Research On The Formal Description Method Of Vision FBD

With the rapid development of industrialization,more and more vision technologies to be applied in industrial production with PLC.The IEC 61131-3 standard and PLC OPen international standards only regulate the logic control programming and motion control programming,but did not develop PLC vision programming specification.The mainstream platform of PLC programming also has not yet supported vision development.This seriously hindered the development of PLC.FBD is one of the commonly used programming languages in the field of PLC.Therefore,the design and development of vision FBD programming platform will be able to solve the current problems.Vision FBD programming platform allows users to quickly customize the vision applications which is combined with PLC.And the key point of the design and development of vision FBD programming platform is the formal description.The main contents of this paper are as follows.1).Based on the full study of the IEC61131-3 standard and combined with the characteristics of the vision algorithm,this paper formally defines the vision function block model.And the interface of vision function block is defined.2).After analyzing the characteristics of the function block in the implementation,this paper propose a model of the relationship among vision function blocks,and then design a vision FBD programming model.3).In this paper,a AOV data model of vision FBD is designed to describe the implementation of vision FBD program,and proposed the conversion rule of vision FBD network to AOV network.4).In order to avoid the problem of semantic errors when the user use the vision FBD programming language to program,the paper designs a vision FBD programming graph grammar based on the research of graph grammar,and a statistic algorithm is proposed to judge the legitimacy of the user program.In this paper,a vision FBD software platform is designed based on the proposed formal description method of the vision FBD language.The proposed design model is verified.Finally,it is proved that the design model is effective and feasible via the identification of the workpiece in the workshop.And it can provide a powerful function of vision processing for PLC equipment.