Research On Positioning Of Robot On Laser Tracker

With the development of modern industry,people’s requirements for the measurement of large-size for three-dimensional coordinate measurement have been getting higher and higher.Yet the traditional measurement methods haven’t met the high precision demand of people.Compared with the traditional measurement,the laser tracking measurement system is emerged.The article of laser tracking interferometry system is based on spherical coordinate principle,including interference measuring optical part of the laser tracking system,the position sensitive detector information collection,hardware and software design,and a detailed explanation of the experimental section.Based on the basic principle of interferometer,the propagation path of the light is analyzed,and the optical path difference is calculated,and then simulated for the interference fringes,according to the output of the stripe for counting the optical path difference.Aiming at the measurement model of the three-dimensional coordinate of laser tracker,the paper introduces the principle of laser tracking.Using the pillow two-dimensional position sensitive detector(PSD)to receive the measured light by the target reflected back to measuring beam lens,formed laser spot on the surface of photosensitive,and make sure there’s center of gravity position,after the photocurrent signal processing,the conversion and signal amplification circuit,a digital signal by A/D input after the FPGA.In the design,according to the requirements,it firstly selected the main hardware systems,and then analyzed the relationship between beam propagation and transit,and then congruent relationship between the coordinates of PSD.Date analysis and error analysis on PSD were also selected.The design of this paper required vertical and horizontal motors.The section of the motor mainly considered the rotation speed,encoder and controller.The hardware configuration of signal acquisition part and tracking control part mainly include the circuit Settings of PSD,racking control board FPGA,selection of I/V conversion circuit,A/D conversion circuit,and the selection of tracking control motor.The article used Verilog HDL language design software part.AD sampling software parts controlled information collection.The AD sampling circuit converted the light of the PSD signal to voltage signal of the data,input into the FPGA to coordinate operations through the algorithm which could calculate the position of light spot and the turning Angle of motor.Then the motor drive completed tracking,based on the Angle around the corresponding point of view.After completing the above design,the whole part of the design is verified.Experimentally,which included the simulation and analysis of interference fringe,the least square method to verify the linearity of the input voltage of PSD and processing circuit? The influence of the distance between the laser head and PSD on the measurement data was analyzed.The effect of background light was also verified by adding optical filter,which showed that the precision of laser measurement could be improved by adding optical filter.In the end,the experiment’s advantages and disadvantages were summarized,and the improvement of hardware and software was proposed.For example,the SNR of PSD could be further optimized.The date could be improved by using DSP.In the control of servo motor,the oscillation phenomenon might be reduced further.