First Robotics

Trajectory and interactive plot for a large, light ball

This year’s FIRST FRC challenge involves moving around a large ball. The trajectory will not be a simple parabola as in the case for motion in a gravitational field in a vacuum, because drag will play a sizable roll. I used standard equations of motion which take into account drag to offer up this interactive trajectory plotter.


Trajectory and interactive plotter of a large, light ball

Look, the physics hasn’t changed since the challenge of a couple years ago when the motion of smaller, heavier foam balls was the challenge. Drag is drag. So I really didn’t have much to do at all but to recognize that I could liberally steal from my previous effort: Deluscious foam ball trajectory

Admin First Robotics

Interactive Frisbee Trajectory

The FIRST FRC challenge for 2013, Ultimate Ascent, involves shooting heavy flying discs (sturdy Frisbees) into goals. The physics of the equations of motion have been studied and published. I’ve created an interactive web page which allows you to vary some of the initial conditions to see how the trajectory is affected.

The details
Go here for the web page.

For last year’s challenge, foam balls were to be shot into a basketball hoop, so similar equations of motion applied. Here is that page.

First Robotics

The best Labview shortcuts and tips

Labview is used for real-time instrument controls and in First Robotics. It is a purely visual programming environment, which is very strange for me. I am a complete Labview amateur. If you’ve read some of my other posts you might see a pattern emerging! But nevertheless I know a few things. Then I use the program so infrequently I forget them. And Labview is the kind of program where you can spend a lot of time that could have been saved if you just knew a better way. So here is the better way…

The most useful Labview shortcuts
– undo the last thing you did. I think you can undo more than just the last by repeating
– remove broken wires
– to toggle between Front panel and Block diagram
– context-sensitive help
– run the VI
and hold-click, then drag mouse and release – do this between two nodes to push them (and everything else) apart. Works horizontally and vertically!
– Select (a node), -click, move mouse nearby and release – to create a duplicate of a node
– Right-click a node, then choose similar items from this function palette – to quickly find a related function

– Rt-click on wire, then Clean wire – to make it more tidy
– Click while dragging wire, then move the mouse at a right angle – to create a right-angle bend in the wire just where you want it

Labview mentor training This is a really helpful link for mentors as well as students.

The best resource I have found

Team 358 has put together the best resource for FRC teams I have found – every basic- and intermediate-level difficulty thing you’ll need is explained on this one page. Well worth a bookmark. Thank you team 358! (2/2016 update) But see the references for a working link to this page…

That’s about all I know!

References and related
Team 358’s web site is often not working. I have found a working copy on the Wayback machine of their great Labview tutorial: Team 358 Labview tutorial on