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Electronics => Electronics => Topic started by: ykhoody on October 20, 2011, 02:32:51 PM

Title: Self balancing bicycle prototype using flywheel(reaction wheel)
Post by: ykhoody on October 20, 2011, 02:32:51 PM

Hello everybody,
Well I'm a level 4 mechatronics students from Mauritius and doing my project on a self balanced bicycle which uses a flywheel to achieve this.A better view of it can be seen on:
http://www.youtube.com/watch?v=0312B...eature=related (http://www.youtube.com/watch?v=0312B...eature=related)
OR EVEN ON:
http://www.youtube.com/watch?v=d1Uy7...eature=related (http://www.youtube.com/watch?v=d1Uy7...eature=related)
http://www.youtube.com/watch?v=AvGUu...eature=related (http://www.youtube.com/watch?v=AvGUu...eature=related)

During the past 3 weeks,I've been struggling on calculation of torque(flywheel motor) and I'm stuck.
I have been using the formula T=J*alpha,
where J=moment of inertia and alpha=angular acceleration.

I have assumed overall mass of prototype to be around 2.5 kg,radius of flywheel=5 cm,mass of flywheel=0.5kg,radius of driving wheel=5 cm,max permissible tilting angle=30 degrees.

Could you please help me in selecting my 12V DC motors:flywheel motor(rpm,torque)
Driving motor(rpm,torque)
and flywheel specifications(radius and mass)
and finally if gear box(reduction gear) is needed,its ratio??
Thanking you all in advance.
Best regards

Title: Re: Self balancing bicycle prototype using flywheel(reaction wheel)
Post by: newInRobotics on October 20, 2011, 03:41:40 PM

Quote from: ykhoody on October 20, 2011, 02:32:51 PM

I have been using the formula T=J*alpha, where J=moment of inertia and alpha=angular acceleration.

Torque has nothing to do with moment of inertia multiplied by angular acceleration. Torque is ability to lift certain weight with certain length of lifting arm. For Your flywheel at least 0.001kg.m (0.073lb.f or 0.01N.m) torque motor has to be used; go at least for double torque to be on the safe side (http://www.ebay.co.uk/itm/Mabuchi-SPR280-Volt-dc-Motor-/390356253507?pt=UK_AudioElectronicsVideo_Video_TelevisionSetTopBoxes&hash=item5ae30bbb43).

Quote from: ykhoody on October 20, 2011, 02:32:51 PM

Driving motor(rpm,torque)

We know wight of Your bot, but what also is needed is height. Favor torque over rpm when You pick motor.

Quote from: ykhoody on October 20, 2011, 02:32:51 PM

and finally if gear box(reduction gear) is needed,its ratio??

When You find out Your torque values needed, then You can start picking motors according to voltage and current preferences. After that, You can choose suitable gearbox. Buy how much You reduce rpm - You increase torque (with some inefficiency penalties to both). Another option is to buy already geared motors.