To achieve a good control performance of automatic gantry crane system, sensors are indispensable instrument for feedback signals. However, sensing the payload motion of a real gantry crane, particularly swing motion, is troublesome and often costly. Therefore, sensorless anti-swing controls for automatic gantry crane system are proposed in this paper. The proposed sensorless anti-swing controls are based on mathematical model of the crane based on two approaches. First, a soft sensor based on mathematical model of the crane is introduced to substitute the real swing sensor. In this method, the swing motion of the payload is estimated based on the mathematical model from the measured trolley position. Second, a reference modifier is introduced to produce anti-swing trajectory while performing trolley positioning. An experimental study using lab-scale automatic gantry crane is carried out to evaluate the effectiveness of the proposed sensorless anti-swing controls. The results show that both proposed sensorless anti-swing controls are effective for payload swing suppression since it gives similar performance to the sensor-based anti-swing control. Moreover, the proposed methods are also robust to deal with parameter variations. However, the first method has better performance than the second method.
anti-swing, gantry crane, model-based, sensorless
