Motor Breaking HELP

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samlan16
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Re: Motor Braking HELP

Post by samlan16 » March 24th, 2016, 5:15 am

GoldDigger wrote: My car broke today. I'm screwed.... It originally traveled straight for up to 12 meters with only 10 cm of curvature, but now it f***ing curves 30 cm at just the 5 meters mark. Do i just kill me myself? I think i should
Um, no. We all deal with technical issues on our builds.

Try aligning your wheels again. If that fails, consider using a microprocessor to cut power to your motor instead of physical brakes.
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Re: Motor Breaking HELP

Post by Bazinga+ » March 24th, 2016, 5:54 am

GoldDigger wrote:Yeah one axle drive axle with gear ox and motor, while the other axle has the wingnut breaking and microswitch.



My car broke today. I'm screwed.... It originally traveled straight for up to 12 meters with only 10 cm of curvature, but now it f***ing curves 30 cm at just the 5 meters mark. Do i just kill me myself? I think i should
If time is an issue then you just need to find a quick way of realigning/adjusting one of your axles. If that's not possible then check if it curves consistently. If its curving consistently then just calibrate it with a curve and change the angle at which you launch it every time Not great but it'll work.
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Re: Motor Breaking HELP

Post by iwonder » March 24th, 2016, 8:45 am

Bazinga+ wrote:
iwonder wrote: The way it sounds you're only using 1 of 2 axles to brake right now, anything you can do to brake with both axles will help dramatically.
Would it? In theory it shouldn't.
How wouldn't it?
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Re: Motor Breaking HELP

Post by Bazinga+ » March 25th, 2016, 7:42 am

iwonder wrote:
Bazinga+ wrote:
iwonder wrote: The way it sounds you're only using 1 of 2 axles to brake right now, anything you can do to brake with both axles will help dramatically.
Would it? In theory it shouldn't.
How wouldn't it?
It wouldn't help with his problem because you don't want both axles to completely stop moving because then the car will still skid to a stop. You want the axles to constantly deccellerate to a stop and be able to avoid error in skidding.
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Re: Motor Breaking HELP

Post by windu34 » March 25th, 2016, 12:43 pm

Braking with both axles should help because there will be more contact with the floor thus the coefficient of friction should be increased
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Re: Motor Breaking HELP

Post by Bazinga+ » March 25th, 2016, 3:29 pm

windu34 wrote:Braking with both axles should help because there will be more contact with the floor thus the coefficient of friction should be increased
No thats not why. The coefficient of friction depends only on the material, not contact area. But friction force is friction coefficient times normal force so yes breaking with both axles should double your force from traction. The problem is you need to gradually slow down and not just slam a wingnut in and skid to a stop, which is difficult to implement on both axles.
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Re: Motor Breaking HELP

Post by iwonder » March 25th, 2016, 6:41 pm

Bazinga+ wrote:
windu34 wrote:Braking with both axles should help because there will be more contact with the floor thus the coefficient of friction should be increased
No thats not why. The coefficient of friction depends only on the material, not contact area. But friction force is friction coefficient times normal force so yes breaking with both axles should double your force from traction. The problem is you need to gradually slow down and not just slam a wingnut in and skid to a stop, which is difficult to implement on both axles.
But in a thread discussing motor breaking, that suddenly becomes incredibly simple to implement.
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Re: Motor Breaking HELP

Post by cantthinkofausername » March 25th, 2016, 9:50 pm

OK, before anyone posts another word, this typo is hurting me. Braking is not breaking. We DO want our EV's to brake on any mm mark given. We DO NOT want to break our motors.

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Re: Motor Breaking HELP

Post by Bazinga+ » March 26th, 2016, 8:40 am

iwonder wrote:
Bazinga+ wrote:
windu34 wrote:Braking with both axles should help because there will be more contact with the floor thus the coefficient of friction should be increased
No thats not why. The coefficient of friction depends only on the material, not contact area. But friction force is friction coefficient times normal force so yes breaking with both axles should double your force from traction. The problem is you need to gradually slow down and not just slam a wingnut in and skid to a stop, which is difficult to implement on both axles.
But in a thread discussing motor breaking, that suddenly becomes incredibly simple to implement.
You would need 2 motors and 2 wingnuts for thatm one on each axle, which isn't desirable because your error is doubled.
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Re: Motor Breaking HELP

Post by iwonder » March 26th, 2016, 10:32 am

Alright, fine.

One axle has a wingnut brake, the other has a motor, that's what we're talking about, right? There's already some sort of switch to turn off the motor. Using that switch, remove the battery and put say a 3-5 ohm resistor across it instead. The motor wouldn't 'slam on' the brakes, because of the resistor, but it would help.
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