Archive for May, 2009

Some Random Stuff

GPS Module and Antenna

U-Blox GPS and Satantel Antenna

One of my friends working on a GPS project of his own managed to aquire some Sarantel Helical antennas, and got some for me as well. I’m planning on using them with the U-blox GPS module I have had sitting around. (I originally bought the GPS module for a MUAV autopilot I’ve been slowly designing, but when I got busy with work it got put aside and technology outpaced my design. For the MUAV autopilot I’m now intending on using a smaller, lighter GPS module which has freed up this one for service on my Quadruped). I’m still mulling around on choosing an LNA to throw in between the radio and antenna to improve sensitivity, so the PCB design is stalled until I make a selection.

Four Legs in progress 2

Teaser Photo

Although the GPS is “technically” able to attain a GPS lock indoors according to the literature, I’m not going to count on that. The camera will be used for indoor navigation and world modeling (I’ll post more on the progress of that later), while the GPS will be used primarily for outdoors navigation. The main reason for this is I’m thinking of having a go at the Robo Magellan competition put on by the Seattle Robotics Society. Although for the general flat environment a small walker is at a huge speed disadvantage to the larger wheeled or tracked rovers that typically enter, I’m more interested in the technical challenge of designing a robust and adaptive walking/navigation algorithm for the robot than winning.

Populated Mobo

Mini Sumo Brain

As a bit of an unrelated note, here’s a picture of the populated circuit board for my mini sumo. Now that there’s no pressing deadline to get the robot working, I’ll have more time to fiddle with this board and get FreeRTOS up and running on the LPC2138 to manage the data and computational requirements of some of the more complicated sensors I’m throwing into this sumo robot for no other reason than “because I thought it would be a good technical challenge”

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2009 Western Canadian Robot Games I

Super-Secret-Backup-Plan-1

The HC12 Motor Controller Board modified as a sumo controller

I spent the second half of last week scrambling to get my mini sumo robot, 1.21 Gw into a working condition for the robot games. I populated the circuit boards mentioned in an earlier post but as I grew low on time I decided to put those aside for this year. Instead of trying to teach myself a new architecture (LPC2138), I decided to concentrate on programming the robot using a board I was familiar with, my HC12 based motor controller design. (This was the prototype motor controller for my Quadruped walker, so I had some base code already written for it, which went a long way towards getting my sumo robot programmed in a little over a day)

May 2009 Weigh In

331 Grams!

I made the decision to forgo edge sensors for this competition, and instead chose to make the robot as aggressive as possible, the theory being that if I push the  opposing robot off the edge before my robot gets to the edge, I won’t need edge sensors. In the end, I managed to get a working robot, measuring 98mm wide by 97mm  long, and weighing in at only 331 grams!.After I finish the actual controller board I intend to use on this robot, I’ll have to make some weights to bring it closer to the 500 gram limit.

In the end, I placed first in the advanced mini sumo category, though I had some good competition! For more videos, check out the WCRS website. I will try to post my own pictures and videos when I get a chance.

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