An electrohydraulic system for synchronized roof erection

To raise the 6075-ton roof frame of the Shanghai Grand Theater as a whole to a height of 26.5 m, an electrohydraulic proportional control system was developed. The arrangement of the lifting stations, the method for uniform load distribution among the spiral lift strands, the hydraulic system, the synchronization control system and the simulation and test results are presented. A "reference station-following station" control scheme enables nonsynchronous height errors between the reference station and the following stations to be controlled within +/- 4 mm during the whole lifting process. The procedure employs three incremental constrained step proportional-derivative (CSPD) controllers. The extensible design of the pump units makes this lifting technology very flexible and one that is suitable for raising structures with various sizes and weights. (C) 2003 Elsevier Science B.V All rights reserved.