Voyager... GPS guided autonomous outdoor LEGO robot

[John Brost]

A while ago I watched as Steve Hassenplug started building and testing an
outdoor GPS guided LEGO robot to compete in a RoboMagellan contest he called the
Green Monster.  It was great fun watching it drive outdoors.  After some gentle
prodding, I decided to give it a shot for myself.  Voyager is the result.
Here's the NXTLOG page about it:

http://mindstorms.lego.com/nxtlog/ProjectDisplay.aspx?id=0084709f-625a-4816-aabb-98291610c18b

I recently managed to rid it of its R/C leash and go fully autonomous using
RobotC and a BT GPS receiver.  Here's a video of it driving a course I defined
with flags.  

http://www.youtube.com/watch?v=fhhpetNNnMw

The GPS locations of the waypoints are defined prior to the run and recorded to
a file.  The navigation program then reads this file and navigates to the points
using real-time GPS readings to adjust its course.  It also uses an on-board
HiTechnic compass sensor for navigation.  Once Voyager gets within 50" (defined
in the program) of the target waypoint, it automatically increments to the next
waypoint in the sequence.  After the last waypoint, it automatically returns
home to the first waypoint.  It can record & follow up to 20 waypoints including
the starting waypoint.

John

[Steve Hassenplug]

On Tue, Apr 29, 2008 at 9:00 AM, John Brost <john.brost@...> wrote:
> A while ago I watched as Steve Hassenplug started building and testing an
> outdoor GPS guided LEGO robot to compete in a RoboMagellan contest he called the
> Green Monster.  It was great fun watching it drive outdoors.

I don't remember if I posted it, but here's the web page...
http://www.teamhassenplug.org/robots/GreenMonster/

>  After some gentle
> prodding, I decided to give it a shot for myself.  Voyager is the result.
> Here's the NXTLOG page about it:
>
> http://mindstorms.lego.com/nxtlog/ProjectDisplay.aspx?id=0084709f-625a-4816-aabb-98291610c18b

This is very nice, John.  Very cool to watch it drive outside, on it's own.

Steve

[David Koudys]

In lugnet.robotics, John Brost wrote:

> A while ago I watched as Steve Hassenplug started building and testing an
> outdoor GPS guided LEGO robot to compete in a RoboMagellan contest he called the
> Green Monster.  It was great fun watching it drive outdoors.  After some gentle
> prodding, I decided to give it a shot for myself.  Voyager is the result.
> Here's the NXTLOG page about it:
>
> http://mindstorms.lego.com/nxtlog/ProjectDisplay.aspx?id=0084709f-625a-4816-aabb-98291610c18b
>
> I recently managed to rid it of its R/C leash and go fully autonomous using
> RobotC and a BT GPS receiver.  Here's a video of it driving a course I defined
> with flags.
>
> http://www.youtube.com/watch?v=fhhpetNNnMw
>

<snip>



> John

That was fantastic!

Spotlighted for sure!

Dave K

[Rob Hendrix-2]

"John Brost" <john.brost@...> wrote in message
news:K0384x.Lzu@......

>A while ago I watched as Steve Hassenplug started building and testing an
> outdoor GPS guided LEGO robot to compete in a RoboMagellan contest he
> called the
> Green Monster.  It was great fun watching it drive outdoors.  After some
> gentle
> prodding, I decided to give it a shot for myself.  Voyager is the result.
> Here's the NXTLOG page about it:
>
> http://mindstorms.lego.com/nxtlog/ProjectDisplay.aspx?id=0084709f-625a-4816-aabb-98291610c18b
>
> I recently managed to rid it of its R/C leash and go fully autonomous
> using
> RobotC and a BT GPS receiver.  Here's a video of it driving a course I
> defined
> with flags.
>
> http://www.youtube.com/watch?v=fhhpetNNnMw
>
> The GPS locations of the waypoints are defined prior to the run and
> recorded to
> a file.  The navigation program then reads this file and navigates to the
> points
> using real-time GPS readings to adjust its course.  It also uses an
> on-board
> HiTechnic compass sensor for navigation.  Once Voyager gets within 50"
> (defined
> in the program) of the target waypoint, it automatically increments to the
> next
> waypoint in the sequence.  After the last waypoint, it automatically
> returns
> home to the first waypoint.  It can record & follow up to 20 waypoints
> including
> the starting waypoint.
>
> John

So does the GPS talk directly to the NXT?
What's the accuracy?

Great work and a nifty bot!!

-Rob
www.lifelites.com

[John Brost]

In lugnet.robotics, Rob Hendrix wrote:
>
> So does the GPS talk directly to the NXT?
> What's the accuracy?
>

Yes, the GPS communicated directly to the NXT via bluetooth.  I can't remember
who it was that figured out how to do this, after most of us thought it was
impossible, but it does work.

It's difficult to quantify the accuracy.  I have it set that when it gets within
50" of the waypoints, to count that as arriving, and increment to the next
waypoint.  That worked out pretty well, it never overshot or undershot a
waypoint ( I ran it several times).  The big thing with these little receivers
regarding their accuracy is from hour to hour or day to day.  I am sure that if
I went outside today (I filmed the video yesterday), the same values that took
me to the waypoints yesterday may not be very close to the same exact locations
today.

The specs on the GPS I'm using right now as it is set up is 5m.  Obviously using
it the way I am right now (record waypoints, immediately turn around & navigate
to the waypoints) allows me to do better than that.  I was also outside in a
wide open area... the little ones are especially vulnerable to trees, building,
powerlines, etc. interfereing with GPS reception.      


> Great work and a nifty bot!!
>

Thanks!


John