To solve workpiece offset and deflection problems of welded I-beam and box beam structures in automation production,apose detection method of fillet welds was proposed based on laser displacement sensors.An arc length model of fillet welds was established,the effects of weld poses on arc length were analyzed.Based on Fourier analysis,a decoupling algorithm was put forward for pose detection,which realized the detections of lateral deviations,longitudinal deviations,groove angles and deflection angles of fil...