| In the field of modern industrial production and scientific research, large travelprecision positioning system occupies an important position. With the continuousdevelopment of science and technology, the required positioning accuracy for positioningplatform is becoming higher and higher. To meet the requirements of emerging fields, suchas nanometer lithography, ultra-precision machining and microelectronics engineering andso on, for high precision positioning. This paper is for the large travel precision positioningplatform which driven by linear motor, supported by aerostatic, starting with the analysisof deflection error, studying the influence of the deflection error on the positioningaccuracy and the corresponding error compensation method.This paper carries theoretical analysis aimed at the causing factors of the large travelprecision positioning platform’s deflection error, and builds the corresponding error model.Based on mass spring damping system simplified by static-pressure air-bearing sliders,establish a two degrees freedom deflection vibration model of the precision positioningplatform, calculate the natural frequency of the system, and study the amplitude ofdeflection error. According to the above results, index requirements of the error detectionand compensation system are proposed.Analyzing the deflection error characteristics of the platform, design a kind of highfrequency response and non-contact deflection error detection system combined with flatfeet and micro displacement sensor. Detection algorithm model is established, whichprovides the theoretical foundation for real-time error compensation. Design a micro errorcompensation platform based on piezoelectric actuator, oval amplification mechanism andflexible hinges as transmission. Combining with the theoretical mechanics principle, themicro platform is simulated by finite element simulation analysis, research on its dynamicand static characteristics, and the geometry dimensions are determined. In view of themicro compensation platform, study the feedforward control algorithm to improve thehysteresis characteristics. Build a large travel precision positioning system based on error compensation system,and micro displacement compensation platform is set to experiment. Through thedeflection error compensation experiments, we can get results on before and after errorcompensation, which verify the large workspace precision positioning system can achievehigh precision and large travel precision positioning. |
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