INTEGRATED SENSORS DETERMINE ROBOT COORDINATE PARAMETERS

This paper describes methods to determine the robot coordinates in the assembly coordinate system. These methods are implemented in the control software of the direct drive industrial SCARA-robot, which was developed at our institute in cooperation with robot industries. The robot model and the numerical analysis of the error reproduction model from the SCARA could be reduced to a two dimensional structure. This model allows to describe arm length- and angle errors dependent on states. Furthermore it is possible to compute the robot coordinates in relation to angle- and temperature values. The inverse kinematic transformation of the SCARA has two solutions. This fact allows to describe a relation between the angles and the arm lengths. This relation is used to reduce the errors of the robot coordinate parameters. Hereby it is possible to manufacture only one arm segment with high precision, because the other arm segment can be measured with the robot sensors.