A PC-based control method for high-speed sorting line integrating data reading, image processing, sequence logic control, communication, and HMI

Tianzhong Xiong,Wenhua Ye

doi:10.1063/5.0031302

Abstract

The vision-based automatic systems for in-line detection, identification, and separation are widely used in the industry, and it is difficult for such systems to achieve a simplified structure, high speed, high efficiency, and integrated coordinated control. Taking the dual-energy x-ray transmission solid waste high-speed sorting line as an example, an automatic control system was proposed, integrating data reading, image processing, sequential logic control, communication, and human–machine interface based on a personal computer with a general operating system. The hardware platform was introduced, and the design principles of operation parameters were investigated. The software was developed in C language with Microsoft Visual Studio 2012. The multi-core multi-thread technology has been utilized in which the optimized process-thread settings (OPTS), first-in first-out (FIFO) stacker, variable sharing between threads, and encoder position synchronization were employed. The whole system was experimentally verified at the line speed of 1 m/s. The results showed that the average scan cycle of sequential logic control was only 15 µs, which could fully ensure the real-time high-speed logic control and accuracy of position synchronization, OPTS improved the stability and disturbance rejection, FIFO stacker and variable sharing between threads was adapted to the realistic buffer materials, the encoder position synchronization avoided the accumulation of measurement errors, and the main operations run in parallel and coordinately and were suitable for the high-speed separation of multiple columns of irregular materials. The presented control system has the advantages of near real-time, high speed, high efficiency, low cost, easy reconstruction, and capability to manage and control integration and has a good practical application value.

Highlights

Nowadays, the products in the industry update rapidly, the labor cost gradually increases, the market competition gets fiercer, and health and environmental protection draw more attention
The results showed that the average scan cycle of sequential logic control was only 15 μs, which could fully ensure the real-time high-speed logic control and accuracy of position synchronization, optimized process-thread settings (OPTS) improved the stability and disturbance rejection, first-in first-out (FIFO) stacker and variable sharing between threads was adapted to the realistic buffer materials, the encoder position synchronization avoided the accumulation of measurement errors, and the main operations run in parallel and coordinately and were suitable for the high-speed separation of multiple columns of irregular materials
The detection data could be stored as raw data and/or BMP image by human–machine interface (HMI) configuration for offline analysis; the image could be displayed in real-time, but it needs a lot of computer resources

Summary

Introduction

The products in the industry update rapidly, the labor cost gradually increases, the market competition gets fiercer, and health and environmental protection draw more attention. As far as sorting is concerned, high-speed automatic sorting lines are mostly based on various sensors, and the visual sensor is the most widely used because of its remarkable nondestruction and rapid detection.. The collection of image data is often completed by using a visual sensor plus a dedicated controller and circuit and read and processed by using a host computer (usually a PC) through a communication interface and protocol.. The vision-based automatic sorting line requires in-line detection, identification, and separation.. The vision-based automatic sorting line requires in-line detection, identification, and separation.7 For these operations, in-line and parallel control of data reading, material identification, material buffering, position synchronization, and accurate separation are often needed. There is an urgent demand for the further research on the architecture and method of the vision-based high-speed automatic sorting control system to resolve these problems in practical applications

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Methods

Results

Conclusion