Belt-Line Cartesian Sortation Cell for Gentle Quality-Based Routing of Discrete Items

This paper presents the design and realization of a compact conveyor–sorter cell that combines a belt-type transport line with a three-axis cartesian gantry to automate quality-based routing of individual items. A cushioned belt with integrated dividers conveys objects received from an upstream vision module, maintaining orientation and spacing while an infrared presence sensor precisely localizes each unit on the line. A cartesian handling unit, driven by stepper actuators and controlled via an embedded single-board computer, executes sequential X–Y–Z motions and uses a pneumatic vacuum end-effector to pick items from the belt and place them into destination chutes according to classification results. Kinematic modeling based on Denavit–Hartenberg parameters is used to size the motion system. At the same time, experimental trials quantify achievable transport and sorting rates at selected operating speeds, including a parametric analysis of conveyor speed effects. Test runs on a 40-apple mixed batch (two colors, fresh vs. rotten), each apple passed three times for 120 pick-and-place operations, demonstrate reliable singulation, gentle transfer without surface damage, and repeatable placement under the tested configuration and operating conditions, with total system cycle times of approximately 74~s per item at the nominal belt speed of 126~mm/s. The upstream vision module was simulated through manual category entry during these experiments; the results therefore characterize the handling subsystem given correct labels and illustrate the suitability of the proposed architecture as a modular conveyor and sorter subsystem for automated inspection and packaging lines, with validation on other produce types left as future work.