Information interaction model for flexible production line control system of customized home furnishing

Mass Customization (MC) has become the mainstream for home manufacturing industry. However, in many small and medium-sized enterprises, individual work section leads to the stagnation in information transmission, and the incoordination in action, due to different types of control systems and bus. The aim of this research was to establish a kind of data information interaction method to solve these problems. The technological process and function of work sections were analyzed based on the composition of flexible production and intelligent manufacturing of customized home furnishing. In plate-type, several specific sections were chosen to construct the control system model of flexible production line. The applicable hardware modules or software programs were added to incorporate controllers of each section into Modbus TCP/IP protocol. A data information interaction model was be established: firstly to develop a new design using object-oriented programming concept, then to analyze the overall structure of model and details in implementation, finally to instantiate and verify when operating the control system in a flexible production line. The established control system model included seven work sections, such as gantry sorting, RGV carrying, cutting, three-dimensional cashing, banding, punching and last cashing. The controllers and drivers in each section consist of the dominating PLCs and servo systems in control model. Four types of PLCs including Siemens, Schneider, Beckhoff and Delta, and five types of inner driving methods comprising DRIVE-CLiQ, Modbus RTU, high-speed pulse, CANopen and EtherCAT were chosen to set up the whole control system. The data information interaction model was established based on the Modbus TCP/IP bus and class object. All the controllers of work section were set as Modbus TCP/IP Servers, and the global system controller as Client. Five public classes and seven private classes were abstracted in the model. The former consisted of servo motor class, converter motor class, workpiece class, instruction input class, and status output class. The later involved gantry sorting robot class, RGV carriage class, cutting saw class, three-dimensional cashing class, banding line of U type class, punching robot class, and last cashing area class. It was necessary to make attributes and methods that inherited from private parent class and five public classes for building specific work section object. To instantiate data interaction model, it needed to construct mapping relation between attributes of work section object and Modbus register addresses, including starting point, ending point and buffer length. Based on the structures of work section object and redundancy of development, the length of address for each section object was set as 200 words, where the attributes were allocated a definite location. Therefore, writing-in and reading-out of data were carried out according to certain address space, which was operated by a uniform function corresponding to method of work section object. In software of TIA Portal, programming of data interaction method and model was realized by invoking function of MB_CLIENT and modifying input and output parameters. A physical prototype of flexible production line model was tested, where information was successfully transferred among different work sections, and data was interacted among the PLCs by modeling based on Modbus TCP/IP and object-oriented programming. The established model realized data sampling and interaction in a frequency of 5 Hz with interaction accuracy 100%, indicating that the proposed model can be easily transplanted and expanded to meet the process requirement of custom home flexible panel production lines. This finding can provided a potential template of data interaction, and interface technology for the flexible panel production of customize home furnishing.