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

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.

Combination of Dual-Energy X-ray Transmission and Variable Gas-Ejection for the In-Line Automatic Sorting of Many Types of Scrap in One Measurement

“…A line array of gas-ejection separation components was used to separate materials. The operation parameters are summarized in Table 2, and the design principles can be found in Reference [39]. The accelerated high-speed cathode rays (electron) in the X-ray source bombarded the anode target to produce bremsstrahlung continuous spectrum X-rays.…”

“…Improving their quality, efficiency and coordination can comprehensively enhance actual sorting quality. Our previous work explained the problems of detection, identification, separation and coordination in the system control process [39].…”

“…Under the PC (personal computer) general OS (operating system) Windows 7, the software was developed with the C language of Visual Studio 2012. The system achieved accurate and coordinated control, and integrated data reading, image processing, identification, logic control separation, communication and HMI (human-machine interface) [39].…”

“…The schematic diagram is shown in Figure 6. Position synchronization and variable action on a range of materials during gas-ejection were also expounded comprehensively in our previous research work [39]. Here, variable gas pressure and/or variable action time were used to change the action impulse of gas-ejection, by which the falling points of various materials could be well controlled and one-time separation of various materials also could be realized.…”

“…The operation principles are as follows: (i) gas pressure can be changed by means of analog signal to control the electro-pneumatic proportional valve. (ii) Action time can be changed by means of changing the ejection range of materials mentioned in Reference [39] because the action range of gas-ejection is directly proportional to the action time at constant line speed. For the shredded bulk materials, in general, the lower the density, the lighter the weight.…”