Design of fruit sorting system based on PLC

Abstract To overcome the limitations of manual fruit sorting—such as inefficiency, high labor costs, and inconsistent quality—this study designs and validates an intelligent fruit sorting system centered on a Mitsubishi Programmable Logic Controller (PLC). The system integrates multi-sensor data fusion, combining machine vision, weight sensing, and near-infrared spectroscopy, to achieve automated, high-precision grading of fruits—this fusion strategy is consistent with the multi-source information feature fusion algorithm proposed by Zhang et al. (2023), which verified that integrating heterogeneous sensor data can significantly improve the accuracy of agricultural product quality detection[1] based on size, weight, surface defects, and internal quality. A modular mechanical structure ensures adaptability to various fruit types, including blueberries and cherimoyas. The smart juice manufacturing system utilizes PLC technologies to enhance efficiency, productivity, and sustainability. The Siemens S7-1500 PLC is employed for modular programming, managing units like fruit juice and sweetener water production. Safety interlocks and sensors ensure precise control and operator safety. Focusing on the issues of low efficiency in pear picking and processing, excessive manpower input, and easy fruit damage that affects fruit farmers’ income, we designed a pear picking and comprehensive processing integrated machine with PLC as the core control module, integrating 3D printing technology, software design principles, mechanical design principles and photoelectric sensors. The machine achieves three functions: pear stem cutting, bag removal, and netting removal, and consists of five mechanisms: conveying mechanism, stem cutting mechanism, bag tearing mechanism, bag blowing mechanism, and netting mechanism. We completed program writing and debugging in Mitsubishi GX Works2 software, and the results satisfy the demands of the machine’s motion control.