Large Diameter Grating Splicing Error Control Technology Research

Researchers try their best to achieve high-energy short pulse for its application to fast ignition and some other fields. However, the aperture and threshold of the compression gratings determine the maximum output energy for all short-pulse laser systems which use the chirped-pulse-amplification(CPA) technology. Because of technically difficult and financially impractical when manufacturing individual large gratings, many researchers have presented the most efficient method to increase the grating size, which is to mosaic two or more gratings into an equivalent single grating. Environmental vibration and temperature change have different effect on the grating tiling errors. According to above principles, different control methods are proposed to achieve stability control of the grating tiling. The main contents are as follows:Firstly, Basing on the characteristic analysis of the grating tiling under environmental vibration, how to decrease structural response of the frame is discussed. Vibration isolation platform that adapts the technology of negative stiffness is used to keep the frame away from the highfrequency and broadband vibration,and experiment is done to test whether the platform has effect on the environmental vibration or not.Secondly, something has been done to satisfy the requirements of the grating tiling. As we all know that it is important and necessary to keep high accuracy, quick response and great stability when using the technology of grating tiling; and also there are much nonlinearity and uncertainty when doing the PID closed-loop control, according to all above of these, signal neuron adaptive PID control algorithm is improved. Using changeable neuron proportionality coefficient (K) instead of constant K value, Simulative result indicates that the proposed control algorithm will not bring greater overshoot with quicker rise-time than the traditional PID controller.Thirdly, basing on the control of environmental vibration and the improvement of PID control algorithm, some experimental researches have been studied. Drift of the grating-tiling in low-frequency is controlled by using PID closed-loop control, which is mainly composed of piezoelectricity drivers and capacitive sensors.Finally, the results of the experiment show that the control method has many advances, it not only makes the grating-tiling smaller tiling-errors, but also can keep the system stable for a long time, at the same time, the validity and practicability of the proposed algorithm is proved and the proposed control algorithm can guarantee the precision of the grating-tiling.