SYNTHESIS OF MINIMAL SCHEMES OF SYSTEMS CONTROL OF HYDRAULIC AND PNEUMATIC DRIVES

Abstract

The existing schemes of command apparatus are presented. Their analysis is carried out and the shortcomings are indicated. The scheme of afundamentally new command apparatus is given, which can significantly reduce the number of its elements. The synthesis of the pneumatic controlsystem of the foundry machine was carried out on the basis of the design approach proposed by M. Cherkashenko, which as a result led to a reductionin the devices by 3.5 times. A graph of operations of the pneumatic control system of the molding machine is constructed. A matrix ofcorrespondences is obtained, which determines the correspondence between the signals that cause transitions and the complete input sets acting in thetransitions. Analysis of the matrix of correspondences made it possible to identify and eliminate contradictory transitions. On the basis of theelongations, a system of equations describing the scheme of the control system is synthesized. Further, minimization is performed due to factorizationand decomposition of equations, and obtaining equations in their final form. A diagram is presented pneumatic control system of the molding machine,consisting of a command apparatus containing three cells, five cylinders, two vibrators, six limit switches, a time relay and other devices. The circuitsimultaneously uses the functional and logical capabilities of limit switches, the possibility of implementing the functions of three variables bydistributors. Thus, the use of the proposed command apparatus, in contrast to the existing schemes of command apparatus, can significantly reduce thenumber of distributors in the synthesis of the command apparatus itself and significantly reduce the number of elements when using the chosenapproach to the design of circuits of pneumohydraulic control systems.