The results in Figure \ref{624809} indicate it that the excavation rate behavior of CASPER exhibits quasi-linear trends across all independent variables. For both the wide and narrow outward churning configurations C1 and C3, the ramp system was unable to collect any granular media at ramp angles of 35 and 40 degrees. Even at 45 degrees, C1 and C3 were only able to excavate at 40 RPM, the fastest angular velocity tested. This illustrates that for CASPER, the excavation rate capability can be dramatically increased by simply rotating the front pontoons such that the material is churned inwards, as was done for C2 and C4.. In addition, churning inward creates an elevated wake of material, which means the ramp motor requires less angular displacement and thus, less work to deposit the material in the collection bin.
Unsurprisingly, the excavation rate increases as the screw angular velocity increases. This is because there is a greater mass flux of granular media flowing onto the ramp edge, which allows the material to build up to a greater height on the blade itself prior to the ramp rotation. For similar reasons, the excavation rate increases as the load time increases. By increasing the load time, the granular media is given more time to build up prior to ramp rotation. It appears that there is a bit of a diminishing returns phenomenon with respect to load time. In other words, the increase from two to four seconds in load time yields a much higher marginal increase in excavation rate in comparison to the marginal increase from four to six seconds. Finally, it was observed that the width between the front pontoons has no significant impact upon the excavation rate.
Power