motormodel is practicable. This work may establish basic foundation for nonlinear modeling of USM.

Abstract: Length and support mode are the key to restrict the ultrasonic motor miniaturization. This paper presents a miniature langevin-type ultrasonic motor stator, it has both short length and simple support mode. With fixed-free ends, the stator adopts a square base and is fixed at its four corners. A new excitation mode is utilized to solve the problem of insistence of excitation position in the conventional excitation mode. Since the stator is unsymmetrical along the circumferential direction, there should be an optimal excitation angle. By using finite element method, axial displacement and radial displacement of nodes are achieved along the outer edge of the upper end of the stator when excitation angle is changed , then the results are analyzed and the conclusion can be reached that 45^o is the optimal excitation angle. Finally, a photo of the stator prototype is presented.