Single vs Multiple Speed Gearbox

[techhelpbb]

I agree with the others. It depends on your strategy. In effect you have have lower speeds with more torque or high speeds with less torque. You can even create a higher speed that wouldn't allow the robot to break inertia and switch into it from the lower gear (like an automobile's higher gears).

If you just want to hold ground, there are other ways to achieve this than using drive train torque. You could simply plant your robot like a backhoe does to improve stability while digging. One could even rig a ratchet or something like that so they can only advance in one direction till they loose traction on the carpet. If you increase the surface area on which the additional support touches the carpet you can create a situation where another robot up to the legal weight would probably trip their breakers or loose traction before your robot moves. Be kind of fun to watch a team that usually just plows things out of their way find their 'unmovable' object.

[Jonathan Norris]

For the majority of offensively focused robots, getting in pushing matches is just bad strategy, avoiding defense should be your priority. In my experience acceleration is just as important as top speed, I'd take a 6-CIM 1 speed drive over a 4-CIM shifter. And in most cases prefer the simplicity of a 4-CIM 1 speed over a shifter.

[D.Allred]

We used 2 speed gearboxes in 2014 and have been single speed every other year.

2014 seemed like a good year for using 2 speeds, but ironically ended up in low gear most of the year. Bottom line, the driver needs lots of practice if you end up manually shifting. Our driver was comfortable in high gear at the shop practicing one-on-none. Things got a bit more chaotic on the field three-on-three, and he didn't feel in control at top speed.

The other design consideration is acceleration and distance. Top speed might be less important than good acceleration over a short distance.

David

[messer5740]

We had a single speed gearbox this year and played a TON of defense. Even though we did not have very high torque, we still played great defense by gaining speed and ramming the opponent before they made a shot. Other teams we had competed with used two speed gearboxes, but they mostly stuck to high or low gears and did not venture out of the driver's speed and torque comfort zone. It all depends on how your driver uses the different setups.