Research On Jacking System Of Special Lifting Platform For Integrated Lifting Equipment Of Prefabricated Building Construction

With the industrialization of China’s construction,in order to solve the problems of low efficiency and difficulty in safety control of traditional lifting equipment,the Ministry of Science and Technology approved the "13th Five-Year" key R & D plan for "key technology and equipment for efficient lifting and installation of construction site components." Carry out R & D of "automation,digitization,modularization,platformtype large-scale assembly building efficient lifting and installation comprehensive equipment that integrates automatic picking and placing of components,lifting,posture adjustment,positioning,and joint construction." This article is to solve the problem of positioning guide reliability during lifting of the special lifting platform for integrated lifting equipment of assembled building construction;uneven load distribution of the platform,due to the temporary positioning bracket placed on the lifting platform and two six-degree-of-freedom cranes Complex working conditions with uneven load of multiple legs;technical difficulties such as large span between jacking cylinders,and a set of distributed hydraulic control system with multiple hydraulic cylinders synchronous lifting based on distributed layout.First of all,by studying the composition and principle of the hoisting equipment for the construction of assembled building components,a synchronous jacking system for a special lifting platform was designed,including the mechanism design of the platform lifting system,and the design of a single-leg hydraulic circuit based on distributed control.Select the key hydraulic components on the jacking circuit and the design of the control scheme.Secondly,aiming at the problem of guidance reliability during the multi-cylinder synchronous lifting process,taking the special lifting platform for integrated lifting equipment of assembled building construction as the object,and using rigid body mechanics analysis methods to determine the guidance clearance and guidance distance and the maximum allowable synchronization error Correlation,and select the appropriate settings of the guide gap and guide distance,determine the platform synchronization error threshold,use Adams for simulation verification,and determine the reasonableness of the threshold setting.Provide a reference for the selection of synchronization error control methods and synchronization control strategies.Then,in view of the synchronization error control problem of the hydraulic lifting system in the special lifting platform,the characteristics of the valve-controlled hydraulic speed control system and the variable frequency pump control hydraulic speed control system are analyzed,combined with the special lifting platform multi-hydraulic cylinder synchronous lifting working environment,the variable frequency pump is selected Control the hydraulic speed to control the synchronization error.Finally,based on the demand of the multi-cylinder synchronous control during the lifting process of the special lifting platform,according to the characteristics of the load of each lifting cylinder changing with the working conditions during the lifting process,the master-slave,master-slave and virtual spindles are analyzed,Cross-coupling,deviation coupling,and adjacent coupling synchronous hydraulic control strategies,focusing on the main command,virtual spindle,and adjacent coupling synchronous control strategies,three motors are used as control objects to simulate and verify their Synchronization,stability and anti-interference ability.Finally,the adjacent coupling synchronous control strategy with better comprehensive performance is selected.