Study And Design Of Laser Scanning System Of Large Size Moving Objects

With the needs for reforming the civil aviation airport information, it has been a trend that the intelligent docking guidance system replace the manual ways. Based on the demand of airport and the disadvantages of existing guidance system, this paper, combines with image recognition method and laser scanning detection method, designed a high accuracy, intelligent guidance system, which is safer than other ways. This paper also introduces the theory and design method of laser scanning system in detail.For the limitations of the scanning range and speed of existing laser scanner, this paper achieves a new laser scanning system to scan large size moving objects, which is based on dual galvanometric structure. And it provides detailed information on the application background, theory analysis, data processing, error analysis and correction, hardware and software design and so on.Regarding the errors of dual galvanometer structure, according to the mechanical dimensions and geometrical relationship, this paper establish the mathematical model to calculate any point coordinate expression, analysis the sources of system error, and calculate the maximum allowable inclination angle in six degrees and maximum input error of installation height. By presenting the error correnction methods of distance error, angle error and non-linear error, it improves the output precision of laser range finder, reduces the angle error and eliminates the pillow error.This paper presents the basis for selection of physical zero point to solve the uncertainty stepper moter position and the method of rapid return to zero point in different occasions. By using sub stack method, calculate the mean and probability of each stack data to improve the accuracy of the distance measurement. This paper also shows the pre-processing method of scanning data, through multi-value average, data clipping, median filtering and speed compensation to make 2D scanning curve closer to real curve, and realize 3D scanning for a moving object.The system scan controller is ARM+FPGA architecture. ARM is mainly used to communication, data acquisition and data processing. FPGA mainly controls the step motors. By using both ARM and FPGA in a controller, we can improve the precision of scanning system and enhance the flexibility. This paper demonstrates the hardware and software implementation of the system, displaying the scan controller circuit design, software design, the timing generation of motor control, configuration software design. Finally, we show the test results of the system that the distance measurement, angle control, scanning speed and accuracy, zero point processing and the result of plane all can meet the application requirements.