Research And Design Of System For Small Angle Measurement With Super Precision

At present, a datum plane-conversion scheme is introduced in the sight system of active ground-to-ground missile. In this scheme the datum plane of sight system is transferred from inertia combination to missile terminal, and the angle of two datum planes is measured at the Technical Position. This scheme availes both to shorten Launch Distance and to shift shooting direction easily. But repetitious launching tests show that there is a remarkable error in the measurement of the angle which is measured in the Technical Position. The error has so notable effect on sight precision of weapons that this scheme is abandoned in the design of later missile weapons. Basing on carefulness analysis of error source, a new measuring system for small angle is designed in this paper. With super measuring precision it can be used to replace old measuring instrument.In this system, an inclinnation transducer with super high measuring precision is applied to catch angle signal, and an new MCU embedding 24-bit ADC is used to acquir and process datum. To improve measuring precision, a precious electrocircuit is designed, which is used to measure and control transducer temprature. Based on analysis of several control algorithm, a Fuzzy control algorithm is adoped to control the surface temprature of inclinnation transducer, and an error correct model is worked out by data fitting method, which is valid within a small temprature range. The super precision of angle measurement is ensured by correcting the acquired datum at certain temperature.Besides, in system design, a modular structure based on the serial bus is adopted, the primary module is connected with other data-acquiring modules via general RS485 serial communication standard bus. through which, the system can measure several points at the same time, at the other hand, it become more easy to distribute the system tasks in balance and realize complicated control algorithm on MCU.At last, the measuring error of the whole system is analyzed in detail, which shows that this measuring system can meet set specifacation.