Optimization And Control Of Palletizer Hydraulic Systems

In the new situation of rapid economic progress, the urban development deepens, and various types of bricks are largely used in construction and other industries. Traditionally, production of bricks not only consumes too much clay which has been limited, but also makes serious environmental pollution. In the process of seeking solutions to sole this contradiction, block making machine has been developed rapidly. Block making machine is a kind of equipment of using industrial waste (fly ash, slag, etc.) as raw materials which is mixed with a certain percentage of water, and then presses them to be necessary shapes.For the convenience of transportation, blocks often should be piled into a needed type. So blocks must be held, lifted by the lifting device which can move them to the specify place, and then these actions are repeated to complete the operations of block handling and palletizing. Palletizing machinery is playing very huge role in the block production line, which can greatly reduce labor intensity and improve the working environment and production levels.When palletizing equipment start and stop with block, blocks often fall off if the acceleration is too big and the work period will be extended which will affects efficiency if it is too small. To solve this problem, from the point of view of energy saving and optimization of the hydraulic system, this thesis completed the following work.In this article, electric hydraulic proportional valve is used to control the lift cylinder. Electric signal is setted and rational voltage curve is disigned to achieve the work cycle including smooth start cylinder, high-speed operation and non-impact stop, which can both improve speed,reduce the operating cycle and avoid the block fall off.In order to reduce the impact of hydraulic cylinder (hydraulic motor), conic is selected as the run curve, and model of proportional valve controlling hydraulic cylinder is founded. To find the relationship between motion curve and control voltage (current) of proportional valve, operation of the palletizer is analyzed and calculated.Conditions of the palletizer production line are analyzed and work program is determined to design flow chart. Siemens S7-200 PLC is chosen as the main controller, whose type and I/O terminal assignment are determined by control requirement of production line. In order to achieve automatic control and production automation, programs are written through STEP-Micro/WIN4.0 programming software according to different work ways (manual and automatic).Finally, a simulation software named S7-200.EXE is used to test, modify and debug the program.Through the research to hydraulic system of palletizing machine, the existing problems were solved, which can improve efficiency. And useful attempt was made in improving reliability. Meanwhile, the electrical control system was researched, which is useful in the transformation, redesign and control of similar hydraulic equipment.