Automatic Control System Of The Bridge Type Grab Ship Unloader

With the development of automatic control technology, grab ship unloader gradually entered the times of semi-automatic control or automatic control from the long era of manual operation. This project is a successful typical application of automatic control technology. It helps the driver get rid of high-intensity work, get full use of all kinds of sensors, modern PLC system and DTC converter, and makes the efficiency of the expensive grab ship unloader be highly increased under the premise of the safety of the unloading process, so that customers could get higher efficiency.There are two major issues in the process of grab ship unloader automization. One is grab anti-swing and the other is grab obstacle avoidance. The key approach of resolving the first issue lies in the theoretical analysis of the car-grab system. This paper analyzes the way in which the grab is forced and establishes the mathematic relations between car running mode and grab swinging. Taking the optimal time control of fixed distance and the grab anti-swing control into account, this paper raises two car operation modes. With the confirmation of the mechanical system dynamics and kinematics simulation software ADAMS, these two operating modes can realize grab anti-swing effectively. To improve the unloading efficiency higher, this paper also raises a new way to unload materials by flinging the grab, which could be combined with the two operating modes outlined above. However, grab obstacle avoidance must be resolved by seizing the main contradiction. It can be simplified and be solved successfully by two safety lines.The control methods raised in this paper have been certificated by Beilun Power Plant 400 t/h limestone grab ship unloader. They perform well in the aspects of safety, time optimization and grab anti-swing. Meanwhile, this paper will also introduce ancillary facilities as well as design ideas which could put the system into operation.