I’m a little confused here, is there any reason rubber bands pulling the sprocket down as a tensioner is more efficient than just a axle on pillow bearings holding it? Doesn’t the pillow bearing design allow for a more constant tension on the chain rather than the rubber band method?
Not really, usually a static tensioner does it just as well. That’s why I said it’s probably not worth it.
What mechanism do you need 6 motors for?
This would give the pushing power of 3 motors, rather than using the 3rd motor to steer.
This would be pretty pointless, as you would still have the same power as a 2m base. You could do it, though. It would just kind of be a waste of a 3rd motor, since you can already turn a lot better with only two wheels.
we have our drive 4 motors but 100rpm. Should we put it at 200rpm or not? We kind of like the extra torque, and speed wont necessarily be a big problem since the cubes are spread out across the field. I would just like to hear your opinion.
My team generally prefers speed in our drivetrain, but it depends on what your robot’s main functions are. You could always use 200RPM motors and gear the drivetrain for torque or vice versa. In general however, the best robots are usually fast.
you could use a ratio to get something in between, but I personally would go for the 200RPM
Speedier drive trains are typically better if you want to compete on the higher levels. While the torque is nice the small amount of time you shave off here and there with a faster drive can make all the difference. My experience has shown me to never underestimate the value of a little extra speed.
4 motor drive is always the best, less strain on the motors. You also have more pushing power if you encounter defense.
Not gonna lie I used to be a strong advocate for 2 motor drive trains. Then I built my bot. After all of the added weight, we went from uncontrollably fast to “are the motors even running” and “the motors are getting really hot”. So after some design changes, we went ahead and removed a piece from our bot using 2 motors and put them into our drive. Our best decision ever. Even though we tried gearing the 2 motor drive train for both torque and speed (during prototyping), the shear speed and power from a 4 motor drive train is something that I doubt will have me ever going back to a 2 motor setup. For terms of torque and speed, I feel that speed (as long as its not geared for speed at an insane level) is king over torque as unless you are a pushbot or wallbot, you will never quite need a torque ratio to fend off other bots. As mentioned before, the small increase in speed also helps you compete as this essentially means you can score and defend much faster than your opponents. Remember, defending doesn’t necessarily mean winning every single push battle. As long as your robot is fast and can stand in front of others to defend, you are totally capable of winning.
@MostLikelyAHuman ostLikelyAHuman I don’t think you understand how to use chain because if done right it is easy to obtain the right tension. Also someone else said you lose power when you chain your drive that is kinda of true but isn’t 30 present it is more like 5ish imo just from friction. Also I don’t think you are understanding the competitive side of VEX robotics because you have to have a 4 motor drive. You will be slower to all the cubes you won’t be able to play any defense even against the high gear ratios the good teams are running.
2 motor drive = no
only do 2 motor drive if you want to be a skills bot