The Motion Control System Of The Moving Bridge Three Coordinate Measuring Machine Based On PMAC

With the progress of the modern science&technology and the rapiddevelopment of industrial automation, the three coordinate measuringmachine is becoming more and more widely used in many fields. It isplaying a more and more important role not only in the fields of precisiontesting and product quality controls but also in product design,manufacturing, process control, etc.As the key integral part of the three coordinate measuring machine,the motion control system directly determines its efficiency and precision.With the coordinate measuring machine with mobile bridge type as theobject of the research, this paper intends to carry on the design and research of its motion control system, aims to improve its workingperformance. Firstly, through the analysis of the mechanical structure, thispaper selected the control system structure based on the PMAC motioncontrol card, formed an open motion control system of “PC+PMAC” andmade a detailed design of the motion control card. Then the paperdeveloped the following software: the upper computer control programs,the motor control programs, the lower position machine programs and thePLC programs.Through the analysis of the control algorithm, this paper introducedfuzzy control algorithm which is based on the existing PID control andformed the fuzzy PID control algorithm. Then the paper carried on thedesign of the fuzzy PID controller by using MATLAB and obtained thethree-dimensional diagram of the output variables. Finally, through theuse of the Matlab/Simulink software, the paper carried on the simulationabout the servo system, which verified the excellent system response ofthe fuzzy PID controller. In the end, the paper carried out the experimental analysis of themotion precision of the system, aiming to test and verify the repeatedmeasurements and the stability of the motion system. After having got theerror value of the system, the paper amended the error value through theerror compensation function of the PMAC controller card. After thecompensation, the measurement error value of the system is greatlyreduced, and the motion precision is also improved. Through the furthertest of the velocity’s influence on precison, it can be found that thevelocity has little effect on the control precision, and the stability of thesystem is better.Through the design of control system of the hardware and softwareand the further control analysis and test, this paper completed the basiccontrol requirements, which not only lays the foundation for theimprovement of the overall control and measurement system but alsoprovides a new platform for the upgrade and the transformation of themeasuring machine.