The specified tests are primarily intended to develop and verify individual robot specifications, prototype testing, or acceptance testing. The first version of this standard, ISO 9283:1990, did not specify standard test paths and test loads. The length of the paths and size of the test loads were specified as a percentage of the robot workspace and rated load. Since no two robots have the same workspace and rated load, it was not possible for them to be tested under the same conditions, thus making comparisons very difficult.
The test planes and test paths of this standard are defined with respect to a cube located inside the workspace of the robot. Various diagonal planes of this cube are used to locate the test planes, paths and points. This standard specifies tests for the measurement of fourteen performance characteristics. The most commonly used characteristics are those of accuracy and repeatability.
From the figure above, the robot was commanded to move to the origin of the coordinate frame (rectangle), but instead attained all the positions marked by the triangles. The centroid of these positions, called the barycenter by this standard, is marked by the cross. The cloud of attained positions usually forms an ellipsoid. The lengths and orientations of the principal axes of this ellipsoid provide significant information about the performance of the robot at this position of its workspace. To average the results of this test over a significant portion of the workspace, both the US and ISO standards require that this test be performed at several locations on the test plane and that the data are mixed together.
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