Rassor Drum

grabcad

OPERATION PRINCIPLE The rassor drum acts as a milling tool, removing a layer of soil and retaining it in its cavity. Optimal shape requires a spiral design that carries regolith inside the drum and releases it by reversing direction. Like milling tools, rotation can be clockwise or counterclockwise, with differing results. In my model, clockwise rotation causes the loading mouth's edge to hit the outer layer of soil moving downward, while counterclockwise rotation maintains constant contact with the ground, removing a layer as it lifts. Each rotation direction presents pros and cons. In the first case, large stones would be driven into the ground, hindering rotation. In the second case, stones would be lifted away from nails crawling on the ground, breaking up compacted soil and removing stones, but counterclockwise rotation produces resistance to advancement. The system's flexibility is crucial for addressing diverse operational scenarios. In addition to preconceived movements, I suggest adding a 180° flip of the arm holding the drum pair. This simple modification allows easy direction changes. A built-in mechanism should be complemented by the fact that four drums must consist of two specular pairs, enabling various operating combinations through drive flange mounting variations. Continuing the milling tool analogy, the loading mouth's edge must have a helical shape to reduce rotation resistance and be arranged symmetrically to prevent lateral thrusts on the support arm. For simplicity and reliability, I've chosen to avoid additional moving parts due to severe operating conditions involving dust, temperature changes, and microgravity. Assuming a load capacity of 25-30 liters. CONSTRUCTION TECHNOLOGY Given that the rassor robot relies on arms for advancement and recovery in case of accidental falls into holes, drums must be robust enough to withstand efforts in various directions. Side discs are made from carbon fiber, 1.5 and 2 mm thick, while helical volutes are constructed from aeronautical aluminum. By analogy with the wings of famous airplanes like the Ford tri-motor and Junkers Ju-52, these volutes feature a corrugated profile providing strong resistance. This profile can be easily formed using small calenders with corrugated rollers starting from standard 1 mm thick rectangular aluminum sheets. Attached are images of FEA verification demonstrating minimal deformation caused by a 50N thrust on the edge of a nail. These nails are made from titanium alloy, and locking screws are constructed from stainless steel. The loading nozzle is reinforced by a 3 mm thick titanium alloy sheet with a tooth profile. The entire drum is assembled using aluminum rivets and secured by drive flange screws. Dimensions conform to allowed limits, with the total weight of one drum at 4,864 kg.