Frowny faced Segway pitched me off my ride today

[KSagal]

Yes, it is easy to forget, but it is not uncommon at all to fall or have issues with a new segway. (Or any other device or conveyance)

We all have done it a time or two or more, as was my case. Easy to blame the machine, but more appropriately, in the beginning, we have expectations from the machine, and when it does not do what we expect, we call it a machine malfunction...

Then, when we know better what to expect from the machine in a given circumstance, we find that we do not have the problems or the falls.

Perhaps it might be better to say I did what I thought I should do, and fell off. Later on, I learn that what I thought I should do was not what I actually should do, and then I really did do what I Should do, and I no longer fell off...

[KSagal]

Originally Posted by dale@thecoys.net

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.

I understand, and it is worth saying, that a fully charged battery will cause the machine to go into a reduced performance mode more quickly than a lower charged battery, but it will not do exactly what the OP described. (At least I have never seen a fully charged battery cause the things described)

Most of us have had problems the first few times we tried to glide down a large hill, as Bob mentioned, because the segway balances on a different point, and 'feels' very different than on level ground.

I believe I was leaning so far back it felt weird. It was fine, but perceptions were way off the first few times I did it.

The solution is to simply glide down the hill slowly, and stand where you should, and lean as you need to. Do not fight the machine, and it will serve you well.

I think of it more like a horse than a machine. You kind of need to 'negotiate' a common plan of action. (After a while you realize that the segway is closer to an extension part of your body, than a separate machine. And just like we learn to sit up, then roll over, then crawl, then walk, then run, we also have to learn how to use the segway.

The smartest thing I feel the OP said was that he was going to go slower till he felt more comfortable going at speed. That is his exactly right solution.

[dale@thecoys.net]

Originally Posted by airdale

slightly off topic... When is it charging? When the /!\ is on with the frown?

It's charging (essentially) any time you are going downhill.

AFAIK there is no particular indication if the batteries aren't already fully charged.

But if your batteries are fully charged, then the Segway will slow down a lot (going downhill). I'm not a student of what "indications" there are, nor of possible differences between models and software versions.

Note that we don't know what model the OP has.

I agree that the Segway would not "pitch you off" for this reason - but if someone didn't understand what was going on, and tried to "compensate" by leaning forward or back or whatever, the frequently-seen "forward/back oscillation mode" could make it seem like ejection.

[terryp]

It's also worth mentioning that pressure differences between the tires can cause weird things to happen - one of which is the machine leaning forward further than feels comfortable. There's an explanation of this on INC's website. I've only experienced it on level ground, but I can imagine it could be really scary on a downhill.

[dale@thecoys.net]

It would be really nice/helpful if eniveld (who posted the question) would provide more details and/or feedback.

[Bob.Kerns]

Originally Posted by airdale

slightly off topic... When is it charging? When the /!\ is on with the frown?

To add a bit to what Dale said ...

Any time the controllers need to slow down the wheels, it has to take in energy (basically, make the motors act as generators). When it can, it sticks this energy into the batteries.

So in theory, it's charging the batteries any time you slow down.

[KSagal]

Originally Posted by Bob.Kerns

To add a bit to what Dale said ...

Any time the controllers need to slow down the wheels, it has to take in energy (basically, make the motors act as generators). When it can, it sticks this energy into the batteries.

So in theory, it's charging the batteries any time you slow down.

I was good till the end. If the machine slows down because it forced the rider to slow down, like at max speed or when gliding down hill, and speed limiting itself.

I can only imagine that speed limit push back, and speed limited slowdowns consume power.

So, while I agree that the motors will act as generators when the machine slows down, or more specifically, will act as generators when the machine is rolling but not requiring energy supplied by the batteries and motors to move forward, (because the energy is supplied by momentum or gravity), I am not sure if they will create more power than they consume any time you slow down, or just many times.

I suspect that they act like generators many times, but not at all times you slow down...

[dale@thecoys.net]

Originally Posted by Bob.Kerns

When it can, it sticks this energy into the batteries.

I suspect this is absolutely the case.

I'm also sure that there are times when the requirement is "slow down really quickly", so the servo motors are powered "in reverse", using energy rather than recovering and storing it.

And I'm sure there are times when the controller can recover a small amount of energy in the simple process of slightly slowing down. It's really difficult for the controller to tell the difference between "slow down a bit" and "don't speed up going down this hill".

Of course, none of that relates to the OP's question. The only potential relationship is the additional controller requirement to try to avoid overcharging the batteries, if they are already fully charged.

[Bob.Kerns]

Originally Posted by dale@thecoys.net

I suspect this is absolutely the case.

I'm also sure that there are times when the requirement is "slow down really quickly", so the servo motors are powered "in reverse", using energy rather than recovering and storing it.

And I'm sure there are times when the controller can recover a small amount of energy in the simple process of slightly slowing down. It's really difficult for the controller to tell the difference between "slow down a bit" and "don't speed up going down this hill".

Of course, none of that relates to the OP's question. The only potential relationship is the additional controller requirement to try to avoid overcharging the batteries, if they are already fully charged.

Originally Posted by KSagal

I was good till the end. If the machine slows down because it forced the rider to slow down, like at max speed or when gliding down hill, and speed limiting itself.

I can only imagine that speed limit push back, and speed limited slowdowns consume power.

So, while I agree that the motors will act as generators when the machine slows down, or more specifically, will act as generators when the machine is rolling but not requiring energy supplied by the batteries and motors to move forward, (because the energy is supplied by momentum or gravity), I am not sure if they will create more power than they consume any time you slow down, or just many times.

I suspect that they act like generators many times, but not at all times you slow down...

Nope, as counter-intuitive as it sounds, you can't slow something down by putting energy into it. That's basic physics.

From an electrical point of view, there's no magic switch that makes a motor behave differently. If you apply current to create a torque, and it's turning in the direction that's opposing the torque, that motion is going to create a voltage corresponding to that motion.

In a motor, current is proportional to torque, voltage is proportional to voltage. You can play games with how you connect the windings, etc. and change the constant of proportionality, but you can't change that fundamental fact.

If you're slowing it down, you're taking out energy, and that energy has to go somewhere. If not the battery, then it has to be dissipated as heat, in some resistive load.

But the motors, when braking, are always acting as a generator.

Here's an example (of many) of using resistive loads to achieve braking:

http://www.postglover.com/cranecontrol.html

Really, the only alternative besides storing the energy or using a resistor of some type, is to use a friction brake -- the mechanical equivalent of a resistor.

[dale@thecoys.net]

Absolutely correct, Bob. I was apparently suffering from a bad case of recto cranial inversion. I should have stuck with basics.

Originally Posted by dale@thecoys.net

... The only potential relationship is the additional controller requirement to try to avoid overcharging the batteries, if they are already fully charged.