I’d like to simply start naming motors, wheels, and chassis that would work to produce those speeds, but there’s quite more than a few that would.
For instance, a 207rpm motor with 5" tires would do the trick.
But, so would a 344rpm motor with 3" tires.
Good news, though.
The LM wheel calculator helps you determine just that:
lynxmotion.com/images/html/wheelspd.htm
Skid steering (one motor per wheel) isn’t the most efficient means when one needs to maintain high speeds while turning.
Skid steering is nice if you have to turn on a dime (without much positional accuracy), but it doesn’t sound like you’ll need that.
In that case, you might want to go with an Ackerman steered (one drive motor, one steering motor) vehicle.
A car is an example of this.
There aren’t any kits on the LM site that’d would fit that setup (you’d need a right angle gearbox to translate the motor rotation), but almost every RC car would.
If you’re enamoured of using the 4WD design, then calculating the maximum speed is simple.
Use the LM wheel calculator program (see above), and you can calculate the top speed of your bot.
Keep in mind that the motors usually specify their no-load speed.
When you make them drag around the weight of your bot, they’ll be considerably slower so go with motors that are faster than you’d actually need.
Once you know the tiresize and motors, you can get a HUB that mates them.
Then you can chose the speed controller that suits the current draw of your motors.
Then you can decide which micro you’d like to use.
And then batteries and a charger.
I’d say… leave the chassis to the end.
Deciding on one now will limit you to using what fits within it.
As for tracking that solid line, how about a camera?
You can get a cheap wireless camera from geeks.com.
Link the reciever to a TV tuner card, and you’ll be able to wirelessly process the video stream using the free RoboRealm software.
Roborealm is VERY easy to use, as it lets you simply point and click to do most of it.
There’s even a linefollowing tutorial on their site:
roborealm.com
Then you just need something like a bluetooth module (wibotics.com) to wirelessly send info back to your microcontroller.
Instead of doing all that, you could use something like the CMUcam which is an integrated camera and processor package.
That way, all the processing would be done right on your robot.
The disadvantage to that is that you’d need to understand more about the hardware and software, and you don’t get to view what the robot is seeing, as you would with the roborealm software.
It’d probably be a good idea to suppliment the camera with old-school sensors, like phototransistors.
These are great for detecting lines at low speeds, but can easily get confused at higher speeds and with bad light conditions.
I don’t think either just the camera or just the phototransistors would work alone at those speeds.
The chances of error are very high.
But, I think you could get good results out of using both.
