Comments on: Mecanum Lawnmower? http://www.robogreg.com/needel/205 An outlet for a Yankee Engineer living in Jackson TN Wed, 28 Apr 2010 18:02:05 -0400 hourly 1 http://wordpress.org/?v=3.0.1 By: Greg Needel http://www.robogreg.com/needel/205/comment-page-1#comment-1194 Greg Needel Tue, 09 Jun 2009 22:30:56 +0000 http://www.robogreg.com/?p=205#comment-1194 I have thought about using a roomba style logic to run the system, but I think it is a bit more complicated then that due to the constraints of the system. One of the things which helps the roomba is that the floor is reasonably flat. It spirals out and every time it bumps something draws a virtual point which it uses to develop a full map. One of the constraints of this system is that the roomba's wheels don't slip, if they did it could skew the whole map. Additionally there are no physical walls on all sides to define the area like the roomba has. In most of the robotic lawnmowers that are on the market they use a buried wire, just like an electric dog fence. While this does give the virtual walls it still has flaws. I have been considering using corner beacons, such as IR, wifi, or gps so that the robot knows it's position relative to the world and wheel slippage does not have an effect. Each one of those sensor systems has its pros and cons, such as consumer gps is low accuracy (I am not going to do a differential system for this) IR is weather/temp dependent, and Wifi is a bit more complicated. Most likely it will be some hybrid system for navigation. The first thing I am going to focus on is the mechanical challenges of the system, as I can always integrate different controllers, sensors, and other electronics to run it. Thanks for the ideas keep them coming! I have thought about using a roomba style logic to run the system, but I think it is a bit more complicated then that due to the constraints of the system. One of the things which helps the roomba is that the floor is reasonably flat. It spirals out and every time it bumps something draws a virtual point which it uses to develop a full map. One of the constraints of this system is that the roomba’s wheels don’t slip, if they did it could skew the whole map. Additionally there are no physical walls on all sides to define the area like the roomba has.

In most of the robotic lawnmowers that are on the market they use a buried wire, just like an electric dog fence. While this does give the virtual walls it still has flaws. I have been considering using corner beacons, such as IR, wifi, or gps so that the robot knows it’s position relative to the world and wheel slippage does not have an effect. Each one of those sensor systems has its pros and cons, such as consumer gps is low accuracy (I am not going to do a differential system for this) IR is weather/temp dependent, and Wifi is a bit more complicated. Most likely it will be some hybrid system for navigation. The first thing I am going to focus on is the mechanical challenges of the system, as I can always integrate different controllers, sensors, and other electronics to run it.

Thanks for the ideas keep them coming!

]]> By: Chris England http://www.robogreg.com/needel/205/comment-page-1#comment-1193 Chris England Tue, 09 Jun 2009 21:53:41 +0000 http://www.robogreg.com/?p=205#comment-1193 Just curious, have you looked into the roomba modification scene? I've seen them modified for some interesting purposes, and I believe they even sell some sort of developer kit for them. It seems like the roomba has a pre-existing programming/circuitry to do exactly what you want, just meld the lawn mower chassis to the roomba brains? Just curious, have you looked into the roomba modification scene? I’ve seen them modified for some interesting purposes, and I believe they even sell some sort of developer kit for them. It seems like the roomba has a pre-existing programming/circuitry to do exactly what you want, just meld the lawn mower chassis to the roomba brains?

]]>