Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: spidermax on March 09, 2013, 08:06:49 PM

Title: First time building
Post by: spidermax on March 09, 2013, 08:06:49 PM
Hi all

This is my first robot and all is going good, i building a tracked robot i have tracks made and have a body for the robot, one track is fitted at the moment but should get around to getting the next on in a day or so.

not im looking at the electronics and the one stopping point for me is a motor ( it seems this is where most people need help when building for first time) i know the size of my drive wheel for the track which is 226mm  now im not sure i got this right but to make it move 2 meters per second (not even sure how fast that is realy) i worked it out at 8.8rpm looking at other posts that doesnt seem right people are talking about 150 rpm and more am i missing somthing?

Regards

Max
Title: Re: First time building
Post by: jwatte on March 09, 2013, 10:57:17 PM
I assume 226mm is the circumference.
For 2 meters per second (7 kmph or 4 mph) you need about 8.8 rev per second, which is about 500 rpm.
Title: Re: First time building
Post by: spidermax on March 10, 2013, 08:17:48 AM
Hi

Yes 226mm was the circumference. being daft and it being late last night i was getting rps mixed with RPM looking at it today 500rpm seems about right. ill post the pics up as i get further along with the project.

Max
Title: Re: First time building
Post by: waltr on March 10, 2013, 08:22:09 AM
2 meters per second is pretty fast for a small robot.
Try laying out the 2 meter distance on the floor. Tie a string to an object, place the object at one end  of the 2 meter space. Then time 1 second and pull the string to move the object the 2 meter distance.
This will give you a good idea of how fast 2 meters per sec is.
Title: Re: First time building
Post by: spidermax on March 12, 2013, 03:57:45 AM
Yeah I've done that and your right that would be rather fast, I know it's a bit like how long is a peice of string but what speed would you recommend for a first build ?
Title: Re: First time building
Post by: jwatte on March 12, 2013, 04:10:46 PM
Pick your wheels to fit the size of the overall robot, spin them at 60 rpm, and whatever speed that gets you, that's probably a good speed for a first project.
Although there's nothing inherently *wrong* with putting bigger/faster things on there, assuming weight and power don't become a problem. You may want to drive it slower in the beginning, until your control mechanisms become robust enough to keep up :-)