Researsh On Performance Of Ultrasonic Motor Based For Two Axis Pointing Mechanism

At present, the satellite technology becoming more mature and not only promote the development of micro-nano satellite, but also promote the development of small-sized precision drive technology.The existing satellite in biaxial oriented drive is mainly composed of traditional servo motor and reducer, complicated structure, large volume, can not fully meet the needs of the development of micro-nano satellite technology, especially in the area of light small precision drive technology.Therefore, developed a structure of small size, lightweight, high driving accuracy of precision drive becomes the key problem at present.Ultrasonic motor(ultrasonic motor, the unsharp mask for short) is a new type of direct-drive motor, small volume, light weight, do not need to gear box can realize low speed high torque, and position control precision is high.So the main research content of this article is how to realize low speed high torque ultrasonic motor and high precision operation, and the applications of ultrasonic motor to two-axis pointing device, to realize two-axis pointing to the goal of lightweight, low speed and high precision.This article mainly from two aspects of structure and control of large torque at low speed and high precision of the ultrasonic motor is analyzed theoretically.Theoretical studies have shown that the biggest theory of ultrasonic motor speed and stator of some main parameters have close relations, and to realize the ultrasonic motor running at low speed, also need the combination of frequency modulation and step speed regulation control strategy;Friction material affect the performance of ultrasonic motor output analysis showed that the elastic modulus and the elastic coefficient of friction material determines the output torque of ultrasonic motor;Another theoretical studies have shown that ultrasonic motors can achieve high precision not only with the stator tooth groove width and driving principle of ultrasonic motor has the close relation, and mainly depends on the quickness of ultrasonic motor response.Large torque at low speed and high precision of ultrasonic motor based on theoretical analysis, vibration analysis of ultrasonic motor stator.Based on the modal analysis and harmonious response analysis of ultrasonic motor stator for determining main parameters on the ultrasonic motor stator rotation speed and the influence law of rotating accuracy, finally to determine the optimal structure parameters.Based on the special conditions of friction material requirements, selected three kinds of friction materials, and compare the performance of the ultrasonic motor under different materials, choose the optimal performance of friction materials, finally finish the improvement design of ultrasonic motor.To improve mechanical properties as well as the rotating precision of ultrasonic motor before and after the test;Then complete the biaxial refers to the configuration design of institutions, the ultrasonic motor is applied to two-axis pointing device, speed for two-axis pointing to institutions and pointing precision of the experiment test.The experimental results show that the improved performance of ultrasonic motor is better, can meet the requirements.Finally will improve the whole body after the validation test, mainly in high and low temperature, under the sinusoidal vibration and random vibration test.The test results show that the improved mechanism can meet the requirements. In addition, the ultrasonic motor weight substandard problems, so in this paper, the ultrasonic motor weight and weight reduction design of the structure.