We are currently working on redesigning our base. We were wondering if it would be safe (Without cutting out) to have a six motor HS base with a gear ratio of 1:2 for speed(using chain). We are not really worried about lack of pushing power, we just want to be able to get a lot of mobile goals in skills.
How much does your robot weigh? I think the working limit for 6 motor HS is around 20lbs (correct me if I’m wrong), but if you’re under 15lbs then you should be absolutely fine with 1:2 exterior gearing. You could even do turbo motors, I think.
We have a 4 torque motor 1:1 chain drive, and I’m going to upgrade to HS motors (it’s a chain bar/MG bot at about 14lbs), and people are telling me that it should work. I’ll update you when we test it.
ALSO: Make sure you have no friction on the drive train. Make sure all shafts have bearings and nothing but smooth metal or air contacts the chains. If your wheels or some bolt or something is hitting the chain or wheel, you will have problems.
@Royal_xD I believe that it is 4 motor HS that is around 20 pounds not 6. I think the exact number is 19 pounds.
@Ethan W. Actually, you’ll need 6 motor HS for 20 lbs. I’ve tested it, and four won’t be enough to work a 20 lbs robot for more than 30 sec - 1 min before burning out.
I’m guesstimating that my robot weighs 20 pounds or more (definitely more with a mobile goal) and it is 4m high speed on 4" wheels and the only time the drive has burnt out was when I was goofing around by simulating strafing with our tank drive by driving back and forth rhythmically on either side of the drive. My drive understandably did not appreciate this (if you saw this, you would understand it is a recipe to burn out). That being said, it was drivable within 15 seconds of waiting. There should be no problem if you minimize friction.
+1. My robot is 6 motor turbo (essentially the same stall torque as 4 motor hi-speed) and around 20 pounds with a mobile goal. I’ve not burned out in a match to date.
My robot is around 15-16ish lbs and is an internal, I’m fine with 4 motor HS and rarely burn out. Just in case, I air dust all my motors before each match to keep them cool and from burning out (rare though)
6m speed 1:1 makes for a great balance of speed and power IMO. Our robot, which is fairly light (all aluminum, plastic screws, etc. IDK in actual units), was having some struggles tripping on 6m turbo 1:1. We could barely get through a skills match and could not play defense whatsoever. Since 6m speed 1:2 has less torque than 6m turbo 1:1, I definitely wouldn’t recommend that ratio. Maybe it’s just my experience, but this year has taught me that torque is a lot more important than speed.
An important point that a lot of teams ignore is that acceleration is often more important than top speed. Sure, going 6 motor turbo will definitely make an unloaded drivetrain faster, but with heavy robots, it can take a while to (or never!) reach that top speed. Especially in a match, when most of your driving is going to be in short bursts, trading that top speed for a faster acceleration can yield better real-world results.
This is super important. I think top speed is only important in skills and maybe kamikaze autons.