There has been alot of talk, email, posts and phone calls about A, B & C. We are currently working on a visual guide and ask that you send in you thought and comments about the pull types and more importantly techniques that you feel work best for each letter.
The system has an underlying control loop which ensures the average speed over the slalom course is kept to a close tolerance. Overlaid on this are additional gains intended to influence the "feel" of the system. These are "Decel" and "Accel" gains. The decel gain acts to eliminate any deceleration, and will tend to add fuel any time the boat is decelerating proportional to how large the gain is and how big the deceleration is. Similarly, the accel gain acts to eliminate accelerations, and will tend to reduce fuel when the boat is accelerating proportional to gain and acceleration magnitude. So, a bigger decel gain will tend to be more aggressive in adding fuel when the skier loads the boat and causing it to decelerate, and a bigger accel gain will be more aggressive in reducing fuel when the skier unloads the boat. The decel gain is active any time the boat is decelerating, regardless of whether the actual speed is above or below target, and the accel gain is active only when accelerating, also regardless of actual speed. Therefore an assymmetric feel is possible by manipulating these gains, although there are more subtle interactions with the underlying average speed control loop which can make the interactions more complex. A/B/C allows three combinations of the decel/accel gains as listed above to be selected "on-the-fly" There may have been some flip/flopping of the A/C aggressiveness terminology as we went through the development last fall and spring, but we tried to keep the directional relationships between A/B/C similar when we settled on the RevP settings, just with considerably less agressive responses.
It's difficult to nail down a universal description because different skiers with different rhythms at differing rope lengths perceive things in very different ways, but here's a description of how the gains work I put together for someone some time ago: Andy Mapple came up with shorter summary of this from the skier's perspective: A= Softer pull out of the buoy, but maintains a tighter line into the buoy
B= Equal application of speed and deceleration as needed. Responds same to applying power, as bringing it off.
C= Quicker reaction out of turn, allowing for less pull into next buoy. |
