Research On Key Technologies Of Non-contact Measurement Based On WMPS

With the large-scale production technology and equipment manufacturing level continuous development of precision measurement system for large-size measurement accuracy,efficiency,range and flexibility put forward higher requirements.The workshop Measuring and Positioning System(wMPS)can effectively meet these new requirements,so wMPS has become a hot issue in the field of large-scale measurement research.Existing wMPS coordinate measurement probe is generally realized by a vector stick fixed several receivers,namely a kind of contact measurement.Such kind of contact measurement in the large and complex field environment may cause the flexible analyte surface deformation and exist hidden part within the measurement space.Therefore,this paper presents a non-contact spatial coordinates measuring method combining wMPS with laser ranging.The main contents are summarized as follows:1.The working principle of wMPS was analyzed.Thereout,the mathematical model of wMPS was deduced.Phase-shift laser ranging method is studied.Combining the ranging principle and wMPS,the measuring model of wMPS non-contact target was deduced according to rigid body pose description methods.2.Based on the mathematical model of the wMPS and combined with the constraint relation measure target,the objective function for calculating position and posture can be obtained.The methods to estimate initial value of multi-stations condition and single station condition are given.The measurement of target position and posture can be achieved by the L-M iterative method.3.The methods to calibrate the laser plane parameters and global orientation parameters are studied.By ensuring the interconvertibility of wMPS receiver and laser tracker reflector,laser tracker can be used to calibrate the position parameters of control points.Based on the high precision of 2D-PSD to measure gravity center of beam spot,the methods using single point constraint or coordinate matching constraint to calibrate laser ranging sensor parameters are studied.4.The measurement error of the target is analyzed by Monte-Carlo simulation.The experiment platform including two stations wMPS and four control points target is set up,and calibration of the whole system is completed.Finally,the measuring accuracy of target is verified by conducting several experiments.