Performance optimization of automatic ship unloading for GSU

SUN Bin, WANG Xuchang
(ABB Engineering (Shanghai) Limited, Shanghai 200001, China)

Abstract: In order to improve the performance of automatic ship unloading of GSU (grab ship unloader), grab sway control and load path optimization was carried out. Based on the law of grab sway, sway control was optimized to improve the periodical acceleration/deceleration method. During acceleration and deceleration, twostep acceleration/deceleration method was adopted to eliminate load sway. When the grab approaching the hopper, fly unloading was achieved by controlling the grab sway forward and keep a constant angle, and unloading cycle time was effectively shortened with the proposed method. Grab path was optimized by applying different trolley control strategy to different working areas. An optimal safe level was found out for each grab position. When the grab is above the safe level, trolley and hoist move simultaneously, obtaining a shortest safe grab path that goes over all obstacles. Site test results indicate that efficiency of auto unloading was greatly improved after optimization.
Key words: grab ship unloader(GSU); sway control; path optimization