FRC1899 Shooter Prototype

[JamesCH95]

Originally Posted by Nuttyman54

An clever way to solve this is not to measure distance, but force. 190 utilized this on the 2010 robot, which had a surgical-tubing powered kicker. We mounted strain gauges on the struts which anchored the surgical tubing, which allowed us to monitor the strain (due to the deflection force provided by the surgical tubing), and correct for surgical tubing deterioration. It also meant that if the tubing ever got too worn out or broke, we could just replace the bands and not worry about getting exactly the same length/tension.

The 2010 application was much less sensitive, and I don't remember if we ever actually used it in our competition code, but we had the capability and proved that it worked. In an application like this where the accuracy is incredibly important, the ability to not have to re-tune your launcher if you have to replace the tubing could be very critical.

That's not a bad way to do it, and it certainly is better than doing nothing, but force != stored energy when the spring rate is changing.