Research On Deformation Measurement Of The Linkage Of Articulated Coordinate Measuring Machine

Articulated Coordinate Measuring Machine is one of the portable coordinatemeasuring instruments, whose advantages include a wide measuring range, theflexible freedom, light-weight etc.. The self-weight of the linkage of ArticulatedCoordinate Measuring Machine is one of the key factors to affect its measuringaccuracy. Based on Parallel Double-joints Coordinate Measuring Machine, thispaper researches the deformation error of the linkage caused by its weight anddevelops a test system for the deformation of the linkage by applying for LaserDiode and Position Sensitive Detector. The main achievements are shown as:1. The kinematic model of Parallel Double-joints Coordinate MeasuringMachine is established by the modified D-H theory. And its error source isanalyzed to establish systematic error model and random error model.2. The mechanical structure of its measuring arm is the cantilever type. Theforce deformation error model is established by analyzing the staticscharacteristic of the Z axis vertical shaft, the slider, linkage1and linkage2.Meanwhile, the force deformation error is individually calculated by usingMatlab and simulated by ANSYS.3. The test system of the linkage deformation is developed based on LaserDiode and Position Sensitive Detector. The signal process circuit is designedand the data processing software is developed based on Labview.4. The nonlinearity of Position Sensitive Detector is calibrated by usingKohzu precision displacement platform and BP algorithm. The stability, driftingand the ambient light influence on the accuracy of the test system areindividually tested. Those results demonstrate that its stability is very well, itsdrifting is very small. The weaker the ambient light is, the smaller impact on itsmeasuring accuracy.