| 摘要 |
The robot is started after a groove line of a workpiece to be welded is taught to the robot as a target movement locus for the distal end of a welding torch, by using a fixed coordinate system. A control unit of the robot calculates a position (Pi) of an individual interpolation point in the fixed coordinate system in accordance with data specified in a program (S5), and successively calculates corrected positions Pi' (Xi+(sigma)xr', Yi+(sigma)yr', Zi+(sigma)zr') of respective interpolation points by using a cumulative value of correction amounts (S8). The correction amounts are obtained through transformation of an output of a visual sensor, representing a deviation of a current moving position of the torch from the groove line in a predetermined coordinate system defined by the current position and a current moving direction of the torch end, into a correction amount in the fixed coordinate system. In accordance with the result of a second transformation of the corrected positions Pi, individual axes of the robot are controlled such that the torch end is moved sequentially to the corrected positions (S9), to thereby move the torch end along the target locus. The correction is carried out each time the position of the workpiece is moved.
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