Abstract: A workpiece handling machine having an annular barrel structure capable of vibration caused by a plurality of vibration suppliers equipped with unbalancing weights includes a sensor system which is sensitive to any difference between the reference rotational angular phase of one unbalancing weight and those of the other unbalancing weights, and a control system which is responsive to the detected signals of the sensor system for providing an analog or digital feedback control, which adjusts the phase difference to the target value. As such, not only is the synchronized phase of rotation permitted, but also the advance angle of the unbalancing weights with regard to each other can be chosen, depending upon the operational requirements such as the kind of the workpiece and abrasive media, the workpiece working conditions, the time period of the operation, and other parameters.