Research On Logic Control Of Production Line Simulation

Digital factory is an important part of intelligent manufacturing.Production line simulation can carry out pre-planning,analysis,evaluation and verification for the layout of production line and process flow of the factory,and find out the deficiencies in the design for correction and optimization timely.Due to the improvement of industrial robots' performance such as speed,repeatable positioning accuracy and reliability,the application scope of industrial robots in the field of production and manufacturing is wider.Simulation of intelligent production line with robot participation in advance can shorten manufacturing cycle and enhance market competitiveness.This paper studies the key technologies in the design and implementation of the simulation platform based on demands such as logic control of the plant production line.In view of the characteristics of large number of models and inconsistent formats in the production line scene,the open source virtual-reality(VR)engine OSG suitable for large scene rendering was adopted to organize.Geometric and topological information of STEP and IGES model were visited by the open source geometric engine OCC.Then,model visualization and interaction can be realized.Aiming at the logic control problem of virtual production line,simulation schemes based on XML description and simulation action node as the core are proposed.According to the process flow of the production line,the control logic of the production line that needs to be simulated is determined.XML is used to describe the logic relationship of the production line model.Considering the readability and universality of user operation,a method of combining the simulation action node with the semaphore is proposed to establish the production line logic,and the simulation is realized by multi-thread and timer animation technology.To optimize the method of the simulation logic control,the finite state machine(FSM)model is used to describe the production line logic,and combining with the controller program in real manufacturing is discussed.According to the theory of finite state machine,the state transition model of production line is established.Then PLC programming language SFC is adopted to establish the model,which complies with IEC61131-3 standard.Compiling PLC program to C intermediate code,the basic idea of explaining and executing C intermediate code on simulation platform is proposed.Based on the above research,production line simulation prototype system is developed.A typical robot production line is taken as an example to test the simulation,and a simple PLC program is taken to test that the C intermediate code is interpreted and executed by the simulation platform.As a result,the feasibility of the key technologies in this paper is verified.