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View Full Version : Innovation series, episode 4: perfect pull


seansherrod
07-07-2010, 03:43 PM
Note that this is episode 4 so if you're just jumping in, you might find it helpful to go back to episode 1 for the intro.

You might have figured out the idea from the title already. It's pretty simple. Basically, this is an enhancement to the speed control system frequently offered by Perfect Pass. The speed control systems today can hold plus or minus a couple of tenths of a mph in steady state (constant speed). It seems like it would be a relatively minor enhancement to enable the systems to control speed during a dynamic state (acceleration). I'd like to be able to 'teach' the speed control system how to do a pull so that it can mimic the acceleration curve I taught it up to the set speed.

I figure that this is most helpful when I'm boating with friends that are't as familiar with pulling a skier. I don't always feel like training them (from the water) how to pull a skier just because I feel like going for a ski run. By the way, I do mean friends here because my wife is a fantastic driver so I've got no concerns there - this really is for friends in my case.

It would be nice to have the option to select from several acceleration curves: wakeboard, ski, etc. As with the previous posts, feel free to offer related suggestions or tell me where this option is available if I just missed it.

Jesus_Freak
07-08-2010, 01:16 PM
From a purely "controls" standpoint, the ramping of a setpoint should be inconsequential.

In terms of implementation, what has been tried in the past, what is available now, etc., I would be interested as well. Anyone?

shepherd
07-08-2010, 02:55 PM
Sounds like a great idea to me. Such a system could have selectable, pre-set acceleration profiles designated A (slow and easy), B, C, and D (throttle slam). For example, it would be nice if a beginning skier/boarder, or a guy recovering from an injury, could say "give me a 'A Pull-up' please."

Ha! Now PerfectPass has to list us as co-inventors when they file their patent application. :D

cbryan70
07-08-2010, 03:01 PM
This has already been done in an older system. I also beleive mercury has this with there smartcraft as well

FrankSchwab
07-08-2010, 03:08 PM
Actually, such a thing did exist, and my friend has it in his PS190. It was a competitor for PP, called "Accuski". Lots of links on Google.

It was remarkably helpful in teaching, as the pullout was very consistent from run to run.

You could set the type of pullout (wakeboard, slalom, etc), crew weight, skier weight, various others that controlled how hard the pullout was. It had both RPM and Speed modes, depending on what you were doing - RPM was most accurate for slalom, but Speed was most accurate for wake, IIRC.

We've been occasionally working on a copy for the last several years - one of us spends a couple of days on it every six months or so.

/frank

Bruce Carr
07-08-2010, 03:12 PM
This capability was standard on the Accuski speed control system. It is called the "auto up" feature. You choose the accelleration rate ranging from 1 to 100 for up to 10 individual skiers (also stores the individual skier weight, starting speed, etc); 100 being full throttle. With a touch of a button, the system was armed, the you simply pushed the throttle forward about 60 -70 degrees and the system would automatically perform a nice rolling accelleration with an intensity defined by the rate chosen. Also, the Accuski does not require all the other inputs (Kx,Px, A1 -C3blah, blah) required by the more common perfect pass and zero off. To this day, I don't know why perfect pass beat out Accuski.

shepherd
07-08-2010, 05:01 PM
I wonder why PP didn't adopt this feature into their system. Expense or lack of demand??? If the Accuski system has been in use more than 20 years, any patent would have expired or otherwise be unenforceable by now, so that shouldn't be a reason (unless the Accuski system is relatively new).

east tx skier
07-08-2010, 05:38 PM
I wonder why PP didn't adopt this feature into their system. Expense or lack of demand??? If the Accuski system has been in use more than 20 years, any patent would have expired or otherwise be unenforceable by now, so that shouldn't be a reason (unless the Accuski system is relatively new).

My guess is that that wasn't something PP thought was worth incorporating. Even so, my guess is there are probably a few years left on that patent.

TX.X-30 fan
07-08-2010, 06:13 PM
Seems hard to believe it would make much difference.

ski_king
07-08-2010, 06:16 PM
I wonder if PerfectPass left if out because of a liability issue.

A accelerating high powered ski boat with the driver watching his skier could be considered to risky to take to market.

east tx skier
07-08-2010, 09:35 PM
Seems like an added expense that not a lot of people would want to pay extra for.

Jesus_Freak
07-09-2010, 01:08 PM
Seems like an added expense that not a lot of people would want to pay extra for.

I dont see how much more it would cost to have a few more data tables and ramping programs. Seems like the expensive "stuff" is already there...

Craig
07-09-2010, 01:30 PM
If Perfect Pass is there it should just be some software additions. This should be minimal cost addition to the entire system.

That said, implementing the correctly engineered control algorithm for this type of thing that is going to work for each boat and engine would not be a trivial task. I know a decent amount about controls but I am not a controls engineer so it could be easier than I think.

This type of system would need to be bulletproof with no risk of accelerating out of control and damaging the engine or the occupants/skiers. This factors into the implementation again, it would need to be implemented really well to be effective.

Bottom line, I like the idea, it would need to be well designed.

What I really want is speed and path control. I want a system that will maintain a straight path in the slalom course. Another idea that would need to be well thought out and with a much smaller market to pitch too (basically tournament 3-event skiers).

I love the thought of reducing the learning curve on new drivers. I feel like it takes weeks to get a new driver to a point where they are no longer hurting my skiing.

east tx skier
07-09-2010, 03:30 PM
I dont see how much more it would cost to have a few more data tables and ramping programs. Seems like the expensive "stuff" is already there...

In accuski's case, it involved extra hardware. Seems every bit of hardware external to the system is another 200. I have enough settings to adjust as is.

But honestly, I'm guessing Accuski still has a year or 4 on the patent.

TX.X-30 fan
07-09-2010, 03:55 PM
Funny how skiing/boarding problems seem to always be the drivers or boats fault.......... :D

Jesus_Freak
07-10-2010, 04:42 AM
But honestly, I'm guessing Accuski still has a year or 4 on the patent.

OK, but patents exist to provide disclosure and legal bounds, not complete road blocks.;)

Bruce Carr
07-10-2010, 10:16 AM
With the accuski (or any other speed control I would think) there is no additional parts required to implement the "auto-up" feature except for a single arming button in the head unit. Its all implemented in the software so there would be minimal (if any) additional cost to implement the feature. As far as a safety hazard, it is really no different than any other speed control. After pushing the arm button, you still have to advance the throttle manually to about 1/2 (or further)throttle position and the auto-up controls the acceleration with a user defined rate and intensity. The advantage being that you can just advance the throttle as quickly and as far as you like and the computer is going to advance the throttle at the preset rate and intensity regardless of how quickly or to what position the driver sets the throttle lever. If for any reason the driver wanted to abort the pull up, all one needs to do is pull back on the throttle just like any other speed control.

FrankSchwab
07-10-2010, 03:33 PM
Bruce -
Accuski isn't quite like that - at least, the one I've used.

There are two arming buttons - an "arm" on the head unit, and a "go" on the floor. In operation, the skier yells "Arm it", and the operator puts the boat in gear at idle, and pushes the "Arm" button. A beeper starts beeping. When the rope tightens and the skier is ready, he yells "Hit it", and the driver presses the floor switch. Accuski then accelerates the boat to the set speed.

Stopping is done one of two ways - pressing the floor button again, or pulling the throttle back to neutral. If you want to take over, you advance the throttle until you start to feel acceleration (meaning you're asking for more speed than Accuski), then push the floor button.

/frank

east tx skier
07-10-2010, 10:41 PM
OK, but patents exist to provide disclosure and legal bounds, not complete road blocks.;)

Yeah, sure.

As a lawyer, were I to invent something, start a business with a snazzy name, my philosophy is never to be sued. Yes, you can push the boundaries if you don't mind paying a lawyer. We prefer it, of course.

Jesus_Freak
07-12-2010, 12:38 PM
Yeah, sure.

As a lawyer....

Yes, I remembered and knew you would like a healthy IP discussion. :)

Bruce Carr
07-12-2010, 12:56 PM
Bruce -
Accuski isn't quite like that - at least, the one I've used.

There are two arming buttons - an "arm" on the head unit, and a "go" on the floor. In operation, the skier yells "Arm it", and the operator puts the boat in gear at idle, and pushes the "Arm" button. A beeper starts beeping. When the rope tightens and the skier is ready, he yells "Hit it", and the driver presses the floor switch. Accuski then accelerates the boat to the set speed.

Stopping is done one of two ways - pressing the floor button again, or pulling the throttle back to neutral. If you want to take over, you advance the throttle until you start to feel acceleration (meaning you're asking for more speed than Accuski), then push the floor button.

/frank


Frank,

The early generation of the Accuski had a foot switch. The later models got rid of the foot switch and works as I described. Bruce

shepherd
07-12-2010, 05:18 PM
Yes, I remembered and knew you would like a health IP discussion. :)

Patents are good for 20 years from the date the application is filed (or 17 years after the patent issues if prior to 1995). I assumed the Accuski system was older than that but ICBW. Assuming there actually is a patent owned by Accuski (a quick search didn't uncover one), and assuming that it is still enforceable, PP could always request a license. Whoever owns the patent would probably be very willing to license it since there doesn't appear to be any competing systems on the market -- unless there are plans afoot to market a system in the near future.

Jesus_Freak
07-14-2010, 08:42 AM
Patents are good for 20 years from the date the application is filed (or 17 years after the patent issues if prior to 1995). I assumed the Accuski system was older than that but ICBW. Assuming there actually is a patent owned by Accuski (a quick search didn't uncover one), and assuming that it is still enforceable, PP could always request a license. Whoever owns the patent would probably be very willing to license it since there doesn't appear to be any competing systems on the market -- unless there are plans afoot to market a system in the near future.

First let me say that my previous post was supposed to read healthy IP discussion. :o Oh well.

Second, you raise a great point. Licenses are normally available for the right price. The main reason I brought out IP issues was related to complex nature of choosing verbiage and being awarded claims by the USPTO. Depending on how things are drafted, the entrepreneur may or may not have a viable option for marketing an improvement to existing patented systems. Sometimes patents are weak, allowing plenty of perfectly legitimate wiggle room.

JohnE
07-14-2010, 08:51 AM
I throttle down and if they can't hang on then too bad.