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Unread 18-11-2001, 14:38
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Re: Re: Simply Friction

Quote:
Originally posted by P.J. Baker


This is more or less backwords.

The losses in the system will not actually increase that much as the robot accelerates.

The force (torque) output from the motors will decrease as the robot accelerates.

There is a limited amount of power available from the motors. The power from the motors is equal to the product of the torque they provide and the speed at which they are turning. As the RPM's of the motors go up, the amount of torque they can supply goes down. Eventually, the available torque is reduced to the point where it is equal to the frictional losses in the system and the robot stops accelerating and continues on at constant speed.
So, the only way to measure the robot speed is to either measure the friction in the system... or to actually record the speed of the robot (like timing the robot's time to race across the field". I don't suppose there's any other way to do this.

As for the force the robot is pushing, since the frictional force from the wheel to the ground is the maximum amount before the wheel start the skip, we can only increase the mass of robot or better traction on the wheels to increase how hard it's pushing.

When a robot is pushing another around, what's really happening is that the robot have more traction/mass/ratio/power, where traction and mass increase the max. frictional force on the wheel, and a better ratio to keep the motor from stalling/heating up (which reduce motor power and draw too much current).

And of course, making sure the wheels are always touching the ground is important too.

May I assume that the Technokats robot from last year is going to have the strongest drive train to push everyone around since they have extremely good traction fron tank tread, and dual motors design with 4 motors on the drive train?

Last edited by Ken Leung : 18-11-2001 at 20:14.
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