Research On Remote Measurement And Control For Displacement Based On Position Sensitive Detector

Resonance inelastic X-ray scattering(RIXS)is a kind of physics experiment device to study the electronic structure of materials using X-ray spectrum,which can obtain the information of orbital excitation,spin excitation and so on.In order to reduce CCD pixels information confusion caused by low-frequency vibration and temperature drift and improve the energy resolution of RIXS,a remote measurement and control system for displacement based on position sensitive detector(PSD)was proposed.In this thesis,the current formulas of tetra-lateral PSD and quad-lateral PSD are established according to the transverse photoelectric effect equation.The differences of the two PSD measurement displacement and motion displacement are analyzed through the electrode current simulation.In order to improve the global position detection accuracy of PSD in region B,the interpolation models for quad-lateral PSD are established based on bilinear interpolation algorithm and bicubic spline interpolation algorithm.According to the working principle of the piezoelectric actuator,the mechanical and electrical coupling theoretical model based on the hysteresis effect is established.Furthermore,the parameters of the motion model are identified according to the step response curve.The constraint equations of zero vibration input shaper(ZV)are derived and the natural frequency differential constraint is proposed to improve the system robustness.The input shaper is designed according to the time-domain response of piezoelectric actuator model.Initial PID parameters are abtained by family-tree adaptive genetic algorithm(FAGA)whose global optimization ability and convergence speed is better than the standard genetic algorithm.A fuzzy rule table is established according to the adjustment experience of PID parameters and the quantization coefficient of the fuzzy controller is also optimized by FAGA.A closed-loop control system based on fuzzy PID controller is established for piezoelectric ceramic motion system.In order to reduce the effects of laser drift and air turbulence,a closed long-distance measurement system using single-mode fiber coupled laser is established.The acquisition and feedback control interface based on Labview is designed,which can control the relative displacement between laser and PSD at the micron level.In order to improve the energy resolution of RIXS line station by controlling the relative displacement of CCD cavity and grating cavity,a remote measurement and control system for relative displacement based on PSD sensor is established,which provides a basis for the design of RIXS.