Skip to main content

Recently I discovered what seems to be a rather shocking delay in the pneumatic gates at our local velodrome: The gates take about 0.05s (after clock is triggered) before the jaws begin to let go of a wheel. Furthermore, the delay ranges randomly for both gates from about 0.04s to 0.06s.

My questions:

Is this kind of delay 'normal' for track gates?

Do countdown clocks normally account for the time it takes a pneumatic valve to 'start'?

If not, what is a typical or acceptable delay for a gate to 'open'?

What is an acceptable range for the delay variance?

Does the UCI have any regulations for manufacturers of track and timing equipment like the FIS ones?

Any info, experiences or pointers would be greatly appreciated.
Original Post

Replies sorted oldest to newest

Interesting discovery. How did you measure the delay? Are you sure your methodology is sound?

What brand is the start gate?

The UCI has weak timing rules - not nearly as explicit as FIS and FEI. Although to their credit, the UCI did ban the AMB Cyclip a few years ago after test data was shown to them proving the Cyclip wasn't accurate to the manufacturer's advertised resolution.

If you can post your methodology, and it is sound & easy to reproduce, I'm sure there are timing guys in this community who will measure the latency in their gates and post the results. I've got access to several different brands, but some gates in the marketplace are rather obscure, such as the Soviet-era, Soviet-built Omega knockoffs used at Krylatskoye 'drome in Moscow.

There aren't too many different brands of these devices. I think it would be a fantastic idea to gather data on every gate we can get our collective hands on. As timing guys, we've all got an implicit obligation to the athletes to ensure the time measurement process is a level playing field. In theory, the governing bodies should see to this, but most of them do not.
Last edited by themightyskunk
I am not sure of anything at all.

The methodology was crude but effective (if only for illustration):

- clamp a normally closed microswitch in the gate jaws.

- trigger gates using countdown sequence, as would be used in competition (abbreviated to a few secs)

- record ToDs for start and from switch in gate on normal competition gear (OGM5005 in this case)

- repeat

The start gate is a no-name brand, custom-made by a local engineering company. The pneumatic valves are SMC, with a rated delay of ~20ms, and there is an interface converter circuit attached to the side of the gate (which I suspect is mostly at fault). They use nitrogen at ~800kPa.

I might be able to test some Omega gates in a few weeks, and will be doing some tests with a higher precision clock to determine the delays between audio signals, start trigger and pulse to starting gates. I'll post them all here once I have some results.

Specifics for the microswitch:

I attached a 20mm microswitch to a piece of aluminium channel cut to the width of a rim (~20mm) such that the actuator prodtruded very slightly over the edge. When clamped, the switch is depressed and "open". By adjusting the position of the switch carefully it was set to close as soon as the gate jaws began to open.

The switch mechanism could probably be improved to reduce the chance that the switch itself is affecting the results - must look into that.

How about a petition to UCI and local cycling federations to pick up their game? I've seen some "records" set recently here which were timed using equipment that has not been serviced in over 10 years and is in error _well_ beyond the FIS guidelines :/

Thanks heaps for the response.
quote:
The start gate is a no-name brand, custom-made by a local engineering company.


Yikes. That sounds like a recipe for disaster. I wonder if the designer and fabricator understood that a typical jitter rate for all the other devices in the timing chain is 1/200,000 of a second, and that devices are homologated using measurement in Parts Per Million?

quote:
an interface converter circuit attached to the side of the gate (which I suspect is mostly at fault)


Good place to start looking.

quote:
I might be able to test some Omega gates in a few weeks, and will be doing some tests with a higher precision clock to determine the delays between audio signals, start trigger and pulse to starting gates. I'll post them all here once I have some results


Would love to see those results.

quote:
The switch mechanism could probably be improved to reduce the chance that the switch itself is affecting the results - must look into that.


I would suggest using a Telemechanique ZB2-BE102 switch. They are box-shaped and 25mm wide, pretty close to the size of a bike rim. They are available in both NO and NC. I would clamp the switch itself into the gate, if it will fit. An added benefit of using a switch like that is you could probably get several of them into the clamp simultaneously and measure the reaction time / variances of the switches themselves, to make sure the switches are consistent, before even starting to measure the consistency of the gate.

They are available through your local Grainger outlet.

quote:
How about a petition to UCI and local cycling federations to pick up their game? I've seen some "records" set recently here which were timed using equipment that has not been serviced in over 10 years and is in error _well_ beyond the FIS guidelines


I'm all for it.

Typically, asking GBs to look at this stuff is like asking to pull their teeth with a Leatherman Tool. For starters, nobody at a typical federation would understand 1/10th of what has been written even in this brief thread. Strike 2: Any kind of testing or homologation costs them money. Strike 3: They wind up with no thanks from the athletes (who also typically do not understand the subject) and with manufacturers screaming at them, because specs and testing inevitably eliminate products from the market. There's certainly plenty of sloppy crap on the market for sports with absolutely no technical timing specs or homologation standards (bobsled, luge, skeleton, speed skating, cycling, swimming, just to name a few).

The FIS and FEI Timing Working Groups, which wrote the specs for their respective sports, were only reluctantly commissioned because they were done on a volunteer basis. Fortunately for the sport of ski racing, the FIS TWG wound up with some serious heavy hitters from several of the major manufacturers, including a guy I consider the heaviest hitter of them all in timing engineering, Ted Savage of Precision Timing in Montreal. The FEI TWG, on the other hand, was composed mostly of people who knew absolutely nothing about the mathematics and engineering of timing in time-of-day. But Ted was on that committee too, so due to his presence, at least they started in the right place. Unfortunately, the FEI standards wound up compromised a bit through the ensuing political process. But compromised standards are better than no standards at all, and at least equestrian sports now have SOME guidelines. Up until two years ago, you could time the Showjumping World Championships or Olympics SJ with a kukoo clock and not violate any FEI rules.

This conversation comes at a good time, as I have heard rumours that the UCI has been petitioned by several of the chip-timing manufacturers to allow transponder timing in certain situations. Since the UCI and AMB were burned with the Cyclip fiasco, one would think that even the sometimes-inexplicable UCI would be open to taking a serious look at setting up some homologation standards for timing equipment used at UCI events.

Add Reply

Post
×
×
×
×
Link copied to your clipboard.
×