A Light-Weight Robotic System for Flexible and Efficient Heavy-Load Palletizing in Cuboid Spaces

Loading and unloading goods in narrow cuboid spaces (e.g., truck carriages) is a critical task in logistics transportation. It is often time-consuming, labor-intensive, risky, and therefore is valuable and necessary to be automated. However, due to the complexity of operational scenarios, most existing robots struggle to simultaneously integrate: small size and weight, sufficient load capacity, high robustness, high picking flexibility and efficiency, and good adaptability to narrow cuboid spaces. In this work, we present a light-weight robotic system capable of achieving flexible, efficient, and heavy-load palletizing in constrained cuboid spaces. We propose a novel adsorption-tray hybrid gripper which can significantly reduce the required adsorption area (by 64%) while maintaining high picking flexibility without affecting load capacity. Based on it, we propose the lift-then-pick picking method, and provide the design method of an adjustable picking trajectory, as well as an optimization strategy for the quantity of suction nozzles. Furthermore, we successfully introduce the time-optimal control idea into the picking process based on its unique dynamic constraints, which improves efficiency by 46%. We also implement a compliance control mechanism that significantly enhances the robustness (i.e., nearly doubling the picking success rate). In addition, we develop a specially designed manipulator to carry the gripper. The horizontally arranged degree of freedom configuration and the new rotational joint construction method enable the arm to maintain light-weight while sufficient load capacity. And its coverage of cuboid spaces far exceeds that of traditional industrial arms (100% vs. 53%). Finally, we manufacture a prototype and validate the above advantages through both simulation and real-world tests, confirming its potential for applications.