I’m just wondering what robots usually weight and what drivetrains they have. currently our robot has a 4 motor drive with a 3:5 and a 5:3 gear ratio with 200 rpm motors but we are struggling with motors overheating and friction.
Friction is not a problem with weight it is a problem with how the drivetrain is build and that is probably what is causing the overheating
Our drivetrain is 400 rpm on 3.25”, and the bot weighs 16 lbs. when driving the robot aggressively for 20 minutes, the drive still does not stall.
Is it possible to send a picture of your drivetrain, along with the weight of your bot?
4m Drive, 600 RPM Motors, 4" Omni Wheels, 257 Final RPM.
Robot is pretty heavy with flex wheels and pneumatics, and no issues with overheating or friction.
I suspect that your drivetrain has some friction issues causing the motor to overheat. I also recommend that you put your drive motors on coast instead of break or hold, at least for driving practice.
what do you mean by “and” ?
Sounds like you have 2 gear ratios on the same drivetrain (aka ur wheels are moving at diff speeds)
Maybe they did it to reverse one side?
In addition to looking at the robot weight and drivetrain gear ratio, you need to consider how your weight is distributed and if front and back wheels are connected with chain or geartrain to distribute motor load more evenly.
For example, if they are not connected and most of the robot’s weight is concentrated over the back wheels, then back motors will overheat and shutdown first, then causing front motors to overload and overheat next.
Here are links to some additional discussion about best weight to speed and power ratio for the VRC robots:
My impression over the years was that the best performing robots were around ~16 lbs of weight running on 4" wheels at ~250 rpm with 4 motors or either slightly faster robots running at >300 rpm with 6 drivetrain motors.
We run 600 direct 2.75 on a 15lb robot. Very little issues with overheating and drives for around 10 minutes without burnout.
sorry for the not saying it out right but its a transmission drive. 5 to 3 high gear at 333 Rpm and a 3 to 5 low gear at 120 Rpm
after thinking about it i belive our drivetrain has too many gears (i can get a pic) and the fact that the four motors are basically touching so i feel like a idiot for not thinking it was because they were so close. adding on to the idea of too many gears the motor basically go to one gear that connects to the drivetrain instead of being evenly distributed along the chassis. also everyone has gear reduction on 600 rpm motors while our main drive is a gear increase on 200 so i think we are putting too much strain on the motors along with the fact it needs to push a 24 pound robot. we are planing to redesign the robot but we are going to deal with this issue for now.
and sorry about not responding sooner, i kinda forgor
I guess i was too worried about making the transmission compact that i didnt think about the heat from the motors
I think I found the problem lol
yeah the flex wheels weight a lot and we have lots of unnecessary pieces of metal. I’m designing a chassis that is a little too like 606x for my liking but I hope to be stricter about the weight. I will also post a pic of our transmission which is almost exactly the same as BLRS from Change Up which I didn’t see until I had it CADed,
You could reduce a lot of weight by replacing the metal plates with Polycarbonate (VEX Robotics Polycarbonate & ABS Plastic Sheets - Robosource.net - Robosource.net)