Segway running off

[yosgof]

It’s a known fact that if one gets of an HT while in balancing mode, the machine might take off and travel some distance before it switches off. This feature is clearly stated in both the user manual and the safety video where some potential damage which can be cause by this behavior is vividly shown..

I was just wondering for the reasons for this design.

Clearly the HT has weight sensors and clearly it can identify the fact that there is no rider on. It does the opposite when prohibiting a transition from “balancing” to “power assist” with the rider on. So why let it run rather than make it switch off on the spot?

Mr. Field (may I call you Doug?), if you are reading this your input would be greatly appreciated.


- Yossi
http://gallery.photo.net/photo/3365119-lg.jpg

[voiceguy]

I am guessing that in the event someone would be so bold as to somehow get on the seg without contacting the foot sensors (maybe by stepping on the fenders or some other way) the Seg gives them a chance to wise up and get off (or ON, correctly) before shutting down.

Can anyone out there with technical knowledge on this phenomonon confirm (or expand on) my guess?

Voiceguy

"All I need is a full battery ... and a star to steer her by"

[SegwayUtah]

If you drop off a curb, or hit a bump, there's a good chance that your feet will let off the sensors for a few moments. The HT would rather "run away" for a few seconds than let you faceplant during a seemingly peaceful accidental drop off a curb.

Chris

[yosgof]

Chris, are you saying that in such cases if I press the mode button I could accidentally go into power assist?

- Yossi
http://gallery.photo.net/photo/3365119-lg.jpg

[Tom]

I have a "p" model HT which doesn't have a kick stand, and frequently have occasion to step off briefly and need the Segway to remain in balance mode. This occurs while biding time in a physicians or other waiting room, when opening the occasional door that needs two hands, and a myriad of other times. I merely lean it against a wall, chair, door frame etc., then step back aboard and proceed. If it were to shut down at these times there would be a need to fish the key out of the pouch or a pocket and power it up again. Good luck in Israel.

Tom

[PD1]

I can think of a few reasons. If a person were to dismount, then immediately get back on or switching riders, it would be a problem if the Seg had gone to Power Assist mode. (It is true that if you step on in Power Assist with the platform nearly level, it will switch to Balance mode, but that's a whole other issue.) Another benefit is the ability to reposition a machine riderless but in balance. That's good for up to three feet of distance before the stick shake gives a warning. Finally, a little moving forwards and backwards riderless but in balance is a good way to verify Balance Mode if you can't see the green display in the sunlight. Any other ideas out there?

PD1

The Seg I ride is named after my Aunt Eileen.

[yosgof]

Tom and PD1, you are missing my point.

These are all controlled situations. Zero or slow speed. Very small distances. The safety movie shows an HT running on its own for a distance of what looks like 20 feet. I was talking about shortening this distance.

- Yossi
http://gallery.photo.net/photo/3365119-lg.jpg

[PD1]

My experience is that when you release a Seg standing still, it will natually tilt forward and start to run, stick shake in three feet and safety shutdown soon after. On the ground in about ten feet. The greater the velocity at time of release, the greater the overall distance it will go before touchdown. I think you'd like it to realize this and actively stop itself quicker. That I can't answer. PD1

The Seg I ride is named after my Aunt Eileen.

[Socrates]

Hi Yossi,

well, the HT knows when the rider's weight lifts off of the platform, but the HT will never know if the rider will land again on the platform or took of for a faceplant. For the ocasion that the rider lands on the platform of the HT again, it keeps balance mode for some moments and does not shut off immediately.

I experienced a lot of times that smooth curbs or similar obstacles can easily lift Your weight from the platform. Thank's to LLC our HTs keep balancing themselves and us.

Alexander

[JaredHT]

Just to add my 2 cents,

I can't imagine the Segway traveling for more than 12 or 15 feet TOPS, even if dismounted at full speed (we were practicing ditching techniques with the police). The only instance where it would travel some distance without a rider is if you were to set something onto the platform (bag, briefcase, etc.) while you were off the machine.

As far as losing contact with the sensors, remember that there are two degrees of balance mode, one if there is definitely a rider (or some weight) on the machine, and another if there is no rider.

Peace,

JaredHT
Jared M. Cavalier
[/:)][/:)][/:)][/:)][/:)]
Segway of Ohio
330.535.2200
888.6SEGWAY(673.4929)
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[cmonkey]

One of the uses for riderless balance mode is so you can lean it up against a wall when you need to get off momentarily and you don't want to use the kickstand. (This is shown in one of Segway's old videos where an EMT dismounts and puts the seg into a wall) If you put it power assist and lean it against a wall, the seg may roll back, letting your bag (and contents) drop to the ground.

one example: I use this feature all the time when I roll up to an ATM. I roll up, step off, and let the seg roll into the wall and it stays there in balance mode.

I haven't done any timing experiments, since I don't really feel like smacking my handlebars into the ground, but I will assume the following.
1. The time to shutdown on a runaway seg is probably fixed.
2. The distance is goes can be attributed to how much weight in on your handlebars. i.e. no bag = short distance.
bag with 3 liters water, a pump, powercable, camera, PDA, phones, sandwich, lights, batteries, locks, etc = long distance.

For me the timeout is just fine, but sometimes, I wish it were longer. Sometimes I find myself using the balance feature while walking it around obstacles one handed. Otherwise I have to use both hands to steer when it's in power assist mode. Or when doing a riderless demo, and standing to one side.

hope this helps.

Dave

I love my magic carpet!

[Doug Field]

Hi all,

At zero or low speeds, when the rider is not on board, the HT will travel three feet, warn with a stick shake, then move another three feet before automatically transitioning to follow mode.

"No rider balance" uses lower gains (less torque for a given lean angle) which makes the machine more gentle, and is a great feature for moving the HT up a curb or obstacle.

But at higher speeds--say 12.5 mph (over 18 feet/s), this six feet of travel would only translate to a third of a second. Imagine if the HT stopped balancing if you shifted your feet for a third of a second! So, at higher speeds, a carefully crafted algorithm spends a short amount of time trying to slow the HT while also trying to figure out if a rider is still aboard, before disabling balance mode.

Our software and controls engineers are incredible in their ability to consider human behavior, machine capabilities, and unlikely circumstances in the crafting of these algorithms. They do an amazing job in keep you all safe, in 100 decisions per second that most people will never know are being made...

Doug

"There is nothing more difficult to take in hand, or more perilous to conduct, or more uncertain in its outcome, than to take the lead in the introduction of a new order of things." -Niccolo Machiavelli

[KSagal]

I was told there was a 6 foot electronic leash. (about 3 feet then stick shake for 3 feet, then powerdown, but no brakes, so it can coast a bit)

I thought this was so if you fell off, it would not fall on top of you... Basicly it went to a neutral corner to fall down.

The time delay is correct, to compensate for hang time when the rider may be airborne from a jump of one sort or another.

There is also a weight off, one foot on platform, one foot on ground technique for curbs, that would have problems if there was not a few feet to work with while in balance and off the machine...

I am of course reciting from memory of my training a few years ago and refresher information in the interum, I have an 'E' and if I get off, it just hovers nearby and waits for me... Ha Ha. (Don't you wish you had one now?...)

Actually, I loose all of these "weight off" balance features, because my machine goes into e-stand right away when I get off the rider detects... (There is still a time delay if the machine is moving)

In all, I don't think there is one simple answer to your questions. I think there were many factors that went into that piece of the software. Many of the factors were listed here, and there are likely many more.

Have fun finding all the personalities of your machine...


Karl Ian Sagal

Each road you travel should be just a bit better for having had you pass.