Spinning robot

Discussions around autonomous, semi-automatic and intelligent robots and systems.

Moderators: petec, administrator, BeligerAnt

Andrew_Hibberd
Posts: 1287
Joined: Tue Jan 20, 2004 12:00 am
Location: London
Contact:

Spinning robot

Postby Andrew_Hibberd » Sat Jul 18, 2009 10:47 pm

I have been thinking about a full robot spinner using brushless motors for drive. To work out how to control the robot the wheels need to be stalled for a short time on each rotation. To find out when to stall the motor you need to know the heading of the robot. These are the ideas i have come up with to try and control a fast spinning robot.

a. Encode the wheels, and workout angle of robot from wheel positions. however if the wheels slip the heading is lost.

b. measure the earths magnetic field - i can't find much information on sensors and what is needed to do this. However with brushless motors in the robot there is going to be alot of magnetic field in there.

c. create a led array on one side of the arena and use photo sensors to use this as a reference like the earths field. It may be hard to detect the light with reflections.

Has anyone used any of these techniques before? or does anyone have any other ideas?
TEAM GEEK!

User avatar
BeligerAnt
Posts: 2437
Joined: Wed May 15, 2002 12:00 am
Location: Brighton
Contact:

Postby BeligerAnt » Sun Jul 19, 2009 9:03 pm

I know you can get electronic compasses - my GPS contains one! But I'm not sure how well they deal with other magnetic fields.

You could try an electronic gyroscope or accelerometer but it might need some complex maths to figure out what you needed. Try Analog Devices, they have a range of interesting devices and usually provide a lot of good info. You might also be able to blag a sample or two!

Reflections would certainly cause problems for an optical reference system, and many speed controllers have lights on which could cause more confusion! Not sure the optical system is a good solution, given the variability of arenas, lights on other robots etc.
Gary, Team BeligerAnt

User avatar
joey_picus
Posts: 1136
Joined: Tue Jan 13, 2009 1:51 pm
Location: Lancaster, Lancashire
Contact:

Postby joey_picus » Mon Jul 20, 2009 9:47 pm

Aaron Knight (of the Aussies and of MBX featherweight fame) has done this with featherweights; according to him http://www.spambutcher.com/meltyb.html contains most of the info you need.

Andrew_Hibberd
Posts: 1287
Joined: Tue Jan 20, 2004 12:00 am
Location: London
Contact:

Postby Andrew_Hibberd » Tue Dec 15, 2009 4:01 pm

I have been looking at this again, its a very nice concept but the robot only does 1200 rpm. A full body spinner gains more control and has a better overall weapon and can be driven when not spinning.
TEAM GEEK!


Return to “Autonomous and Intelligent Systems”

Who is online

Users browsing this forum: No registered users and 1 guest