11 Aug 2010 robotvibes   » (Master)



I suppose I am due for an update.  I have been working on the Ultra series robots, Mega and Max.  I have been updating UltraMega, aka Mega, eventhough it has been retired.

There were some wiring issues where the ISP header wasn’t making good connections, and so updating the firmware was a problem.  Also, the IR Sensors were on the same connector, so this had to be fixed as well. So I made these changes to Mega.

Also, replacing the AT90S8515 with the ATMega8515 was done since AVR Studio 4 doesn’t support the older chip, and I’m using the AVR ISP MKII.  Now, Mega and Max have the same code, and are able to run more or less the same.

At this time, Mega has a 2 IR sensors, and is able to do some basic obstacle avoidance routines.  Another behavior that Mega has is the ability to get unstuck if it gets snagged somewhere. It seems to work pretty well. I’m fairly impressed, and it resembles seeing a child get out of some issue in its environment, and it seems as if they are learning.  However, Mega is not learning, but given certain states of it’s sensors, it triggers the behavior to get unstuck. I will do some more basic stuff with Mega, then have it running around again, for demonstrations, etc.

[Later I will probably have Mega and Max in some robot team tasks.]

The progress on Max is steady.  I added the XBee Interface, so now Max may be controlled remotely, via serial commands.  This is mainly for telemetry purposes, such as sensor and odometry debugging.  I have added some code to read the odometry encoders, and later will add the code for speed control.  It’s not getting the wheel rotation fast enough, so I’m still working on the ISR code.

I have also been working with the I2C Compass and Ultrasonic Sensors with the Arduino.  The Compass seems to work pretty well, as I have an actual analog compass (from my Orienteering days) to test the accuracy of the Digital Compass.  I have also installed the Digital Compass in a plastic case to mount away from any magnetic/metallic objects.

The Ultrasonic sensors are impressive, as the readings are coming in real-time.  I am thinking of getting a few more of these, since they work so well.  I am thinking of adding the Ultrasonic sensors and the analog GP2D12 IR Sensors to the front of Max’s chassis.  Experiments with the correct placement will be done, for best results.  On the left and right sides, I will also place some GP2D12 sensors as well, for wall following, and other behaviors.

I have also gotten the shell for Max’s body, and it is nice and slick looking. I’m doing some tinkering to see what mounting method works best, something that’s easy for the body to either remove, or open to work on the innards of Max’s base.  I also just picked up some threaded rods, to install on Max’s chassis, to add a couple of decks.

I’ll try and take some pictures and vids, so please stay tuned…lots to do…til next time.

Syndicated 2010-08-11 15:54:46 from Cyb3rnetx

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