Abstract
Introduction Loading bulk materials into a container through a small upper hatch results in the formation of a cone-shaped pile that must be redistributed after each portion to ensure uniform filling. This paper presents the design, kinematic modeling, and experimental validation of a 4-DoF gantry robot developed for pushing and redistributing bulk materials inside a container under severe spatial constraints. A specialized end-effector, implemented as a rotatable rod with forward-facing blades, enables planar redistribution of the deposited material. Methods A complete kinematic model based on the Denavit–Hartenberg method was derived for reliable control of the end-effector position and orientation. Analytical relationships were derived that determine the redistributed layers using geometric methods. Based on these analytical relationships, a redistribution algorithm was developed that takes into account the cone height, layer thickness, material density, and container geometry. Results Analytical relationships describing the geometry of the redistributed layers were obtained, enabling the development of an algorithm for pushing material parallel to the container bottom. A physical prototype was fabricated, and experimental studies were conducted to measure the normal stresses acting on the pusher rod during material displacement. Discussion The results confirm the effectiveness of the proposed robot design and control approach in achieving uniform redistribution of bulk material loaded in portions within a constrained container environment.