Dual Axis Robotic Table

[MikeH]

Good morning! I'm EXTREMELY new to the world of robotics. I was in the robotics club in High School but aside form those 4 years that's the extent of my experience. I don't know where to begin so I'm here to try and talk to some "pros" to figure out what I need to do.

The company I work for has given me the responsibility of building a dual axis table or finding somebody who can build it for us. Within certain specifications which are listed below:

Rotary Platform Diameter is 13.5in
Vertical Adjustment of 0-4in
Center of tilt to top of 360 degree baseplate must be 9" at bottom
Center of 360 baseplate must be 6.75 from front face of enclosure.
Center of 360 baseplate must be on centerline of housing (9.0" from centerline of mounting slots)
Rotary Range 360 Degrees
Weight Capacity 15-20 lbs
Controller Interface: CAN Bus
Must accept motion control commands from internal software (Uses VB)
Powered by 110 volts 60 hertz.

Now in my mind this sounds like for somebody who knows that they are doing, this would seem like a pretty simple solution. 2 Servos, Motor, breadboard platform. But as far as the communication between software to the motor and what needs to be done that way; I'm at a loss. Could somebody please give me an idea as to where I can go from here; or what this will require? Thanks alot guys!

[jwatte]

Are you sure that a suitable table can't just be bought off-the-shelf?

Anyway, to build the control:
You need a microcontroller with CAN bus to read the commands.
You need some output from the microcontroller to the servos -- I'd suggest an UART speaking RS-485, although specifics depend on the servo.
Then you need the software development environment for the microcontroller you choose.

Unfortunately, most microcontrollers these days are surface-mount only, so "breadboard" might not be the right choice. You can find pre-built modules, though -- anything from the TI Stellaris development platform, to the Freescale mBED socket adapters, to the AVR-based Arduino line.

You also need a power supply of some sort to get the right voltage for the servos, and for the microcontroller. These can be bought off the shelf as "open frame power supplies" -- check a distributor like digi-key.com.

Btw: searching "mcu can" on digi-key returns 5808 different microcontrollers that might be suitable. Seems like something simple like an Atmega16M1 might be sufficient. See if you can find a reference/development board with it already soldered up.
If not, you might try an mBED 1768 module: http://mbed.org/handbook/mbed-NXP-LPC1768

[MikeH]

Thanks for the reply! I looked for an off the shelf product, but they were going for around $12,000-$18,000 and I'm exploring the price difference of building our own vs buying those. You're much more versed in the products of this industry I'm sure, do you have any ideas of off the shelf products? Thanks!

[jwatte]

I'm a total newbie at machines and mechanics; I come from the software and embedded systems background. Hence, why I could perhaps give some pointers on the software/microcontroller question...
If I were to build it, I'd probably use a pair of Robotis MX-106R servos ($500 each,) the mBED microcontroller with a CAN and an RS-485 interface (< $100,) an off-the-shelf power supply ($100) and whatever axles/bearings/plates you need for the actual mechanism ($???, < $500 I think) and a powdercoat sheet steel box. Unless you need precision mounting, such as for CNC milling or whatnot.
I bet those servos would be overkill, but I've been wanting to get my hands on a couple of those :-D
The cost will be in time, rather than materials.