Just a month ago I finished my mini balancing robot: http://blog.tkjelectronics.dk/2012/03/the-balancing-robot/
And now I would like to build a full size one, but I need some help for some parts.
Lauszus, Your mini balancing robot is fantastic! The control looks smooth and all of your peripherals seem to work well together. I admire your libraries for mbed and Arduino - I'll be using those in my projects soon enough.
What size are we talking about? Do you want to ride this larger robot? Any requirements for runtime and terrain capabilities?
The only thing I have right now are the microcontroller (mbed - http://mbed.org/handbook/mbed-NXP-LPC1768), XBee modules (for wirelessly debugging) and a 6DOF IMU - which are all parts I also used for my mini segway. I will also use an Arduino ADK for communication with my Android phone.
I also got some geared motors from an electric wheelchair, but I'm not sure if they would do the job - I would really like to know the opinion of some of the experts around here
The specs for the motors are:
Supply Voltage: 24V
Maximum current: 3.9A
Watt Output: 60W
RPM: 90rpm (2000rpm without gearbox) - it's a 22 ratio gearbox
The full name of the motors are: "Parvalux REF PM 3MB/511592/2B2" - I have no idea what the numbers after 3MB means (3MB are the specific motors and gearbox).
Here is the datasheet for the motors: http://blog.tkjelectronics.dk/wp-content/uploads/ParvaluxMotorSpecs.pdf
The main thing I am worried about is the rpm, as I am not sure if they are fast enough for a balancing robot, but I have seen a lot of people building full size balancing robots with wheelchair motors, so I think they are allright?
Motor choice in this application depends on how fast your robot might fall forward (or backward). The fall speed of a balancing bot is dependent on center of gravity and total mass. Robot's ability to compensate for fall is determined by wheel RPM, wheel diameter and torque.
First step would be to over estimate total robot mass and size. These are determined by robot specification - see questions in second paragraph of this post.
Next, when you have a reasonable location for center of gravity, estimate how fast that mass might fall. Include any possible outside forces in your calculations here.
Finally, you should have a rotational speed. This could be an angular velocity of the CG in relation to the wheel centers.
If you would rather not do math, simulate the entire robot system with wood and weights using your best judgement of position and weight of payload groups. Time how long it takes for your simulated robot to fall from vertical to horizontal (or some number of degrees). That's your angular velocity, sum your components to get a total mass, and this becomes the worst case to design against.
Convert the angular velocity to rotational speed of your axle and compare to your 90RPM for wheel chair motors. I'm happy to help with the simulation/calculations if you can give more detail on your robot system requirements.
I also need a motorcontroller, 24V battery - maybe 36V to make it go faster, some pneumatic wheels (something like these: http://www.northerntool.com/images/product/images/1330_lg.jpg), and some wheel hubs for a key mount.
Robot marketplace has a great selection of batteries and motor controllers. Again the system specs will give you a minimum requirement for runtime and motor current/control protocol.
Andymark has $40 8" pneumatic wheels (http://www.andymark.com/product-p/am-0970.htm?CartID=2) and key hubs (http://www.andymark.com/product-p/am-0077.htm).
I would also need some quality cables, connectors, and some basic stuff like that, that can handle the current.
I use powerpoles for power wiring. Other options are automotive terminals, such as ring or butt crimps. For any crimps you use, get the correct crimp tool. Robot Marketplace or Powerwerx has powerpoles.
For signal wiring it depends on the application. Some options would be pin headers (such as those on end of servo), D-sub connectors (like DB9 or DB25), Centronics, molex, microphone (DIN) connectors, RJ11 and RJ45. I prefer using IDC connectors with ribbon cable for signal connections that need not be shielded. For the few shielded applications I've needed, I used DIN connectors. http://www.allelectronics.com/ is a great supplier for bulk items.
I recommend an enclosure to house your control system. Bring the signal and power connections to one place on your box and mount everything within using fasteners or velcro. Your use of pin jumpers and breadboards on mini balancing robot was effective but dangerous for the system.
I am thinking about ordering everything from Robot Marketplace: http://www.robotmarketplace.com/store.html
And I have already made a post on there forum, but no one has never answered me: http://www.robotmarketplace.com/forum/viewtopic.php?f=5&t=303&p=795
I saw your post on their forum. I'm still waiting for my account to be validated. I came across your post on this forum after searching for your motor. Lucky ;)