Research On Electro-Mechanical Converter For2D Digital Servo Valve With High Frequency

As a key component of the electro-hydraulic control elements, electro-mechanical converter is a bridge of connecting electrical components and mechanical components. The entire performance of digital valves is largely determined by the performance of electro-mechanical converter. When developing high-frequency and high flow electro-hydraulic servo valve, electrical-mechanical converter is required to have the characteristic of high-frequency. Improvement of electro-mechanical converter frequency response and loading capacity is a premise to improve the electro-hydraulic servo valve frequency response. When traditional stepper motor works in a large load occasion (including inertia loading and the spring force), frequency response is limited. In order to solve this problem, replace the stepper motor with coreless DC motor of better performance.Based on coreless DC motor as research object, this paper analyzed its structure and principle and also establishes its mathematic model. A controller of coreless DC motor based on DSP was designed. Three closed-loop control of current-speed-position was used in the experimental study. The experimental results show that this control system can precisely position rotor of the coreless DC motor and increase frequency response of digital servo valve to500Hz.The contents of each chapter are listed as follows:1. Measured inductance, torque coefficient, and other parameters of the coreless DC motor. Established the DC motor mathematic model and drew its the torque equation, voltage equation, and the kinetic equation. Theoretically analyzed the static characteristics and dynamic response, and made simulation in SIMULINK.2. After describing the composition and principle of the three closed-loop servo system, showed the transfer function and dynamical block diagram of the control system, and made simulation in SIMULINK.3. A controller of coreless DC motor electro-mechanical converter based on DSP was designed. Introduce the hardware and software system, and analyzed each module of the system. The implementation of algorithm for producing controlling signal and three closed-loop is expounded4. Built a controller of coreless DC motor electro-mechanical converter experiment platform,and did research on dynamic characteristics of current loop control system, analyzed the step response of the system. Three closed-loop experiment validated the theory and design method of DC motor control system, the experiment results are close to simulation results, suggesting that three closed-loop control strategy can achieve the desired control goal.5. Sum up all the main researches and achievements of the paper and new prospect is put forward.