Electric Vehicle C
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Re: Electric Vehicle C
Has anyone tried using a PID loop to correct for any error in their Arduino distance programming? If so, has it helped significantly decrease your distance score?
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Re: Electric Vehicle C
Make your vehicle heavierNilaiVemula wrote:What are some effective ways to reduce skidding? We have tried balloons around the wheels, friction tape, and electrical tape, all with no avail.
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Re: Electric Vehicle C
This and accelerate and decelerate gradually if you aren't doing sowindu34 wrote:Make your vehicle heavierNilaiVemula wrote:What are some effective ways to reduce skidding? We have tried balloons around the wheels, friction tape, and electrical tape, all with no avail.
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Re: Electric Vehicle C
I wrote some PID code but didn't implement it because there's not much of a point when you can get centimeter accuracy using an encoder. From what I've read, tuning would also be a pain that wouldn't be worth the time.NilaiVemula wrote:Has anyone tried using a PID loop to correct for any error in their Arduino distance programming? If so, has it helped significantly decrease your distance score?
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Re: Electric Vehicle C
Making the vehicle heavier will not help because your maximum acceleration and decelleration depends only on the traction between the wheels and the floor, the mass of the car cancels out (a(max)= F/m=mgu/m=gu, where u is the friction coefficient) The only way to reduce skidding is to get high traction wheels (most everybody uses 'banebots' wheels, they work great) or to accelerate more gradually.windu34 wrote:Make your vehicle heavierNilaiVemula wrote:What are some effective ways to reduce skidding? We have tried balloons around the wheels, friction tape, and electrical tape, all with no avail.
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Re: Electric Vehicle C
The force of friction will scale linearly only in a very ideal situation. With soft rubber treads that will deform as more weight as applied, the traction will go up faster than a linear rate when more mass is added.Bazinga+ wrote:Making the vehicle heavier will not help because your maximum acceleration and decelleration depends only on the traction between the wheels and the floor, the mass of the car cancels out (a(max)= F/m=mgu/m=gu, where u is the friction coefficient) The only way to reduce skidding is to get high traction wheels (most everybody uses 'banebots' wheels, they work great) or to accelerate more gradually.windu34 wrote:Make your vehicle heavierNilaiVemula wrote:What are some effective ways to reduce skidding? We have tried balloons around the wheels, friction tape, and electrical tape, all with no avail.
You can also double up your wheels or increase their width, which doesn't increase the normal force, but still will increase your traction, which again goes against the standard classroom model for friction.
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Re: Electric Vehicle C
While this is true, the effect of adding more weight and getting wider wheels is rather slight, especially of your wheels are clean. Another thing that helped with traction is cleaning the floor before testing/running the vehicle and cleaning the wheels with alcohol wipes every few runs.DoctaDave wrote:The force of friction will scale linearly only in a very ideal situation. With soft rubber treads that will deform as more weight as applied, the traction will go up faster than a linear rate when more mass is added.Bazinga+ wrote:Making the vehicle heavier will not help because your maximum acceleration and decelleration depends only on the traction between the wheels and the floor, the mass of the car cancels out (a(max)= F/m=mgu/m=gu, where u is the friction coefficient) The only way to reduce skidding is to get high traction wheels (most everybody uses 'banebots' wheels, they work great) or to accelerate more gradually.windu34 wrote: Make your vehicle heavier
You can also double up your wheels or increase their width, which doesn't increase the normal force, but still will increase your traction, which again goes against the standard classroom model for friction.
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Re: Electric Vehicle C
Like Bazinga said you could clean the floor before running the vehicle. I did this by using a swiffer and you would not believe how much dirt I picked up on the floor during competition and even testing. Another suggestion, if you don't want to get your wheels wet, is to use the swiffer to clean your wheels too.Bazinga+ wrote:While this is true, the effect of adding more weight and getting wider wheels is rather slight, especially of your wheels are clean. Another thing that helped with traction is cleaning the floor before testing/running the vehicle and cleaning the wheels with alcohol wipes every few runs.DoctaDave wrote:The force of friction will scale linearly only in a very ideal situation. With soft rubber treads that will deform as more weight as applied, the traction will go up faster than a linear rate when more mass is added.Bazinga+ wrote: Making the vehicle heavier will not help because your maximum acceleration and decelleration depends only on the traction between the wheels and the floor, the mass of the car cancels out (a(max)= F/m=mgu/m=gu, where u is the friction coefficient) The only way to reduce skidding is to get high traction wheels (most everybody uses 'banebots' wheels, they work great) or to accelerate more gradually.
You can also double up your wheels or increase their width, which doesn't increase the normal force, but still will increase your traction, which again goes against the standard classroom model for friction.
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Re: Electric Vehicle C
What would your input to the PID controller be then? It would seem as though you'd use an encoder. In which case PID is a valid control scheme, but may not be optimal or advantageous given the parameters of the event.dcrxcode wrote:I wrote some PID code but didn't implement it because there's not much of a point when you can get centimeter accuracy using an encoder. From what I've read, tuning would also be a pain that wouldn't be worth the time.NilaiVemula wrote:Has anyone tried using a PID loop to correct for any error in their Arduino distance programming? If so, has it helped significantly decrease your distance score?
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Re: Electric Vehicle C
Yeah, the input was the encoder - to clarify, you can get centimeter accuracy using an encoder without PID. PID is super cool, but wasn't advantageous for me.andrewwski wrote:What would your input to the PID controller be then? It would seem as though you'd use an encoder. In which case PID is a valid control scheme, but may not be optimal or advantageous given the parameters of the event.dcrxcode wrote:I wrote some PID code but didn't implement it because there's not much of a point when you can get centimeter accuracy using an encoder. From what I've read, tuning would also be a pain that wouldn't be worth the time.NilaiVemula wrote:Has anyone tried using a PID loop to correct for any error in their Arduino distance programming? If so, has it helped significantly decrease your distance score?
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