| Rudder is the actuator of missile servo control system. It is able to control missile wings by air force and pneumatic torque, according to computer command. Thus, missile can cruise in a planned track. Therefore, the servo control of missile rudder plays a very important role in missile guidance.Traditionally, most of missile adopts hydraulic or baric servo system, which has many merits of good dynamic performance and structure adaptability. However, these systems are also have flaws such as complex structure, big volume, high cost, low instantaneous response speed and so on. Compared with these systems, missile rudder digital servo controller is composed by digital signal processor (DSP) and DC motor, which simplifies system structure remarkably. And due to small volume, easy debugging, excellent performance in harsh condition, high stability and precision, the development and research of digital missile rudder servo system has become hot spot recently.This dissertation is mainly on the development of an export certain mode missile rudder digital controller, assignment from a subordinate enterprise of 7th Institute, China Aerospace Science and Technology Corporation. This paper presents the design and development approach on both hardware and software, the designed system, which has the merits such as small volume, low power consumption, high location precision and excellent dynamic characteristic, has already met all system performance requirements. The system zero-error is±0.02°, that means just 1/10 of the error value required; unloaded and elasticity loaded instantaneous response time is 26ms and 38ms respectively, which both are far lower than the requirement. And system has 12Hz bandwidth when 0.4V swept sine wave as input signal. Additionally, the stability, anti-interference and debugging convenience are improved remarkably, compared with former analogue rudder controller.In rudder digital servo controller design, on the software aspect, the common servo controller usually uses the classical position - speed - current three closed-loop control strategy; however, this kind of control strategy has following problems: the implement and tone of the current loop is uneasy, low system track precision and response speed in frequency domain. On concrete control algorithm, the traditional PID control is hard to simultaneously satisfy the system rapidity and low overshoot requirement. Therefore, this dissertation uses a kind of feed-forward-position-speed multiplex control strategy combined with dual-mode fuzzy PID, through the research of servo control strategy and fuzzy control theory,to meets the performance index requirement.On hardware aspect, this dissertation finished control circuit, power driving circuit, as well as signal sampling/converting circuit design. In order to ensure the system precision, this dissertation also developed a special kind of high-precision switching power supply. This kind of fly back switching power supply has high output precision, and peak value of output ripple is less than±20mV, which is only 1/5 of the same level ordinary switch power. Secondly, by hardware anti-interference design and volume control method, high-frequency interference is restrained, system stability is improved and the controller volume is reduced to as much as 3/4 of the former one.Finally, system test results show the feasibility and validity of hardware and software design approach, control strategy and algorithm, given by this dissertation, in missile rudder servo system fulfillment and optimization. |
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