Archive for January, 2009

PID parameter calculation spreadsheet

Thursday, January 29th, 2009

While working on some code for the FIRST team that I’m on, I had decided we were going to need PID control for some portions of our robot. Unfortunately, I have not done a lot of this stuff.. I took a control systems theory class in college, but I never quite saw the value of it at the time (which, I’ve come around now that I’ve seen some practical applications). So, to understand how it works more, I created this spreadsheet with adjustable P/I/D parameters.  I found this to be a useful tool in understanding the output of a PID control system.

Of course, its strictly an ideal model and not particularly realistic (try setting the P parameter to 1)… but its primarily useful for getting that basic understanding. Theres a number of ways it could be improved… feel free to improve it. 🙂

Download the PID spreadsheet

Updates and such

Tuesday, January 6th, 2009

Well, I have a *ton* of things going on right now… I am very busy mentoring for a FIRST team that my company sponsors (the Kwarqs), and some important deadlines coming up at work.. and trying to get my massive updates to Roadnav integrated in.

Speaking of which, I’ve bundled all of my R* and B+ tree code into a library called libsdbx… I need to write more in depth about it, but its a nice header-only C++ library that allows usage of generic R* and B+ trees with either a memory backend or a file-based backend. Its really nice to use, but I think I’m going to hold off on releasing it in a formal package until a final release of libroadnav is created (which will definitely iron out any lingering performance issues or bugs).

Libsdbx can be found in Roadnav SVN at

As I create neat FIRST-related stuff, I’ll be sure to post some of that up here also. I’m really excited about this open source thrust that FIRST seems to be going down lately, its definitely encouraging and makes me want to contribute.