A Coordinate Measuring Method Using Laser Plane Scanners (1st Report)

A Fundamental Principle and Experiments on 1-D Measurement

Abstract

A new measuring method is proposed for estimation of robot positioning accuracy. The principle of the method is that one point in 3-dimensional space can be regarded as an intersecting point of three intersecting planes. The coordinates of it can be obtained by solving simultaneous equations of the three planes. According to the principle, a system consisting of a laser detector on the target point, two horizontal scanners, one vertical scanner and a computer has been developed. Each scanner is used to rotate the linearly spread laser beam called laser plane. The rotation angle of the laser plane can be measured with high resolution (0.26'') by using rotary-encoder and time-conversion method. Laser detector is set at each target point. When the laser plane is detected by the detector during scanning for each scanner, the rotated angle of the plane is measured to give equation of one of three intersecting planes. Finally, the coordinates of target point can be obtained by solving equations of the three laser planes determined above. Experimental results show that the 1-dimensional measuring accuracy is ±30 μm and the standard deviation of it is 10μm within a range of 1 m at the distance of 2 m from the scanner.