05 November 2012

Solidworks to URDF Exporter! (& Future Projects)

I use Solidworks extensively in my mechanical designs, and I've used ROS before in the context of mobile robotics. Given my love for armature robotics, I will soon be using ROS for visualization, control, and planning. 

Now imagine my glee when Willow Garage announces the fruit of one of their summer 2012 interns's efforts: a Solidworks to URDF Exporter!

URDF is an xml-style file format for representing the mechanical properties constraints of your robot. For example, you can have a number of links tied by some revolute joints (generic serial link robot), or a base link with many children and degree constraints for each DOF (Like a robotic human hand). Mobile robots can even utilize URDFs for determining where certain sensors are relative to the base link, etc. TurtleBot's pre-written URDF file contains information on where the wheels are relative to the base link, as well as the position of the Kinect, for the odometry and vision code to use when calculating position or detecting objects. 

For more information on URDF, check out this presentation from ROSCon 2012: 

And It's available like right now right now. I download the file in the above link and try to install it, but: 

DAMMIT. I'm running an x86 OS (32-bit) and this program requires a 64-bit OS. I may try to rebuild it from the available source (YAY OPEN SOURCE!) or even modify the code if need-be. Or I can wait until the 32 bit version is released, even email the developer and see if he needs help/motivation in the 32-bit implementation. 

Also, I want to intern for Willow. They're a kick-ass company, and I believe in their vision for how (the royal) we will advance the field of robotics, through corporate backing open source research. I'm a bit nervous to apply just yet, because I feel I can offer them so much more to judge me by if I apply after I've finished playing with my TurtleBot and using ROS to command TinyArm and design and build DeltaBot and-

DeltaBot? What's that?! 

DeltaBot is a future personal project of mine, scheduled to be completed by the end of January 2013 at the latest. 

It's this: 

A Delta robot is a parallel linkage robot used in manufacturing which has 3 DOFs, X Y and Z. No rotation in this configuration. 
But mine will be on the scale of this one:

Which is a design I really like and am going to use as my main reference. In fact, I want to contact the make of the above little Delta robot and commend them on how nice their design is. When you stand on peoples' shoulders, best thank them and let them know what cool things their efforts paved the way for =].

Mine will be commanded by 3 of the 7 Pittman motors I bought a couple weeks ago. They will be geared down to allow a higher encoder resolution and payload, and controlled by my trusty XMega16a4u because I have experience with the chip, it runs at 32 MHz leaving me plenty of speed for high-precision motion, has 3 built-in quadrature encoder decoders, and I still have a bunch leftover from my TinyArmTroller project. 

OH and I got a few samples of these from TI, which have integrated gate drivers and everything. At 12 A peak, 6A continuous, these are perfect for the 10A peak Pittman motors.


Oh, and I want to control it with this interface: 

Yupp. Freaking sick, right? The future is bright! Blog post on DeltaBot's design coming as soon as I design DeltaBot ^_^!