Background
After a week of riding this feature, I am addicted and I can’t live without it. I am almost certain this will make it to the main package so test it now to get your two cents in.
This was a very simple change to the float package. I took the booster and changed it to be based on roll instead of pitch. The result allows you to tune the board so that it accelerates into your turns. This works with the existing booster inputs.
Versions
0.9.1.1- Includes all my features. You cannot use turn tilt with this version. YOU MUST READ THIS POST TO CONFIGURE SURGE.
0.9.1.1a- Disables surge and sticky tilt so you don’t have to configure those. Allows turn tilt. This is essentially float package 0.9 with the turn boost feature.
Why is this important?
When you want to turn sharply, you have to lean to the inside of the turn. This puts your center of gravity on a smaller turn radius (the path your center of gravity takes) than the board, which will be taking a larger turn radius. A smaller turn radius is a shorter path to complete the turn so the board has to go faster (or your body slower) in order to make the turn. The harder the turn is, the larger the difference between the path length of the board vs. your center of gravity.
Normally, we accelerate the board by pushing the nose down but in some scenarios this will cause the nose to contact the ground, particularly at high roll angles. Turn boost compensates by using the roll so we don’t have to nose down. This allows for a smoother, natural-feeling turn that can also be programmed to be quite “boosty”.
Settings
The settings work very much like the traditional booster but with roll (side to side motion of the board) as the trigger. The boost will start at boost angle and increase at rate: boost current, divided by boost ramp. The boost current is now a percentage that is multiplied by the PID current demand so that turn boost does not override our PID control loop.
For acceleration boost, having a large boost ramp with settings, like boost angle 5 and boost ramp 10, will give a very rounded carvey feel. It will be loose but the extra current is there when you are really deep into a carve. On the other hand, a small ramp, like boost angle 5 and ramp 1, will give a very tight “race-like” feel. It keeps your carve very narrow and controlled. Both these settings will provide excellent low speed maneuverability.
For braking, the boost acts a little differently. Because we want the board to accelerate around our turns, the brake boost acts opposite to the PID control loop to release the braking force. I have not been able to experiment with this as much as I would like because I live somewhere pretty flat, but the results so far have been good. It feels much more like a snowboard in the way it accelerates through the apex of the carve. Doing a snowboard-like sideways stop also feels good. The settings I have used for braking are boost angle 5, boost ramp 3, boost current 60.
Please be careful using high boost current values for braking. As I mentioned, it is percent based and 100% could remove all braking force. In my tests this has not been a problem yet.
What else is included in this behavior?
Very little. I put in a condition so that brake boost does not engage at low erpm. This allows you to hard brake and perform a quick u-turn with the acceleration boost, which was previously inhibited by brake boost.
In the old booster behavior there was code for modifications to the booster strength based on speed. I removed this but consider if you think this would be helpful.
Enjoy!