Viser arkivet for januar, 2011

Optimizing the cornering algorithm for the Grbl acceleration code.

Attempting to discover the best algorithm for determining optimal speed reduction in order to pass a corner at maximum speed but within a set jerk limit.

Red: The jerk-limit, Yellow: The actual jerk, Transparent blue: The sum of incoming and outgoing feed rate. The intersection between the red and yellow is the set of candidate cornering factors, the optimum one is the one where the speed is the highest, i.e. where the blue transparent layer is at its tallest.

The final optimizing algorithm must run on the AVR328 in a matter of milliseconds.

Mad professor control unit

We are experimenting with real time controls for the milling operation and came up with this unit cobbled together from dumpster spoils and the Big Dome Push Button. Now we can tweak the feed rate in real time using the sliding pot, see if we suffer buffer underruns because of poor serial comms and we have two buttons for pause and emergency stop. There is an experimental branch up on github if you want to experiment with real time feed rate tweaking: Control. (Warning: The pins had to be remapped. Be sure to check config.h for the updated pin out.)

In related news: We finally have gotten through most of the code for a look ahead optimizing acceleration manager for Grbl. It is completely untested yet, but if you are so inclined you can have a look at the code in this experimental branch. The details will be explained in a proper blog post later.