Study And Realization Of A Servo System Used In A Mobile Satellite Television Receiver

This paper discusses the process of designing and exploitting a kind of mobile satellite communication system that used in receive TV signal. Using this method, it can reduce the cost and volume of the system. It provides the condition to popularize this kind of the product.The paper introduces the composing and principle of the servo system, and analyses the technique difficulty in system design. The design scheme of the system is confirmed. The interface circuits are designed which are used to connect electronic compass, obliquity sensor and AGC signal to the MUX. Other circuits are also completed, which are used to store, display and collect datum. The internal composing and parameters of two-phase hybrid motor are analyzed. The theory of the constant-current chopper and H bridge are used to design 16 subdivided drive circuit.A formula is disscussed that is used to transform the earth's core, geography and carrier reference frames. The angle of the satellite in carrier reference frame can be worked out by the longitude, latitude and the stance angle of the antenna carrier. These methods are applied to opened loop control. By studying the characteristic of the electro- -magnetic wave, the satellite tracking method is put forward which named bi-directional search adjustable step. This method realizes the closed loop control of the system.The models of the motor, motor driver and transmission machine are built. The Fuzzy-PID arithmetic is adopted to control the servo system. By analysing the system characteristic, the input and output variable are determined for this arithmetic. At last, the Fuzzy Tool Box and Simulink in Matlab are used to simulate the work of the system. In the process, the parameters, control rules are adjusted in order to satisfy the performance request.