LinuxGuy
03-13-2008, 05:03 AM
Those who know me from the Lynxmotion forums (http://www.lynxmotion.net) have probably seen more than they ever wanted to see about W.A.L.T.E.R. ;) I started working on W.A.L.T.E.R. (the Wheeled Autonomous Learning Terrain Exploring Rover) in August of 2006 as my very first robot project. W.A.L.T.E.R. started out as an Octabot II kit from Budget Robotics. To put it mildly, W.A.L.T.E.R. is receiving a MAJOR make over now. I designed a set of brand new and larger octagonal shaped decks based somewhat on the original kit, and fixing what I saw as problems with that kit (wheels not properly centered in the body, all decks were not perfect octagons, etc). So, I designed four decks I believe to be perfect for two wheeled rovers like W.A.L.T.E.R.
I use Alibre Design (http://www.alibre.com) Expert for 3D CAD and I model every robot in full 3D before I even consider ordering parts and starting a build. So far, I have designed many more robots than I can ever probably hope to build, but I also enjoy the design and CAD process very much too. I got together with KM6VV (another Lynxmotion forum user and friend) who has a small Sherline setup. Alan (KM6VV) is a cool fellow and helped me learn what he needed to make stuff from my designs. This is the very first time I have actually seen a design of mine become real and I got a real rush when I saw the first pictures of the new decks. ;) As it turned out, the ONLY problem with my design is that the mounting holes for the Lynxmotion MMT-02 motor mounts are spaced too far apart. I've only been working with 3D CAD since starting work on W.A.L.T.E.R. I'm really happy the way this came out!
W.A.L.T.E.R. started out using continuous rotation servos for locomotion, but gained so much weight the poor servos failed under the load. I have since converted him to roll around on a pair of 5" off road tires on two Lynxmotion (http://www.lynxmotion.com/) GHM-04 (now discontinued) gear head motors controlled by a Dimension Engineering (http://www.dimensionengineering.com) Sabertooth 2x5 motor controller. I also have a Lynxmotion (http://www.lynxmotion.com/) SSC-32 servo controller for servo control and have the Sabertooth 2x5 (bottom deck with the motors) connected to it for PWM based control at present. This is what the software for W.A.L.T.E.R. is setup for right now. I also have a pair of QME-01 shaft encoders for the GHM-04 motors, I2C compass and RTC modules, and a 3-Axis accelerometer to eventually install on W.A.L.T.E.R.
As for sensors, there are currently 5 consisting of 3 Sharp IR Rangers (one on the end of the arm), an IRPD (rear mounted, for sneaky kitty detection), and a PING mounted above the Sharp IR Ranger on the end of the arm. I've been controlling all this and obstacle avoidance so far with a Basic Atom microcontroller made by Basic Micro, but have run out of space for much needed code additions (currently 79 bytes free).
I have decided that I no longer want to use microcontrollers or modules that do not have decent Linux based development tools or are closed and proprietary. I want to do all development I can under Linux from now on and only really need Windows for working with Microchip PICs/dsPICs, Renesas Highspeed Embedded Workshop (which I really do like, and I have four Renesas starter kits), and of course Alibre Design Expert for 3D CAD. Well, OK, I also need Windows for when I want to play WoW (Silver Hand for Alliance and Bronzbeard for Horde) but I have not been able to play for almost 3 months now. :( :(
Right now I am tinkering with the Hammer Board module from TinCanTools (http://www.tincantools.com), which will be W.A.L.T.E.R.'s next main controller. I could wish for more RAM and Flash on Hammer, but I believe it will work out very good for a new main controller. I already have the Hammer Carrier board mounted on W.A.L.T.E.R. and also have the components I need to modify that for dual power (battery or wall wart). I can pretty easily convert the current software that runs W.A.L.T.E.R. over to a language such as Python (http://www.python.org) since I have not used any microcontroller specific features. I have been tinkering with a Subsumption architecture, based heavily on work by members of the DPRG (http://www.dprg.org), for the new control software. I hope to also create a version of software for W.A.L.T.E.R. in Smalltalk (Squeak (http://www.squeak.org)).
My first real project with Hammer is going to be interfacing two Microchip dsPIC30F4012's to it, using I2C, which will each handle the tasks of reading and processing data from the shaft encoders (one quadrature encoder module per 4012), providing five 10-bit ADCs, more GPIOs, and perhaps other things in the future. The 4012's also have a 6 channel motor control PWM module I might eventually implement.
These are my current plans for W.A.L.T.E.R. v2.0. I believe I can accomplish all of this in bits and pieces over a very long time. You can see some early development videos, and some current pictures, of W.A.L.T.E.R. on my website.
8-Dale
I use Alibre Design (http://www.alibre.com) Expert for 3D CAD and I model every robot in full 3D before I even consider ordering parts and starting a build. So far, I have designed many more robots than I can ever probably hope to build, but I also enjoy the design and CAD process very much too. I got together with KM6VV (another Lynxmotion forum user and friend) who has a small Sherline setup. Alan (KM6VV) is a cool fellow and helped me learn what he needed to make stuff from my designs. This is the very first time I have actually seen a design of mine become real and I got a real rush when I saw the first pictures of the new decks. ;) As it turned out, the ONLY problem with my design is that the mounting holes for the Lynxmotion MMT-02 motor mounts are spaced too far apart. I've only been working with 3D CAD since starting work on W.A.L.T.E.R. I'm really happy the way this came out!
W.A.L.T.E.R. started out using continuous rotation servos for locomotion, but gained so much weight the poor servos failed under the load. I have since converted him to roll around on a pair of 5" off road tires on two Lynxmotion (http://www.lynxmotion.com/) GHM-04 (now discontinued) gear head motors controlled by a Dimension Engineering (http://www.dimensionengineering.com) Sabertooth 2x5 motor controller. I also have a Lynxmotion (http://www.lynxmotion.com/) SSC-32 servo controller for servo control and have the Sabertooth 2x5 (bottom deck with the motors) connected to it for PWM based control at present. This is what the software for W.A.L.T.E.R. is setup for right now. I also have a pair of QME-01 shaft encoders for the GHM-04 motors, I2C compass and RTC modules, and a 3-Axis accelerometer to eventually install on W.A.L.T.E.R.
As for sensors, there are currently 5 consisting of 3 Sharp IR Rangers (one on the end of the arm), an IRPD (rear mounted, for sneaky kitty detection), and a PING mounted above the Sharp IR Ranger on the end of the arm. I've been controlling all this and obstacle avoidance so far with a Basic Atom microcontroller made by Basic Micro, but have run out of space for much needed code additions (currently 79 bytes free).
I have decided that I no longer want to use microcontrollers or modules that do not have decent Linux based development tools or are closed and proprietary. I want to do all development I can under Linux from now on and only really need Windows for working with Microchip PICs/dsPICs, Renesas Highspeed Embedded Workshop (which I really do like, and I have four Renesas starter kits), and of course Alibre Design Expert for 3D CAD. Well, OK, I also need Windows for when I want to play WoW (Silver Hand for Alliance and Bronzbeard for Horde) but I have not been able to play for almost 3 months now. :( :(
Right now I am tinkering with the Hammer Board module from TinCanTools (http://www.tincantools.com), which will be W.A.L.T.E.R.'s next main controller. I could wish for more RAM and Flash on Hammer, but I believe it will work out very good for a new main controller. I already have the Hammer Carrier board mounted on W.A.L.T.E.R. and also have the components I need to modify that for dual power (battery or wall wart). I can pretty easily convert the current software that runs W.A.L.T.E.R. over to a language such as Python (http://www.python.org) since I have not used any microcontroller specific features. I have been tinkering with a Subsumption architecture, based heavily on work by members of the DPRG (http://www.dprg.org), for the new control software. I hope to also create a version of software for W.A.L.T.E.R. in Smalltalk (Squeak (http://www.squeak.org)).
My first real project with Hammer is going to be interfacing two Microchip dsPIC30F4012's to it, using I2C, which will each handle the tasks of reading and processing data from the shaft encoders (one quadrature encoder module per 4012), providing five 10-bit ADCs, more GPIOs, and perhaps other things in the future. The 4012's also have a 6 channel motor control PWM module I might eventually implement.
These are my current plans for W.A.L.T.E.R. v2.0. I believe I can accomplish all of this in bits and pieces over a very long time. You can see some early development videos, and some current pictures, of W.A.L.T.E.R. on my website.
8-Dale