Optimization Design For Portal Crane's Luffing Mechanism And Implementation Of The System

The portal crane is widely used in cargo handling at the ports and wharfs,and shipbuilding and constructing at shipyards.It is an indispensable handling equipment in modern production processing.The design process of portal crane is complicated,especially the design process of its luffing mechanism is the difficult and key point.How to achieve the minimum energy consumption of this mechanism is the key point.A design idea was proposed in this paper which contains the optimization for length and cross section of the bar and the dynamic analysis,in order to reduce the manufacturing cost of the portal crane and improve economic efficiency.The specific work is divided into the following parts.(1)The optimal design of the bar and balance system of the four-bar luffing mechanism was researched,and a modified method was proposed to calculate the elevation angle of main boom to ensure the rationality of the optimization results.The 9 key parameters were taken as design variables,and the quality of the luffing mechanism,unbalanced moment,and luffing force of the luffing rack were taken as the optimization objectives.The work performance requirements in the actual working conditions were taken as the constraint conditions to establish the optimization model of the lengths of the luffing mechanism components and the balance system.An improved adaptive weight particle swarm algorithm was used to solve the model to obtain the optimization result.(2)The optimal design of the cross section of the luffing mechanism was researched based on the optimization of the bar and the balance system of the luffing mechanism to achieve the goal of further reducing the system quality.The key section parameters of each bar were taken as the design variables,and the structural performance requirements of the luffing mechanism were taken as constraints,what's more the quality of the luffing mechanism was taken as the optimization objectives.The finite element first-order optimization algorithm was used to solve the cross-section optimal model to obtain the design scheme so that further lightweight the luffing mechanism which could meet the requirements of strength and stiffness.(3)The dynamic simulation analysis of the optimized luffing mechanism was carried out,and the loads of key hinge joints during luffing operation were analyzed.The motion matrix equation for each bar of the luffing mechanism was established,and the motion rules of each bar were analyzed.(4)The C# language was used to develop the optimization expert system for the four-bar luffing mechanism of portal crane,which integrates the functions of the optimization for the bar and the balance system,the optimization for the cross section of bars and the dynamic simulation of the luffing mechanism.And the expert system can simplify the operation of the designers and enhance the practicability of the method proposed in this paper.The luffing mechanism of 40t-37 m portal crane was taken as an example to be optimally designed and dynamically analyzed by using the method proposed in this paper.The application results showed that the weight of luffing mechanism was lighted of 13.1t,and the maximum unbalance moment was reduced by 59.7%,the maximum pull force of the rack was reduced by 29.4%.The hinge point loads and the bar motion rule of the luffing mechanism which was obtained by dynamic analyzed also provided a reference for the detailed design of the luffing mechanism.