Abstract: Coating defects are overcome which occur in the prior art as a result of positional tolerance variations between an automatic spraying device and a part, as the part, e.g., an automobile body, is transported along a conveying system into the spray booth of a coating station during a series coating operation using lacquering robots to apply paint. The distance between at least one fixed reference point on the coating apparatus and a reference point on the automobile body is measured during a preparatory coating operation and stored in the processing program of an operation controlling computer as a standard reference distance value. The reference distance is remeasured for each automobile body during subsequent series coating operations and then compared to the standard reference distance value. The processing program then corrects the movements of the lacquering robots as a function of the calculated deviation to elimate the coating defects arising out of positional tolerance variations.

Abstract: In the case of sequentially coating workpieces, such as motor vehicle bodies, with a program controlled painter-robot, it has hitherto been difficult or impossible to finish painting a partly coated workpiece in the event of an unscheduled breakdown. This was because the robot and the workpiece would inertially overrun their synchronized relative positions after the breakdown, thus making it difficult to resynchronize the two. According to the subject invention, based upon the synchronized relative positions of the workpiece and the painter-robot both at the time of the breakdown and after the unit has come to stop, a path of travel is determined over which the robot is returned accurately to the relative position at which the breakdown occurred. The coating operation is then resumed from this position.