# Society of Robots - Robot Forum

## General Misc => Robot Videos => Topic started by: ykhoody on October 22, 2011, 11:14:01 AM

Title: Self balancing bicycle prototype using flywheel(reaction wheel)
Post by: ykhoody on October 22, 2011, 11:14:01 AM
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:
Self Balancing Bicycle Robot (http://www.youtube.com/watch?v=d1Uy7bU6TII#)
OR EVEN ON:

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: Admin on October 23, 2011, 10:18:32 AM
oh, but you don't need a flywheel, just good steering control:
http://www.societyofrobots.com/robotforum/index.php?topic=14681.0 (http://www.societyofrobots.com/robotforum/index.php?topic=14681.0)

:P

Here is a hint for your calculation. Your moment arm length is the distance between the ground and the spinning mass. So you know the distance and the torque, T, so then you can calculate the force.

torque = force * distance = J * alpha

And when your robot leans over, gravity causes it to fall - another force going the opposite direction. You need both of those forces to cancel each other out (equal each other).