Diff between gen 1 and 2

[SegNerd]

Yes, technically I should've said that the keys on a Gen1 affect your maximum speed and not just your speed.

This thread was supposed to be about differences between the two generations - my point is just that Gen1s have three levels of max speed and you choose between them with the keys, whereas Gen2s have two max speed levels and the key is not involved in choosing between them.

[wwhopper]

Gen one machines (fixed control shaft - twist steer) use i-buttons for keys. Each machine was orginally shipped with a set of keys - each one had a different maximum speed capability. Black slow 5 mpg, yellow medium 8 mph, and red maximum 12.5 mph. These i-button keys could be reprogramed to give you any speed you wanted up to the 12.5 mph and any turning speed you wanted. The color was only an indicator, though you could program a red key to be dead slow. Other key colors are available and programing can only be done by someone who has a laptop and the right program and hardware to do it.

Gen Two machines (control shaft / lean steer frame moves side to side) come with 2 infokeys. These are set with two speeds, a turtle mode and a normal (rabbit mode.) Again the maximum speed is 12.5 mph or anything up to that. The nice thing about the gen two machine is you can take your infokey and program in what ever speed you want for the rabbit or turtle mode by manipulating the infokey buttons from very slow up to a maximum of 12.5 mph. No outside computer, program or hardware required. Many tour companies program their machines at 8 or 10 mph for rabbit mode and dead slow for turtle mode for training.

Though the Gen One machines are great, the Gen Two machines are a much better machine and are more fun to ride. Gen One machines seem to be preffered by the Segway Polo Players, but you can play polo on any Segway you want.

If your budget is $2500 - go the extra $500 and by Dhuggers machine that he just listed for $3K - it will be well cared for and an excellent buy - especially since he is including shipping.

[bentbiker]

Originally Posted by wwhopper

If your budget is $2500 - go the extra $500 and buy Dhuggers machine that he just listed for $3K - it will be well cared for and an excellent buy - especially since he is including shipping.

I PM'd him suggesting the same thing, but I guess he hasn't logged on since yesterday morning. What a missed opportunity.

[Bob.Kerns]

Originally Posted by KSagal

None of the keys mentioned ever change speeds.

Speed is changed on all machines, in all modes, by simply how far you lean... If you lean more, you go faster, if you lean less, (closer to standing straight up) you go slower or stop...

Actually, to be utterly pedantic -- the more you lean, the more you accelerate. The longer you do that, the faster you go.

The keys tell the machine when to make you stop leaning!

[segaddict]

Originally Posted by jryan

The infokey as found on the gen2's cannot change the speed. The only speed changing you so on the gen2 key is by putting it in turtle mode (limiting the speed to, I believe, 6mph or taking it off turtle mode with a speed limit of 12.5). On a gen2 you use the leaning of your body back and forth to change the speed between 0mph and 12.5 mph. The keys on the gen1's just set your maximum speed as well! You cannot adjust your speed on a gen2 using the key. It is all done by your body, however speed adjustment is something most get used to fairly quickly!

Jeremy Ryan

The generation 2 actually has a speed limiter that can be programmer to reach a maximum speed anywhere between 1 mph and 12.5 mph. This is slightly more complex than pressing a button.

Personally, there is no comparison and the gen2 is way superior, but if you want to airline travel gen2 is NOT the way to go.

John

[KSagal]

Originally Posted by Bob.Kerns

Actually, to be utterly pedantic -- the more you lean, the more you accelerate. The longer you do that, the faster you go.

The keys tell the machine when to make you stop leaning!

I am not so sure of this. Acceleration implies an increase in speed. If you lean forward at 2 degrees, you will accelerate from 0 to a fixed speed, and if you maintain that 2 degrees, you will reach a terminal velocity of a speed that is set by the software.

If you lean forward at 4 degrees, you will accelerate from what speed you are traveling at to a new speed. If you maintain 4 degrees, you will maintain that new speed, which will be faster than the speed you maintained at 2 degrees...

While you will accelerate from a starting speed to the new speed as determined by the amount of lean, you will no longer accelerate beyond that speed, and will instead maintain it.

Therefore, you will accelerate and then maintain a certain speed, based on the amount that you lean. I think it is reasonable to shorten this to simply say you will go faster if you lean more. (up to the point that the machine will not allow more speed) If you try to lean farther, it will simply stop you from leaning further.

The machine will still maintain a particular speed for a particular lean angle.

If you maintain the angle of your lean, and it is less than the maximum speed that the machine will allow, it will not accelerate. You can maintain a speed for a long time, and will be affected by battery range, and other issues, but you will not accelerate because you hold the lean longer...

[Bob.Kerns]

Originally Posted by KSagal

I am not so sure of this. Acceleration implies an increase in speed. If you lean forward at 2 degrees, you will accelerate from 0 to a fixed speed, and if you maintain that 2 degrees, you will reach a terminal velocity of a speed that is set by the software.

If you lean forward at 4 degrees, you will accelerate from what speed you are traveling at to a new speed. If you maintain 4 degrees, you will maintain that new speed, which will be faster than the speed you maintained at 2 degrees...

While you will accelerate from a starting speed to the new speed as determined by the amount of lean, you will no longer accelerate beyond that speed, and will instead maintain it.

Therefore, you will accelerate and then maintain a certain speed, based on the amount that you lean. I think it is reasonable to shorten this to simply say you will go faster if you lean more. (up to the point that the machine will not allow more speed) If you try to lean farther, it will simply stop you from leaning further.

The machine will still maintain a particular speed for a particular lean angle.

If you maintain the angle of your lean, and it is less than the maximum speed that the machine will allow, it will not accelerate. You can maintain a speed for a long time, and will be affected by battery range, and other issues, but you will not accelerate because you hold the lean longer...

No, if you don't accelerate, and your center of gravity is not over the wheel, you'll have a net torque, and will rotate in the direction of the lean. So long as you're leaning forward, it has to go faster and faster. That's the only way to balance you.

You can't maintain a lean forward at 12.5 MPH any more than you can at 0 MPH.

(Except for a very small effect from wind resistance, but that's really, really tiny. How much lean do you notice standing on the sidewalk with a 12.5 MPH wind in your face? I can't quickly locate a Reynolds Number value for the human body, clothed (or naked, for that matter) so I won't try to calculate the angle, but I expect it's significantly less than one degree).

(That's the simplified inverted-pendulum explanation. It's actually a bit more complex since there's also torque around the axles, but that's also in the direction of increasing your speed).

It's easier to understand if you draw a force diagram.

The net result is, you'll go faster and faster as long as you lean. When you stop leaning and stand up straight (or it makes you by tipping back), it'll keep you at a constant speed. Depending on how much you leaned for how long, that may be full speed ahead, or zero, or even backward.

I think you can handle drawing the force diagram and working it out, but if you, or onlookers want, I can walk you through the physics.

I can understand how it might FEEL like you're leaning forward. The speed limiter contributes to that, but there's also the whole "naive physics" thing, where our brains process things a bit different than reality. It's a much-studied point -- your expectation is exactly what our brains are programmed to expect. This is a perfect example.

(The term "naive physics" was coined in 1978 by Patrick Hayes in the Naive Physics Manifesto. I can't find an online copy to point you to, unfortunately, but you can find thousands and thousands of citations. It's been studied both from the standpoint of Artificial Intelligence and Psychology. I can't say either field has come to any useful result from all that, but I think you can sum it up as "our brains process things a bit different than reality". In part, I think it's an adaptation to handling events that happen faster than our perceptions, which is more the domain of neuroscience, than psychology).

[Edit: It's also widely exploited in the field of hand animation. Think Roadrunner cartoons...]

[KSagal]

I'm still not getting it...

If you do not shift your weight forward of the center of gravity (the definition of 'lean' in my posts in this thread) than you will not move the segway forward...

If you hold the lean at a consistent angle (I was using 2 and 4 degrees as an example, and if you say they are wrong, I have no problem with that) but it is less than the angle needed for the segway to achieve 12.5 mph, it will accelerate to a set speed, and stop accelerating. It will continue to move forward but will not continue to accelerate.

I understand the word accelerate to mean the increase in speed of an object... More specifically, the rate at which the time an object traveling a fixed distance will take is decreasing. If the time it takes to travel that same fixed distance is increasing, they are decelerating. If they are traveling that fixed distance at a consistent rate of time, then there is no accelerating or decelerating.

My understanding of the way a segway works is not the same a theoretical physics. Since there are actions the segway itself is taking to react to the operator's inputs, force calculations are not enough.

What we are talking about here is the difference between what the segway sees and feels when a person leans, and what an observer sees and feels when seeing a person on a segway, and how that particular segway reacts...

My understanding of what you are saying is that you are only talking about the forces that are being put upon the segway by the person leaning, I am talking about the person leaning, those forces, and the resultant segway's reaction.

I am a nuts and bolts guy. I know that if you do not lean you will not move the segway. I also know that if you lean at a consistent rate, the segway will not continue to accelerate beyond a particular point, and that point will change if you lean more or less.

Of course, I may be all wet. But you have not convinced me of it yet.

[KSagal]

I just thought of a new way to describe my thoughts...

A person is not the same as the hands on a clock. If a person were to watch the hands of a clock, they will see that the second hand takes the same amount of time to 'fall' from 12 o'clock to 1 o'clock as it does from 2 o'clock to 3 o'clock... That second hand has a constant velocity, and no acceleration.

A person, doing a face plant, if viewed from the right angle, will travel a similar path, as their head moves from 12 o'clock to 3 o'clock. The difference is that if a person leans forward, the time it takes to fall from 12 o'clock to 1 o'clock is far longer than the time it takes to fall from 2 o'clock to 3 o'clock. In other words, they are accelerating as they fall. The deeper into the fall they are, the faster they are moving...

If a person had a quick acting speedometer on their nose, they might be moving 4 mph as they pass 1, 14 as they pass 2, and potentially 40 as they approach 3. (I made up these numbers, they are not the real rate of acceleration, but will suffice for my needs)

If you were to have the ability to move the person, feet, hips and everything, in the direction their nose moved from the 12 o'clock to 1 o'clock and were able to do it at 4 mph at the point their nose was falling past 1, then it would arrest their acceleration, and the would maintain a perpetual fall. As long as you exactly matched the forward speed of their body to the rotational speed of their nose, they would not accelerate nor decelerate, but maintain a constant velocity...

What say you to this?

[Bob.Kerns]

Quick response -- I'll try to do better later.

To arrest a person's fall, you have to apply force.

Thanks to F = m * a, the only way to do that is by acceleration. Velocity won't do it. You can analyze the situation identically whether v = 0 or v = 12.5. To visualize the latter situation, think of someone videoing someone from another Segway.

One more way to slice it: The contact patch on the tire can provide two components of force. The force up, if not aligned with your center of mass, produces a torque, leading to face plant city.

But add in the horizontal force, and you can balance everything with a torque around your CG in the other direction. But F = ma! So the whole system (you, Segway, your groceries) accelerates.

In any static situation (static in the sense that the situation is not changing -- there can be constant motion), the sum of all the force vectors, and the sum of all the torques (also a vector quantity), must be zero. Otherwise, you'll have acceleration or rotation. Rotation = face plant.
The only place velocity yields a force is with viscosity, e.g. wind resistance, or similar electromagnetic phenomena, where kinetic energy is being dissipated in a way that increases with velocity. (Simple friction doesn't depend on velocity).

The Segway speed limiter stops the lean by simply accelerating the powerbase a bit more than enough to balance your lean -- bringing it and your feet forward, thus eliminating the lean!

No matter how much you TRY to lean at that point -- it has control, because you don't have anything to push on, but it does. You try to bring your CG forward -- it brings the contact patch forward to match, and a little more so it can bring the speed back down to 12.5 (or whatever speed it thinks you should be limited to).