Speed Limter/Firmware i2

[segwayin]

I just got 2 segways...so much fun. Is there a way to remove the annoying speed limiter? or at least raise it to 18mph.. I hope that no slow pokes get offended by my post ;) I am sure the code will be cracked sooner or later.

[BillK]

Segwayin -
Welcome - you have found the best resource for Segway enthusiasts available (in my opinion).

Regarding the speed limiter - when you realize how the Seg works (that it balances you, and that to go forward you lean forward and it "tries to get back under you" so it moves forward) you realize that if you continue to lean it will have to go faster and faster until the speed of light.

Obviously there has to be some way to stop you from continuing to lean because the speed of light is not reasonable.

After studies and realizing the damage that could be done to the human body un protected at certain speeds and looking at limitations (how quickly can you stop etc) it was determined by Segway, Inc that about 12 mph was the upper limit of what the motors could handle and the Seg's upper limit of woring normal.

They came up with a rather cool way of making you quit leaning forward. They make the Seg TILT back against you. This is so that you CANNOT continue to lean forward as you are reaching the Segs ability to continue to go faster (gear ratios, battery consuption etc.)

I am pretty sure that this is not just a "someone will crack it" thing. I am pretty sure that this is a safety issue and that you will find that the Seg really cannot continue to accomodate the "lean" at faster speeds. But - I am sure that you will get more responses that are technically more explanatory.

Again - welcome to the forum - happy gliding.
Bill

[quade]

I just got 2 segways...so much fun. Is there a way to remove the annoying speed limiter? or at least raise it to 18mph.. I hope that no slow pokes get offended by my post ;) I am sure the code will be cracked sooner or later.

No code need be cracked. There is nothing magical about 12.5 mph. It is, in fact, simply the Imperial Units equivalent of 20 kph.

The Segway doesn't actually "know" how fast it's moving. What it does know is how fast the motors are turning and how large the wheel diameter is supposed to be. Change the wheel diameter and you can change the speed of the device. If you do that it will also affect a number of other things like range and the balance of the device might become a lot more tricky.

[jgrohol]

Don't hold your breath waiting for the "code to be cracked." It's now going on 7 years, and without the right (expensive) equipment, a ton of specialized engineering expertise, and a few spare 80-hour weeks, you'll be waiting a long time.

It's not worth it and so, no, it hasn't been done. If you want to go faster, put larger tires on the thing and "enjoy" the experience.

J

[SegwayDan]

The annoying speed limiter is there more for your safety more than anything else. Face plants are not so much fun. If you pay attention to the speed limiter and think of it as a friendly reminder, you won't have as many face plants.

The machine lives and dies by its ability to stay underneath you. Its power is formidable, but not unlimited. The speed limiter kicks in when that limit is approached and should be interpreted as a warning, not an annoyance.

Fiddling with the code and/or wheel diameter are pipe dreams. Satisfy your speed fetish on some other conveyance and learn to enjoy Segway gliding on stock machines.

[segsurfer]

The annoying speed limiter is there more for your safety more than anything else. Face plants are not so much fun. If you pay attention to the speed limiter and think of it as a friendly reminder, you won't have as many face plants.

The machine lives and dies by its ability to stay underneath you. Its power is formidable, but not unlimited. The speed limiter kicks in when that limit is approached and should be interpreted as a warning, not an annoyance.

Well put, I second BillK's view of segway chat.

[SEGsby]

If I knew I had to fall, I would rather it be at 12.5, then 18 mph...

SEGsby

[Desert_Seg]

If I knew I had to fall, I would rather it be at 12.5, then 18 mph...

SEGsby

As someone who has taken the chest first dive three times, I can fully agree with SEGsby, even if I would like more speed every now and then!

Steven

[sami]

I am sure the code will be cracked sooner or later.
Well.. I just did it for you (see below) - and welcome to the forum

Imagine the great Greek hero Achilles starting a race with a turtle. Achilles is a fast runner, running metres per second, while the turtle is slow and runs at one metre per second. Therefore Achilles agrees to give the turtle some advantage and the turtle starts 10 metres in front of Achilles. The ancient Greek philosopher Zeno found the following “paradox”.

If Achilles wants to get in front of the turtle he first has to run to where the turtle started. But in that time the turtle has bridged some distance, which Achilles now has to run in order to take up. But in this time again the turtle has gone for some distance and Achilles is still in behind of the turtle. This process continues forever and apparently Achilles cannot pass the turtle.

To solve this paradox we have to take a look at the times needed to run these distances. It takes Achilles one second to get to where the turtle started. In this time the turtle runs one metre. It takes only the tenth of a second for Achilles to get there as well. The turtle now runs 10 centimetres, which Achilles passes in one hundredth of a second and so on. So Achilles reaches the turtle after 1S+0.1s+0.01s+...=1.1111...s


The paradox can be solved, if we take into consideration the fact that an infinite series (a sum of infinitely many numbers) may well converge.
To see that the paradox actually never arises, we consider a race, where the turtle gets an advantage of and runs at a speed . Achilles runs at a speed with . Then the time needed for Achilles to reach the turtle is given as:

T=d/v E/j=1 1/Xj

which converges if and only if , so in any possible race Achilles can catch up with the turtle, as was expected.

Hope this helps...

[Desert_Seg]

...Yada Yada Yada (math)...

Yada Yada Yada (more math)...

Yada Yada Yada (even more math)...

T=d/v E/j=1 1/Xj...

Hmmm, anybody want to guess what Sami's profession was? (or is). :D

Steven

[sami]

Hmmm, anybody want to guess what Sami's profession was? (or is). :D

Steven

You are so wrong my friend. I have never had anything to do with turtles, um..eh.. except that my grandpa used to call me a "turtle egg"...

[bentbiker]

. . . runs at a speed [?]. Achilles runs at a speed with [?]. Then the time needed for Achilles to reach the turtle is given as:

T=d/v E/j=1 1/Xj

which converges if and only if [?], so in any possible race Achilles can catch up with the turtle, as was expected. [/COLOR]

Hope this helps...
Sami, did some of your typed characters disappear from your post?

[sami]

Sami, did some of your typed characters disappear from your post?

Apparently they did, but (admittedly) even if they did not, this wouldn't have made the equations clearer to me...

[bentbiker]

Apparently they did, but (admittedly) even if they did not, this wouldn't have made the equations clearer to me...

Now, you are starting to sound like Crash.

[quade]

Hmmm, anybody want to guess what Sami's profession was? (or is). :D

Steven

Copy/paster?

[bentbiker]

Copy/paster?
You are right -- a Copy/Paster/Poser. And here I was trying to make sense out of a post.

http://planetmath.org/encyclopedia/ZenosParadox.html

[quade]

or at least raise it to 18mph.

Ok, so what would it take to do that anyway?

For the sake of argument, let's say the tires on the Segway have a diameter of 17 inches.

C = d * pi

pi * 17 = 53.4 inches

18 / 12.5 = 1.44

53.4 * 1.44 = 76.896

76.896 / pi = 24.476 inch diameter tires

Ya know, that might not actually be all that unreasonable.

[JohnM]

Ok, so what would it take to do that anyway?

For the sake of argument, let's say the tires on the Segway have a diameter of 17 inches.

C = d * pi

pi * 17 = 53.4 inches

18 / 12.5 = 1.44

53.4 * 1.44 = 76.896

76.896 / pi = 24.476 inch diameter tires

Ya know, that might not actually be all that unreasonable.

http://www.waldenwoods.org/eswing/lock%20bm2003/christo.jpg

36 inch wheels - 20.54 mph
Aug 30 2003 Black Rock City, Nevada
http://www.waldenwoods.org/eswing/trials_save1.htm

[segsurfer]

Well.. I just did it for you (see below) - and welcome to the forum

Imagine the great Greek hero Achilles starting a race with a turtle. Achilles is a fast runner, running metres per second, while the turtle is slow and runs at one metre per second. Therefore Achilles agrees to give the turtle some advantage and the turtle starts 10 metres in front of Achilles. The ancient Greek philosopher Zeno found the following “paradox”.

If Achilles wants to get in front of the turtle he first has to run to where the turtle started. But in that time the turtle has bridged some distance, which Achilles now has to run in order to take up. But in this time again the turtle has gone for some distance and Achilles is still in behind of the turtle. This process continues forever and apparently Achilles cannot pass the turtle.

To solve this paradox we have to take a look at the times needed to run these distances. It takes Achilles one second to get to where the turtle started. In this time the turtle runs one metre. It takes only the tenth of a second for Achilles to get there as well. The turtle now runs 10 centimetres, which Achilles passes in one hundredth of a second and so on. So Achilles reaches the turtle after 1S+0.1s+0.01s+...=1.1111...s


The paradox can be solved, if we take into consideration the fact that an infinite series (a sum of infinitely many numbers) may well converge.
To see that the paradox actually never arises, we consider a race, where the turtle gets an advantage of and runs at a speed . Achilles runs at a speed with . Then the time needed for Achilles to reach the turtle is given as:

T=d/v E/j=1 1/Xj

which converges if and only if , so in any possible race Achilles can catch up with the turtle, as was expected.

Hope this helps...

*scratching head*:confused:
-segsurfer

[JohnM]

Ha, ha, ha, ha, ha, ha, ha, ha,
A paradox, a paradox,
A most ingenious paradox.
Ha, ha, ha, ha, ha, ha, ha, ha,
A paradox.
Ha, ha, ha, ha, ha, ha, ha, ha,
A curious paradox,
Ha, ha, ha, ha, ha, ha, ha, ha, ha,
A most ingenious paradox.

[segsurfer]

*scratching head*:confused:
-segsurfer

to borrow a phrase, "once more with feeling":)

[quade]

Ha, ha, ha, ha, ha, ha, ha, ha,
A paradox, a paradox,
A most ingenious paradox.
Ha, ha, ha, ha, ha, ha, ha, ha,
A paradox.
Ha, ha, ha, ha, ha, ha, ha, ha,
A curious paradox,
Ha, ha, ha, ha, ha, ha, ha, ha, ha,
A most ingenious paradox.

You're only allowed to sing that song once every four years.

[segsurfer]

.......? *scratches head yet again*:confused:
-segsurfer

[JohnM]

.......? *scratches head yet again*:confused:
-segsurfer

Please excuse Quade and myself. We're noblemen gone astray.http://forums.govteen.com/images/smilies/pirate.gif

[BillK]

Well.. I just did it for you (see below) - and welcome to the forum

Imagine the great Greek hero Achilles starting a race with a turtle. Achilles is a fast runner, running metres per second, while the turtle is slow and runs at one metre per second. Therefore Achilles agrees to give the turtle some advantage and the turtle starts 10 metres in front of Achilles. The ancient Greek philosopher Zeno found the following “paradox”.

If Achilles wants to get in front of the turtle he first has to run to where the turtle started. But in that time the turtle has bridged some distance, which Achilles now has to run in order to take up. But in this time again the turtle has gone for some distance and Achilles is still in behind of the turtle. This process continues forever and apparently Achilles cannot pass the turtle.

To solve this paradox we have to take a look at the times needed to run these distances. It takes Achilles one second to get to where the turtle started. In this time the turtle runs one metre. It takes only the tenth of a second for Achilles to get there as well. The turtle now runs 10 centimetres, which Achilles passes in one hundredth of a second and so on. So Achilles reaches the turtle after 1S+0.1s+0.01s+...=1.1111...s


The paradox can be solved, if we take into consideration the fact that an infinite series (a sum of infinitely many numbers) may well converge.
To see that the paradox actually never arises, we consider a race, where the turtle gets an advantage of and runs at a speed . Achilles runs at a speed with . Then the time needed for Achilles to reach the turtle is given as:

T=d/v E/j=1 1/Xj

which converges if and only if , so in any possible race Achilles can catch up with the turtle, as was expected.

Hope this helps...

Nicely done - I have heard this a little differently -
We know that any distance can be cut in half - right? No matter how large or small ANY distance can be halved.

Therefore if you jump off a building or out of a plane - no matter how close you get to the ground the distance can ALWAYS be halved - so you will never hit.
;)
Bill

[quade]

.......? *scratches head yet again*:confused:
-segsurfer

It is one of the most famous songs about paradox. It's from a Gilbert and Sullivan light opera who's entire plot revolves around one in particular that only happens to people born on a particular day that occurs once every four years; leap day.

But it really doesn't matter. :D

[JohnM]

I love a good paradox.

http://www.youtube.com/watch?v=q7l4JvNpm7g

But was never a fan of this pair o' docs.

http://i.imdb.com/Photos/Mptv/1319/th-9448_0003.jpg http://i.imdb.com/Photos/Mptv/1066/th-9447-0001.jpg

[segsurfer]

It's amazing how a question about firmware can spiral out of control into a discussion of paradoxes. But nonetheless I like the emoticon JohnM.
-segsurfer

[hellphish]

It's turtles all the way down...

Anyway, the Segway doesn't know how fast the wheels are spinning, or if it does then it doesn't do anything with that data. It is possible for a segway to maintain a top speed of greater than 12.5 mph without modding the wheels. You can replace components on the CU boards which will supply more power to the motors than the stock setup given the same input.

[segsurfer]

interesting

[segwayin]

It is possible to raise the speed limiter..its just a matter of time before someone does it.

[Desert_Seg]

It is possible to raise the speed limiter..its just a matter of time before someone does it.

You are right. Anything is possible, just some things are more improbable than others.

I'd love to go faster....I just don't expect it to be any time soon.

Steven

[Stan671]

the Segway doesn't know how fast the wheels are spinning, or if it does then it doesn't do anything with that data. It is possible for a segway to maintain a top speed of greater than 12.5 mph without modding the wheels. You can replace components on the CU boards which will supply more power to the motors than the stock setup given the same input

The Segway certainly DOES know how fast the wheels are spinning. In fact, that is all it knows - it cannot measure the speed over the ground. The power control circuits in the Segway are far rmore sophisticated than you give them credit for. The motors are controlled both by pulse width modulation and torque (power or current) control. And there is a feedback loop so that when the software asks for a specific action from the motors, it will know if it gets it or not. And if the results are not what the software wants, it will either correct the situation or if it is out of spec, assume that something is broken and cause a shutdown.

As for someone hacking the speed limiter, you have to understand that this is not a simple mechanical device that can be bent to change its effect. The speed limiter is an integral and vital element of the fundamental calculations that are done by the very sophisticaed software that maintains balance. And this software is VERY, VERY will protected because Segway considers this to be the heart of its intellectual property and patented technology.

Software aside, there are physical limitations that also prevent faster speeds. In order for the balance algorithm to work, there needs to be "headroom" between the max allowed speed and the max capable speed. This needs to be available so that the Segway can scoot back under the rider when going over a bump, for example. So, the machine may spin the wheels at 18 MPH for 1/2 of a revolution to play catchup after a bump.

So, if your max allowed speed is 18 MPH and there is no headroom, then the first anomoly on the ground would cause an immediate crash. I have talked with the engineers about the early days before the speed limiter and headroom concepts were developed and the "wild" rides they had. Take the engineers out to the bar during the evenings at SegwayFest - this is when all of the really interesting information is passsed along.;)

So, larger diameter tires are the only way to make the ground speed faster.

[Suzined]

BillK wrote, "...If you jump...out of a plane - no matter how close you get to the ground the distance can ALWAYS be halved - so you will never hit." Okay, so where did I go wrong? Of course my two aerial faceplants were caused by external forces of the 37mm variety. Does that make a difference?

[Macaholic]

I heard there is a guy making custom gears to replace the stock ones. Adds about 4mph top end. i'd be hesitant to try them on an X2 as it would change the torque.

[BillK]

[QUOTE=Suzined;164873]BillK wrote, "...If you jump...out of a plane - no matter how close you get to the ground the distance can ALWAYS be halved - so you will never hit." Okay, so where did I go wrong? Of course my two aerial faceplants were caused by external forces of the 37mm variety. Does that make a difference?[/QUOTE

All I know is that in physics I was told that any distance could be halved. So theoretically no matter how small the distance you can always cut it in half. That means that no two objects can ever come together and touch since no matter how close they get you can always halve the distance. ;)

Now - while that SOUNDS great in a theoretical environment - we know that it's conclusion cannot be true since things touch all the time, and sometimes forcefully!
Bill

[Stan671]

I've been criticized privately for being close-minded about some of the ways that have been suggested here for increasing the top speed of the Segway. And it was implied that since I have not tried any of these methods personally, I am not qualified to comment on them.:(

All I can say is this: I design and build robots as a hobby, have been involved with the Segway PT since the very beginning, have visited the Segway factory numerous times, beta tested products for Segway, attended all but one SegwayFest and spent many hours in personal, private conversations with the engineers that designed the hardware and software that make up the Segway. In others words, I know what I am talking about and I measure my words carefully.:cool:

I am mearly trying to relay to the public this highly technical knowledge that I have learned. I am mearly trying to offer realistic, practical information to balance the off-the-cuff guesswork and suppositions that some have posted here that may encourage other people to ruin their Segways thinking they can just solder in a few transistors or ruin thier bodies in a crash caused by modifying the Segway beyond it's design constraints.:eek:

And for this I get negative rep points from a newbie? :confused:

[pam]

Ah, there is at least one newbie who thinks giving negative rep points are fun, because he thinks he knows it all. Stan, those of us who have been around for some time know and value what you have to offer.
Pam

[Jet]

The gear modification works for first generation Segway's but I believe not for the I2/X2. Weird feeling when you see a Segway accelerate away from you and you are already pushing against the speed limiter.

[Stan671]

The gear modification works for first generation Segway's but I believe not for the I2/X2The internals of the Gen 1 and Gen 2 gearboxes are the same. The only real difference is the output shaft and maybe the output bearing.

The only matter I can think of that might affect this mod is that there may be minor differences between the early Gen 1 gearboxes made and assembled by Axion and the later Gen 1 and Gen 2 gearboxes made by others and assembled by Segway themselves.

[Jet]

The internals of the Gen 1 and Gen 2 gearboxes are the same. The only real difference is the output shaft and maybe the output bearing.

The only matter I can think of that might affect this mod is that there may be minor differences between the early Gen 1 gearboxes made and assembled by Axion and the later Gen 1 and Gen 2 gearboxes made by others and assembled by Segway themselves.

I believe the "brains" and gyros of the second generation are more aware of the dynamics and thus do not respond well to gear changes.

[Stan671]

second generation are more aware of the dynamics and thus do not respond well to gear changesMakes sense. Then I would expect that to apply to wheel diameter changes also, right?

[Jet]

Makes sense. Then I would expect that to apply to wheel diameter changes also, right?

Yes - I believe so.

[Stan671]

Can you get any more info on the gear mod? I have taken apart a gearbox and wonder what they would change to change the gear ratios. The overall ratio for the gearbox is 24:1, motor to wheel. I guess if they lower that ratio to about 18:1, it would increase wheel speed about 4MPH.

[Five-Flags]

Can you get any more info on the gear mod? I have taken apart a gearbox and wonder what they would change to change the gear ratios. The overall ratio for the gearbox is 24:1, motor to wheel. I guess if they lower that ratio to about 18:1, it would increase wheel speed about 4MPH.

Just remember, if you make that change...

A 25% increase in wheel speed means a 25% decrease in torque. How much torque margin is in the stock configuration?

Can you spare 25%?:eek:


Torque is what allows the platform to stay under the inverted pendulum of your body. You do NOT want to exceed those limits -- when you balance a broom on your palm and you can't keep your hand under it, the bristles (your HEAD) hits the ground hard! [xx(]

A 25% increase in speed won't amount to 25% less time over a given distance either. First, with less torque, it will take longer to get up to speed. Also, every bump will be more hazardous at higher speeds, so you'll be slowing more often (which will also take longer) and then re-accelerating.

Physics will not be mocked....[:(!][:(!][:(!]

[BillPaxton]

Yes Stan this has been discussed many times - if you really feel the need to go faster, you would be much safer with larger wheels than altering your gear ratio...unless you know how to recalibrate the firmware that is. But if you do it please video record and post so we can all see if what everyone has speculated is actually what happens.Just remember, if you make that change...

A 25% increase in wheel speed means a 25% decrease in torque. How much torque margin is in the stock configuration?

Can you spare 25%?:eek:


Torque is what allows the platform to stay under the inverted pendulum of your body. You do NOT want to exceed those limits -- when you balance a broom on your palm and you can't keep your hand under it, the bristles (your HEAD) hits the ground hard! [xx(]

A 25% increase in speed won't amount to 25% less time over a given distance either. First, with less torque, it will take longer to get up to speed. Also, every bump will be more hazardous at higher speeds, so you'll be slowing more often (which will also take longer) and then re-accelerating.

Physics will not be mocked....[:(!][:(!][:(!]

[Jet]

But if you do it please video record and post so we can all see if what everyone has speculated is actually what happens.

No speculation - Gear mods work as expected for Gen 1. The worst side effect is depending on the quality of the gear mod and Ratio, your Segway may sound loud and nasty.

There is a youtube video of a Gen 1 Segway with very large wheels establishing a Segway speed record. Although you don't have to mod the gear box to get to the "extreme" speed shown on the video, any mechanical engineer on this forum would understand what you achieve by changing the diameter of the wheel can also be achieved by changing the gear ratios in the gearbox.

[SegwayDan]

You know what you know, so stand by it and be proud of it as well as your contributions to SC.

If you've read any of my posts on this sort of topic, you know that we're basically in accord. My own conclusions were drawn from a viewpoint far more remote from Segway technology than yours, and I'm grateful for your succinct statments of "the truth" as you see it.

Don't worry about the various newbies and their opinions, nor let them shake your certainty. They may have to learn the hard way, when it comes to this "speed fetish." All we can do is warn them.

[quade]

. . . any mechanical engineer on this forum would understand what you achieve by changing the diameter of the wheel can also be achieved by changing the gear ratios in the gearbox.

Because they do, in fact, the exact same thing as far as the power is concerned.

The ability to balance the object however . . . the larger final drive wheels come out ahead since it also raises the center of gravity . . . except for when the limits have been exceeded in which case it's just farther to fall.

Everything is a trade off.

[SegwayDan]

How about that. Something from the Quadester I can agree with.

[Stan671]

Yes Stan this has been discussed many times - if you really feel the need to go faster, you would be much safer with larger wheels than altering your gear ratioDo not worry. I have no plans to mod my Segway in such a way. I will do lots of other stuff, like headlghts, speedometeers, trailers, etc. But nothing that screws around with the basic math of the machine.

[Stan671]

Hmmm ... interesting point: A gear mod vs a wheel diameter mod. They could each achieve the same increase in top speed, but the gear mod would not raise the center of gravity. I am not smart enough to understand how this would affect the algorithms used for balancing. I suppose that each mod would mess with the operating parameters in a somewhat different way.

[dgbint]

.. nothing that screws around with the basic math of the machine.

Of course !

If you step back, and consider whether to have a bit of faith in a team of qualified professional engineers, armed with leading edge technological development tools, guided by experienced business people, together spending many man years optimising performance and minmising risks, and then testing it every way possible ..

OR

on the other hand, a few blokes tinkering in their back garden.


I know where I choose to entrust my life and limbs.

But of course it's a free world, and we are all free to make our own choices, and bear the consequences of those choices.

Michael

[quade]

Try to balance a yardstick on your finger.
Try to balance a pencil on your finger.
Which is "easier" to keep upright?

[Stan671]

The Segway certainly DOES know how fast the wheels are spinning. In fact, that is all it knows - it cannot measure the speed over the ground. The power control circuits in the Segway are far more sophisticated than you give them credit for. The motors are controlled both by pulse width modulation and torque (power or current) control. And there is a feedback loop so that when the software asks for a specific action from the motors, it will know if it gets it or not. And if the results are not what the software wants, it will either correct the situation or if it is out of spec, assume that something is broken and cause a shutdownI have taken apart a Segway motor. It uses brush-less servo technology and can operate up to 8,000 RPM. There are some VERY powerful magnets in there along with coils like you see in any motor and there are also six hall-effect sensors that are used to measure speed and direction. Each motor has two 10-pin connectors on it for the power in and sensor info out.

The algorithms in the software think in terms of RPM of the motor and of torque applied by the motor. The drivers use pulse width modulation (meaning varying the rate and wide of pulses of power to the motors) and current (power) control to tell the motors what they have to do. And the software uses sophisticated positional and speed feedback info from those sensors to see if the motors (and therefore the wheels) are doing what the software needs to keep balanced.

For (an over simplified) example, if the wheel needs to rotate 10% faster in order to get back under the rider, then software will increase the pulse rate 10% to get the motor to spin faster. But if the wheel is up against a bump, then it won't spin faster. So, the software sees from the sensors that the motor is not doing as it is told and then applies more torque (current or power) to the motor to help it over the bump and get it up to the speed the software requires.

In other words, the software controls every aspect of the motor's rotational speed and applied torque and will tell the motor exactly what it needs. And then it makes sure that it gets done. So, no amount of driver circuit changes will allow the motors to do anything other than what the software wants them to do.

This is why any mods to increase the speed must be done "downstream", so to speak, from the motors. That is in the gearbox or with the diameter of the wheels.

[Jet]

But of course it's a free world, and we are all free to make our own choices, and bear the consequences of those choices.
Michael

Absolutely correct - You want to only go as fast as the speed you are willing to fall off. Segway did a good job of establishing 12.5MPH.

[quade]

Absolutely correct - You want to only go as fast as the speed you are willing to fall off. Segway did a good job of establishing 12.5MPH.

There's nothing magical safety-wise about the number 12.5.

In fact, I think if you convert it to metric you'll probably see why it is what it is; completely arbitrary but a nice round number that sounds pretty reasonable.

[SegwayDan]

I'm theorizing based on my own understanding of physics.

If gear diameters or wheel diameters are changed to increase the lateral speed of the machine, and if the output torque doesn't change, that means that acceleration will be reduced; and that the reverse torque from deceleration would be *increased* because of the longer "lever" (wheel diameter). If the system monitors this counter torque it would probably then initiate stick shake sooner than it would without the diameter mods. This would then result in the machine's speed being *less* than stock speed, especially when gliding down inclines.

This tells me that such a modification would result in a machine less capable of staying underneath the rider. That's not a good thing. Certainly not worth the tinkering.

[Jet]

There's nothing magical safety-wise about the number 12.5.

In fact, I think if you convert it to metric you'll probably see why it is what it is; completely arbitrary but a nice round number that sounds pretty reasonable.

I was suggesting 12.5mph/20kmh is a good compromise between speed and safety and not anything to do with its "roundness" after conversion to metric.

[Five-Flags]

I was suggesting 12.5mph/20kmh is a good compromise between speed and safety and not anything to do with its "roundness" after conversion to metric.

was the reason for 12.5 mph, I believe. From what I've read, the existing electric wheelchair laws (at that time) incorporated the 12.5 mph limit, and Segway simply matched those regulations, in order to ease implementation of the EPAMD laws they were promoting.

[Stan671]

Here is Dean Kamen riding what was probably the first Segway modified with larger wheels by an owner. The pic is from SegwayFest in Chicago in 2003. I happen to be standing there at the time and Dean went into the 15 minute long description of how the dynamics are changed with the larger wheels. Some stuff about angular momentum and torque levers, etc. It was mind blowing. Dean was totally accepting of the mod and thought was was very cleverly done. BTW, the machine is called "The Orange Monster". Those are motorcycle wheels and tires and custome made fenders.

http://www.segamerica.org/randomimages/IMG_0935.JPG

[Stan671]

Dan, a Segway with larger diameter tires certainly does go faster than stock. But you are right that it accelerates and decelerates slower.

I don't think the Segway actually "monitors" torque so much as it "controls" torque by controlling the amount of current going to the motor. And when it sends any specific amount of current and voltage to the motor, it knows how much force should be getting applied to the ground by the wheel. And it uses this info in its calculations.

This is why a wheel diameter change throws off the software a bit. But since the software is so robust, it is hardly noticable under normal circumstances. But get near the edge of the envelope and this can go bad very quickly.

[Stan671]

Just to round out the discussion, making the wheels wider does not change the speed, but does affect handling quite a bit.

http://www.segamerica.org/randomimages/XXXT.jpg

[hellphish]

Is that a genII tire I see in there?

[Segwaiian]

Ooh, it's spooky how close our Chat names are.

Having been airborne in an askew position after unintentionally launching off bumps at 10-12 MPH, I don't need 18 MPH. As I tell pedestrians who try to let me pass on narrow sidewalks as I dawdle behind them, "If I wanted to go faster I'd be on something else."

It's about the glide.

If you go to youtube, there are videos of what happens if you lean too far forward.

Also, you can get your thrills on a Segway in other ways than speed. Four words. Segway of New Mexico.

Aloha,
Roger

[SEGsby]

One of the programmer's thats taken a liking to Herbie and is usually the first to borrow the machine and run it around the facility in the evenings, posited this idea to modify the speed of the Segway...

Instead of hacking the firmware (he understood the issues involved), he thought it was far simplier to modify the signal from the revolution counter (the servo motors), and simply divide the outgoing signal counts by 2. That would trick the rest of the system to go much faster to get the same revolution count. This would probably double the speed (25 mph), so you might also be able to run it past the 18 mph limit the physical hardware can do while balancing. Not good. A refined timing mod of 1.5 would get you to about 18.75 mph, which is safer, but more difficult to achieve, timing-wise, with such a theoretical mod.

I do think that this would also make any smaller compensatory motions of the platform incorrect, to balance you properly. Such a global change of data to the computers could manifest in potentially strange and possibly unwanted, dangerous reactions. But this is all just idle speculation by outsiders that know very little about the internal hardware / software of the system...

Still, it's an interesting way to view the problem of increasing a Segway's speed without external mods to the wheels.

SEGsby

[seville]

me too ;))

[forcelite]

I have not read the whole thread so pardon me if this is a reprint,

We have talked about this many times. When segway was first announced it was planned to go 15 mph. The cities that segway was campaigning acceptance for put pressure on Segway to lower the speed. The last speed thread we had we posted articles talking about the 15mph grand announcement. The Segway is completely capable of that speed, its just limited in the firmware, just like a governor on your car.

The only group I know of that goes faster than 15 mph is some people out of the Bay Area, CA. I have had lots of conversations with people down here that know them, including dealers. I dont know exactly what they did, could have been gears or firmware.

We always have people that say its cant be done, this and that. It can be and has been. Not only that, the Segway was designed to go faster than 12.5 mpg plain and simple.

Force

[forcelite]

Segsby. that is a very smart way to look at hacking the system.

[MzSegwayofHawaii]

alright so i'm going to throw in my imput.

while fidgeting with one of those speed radar gun thingies that HPD has....we took an x2 (and someone on it of course) and raced against this thing to see what we could do.

Standard tire pressure for x2=4psi...the more you inflate it, the faster it'll go.
x2 tire pressure at time of race...10psi..to the point to where if you rode it in the sand, it would act like a gen1 and just get stuck..

down the pavement and she's off....clocked 17mph at least twice, we hit 14 a few times too.

it depends on how you ride too...because you 'work' the machine almost like walking or dancing on the platform. (could just be us, we fully utilize the 'hands free' technology)

[Segwaiian]

alright so i'm going to throw in my imput.

while fidgeting with one of those speed radar gun thingies that HPD has....we took an x2 (and someone on it of course) and raced against this thing to see what we could do.

Standard tire pressure for x2=4psi...the more you inflate it, the faster it'll go.
x2 tire pressure at time of race...10psi..to the point to where if you rode it in the sand, it would act like a gen1 and just get stuck..

down the pavement and she's off....clocked 17mph at least twice, we hit 14 a few times too.

it depends on how you ride too...because you 'work' the machine almost like walking or dancing on the platform. (could just be us, we fully utilize the 'hands free' technology)

Channelle, does Segway of Hawaii service the police model gen1s for the Honolulu Police Department? An officer who has been on them, but is not on Segway patrol detail, told me that they can go 15 MPH.

That extra 2.5 MPH would make all the difference in apprehending a crook on a Segway, I guess.:D Or catching a stolen Segway, of course.

BTW, does anyone know how accurate radar guns are at this low speed range?

Aloha,
Roger

[KSagal]

It might serve you guys well to research this topic on this very forum...

It has been discussed before and discussed to death...

Of course a segway can go 17mph. They do it all the time... That is not the question.

I had my e167 over 17 mph, and asked and had Segway Inc. document it for me, and they were happy to do it...

Here is the the way it works. (I had a computer on board that was monitoring the details of my segway, and we later downloaded the info, and plotted it...)

I was going a hard 12.5 mph, leaning into the speed limiter. I took my upper body strength, and pushed hard, trying to push thru the speed limiter...

I was able to push the handle a bit forward. At this point, for argument's sake, I will say I, my upper body, was moving at 13 mph. In order to slow me down, the wheels have to speed up faster than 13 mph to get in front of me. Once in front of me, with me being forced to lean back (my upper body behind my feet) it can slow down.

Now, if I am moving 12.5 mph, and lean forward hard, and speed up my upper body a bit, than clearly the wheels have to be able to go faster than that to get in front of the center of gravity. In my case, I recall at least 17 mph.

But here is the kicker. It all takes place in less than a second. This is not an increase in speed, as much as a technical maneuver, and has to be very fast. If it slowly increased in speed like it does when you lean forward, there is very little momentum shift. This has to include very much torque in order to have the platform get in front of your chest.

Now... If you were to use that amount of power to maintain 17 mph, and you were cruising at that speed and the tires hit a minor bump or pebble, they would slow down a tiny amount to climb the obstacle and the machine would have the power to continue, but would it have the instant speed and torque needed to thrust the wheels in front of the upper body that is now moving at 18 mph, due to falling forward because of the momentary slowdown...

Let's look at the numbers we know... IF 12.5 mph required a burst to 17 to get in front of the problem, that is about 4.5 mph, or approximately 33% increase in speed INSTANTLY to make this work...

Now, the same situation at 17 mph would require a 33% burst to 22? 23 mph. While we know the maximum speeds of the motors, we know the maximum rpms, the gear ratios, and the like, I will leave it to those smarter than me, to tell me that these machines can get to 22 mph instantly, in order to fulfill your dream of a segway that can cruise at 17 or 18 mph...

One last thing, I know a person who was on the developement team, and he tells stories of before the speed limiter, and just pushing on the handlebar lower and lower, going faster and faster until you just started to skid along on your knuckles and eventually your face... Interesting stories, but also a bit scary on todays standard...

[BillPaxton]

just get yourself a purple key!

[seville]

SO, what is the plan ? how to get 17 mph?

[quade]

SO, what is the plan ? how to get 17 mph?

Make a 24 inch tire and wheel. Not -exactly- 17 mph, but close enough for jazz.

[SEGsby]

Thanks, I'll pass that along to the programmer here...

SEGsby

Segsby. that is a very smart way to look at hacking the system.

[segwayin]

I know someone can hack the segway system and increase the speed limiter...if it can be done on $100K cars then it can be done on the segway :). Another option is change the internal gearing instead of changing the tire size; anyone tried this yet?

[MJEdelman]

I know someone can hack the segway system and increase the speed limiter...if it can be done on $100K cars then it can be done on the segway :). Another option is change the internal gearing instead of changing the tire size; anyone tried this yet?

I don't think changing the software on a car is on a par with changing the software on a Segway. The software in a car does not manage the payload (weight) or balance...

While I'm sure something can be done to increase the speed, I say leave well-enough alone... (When I want to go fast I take my car to the track and get it out of my system :))

[jryan]

I am of the philosphy that if someone wants to tinker with new things to try to get a desired result all power to them! Just know that if you get injured, which you very well may, it is solely your fault! That doesn't bother me much as far as tinkering goes as pain is just a temporary sensation!

I also have to add, that you should keep in mind you may not be able to reverse what you did. Therefore be prepared to lose a Segway out of it! Now if neither one of these bothers you and you have enough money to get a new glide should yours become inop, go for it!


Jeremy Ryan

[Stan671]

The Segway's motors are rated for 8,000 RPM. Do that math and that translates into just over 18 MPH as the maximum speed the motors could make the wheels spin.

Even if you could fool the software into thinking that 8,000 RPM is just cruising speed, there would be no "headroom" in the RPM range for the wheels to spin faster to compensate for balancing and hitting bumps.

Someone knows of people in the Bay Area going 15+ MPH on a regular basis. Perhaps they can be convinced to post here about how they do it. Someone accomplishing that should be wanting to brag about it. I don't know why we are speculating when there are facts by people in the know that can be presented here.

[Seginaway]

I'd be very happey to be able to pick up a couple mph. If it could done without serious rebuilding or re-programming I'd be willing to test it. Since my terrain allows me to rarely use sidewalks, mostly use established bike lanes, wide cart paths with few pedestrians and the open road it is just what I need. For gliders that are in more congested areas than I, I can see why it wouldn't be desired as much but most of my glides are full against the limiter.

[segwayin]

Changing the tires/wheel size is the safest way to increase speed. Are bigger tires available? Maybe a new tire/wheel combo and fender kit to match would be a big seller on ebay. Even 3mph higher top speed would be worth $1000 to me.

[SegwayDan]

Your pipe dream is unrealistic.

Speed is directly proportional to wheel diameter. The stock wheels have a diameter of about 18.75 inches. To get 15.5 mph would therefore require a wheel diameter of 23.25 inches. That would also raise the platform about 2.25 inches, and would require the tube cross section to also be 2.25 inches larger--or larger custom wheels.

That would make the wheels too big, to say nothing of reduced performance/safety margins.

[segwayin]

Your pipe dream is unrealistic.

Speed is directly proportional to wheel diameter. The stock wheels have a diameter of about 18.75 inches. To get 15.5 mph would therefore require a wheel diameter of 23.25 inches. That would also raise the platform about 2.25 inches, and would require the tube cross section to also be 2.25 inches larger--or larger custom wheels.

That would make the wheels too big, to say nothing of reduced performance/safety margins.


Dan,
F50 Ferrari in your avatar...everyone has pipe dreams.

I want a faster segway and I know someone can make it happen, just a matter of time.

21" tires would give a 10%+ increase in top speed.