| Compared with the traditional measurement system based on coordinatemeasuring machine (CMM),robot flexible coordinate measurement system hasadvantages of non-contact detecting, fast speed, good efficiency, online real-timemeasurement and moderate precision,this system applies to modern mainstreammulti-vehicle production line,and has become the trend of the measurement andinspection of the car body and its components.Since the system calibration and the compensation of robot motion error are thetwo critical techniques in guaranteeing the measurement precision, by analyzing themethods that have already been used in these two techniques, this paper proposed thesystem calibration technique and the real-time compensation of robot motion errormethod which are suitable for the industrial site.The main work of this paper includes:1. Detailed researches on the robot, its calibration technique and visualmeasurement technique; the overall scheme for system calibration.2. The analysis on the advantages and disadvantages of the existing calibrationmethods; the proposal of specific modeling methods for hand-eyerelationship, the forward motion model and the external pose of the robot;and the transformation from the visual sensor coordinate to the car bodycoordinate bya series of coordinate transformation chain.3. Both effect from the temperature factor and experimental analysis on thecompensation method of robot motion error; the design of calibration ball fortemperature compensation and the proposal of on-site temperaturecompensation method based on fixed spatial points.4. The calibration experiments undertaken according to the establishmentmethods of the three parts of the whole system calibration and the solution tothe transformation matrices of each part.5. The design of compensation experiment, the validation of the feasibility ofthe on-site compensation method of robot motion error base on fixed spatial points which has obtained good compensation effect. |
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