Digital control of trolley position and payload vibrations of non-linear Quanser three degree of freedom crane

In these days, three degree of freedom (3DOF) cranes are considered as backbone in most of industries. It is mostly used for picking and placing of heavy objects from one place to another place. The common part in mostly cranes is jib system. Two main tasks of jib system are movement of the trolley and loading/unloading of the payload. The safety of crane mostly depends upon these sub tasks. In most cases, number of unwanted vibrations due to undesirable initial jerks of trolley results uneven operation of crane. These jerks are usually happened during acceleration in the start and deceleration in the end of crane operation. So, it is desirable to develop a control technique that tries to reduce theses initial trolley jerks by providing a reasonable input to the trolley. Moreover, reduction of jerks reduce the payload vibrations. So, it results smooth operation of crane. In this research work, we have implemented PD control technique for payload vibration and trolley position control of jib system of three 3DOF crane. The gains of PD controllers have been found through two methods namely LQR and pole placement. The performance of controllers have been investigated on Matlab/Simulink. The results shows the effectiveness of PD tune by LQR as compared to PD tune by pole placement in context of settling time and rise time of both trolley position and payload vibrations. The former technique is also helpful in reduction of payload vibrations or payload load anti-swing. It has also improved the overshoot of the trolley.