Ground Pressure

1. Ground Pressure • Rating = 2.6 • The lower the ground pressure, the softer the material the vehicle can traverse, i.e. sand or loose gravel. • Ground pressure can be decreased by: • increasing the surface area of contact between the ground and the vehicle • Reducing the vehicle mass • Greatest contact surface area can be achieved through using tracks instead of wheels • Tracks are incidentally much heavier than wheels, and also emit a much larger audio signature, making stealthy movements difficult at best

2. Robustness • Rating = 1.7 • Defined as the ability to withstand punishment • As an off road vehicle, the BURRO must be able to withstand jostling from rough terrain and collisions with obstacles • If the vehicle were to see combat, it should be able to withstand small arms fire, as there is little doubt a soldier may use it for cover • Likewise the BURRO must be designed such that any damage it sustains will not affect whatever cargo it may be transporting

3. Amphibious • Rating = 3.6 • The ability to traverse deep water, or ford running water • Vital if vehicle is to be able to cross any terrain • Helpful in crossing rivers and small marshlands • Requires more components • Waterproofing • Water propulsion • Added weight and size • Unsure of usefulness • Concessions of size and weight

4. Fail-Safe Design • Rating = 1.5 • Designs that allow the vehicle to continue to operate without interruption • Failures are automatically compensated for • Could be implemented into power train and other systems • Ensures that supplies are delivered • May be difficult to provide total fail-safe design

5. Power Density • Rating = 1.1 • Defined as the amount of power delivered by a power source • Extremely important • Power density must be equal or higher than needed to ensure proper operation • Limits the number of power supplies that may be used • Some power supplies just do not have the ability to power a system such as the BURRO • More weight, speed, etc… = more power density required

6. Turning Radius • Rating = 2.2 • Turning radius is important for maneuverability in tight areas. • It would be especially important if traveling off-road, in order to maneuver around objects. • It can be difficult to get a small turning radius if the steering tires are powered. • The shorter the wheelbase the smaller the turn radius. • A skid steer design would allow for a zero turn radius, but would require a unique drive train and may effect weight. • A skid steer design would also eliminate the need for sensors in the rear of the vehicle because it would not need to reverse.

7. Resistance to Anti-personnel Mines • Rating = 3.0 • More than 700 types of known antipersonnel mines; most common is the "blast mine" • Usually contains 25g-250g of high explosive (~4190 J/g) • Hard to determine force of explosion due to factors such as shape of charge, soil type, depth of mine, shrapnel, etc. • Most anti-personnel mine triggers require a minimum weight of ~ 5 kg