Design and simulation of a robotic cart with integrated storage unit for capsicum harvesting: Motion analysis and DEM evaluation of storage tray dynamics

Abstract

This study presents the design and simulation-based evaluation of a robotic cart system with an integrated storage tray for efficient, damage-free capsicum harvesting in greenhouse environments. The objectives include: (1) development of a compact robotic cart with an ergonomically designed tray suitable for confined greenhouse pathways and robotic arm accessibility, (2) structural verification and motion analysis of the tray during extraction to ensure handling ease and stability, and (3) Discrete Element Method (DEM) simulations to assess mechanical impacts on capsicums during deposition and transport. The cart features a 700 mm width, a 630 mm-high platform, and a 900 × 600 × 250 mm high-density polyethylene (HDPE) tray with thermoplastic polyurethane (TPU) lining, optimized for secure fruit handling. SOLIDWORKS structural analysis confirmed tray integrity under 98.1 N load, with von Mises stress of 202 N/m² and minimal displacement. DEM simulations in Altair EDEM showed that 400 mm free-fall drops induced peak impact forces of 3.3 N, while tray extraction produced inter-fruit forces of 3.2 N, both below the bruising threshold of 5–6 N. Force and velocity analyses indicated smoother, prolonged interactions during tray extraction compared to brief high peaks in free-fall deposition. These results demonstrate system’s potential to minimize mechanical damage and provide a virtual design-verification framework for robotic greenhouse harvesting.