Car-body inspection system using industrial robots

Abstract

Inspecting the dimensional accuracy of a car-body in assembly line is a very important process to assure high productivity. Now there exists two common inspecting methods in practice. The one is to measure the sampled car- body in three dimensional measuring machine, and the other is to measure the car-body in process using many sensors fixed to a jig frame. The former method takes too long to inspect the sampled car-body of the same sort, and cannot therefore give error trend of the whole production. On the other hand the latter lacks flexibility and is costly to construct the cell. By using industrial robots and sensors Robotics Lab. at KIST developed an in-line car-body Inspec-tion (CBI) system which ensures high flexibility and sufficient accuracy. This CBI cell operates in real production line and measures the target points in non-contact with camera and laser displacement sensor (LDS). This system can handle about 15 measuring points within a cycle time of 40 seconds. A process computer controls the whole process such as data acquisition, file handling and data analysis. The length of the robot arms is changed according to ambient temperature and it affects the measuring accuracy. To compensate this error, a robot arm calibration process was installed. ？ 1992 IEEE. All rights reserved.