Design And Realization Of Electric Control System Of Portable Laser Tracker

With the advent of laser technology in the 1960s, high-precision measurement technology came into a new period of development. Compare with electromagnetic waves and ultrasonic waves, laser which was widely use in the field of high precision measurements have many characteristics, such as highly monochromatic, high directivity, good coherence and so on. So laser tracking measurement techniques increasingly attract people's more and more attention. At present, the main trends in the development of laser tracking measuring instrument is improving the measuring accuracy of system and reduce the external volume of system which have great significant for increasing real-time and accuracy of measuring system.The goal of this subject aims at researching high precision laser tracking measurement system that have some advantages of portable, small size, high accuracy, good stability, and the main task is designing and achieving the electronic-control system of portable laser tracking measurement instrument.The electrical control system is mainly consists of ARM9 microprocessor, FPGA chip and other peripheral components. The core of the electrical control system is the digital control module which includes ARM9 microprocessor and FPGA module. Based on the embedded operating system, the ARM9 microprocessor is mainly responsible for collecting sensors'data, communicating with upper computer and managing data, controlling real-time tasks as well as PID tracking controlling operations. FPGA module implements that collecting the incremental encoder, ADM IFM and PSD signal by using Verilog HDL language for programming and the LVDS interface, and counts incremental encoder accurately by using the state machine mechanism. In this way, FPGA improves reliability and stability of the system, and implements measuring the motor's speed, determinating the motor's direction and communicating with external data-processing module. Robust PID algorithm design of the motor controller. acquisition of location deviation signal as speed reference signal, speed of the electrical signal as a feedback signal, form a single closed-loop speed control system. Experimental verification of a system of tracking characteristics, about 35 meters range with good tracking performance. Finally, we make the software simulate for circuit and test the whole system. Through analyzed the data, demonstrates that the electric control system which was designed by us be able to achieved that tracking level angle measuring range from -270 degree to +270 degree and vertical angle measuring range from -45 degree to +45 degree, and achieving the measurement accuracy both level and vertical angle measuring are in 3.5 degree, system track precision better than 2 angle min, maximum track angle speed 2rad/s, maximum track angular acceleration 1rad/s, reached track system of index requirements, which meet the requirement of the tracking system's index.