Frowny faced Segway pitched me off my ride today

[eniveld]

Well I guess I should have slowed down when serious (not frowny) face showed up. I was descending a fairly big hill - about 700 feet high - at about 4-5mph and I was going at what I thought was my downhill limit, when Segway seemed to get confused.

It seemed Segway could not figure out how to level itself. It kept slowing me down until I was going backwards, uphill. I stepped off, reset things, and got back on again. This time Segway seemed to purposefully pitch me forward right over the thing and I went tumbling down hill. Thankful for my helmet, wishing I was wearing gloves. I was not on a particularly steep hill, I was going only 2-3 mph, and it just couldn't figure out which way was up.

Has anyone run into a situation where you just could not go downhill? Or the unit just pitched you forward? Or got confused about which way was level? It's kind of made me a bit less confident of going faster until I figure this out.

-- From a first time poster an Segway newbie.

[Bob.Kerns]

Originally Posted by eniveld

Well I guess I should have slowed down when serious (not frowny) face showed up. I was descending a fairly big hill - about 700 feet high - at about 4-5mph and I was going at what I thought was my downhill limit, when Segway seemed to get confused.

It seemed Segway could not figure out how to level itself. It kept slowing me down until I was going backwards, uphill. I stepped off, reset things, and got back on again. This time Segway seemed to purposefully pitch me forward right over the thing and I went tumbling down hill. Thankful for my helmet, wishing I was wearing gloves. I was not on a particularly steep hill, I was going only 2-3 mph, and it just couldn't figure out which way was up.

Has anyone run into a situation where you just could not go downhill? Or the unit just pitched you forward? Or got confused about which way was level? It's kind of made me a bit less confident of going faster until I figure this out.

-- From a first time poster an Segway newbie.

I don't know exactly what happened to you, so I don't know if this is helpful, or not.

But one thing that happens when going downhill with newer riders is that THEY get confused, but not quite how you might expect.

When you're going down a steep hill, the portion of the tire that contacts the road is further back. That means your weight has to be further back.

Now, usually what happens in that case is people feel like they can't slow it down. But maybe you were at the point in your learning process where you have started to incorporate this, but over-compensated, and brought your weight too far back. This may have been combined with pushing it beyond its limits -- did you get a stick shake before it happened? (I hope you know about stick shake and what it means?)

I'm guessing that it's likely you haven't been consciously aware of this shift. Perhaps consciously observing this might help you sort it out, and shouldn't confuse you too much if you have a completely different problem.

Was this a gen 2 model, or an earlier model?

[Tritium]

I've actually had this happen, I believe it was on a gen 1, I was going down a hill and it didn't know the pitch, so sometimes it'd lean too far forward or too far back.
The only way I could fix it would be to get to level ground and restart it then let it idle against a kerb for a minute.

This may not be the same thing as yours, and I still don't know what causes it, but, I believe I know what you're describing.

[Bob.Kerns]

Originally Posted by Tritium

I've actually had this happen, I believe it was on a gen 1, I was going down a hill and it didn't know the pitch, so sometimes it'd lean too far forward or too far back.
The only way I could fix it would be to get to level ground and restart it then let it idle against a kerb for a minute.

This may not be the same thing as yours, and I still don't know what causes it, but, I believe I know what you're describing.

There's another failure mode that might have happened to you. I've only had it happen on level ground, so I didn't think about it earlier....

If you travel over a rough surface, (badly deteriorated asphalt is where I experience this), at the right speed so the resulting vibration is at the right frequency, you confuse the sensors. On my Gen2, what it does in this case is to *drastically* cut speed, to almost a crawl. It recovers after proceeding at a snail's pace for a while. This happens to me regularly on a particular street on my way to work. It's in a low-rent area, populated with a tow company and a redaimix concrete company.

[MTOBATTERY]

Originally Posted by Bob.Kerns

There's another failure mode that might have happened to you. I've only had it happen on level ground, so I didn't think about it earlier....

If you travel over a rough surface, (badly deteriorated asphalt is where I experience this), at the right speed so the resulting vibration is at the right frequency, you confuse the sensors. On my Gen2, what it does in this case is to *drastically* cut speed, to almost a crawl. It recovers after proceeding at a snail's pace for a while. This happens to me regularly on a particular street on my way to work. It's in a low-rent area, populated with a tow company and a redaimix concrete company.

Bob, I have had this same thing occur on cobbletone sidewalks before. If I went a little slower or a little faster it kept it from happening. I thought I had a machine issue while on vacation because of it. Thankfully it was just the sidewalks that caused it.

[[email protected]]

See my posting (several years ago) about "washboard roads".

I'm also surprised that nobody has mentioned the "prevent overcharging" feature that's operative because Segway charges its batteries while going downhill. Not sure whether that might be applicable here - because the OP didn't say whether the Segway was fully charged at/near the top of the hill.

[KSagal]

Originally Posted by MTOBATTERY

Bob, I have had this same thing occur on cobbletone sidewalks before. If I went a little slower or a little faster it kept it from happening. I thought I had a machine issue while on vacation because of it. Thankfully it was just the sidewalks that caused it.

There was a lot of talk about this when the i2 first came out. There is a shake factor to the balance array software, if I remember correctly...

I recall in the fall of '06 where a cobblestone path was used, and the i2 had a tendency to go into reduced performance much quicker than the gen 1 of the day.

After we were able to produce this reduced performance factor, we found we could do it with rapid movement across some grass fields as well, if there were perceivable 'tufts' of grass that the wheels went over.

Gen 1 will do it, but gen 2 will do it faster.

I never saw anymore than reduced performance however. The machine slows down, and give a flat mouth face, but nothing more.

I suppose if you were not expecting it, and tried hard to ride harder, you might experience something closer to the OP, but I have not tried that hard to over power my machine.

It is kind of like the slow down when going down hills. The i2 is much more aggressive at slowing down on the down slope than the gen 1 was, especially for people who recall earlier software levels. I have seen people over compensate on steep down slopes, because it is kind of counter intuitive, and the problem is the driver, but blamed on the machine...

[dangerlampost]

Sorry I didn't reply sooner but I could not get this forum software to let me sign in again despite multiple password resets, so this is the same person who posted the original message but on a different account... Thank you everyone for your responses.

I did figure out what this problem is - with help from my local (Oakland, CA) Segway dealer, who relayed advice to me from none other than Steve Wozniak of Apple fame, who apparently glides down a big hill in Los Gatos regularly and has a similar issue.

Apparently, if you go down a big (as in 700 feet high) hill with a full battery charge, the regenerative breaking will eventually cause the battery to overheat. So Mr. Segway tries to slow you down, more and more, and basically tries to stop you from going down hill. Not realizing why this was happening, I kept urging Mr. Segway forward, and Mr. Segway said backwards only. So I turned around, started going up hill for about 10 feet, then turned around and started going down hill. That's when Mr. Segway actively pitched me forward downhill with a frowny face.

The work around: Drain your battery a bit before going down hill. Or, periodically stop going down hill, and turn around and go up hill to burn off some charge. Since I started doing this, I've had no problems.

I can reproduce the original problem by going down the big hill with a full charge.

I think this is somewhat of a design flaw, in my humble opinion.

I want to point out that I believe I have excellent Segway balance skills, routinely go up and down very steep hills, over modest bumps, turn around on steep grades, and so on and have never had a balance problem. So I don't think it's my inability to balance the Segway.

[jgbackes]

I have this same problem my house is on the top of a very high hill. Like you I have found the only way to safely get down the hill is to go even higher first. I don't think it's a design flaw, the energy has to go somewhere and since the batteries are full I prefer the stick-shake and shut down to the unit catching on fire

Have fun gliding!

jeff

[KSagal]

I find this interesting. Apparently segway owners who live in a small valley have an advantage to those who live on hill tops.

From full charge to glide out of the valley, there is no problem, and coming home, you are charging more, and consuming less, so you always get home.

From a full charge to glide off your hill, you have to waste some energy before gliding down off the hill, but you consume greater amounts of power to get home, and potentially need the power you wasted.

Top this all off with the fact that Dean Kamen lives on top of a hill! How weird is that? I believe he lives on the tallest point between Manchester NH and Boston, and has line of site to each.

I wonder if he has a secret trip for gliding off his hill from home...

By the way, I keep my segway in the cellar, but I access it thru my garage, which is under my house. So, within 50 feet of unplugging my ride, I have to glide up my driveway, and I live on a cul de sak, but the road it is on has a small hill, UP to get to the main road. So, I guess I do live in a small valley. Yeah me!