NewBOT
- Actuators / output devices: 2xGM8 Motors
- Control method: autonomous
- CPU: Rabbit RCM3400
- Power source: 6xAA NiMH
- Programming language: Dynamic C
- Target environment: various
9-Oct-08 - First Drive!
Always a proud day, like baby's first steps. In the video i'm using the WASD keys to drive and steer. The speed control is working very nicely. With the manual control I am currently dividing the 10-bit pulse width into 10 gradients which makes it a little jerky. When autonomous it will be allowed 100 discreet speeds in either direction. It's open loop for now because i haven't found any encoders small enough/cheap enough.
The install of the motor controller into the track unit was frustrating (very short wires) but it turned out nice. I'll post somepics and a video demoing the ease of disassembly soon. I have been collecting inspiration over the last couple of weeks and will leave you with this:
http://www.youtube.com/watch?v=Y6ljFaKRTrI&feature=related
29-Sep-08 - Finally....POWER!
So, after a lot of playing with different power sources, I decided to go with some good quality, 3A low drop-out linear regulators. I'm still playing with the boost circuit, but I didn't want it slowing down this project, so they are diverging for now and hopefully I will add it back in later.
Last night I got it up and running a few test programs. The Pololu soft power switch is very, very nice. I tested one of the motor controllers (just fwd and rev) and wrote some routines to handle the pulse width so tonight I should have some first drive video for you. But here are some pics for now.
25-Sep-08 - A Step Back in Power
So due to an error in the digikey catalog, the voltage regulators that I bought don't work for my application. The catalog says the drop-out voltage is 3 Volts when its actually 7V!!! So I'm redesigning the power circuit to mock the power circuit on the Pololu 3pi, which runs down to 1.6Volts!!! They do it with a very nice Boost regulator that runs at 9.25 Volts and feeds a linear regulator. Check out the schematic if you're interested, its a REALLY nice way to run a robot off of 4-6 AA batteries and really get all the juice out of your batteries:
http://www.pololu.com/file/0J122/3pi_quickstart.pdf (top of page 2)
They wouldn't tell me what the boost regulator was because they are going to start producing/selling thepower circuit, but luckily I have a friend that has a 3pi prototype so we figured it out. They parts are on the way! This will set back my first drive till sometime next week. Sorry Fritz :-)
23-Sep-08 - Change of motor plans
So I've decided not to use the Solarbotics GM10 (http://www.solarbotics.com/products/gm10/) motors. I have 4 of these to spare if anyone needs them send me an email at thekeywork2@gmail.com and we can talk about it. Please do NOT post in the comments section, just shoot me an email.
As for the robot, i'm building the power circuit today (pics tonight) and starting on the code. I've decided on the pololu TB6612NFG motor controllers for the drive wheels (http://www.pololu.com/catalog/product/713).
19-Sep-08 - Another Elaborate Chassis
OK, OK...I broke away from the minimalist simplicity of my last project (http://letsmakerobots.com/node/1996) and built a slightly more elaborate chassis. The box is made from sintra and is held together using counterbored 2-56 screws. The "tread units" come off with a single screw (later a single screw and connector for power and control) and i'm planning on housing the motor driver inside the individual tread units making them fully detachable. I like compartmentalisation for some reason. check back soon!
19-Sep-08 - Ground Clearance
Great idea voodoobot! Check out the new pic to see this implemented. It allows for 1.5" of ground clearance. This is with 22 links of Solarbotics tread with a 3" wheelbase. I used 1/4"-20 shoulder screws to mount the idlers (had to bore them out just a little) and 3mm Sintra (expanded PVC) for thesupport structure. Now that the treads are done, today i'll be working on chassis design and motor controller/processor placement. Check back soon!
18-Sep-08 - A Clean Start
So I've wanted to build a tracked robot for quite some time, but have never found any tracks that I really liked until I found this website, saw the YDM, and fell in love with the solarbotics tracks. So here is the start of my next robot. I won't give way too much right now except that i'm using an RCM3400 processor from rabbit semi and am going for a YDM-like final result.
Pictured is my track layout. I integrated the GM8 motor into the track holder so that the track-drive mechanisms are separate components.
Oh, and I never name robots till they are done...hence NewBOT.
Hey, it seams like there is
wall-e
Triangles
I've seen this design used many times. I think even "Jonny 5" in the movie "Short Circuit" had it.
Can anyone tell me the purpose? I would have thought that a more useful arrangement would have been to have the tracks angled up at the front and back (like a tank) rather than angled down at the front and back.
Anyone?
Clearance Clarence
That;s the only reason I could see, is to get the motor up on the higher sprocket, to allow a little more open space. Which isn't being done on this robot since the motor drives the back track.
I like the look of tracks arranged this way, but you're right, it would be more effective to have at least front and maybe back upward slants.
This also keeps the upper
clearance
Oops, had not noted the pic, only seen the vid
I've been looking at this
I've been looking at this design as well, haven't bout the tread kit though just yet.
Have you looked at mounting the motor on the higher sprocket to give a bit more ground clearance? Thats one of the issues that I found with the 2 sprocket setups, always too low and anable to get over angled terrain due to underside clearance. 3 sprock with the high motor mount seems best to solve this.
Looks Great !
Your style is wicked!! I
Thanks dude. I'm sparing
looks awesome! btw, is
looks awesome!
btw, is that coolant(80/20 mix) in the bottle in the top(new) pic, or is it some new wierd gatorade?!?!?! ...what are you building that requires that?!?! :)
lol! thats actually 50/50
WOW. I love the look of the
WOW. I love the look of the material and the triangle track set up. Are you intentionally making a wall-E type bot? If wall=E was brand spankin new thats what I imagine he would look like!
Depending on your main floor surface those rubber grommets on the tracks might make turning tough. My last robot used the cheap tamiya tracks and it always throws one off trying to turn on my rugs.
Incidentally, that stuff sintra, is it easy to find and work with? Im looking for material to use on my next bot but I dont know what I should get, and living in an apartment I`m limited on how much drilling and sawing I can do :/
i'm hoping for more of a
i'm hoping for more of a multi-terrain robot. I've got the high-torque motors on it right now. i might switch to the high speed if turning isn't an issue. i just wanted multi-terrain capabilities and those treads have NO grip out of the box.
I got the Sintra from solarbotics because i was already ordering from them, but i'd normally just get the regular expanded PVC that they sell at mcmaster. the sintra stuff is less dense and cuts easier if you dont have access to machine tools, but they are both light weight and take well to machining, hand cutting, sanding and glueing.
Oh, and definately Wall-E inspired!
Cool treads but..
I'm suprised it took so long
Inspired by ydm too
such a beautiful
such a beautiful chassis!! well done!
:-)
Way cool with the rabbit! I
Way cool with the rabbit! I haven't seen a uC from that family since the days where I did some freelance work with the Rabbit2000. Dynamic C is awesome with the concurrency constructs and all IMHO. I think that was actually my first steps with uC's!
Looking very much forward to seeing this completed!
I want to see the video of
I just ordered the Motor
Artys just throw stuff
That's a really nice
That's a really nice frame!
Not a lot of people concentrate on the finishing job on their robots, but this one is very cool.
I see that you added wire grummet to the tracks, good idea !
Green
What's that bottle of green stuff in the background?
Soylent Green is people!