Acceleration and Braking - The Subjective Feeling of Difference Between EUCs

[Rawnei]

Foreword: If you don't agree with my conclusions that's fine but please explain why you don't agree with me and explain why you think there is a fundamental difference between acceleration and braking between different wheels.

This is a very interesting phenomena which I see all the time, riders asking how fast X wheel can accelerate or brake, comparing various wheels to each-other in terms of acceleration and braking performance, claiming that wheel X feels much easier to accelerate and brake than wheel Y or complaining that their wheel can not accelerate or brake hard enough.

And then I'm not talking about the small amount of riders that races on a race track chasing seconds of their time, this is regular riders who ask these questions multiple times weekly in forum theads here, in facebook discussions and in chats, it seems to be on top of everyone's mind when comparing different wheels.

Controversially when I say that it just depends on how hard you are leaning people raise their eyebrows in response as if I am speaking a different language or telling me that it's not that simple.

Some basic fundamentals of a self-balancing electrical unicycle

A self-balancing electrical unicycle will try to balance itself in the forward or backward direction at all times as to keep it from falling, that is the fundamental function that it performs, for simplicity the main tools that it has to perform this task is a gyroscope and a motor.

The only thing it can really do is spin the motor to keep itself balanced, if the motor would spin too fast or too slow balance will be lost and it will fall thus the speed of which the motor is spinning is essential.

So what happens during acceleration and braking?

When the rider leans the EUC must respond by spinning the motor to keep the balance, the harder the rider leans the faster it must spin the motor, thus acceleration and braking is the result of the rider leaning forward or back, this is a very fundamental fact. Depending on how hard the rider leans acceleration or braking will be stronger, thus the control over acceleration and braking is 100% in the hands (or feet if you so will) of the rider.

So what are various tools that can help us lean more?

Power Pads are essential if the rider wants to gain more leverage over their wheel, properly versus poorly configured power pads (which is a very individual thing due to various physical differences of our bodies) can make a world of difference how much someone can leverage their wheel and how much they can lean. Power Pads will help the rider applying leverage over the wheel without feeling like we're going to fall off the pedals thus allowing us to be more confident and be able to lean more.

Ride Modes / Pedal Modes determine how the pedals behave and how it feels that the wheel is responding when you lean, in itself it doesn't change the fundamental task of balancing that an EUC performs but it can change the subjective feeling for the rider, in some cases making the rider feeling more or less confident affecting how much and how fast they lean.

And last but not least experience plays a big part of all of this, an experienced rider who practiced acceleration and braking on a specific wheel with their specific setup will be able to accelerate and brake a lot stronger than someone who didn't.

So what about different wheels "feeling easier" to accelerate and brake than other EUCs?

Now this is the crux of it, since the only thing an EUC can do is spin the motor and it all comes down to leaning why do so many riders "feel" that it is easier to accelerate or brake one wheel over another?

Power delivery plays a factor, but not in the way a lot of riders seem to think, more power doesn't mean the wheel will suddenly spin faster (if it did then we would fall), instead I suggest that a more powerful wheel can make the rider feel more confident and daring to lean more because they will be less afraid of overpowering and overleaning the wheel, but this doesn't just happen by itself, you still need proper pad setup, practice and experience.

Another thing to consider is the weight of the wheel, weight still does not change the fundamentals of how the wheel works but it changes what the rider is experiencing and how much leverage they feel they have over the wheel, in other words weight of the wheel can also affect how confident the rider feels which can also be improved with practice.

And here's the thing, feeling confident and exploring the limits takes time, experimentation and practice, it doesn't come by itself, unless you have done all you can to experiment and explore the limits of your particular wheel then there is most likely untapped potential that you are not using, swapping to a more powerful wheel will not necessarily change that, if your pads are in the way and does not let you lean as hard as you want to it wont matter how powerful the wheel is, you are not using the potential that is already there and complaining about something that could potentially be better.

Case in point: I feel more confident accelerating my Sherman S or my Patton over my S22 at higher speeds, that is because I have explored the limits of my wheels and I have overleaned the S22 at high speed, the S22 doesn't "accelerate slower" it's just me holding back after a certain point because I am less confident and more afraid to overlean my S22 than I am overleaning my Sherman S or Patton, I can still brake equally well on all 3 of them regardless of this.

I suggest to anyone not happy with the acceleration and braking performance of their particular wheel the first thing they should do is analyze how their pads are setup, what is their foot position, practice acceleration and braking, does something not feel comfortable or does something feel like it's holding you back from leaning harder? Can something be changed? In most cases I suggest that it's not the wheel it's the rider that is not tapping into the full potential that is right there. If you have explored all this and come to the conclusion that you are not confident to accelerate or brake harder due to the lack of power of your wheel then a more powerful wheel could be the answer.

[The Brahan Seer]

1 hour ago, Rawnei said:

Power delivery plays a factor, but not in the way a lot of riders seem to think, more power doesn't mean the wheel will suddenly spin faster (if it did then we would fall

But the more powerful a wheel (motor/voltage) the quicker it reaches the spin/rpm required to keep you 'balanced' going forward or back? no?

 

1 hour ago, Rawnei said:

the weight of the wheel, weight still does not change the fundamentals of how the wheel works

But it changes the amount of work the motor needs to do to reach its spin.  Which could change the speed at which it reaches the spin/rpm required? no?

[Rawnei]

16 minutes ago, The Brahan Seer said:

But the more powerful a wheel (motor/voltage) the quicker it reaches the spin/rpm required to keep you 'balanced' going forward or back? no?

 

But it changes the amount of work the motor needs to do to reach its spin.  Which could change the speed at which it reaches the spin/rpm required? no?

No, it's all about keeping balance, if wheel was not powerful enough to keep balance it would fall.

[The Brahan Seer]

Just now, Rawnei said:

No, it's all about keeping balance, if wheel was not powerful enough to keep balance it would fall.

 

As you lean further forward the motor compensates to keep balance by accelerating. The more powerful the motor the easier it is for it to chase that equilibrium? or are you saying that it has to reach the equilibrium right from the start and so this makes no difference to the torque and its purely your technique and lean (which may have been demonstrated by RogerEUC recently climbing a dam using the Lynx and the SS.) But if we give him the Lynx could he make it go quicker than the SS? in this scenario?

So what if it is too powerful? as soon as you leaned forward or back it would drop you. We have wheels with all different power and voltage ratings. So the only difference this makes is to the top speed achievable? (Which to be fair has been demonstrated with the AVS races stats on this forum) and its only the wheel diameter and technique that controls torque? 

But what else stops the wheel from being over or under powered? your lean angle? battery and how the algorithm controls the power to the motor?

Maybe it is this algorithm that people can feel the difference in? as in how it implements reaching the balance and the power delivery though the battery/voltage?

 

 

[Rawnei]

25 minutes ago, The Brahan Seer said:

As you lean further forward the motor compensates to keep balance by accelerating. The more powerful the motor the easier it is for it to chase that equilibrium? or are you saying that it has to reach the equilibrium right from the start and so this makes no difference to the torque and its purely your technique and lean (which may have been demonstrated by RogerEUC recently climbing a dam using the Lynx and the SS.) But if we give him the Lynx could he make it go quicker than the SS? in this scenario?

So what if it is too powerful? as soon as you leaned forward or back it would drop you. We have wheels with all different power and voltage ratings. So the only difference this makes is to the top speed achievable? (Which to be fair has been demonstrated with the AVS races stats on this forum) and its only the wheel diameter and technique that controls torque? 

But what else stops the wheel from being over or under powered? your lean angle? battery and how the algorithm controls the power to the motor?

Maybe it is this algorithm that people can feel the difference in? as in how it implements reaching the balance and the power delivery though the battery/voltage?

Go back to the basics, all the motor does is keep balance, nothing else, when you lean it needs to spin faster to keep balance. The only difference between a weak and a powerful motor is how hard or easy it would be to overpower it from leaning too hard.

In both scenarios, accelerating on a straight or climbing a steep hill as you mention both of them are still a result of the rider leaning, what Roger demonstrate on the Lynx is not only his skill level but also that the high torque of the Lynx resulting in that he was confident leaning hard and that the wheel did not struggle going up a steep slope but it's still Roger leaning to make it happen.

Wheels can not be "too powerful", again back to basics, all it does is keeping balance, if it didn't keep balance it's no longer a self-balancing device.

And like I already wrote if the wheel is more powerful the rider can feel more confident and ask for more from the wheel...

...but what I am also claiming is that a lot of riders who complain about lack of acceleration or braking is not using the potential of the wheel they already have, instead they are looking towards a different wheel, say the Lynx, thinking that it will automatically make them accelerate faster or brake harder when they could already be doing that on the wheel they have.

At the same time Bob who rides his V11 is already super happy with acceleration and braking, he isn't looking to be asking for more acceleration and most likely wouldn't attempt to accelerate faster on a Lynx, thus acceleration and braking would be the same for him all things considered.

[The Brahan Seer]

4 minutes ago, Rawnei said:

it needs to spin faster to keep balance

But its how it spins faster that I'm talking about. I understand the theory its the implementation I'm curious about.

Once you have a motor that can keep you up within the limits of a lean do you then have the 'room' to control how the power is delivered?

I agree with you that technique has a lot more to do with it than anything else. We can all get better results by practice and how many of us get and reach the limits of our wheels before buying a new one.

 

 

[xafofo]

3 hours ago, Rawnei said:

more power doesn't mean the wheel will suddenly spin faster (if it did then we would fall)

I don't think this is true, I don't think we would fall. You sound like you're describing a basic inverted pendulum system, but the problem is, humans aren't pendulum sticks, we can balance ourselves.

Your argument is that only leaning can drive the motor. But why can't the motor drive the lean? It can, we would just balance ourselves to compensate, just like on an electric skateboard.

I would guess the V13 accel/brake assist are adding a little more motor power than normal, but in a way that feels natural and ppl can keep balance.

[Rawnei]

18 minutes ago, The Brahan Seer said:

But its how it spins faster that I'm talking about. I understand the theory its the implementation I'm curious about.

Once you have a motor that can keep you up within the limits of a lean do you then have the 'room' to control how the power is delivered?

I agree with you that technique has a lot more to do with it than anything else. We can all get better results by practice and how many of us get and reach the limits of our wheels before buying a new one.

Think of it this way, the reason why the motor even spins at all is because the gyroscope is detecting that it's in an angle, it's trying to correct the angle to achieve balance by spinning the motor.

4 minutes ago, xafofo said:

I don't think this is true, I don't think we would fall. You sound like you're describing a basic inverted pendulum system, but the problem is, humans aren't pendulum sticks, we can balance ourselves.

Your argument is that only leaning can drive the motor. But why can't the motor drive the lean? It can, we would just balance ourselves to compensate, just like on an electric skateboard.

I would guess the V13 accel/brake assist are adding a little more motor power than normal, but in a way that feels natural and ppl can keep balance.

Not sure what you mean by "humans aren't pendulum sticks", the wheel wants to stay upright that is why it spins the motor.

The job of the motor is to keep everything upright at a balance, this is why the motor does not drive the lean.

What do you think happens if you lift the wheel? The motor spins and spins trying to correct the angle until it runs out of power.

Acceleration and brake assist are fancy words to describe pedal angle, it has nothing to do with motor power, it just changes the feedback the rider is experiencing from the pedals, in practice this can lead to the rider being subjectively able to accelerate or brake better because they feel more comfortable doing so, the pedal angle potentially helps the rider gain leverage (potentially as in this is a preference of the rider, many riders would prefer not to have this assist and will accelerate or brake better without it).

[Cerbera]

There is a tremendous difference in ride feel (by which I mean acceleration and braking characteristics) between small wheels and bigger, heavier ones. The smaller the wheel the less input is required to move it, so these little 12 inchers feel like small yappy terriers to ride, and huge ones like V13 and Master-type machines are like pushing treacle uphill without proper pads.

Each time I have upgraded to a bigger wheel the new one has felt sluggish and more luxurious than the previous, as we might expect, and within months of adapting to the new ones the old ones feel unbearably over-reactive, at least until you give yourself time to recalibrate all the muscle memory.

For example it is good that my old Airwheel X5 is on permanent loan to someone else - were I to try and ride that now, coming from a year on a Master I feel quite sure I would over-torque the airwheel into cutout almost constantly.

 

Edited December 4, 2023 by Cerbera

[Rawnei]

7 minutes ago, Cerbera said:

There is a tremendous difference in ride feel (by which I mean acceleration and braking characteristics) between small wheels and bigger, heavier ones. The smaller the wheel the less input is required to move it, so these little 12 inchers feel like small yappy terriers to ride, and huge ones like V13 and Master-type machines are like pushing treacle uphill without proper pads.

Each time I have upgraded to a bigger wheel the new one has felt sluggish and more luxurious than the previous, as we might expect, and within months of adapting to the new ones the old ones feel unbearably over-reactive, at least until you give yourself time to recalibrate all the muscle memory.

 

Yes they do "feel" different from having different wheel circumference and also pedals being lower to the ground, but still the same basic principles of leaning for acceleration and braking applies.

[okvp]

Also because of that balancing principle, no matter how powerful the motor of the EUC is, there is a certain top speed that a rider cannot exceed because the rider cannot generate more torque (rider’s center of mass x distance from the motor axis) to the EUC frame which EUC motor would have to counter by accelerating.
On the other hand, the rider is not able to overload a powerful enough EUC because (as above) he is not able to produce more torque. (Many of the current EUC:s are most likely beyond this point at lower speeds)

In other words, after the certain limit, increasing the power (torque) of EUC motor is useless. This limit determines the maximum power of the EUC motor, it is simply no worth to make them more powerful.

Sure, rider generated torque can be increased by adding distance of riders CoG to the motor axle by making e.g. euc pedals much longer so that rider (CoG) could move forward, but that EUC would not be convenient to ride.
 

[Robse]

Motor, Controller and Gyro also have another important task, to keep the pedals / upper part of the wheel at the angle that the user / the rider wants. I myself have a 1,6 degree permanent pedal dip (down at the front) I feel it gives better feeling with the wheel, better acceleration (and even braking) and I never get tired in my feet..

And then I can agree (with @Cerbera ) , smaller wheels feel rougher, right up to the point where you have ridden for 3 days on a big wheel, and then step down on the small one for the moment to fall forward because you just push as you now are used to do

Edited December 4, 2023 by Robse

[Whalesmash]

20 minutes ago, okvp said:

 

Sure, rider generated torque can be increased by adding distance of riders CoG to the motor axle by making e.g. euc pedals much longer so that rider (CoG) could move forward, but that EUC would not be convenient to ride.
 

To tack on to that, the pedal height also matters since it changes the pivot point of the rider's lean. It's pretty subtle but surprisingly noticeable if you go between the generation of non-suspension wheels vs the newer suspension wheels.

[okvp]

40 minutes ago, Whalesmash said:

To tack on to that, the pedal height also matters since it changes the pivot point of the rider's lean. It's pretty subtle but surprisingly noticeable if you go between the generation of non-suspension wheels vs the newer suspension wheels.

Yes that is because riders inertia is pushing pedals and creating horisontal force component to the pedals. Further the pedals are from center vertically, bigger the force component is. If pedals are lower than center point then the inertia force created by rider is helping both acceleration and braking, but if the pedals are higher than wheels center point inertia is resisting acceleration. Also larger diameter wheel helps, you can have a bigger torque created by the riders inertia with same pedal height from the ground.

Edited December 4, 2023 by okvp

[xafofo]

1 hour ago, Rawnei said:

The job of the motor is to keep everything upright at a balance, this is why the motor does not drive the lean.

What if it didn't? What if when you leaned forward, the motor gave just a tiiiny bit more power than to stay upright? My point is that you wouldn't necessarily fall over, you could adjust balance to compensate. And if this motor assistance was programmed in a smart way where it could detect your intentions, it would feel natural.

Now I'm not claiming that any EUCs do this (I haven't ridden a V13, just going by what others say, I'll trust your word on the pedal lean), it might be that they all are just "trying not to fall over". I'm just pointing out that it's not out of the realm of possibility to have some kind of smart motor assistance.

[techyiam]

Food for thought.

Jack is an insider, and he talks to the CEO's, and engineers at the various euc manufacturers. And he has ridden plenty of wheels.

I am confident that the people behind the firmware of the V14 have full understanding of what I have been pointing out, since they are the ones who have to deliberately implemented it in the V14 as a feature.

You can't explain it using the physics as we understand it. There is something missing. And we have not figured out yet. But they know.

Unless Jack is full of s***.  

Timestamped.

 

[Rawnei]

1 hour ago, techyiam said:

Food for thought.

Jack is an insider, and he talks to the CEO's, and engineers at the various euc manufacturers. And he has ridden plenty of wheels.

I am confident that the people behind the firmware of the V14 have full understanding of what I have been pointing out, since they are the ones who have to deliberately implemented it in the V14 as a feature.

You can't explain it using the physics as we understand it. There is something missing. And we have not figured out yet. But they know.

Unless Jack is full of s***.  

Timestamped.

Perhaps his subjective feeling is that it was easy to accelerate, it still doesn't change the basics and ultimately he's a salesman and this is a promotional video.

[techyiam]

10 minutes ago, Rawnei said:

Perhaps his subjective feeling is that it was easy to accelerate, it still doesn't change the basics and ultimately he's a salesman and this is a promotional video.

We will know soon enough when people get a chance to try out the demo wheels.

What Jack is saying is that it won't be subtle anymore.

Just curious, off the line, among your wheels, how would rank them from easiest to hardest when accelerating: Patton, S22, or Sherman S? This implies using normal amount of effort when you ride around town.

[Rawnei]

16 minutes ago, techyiam said:

We will know soon enough when people get a chance to try out the demo wheels.

What Jack is saying is that it won't be subtle anymore.

Just curious, off the line, among your wheels, how would rank them from easiest to hardest when accelerating: Patton, S22, or Sherman S? This implies using normal amount of effort when you ride around town.

They are all easy to accelerate because I have my pads setup like I need them.

[techyiam]

53 minutes ago, Rawnei said:

They are all easy to accelerate because I have my pads setup like I need them.

But how would you rank them?

Are you saying the Sherman S accelerates as well as the Patton off the line with the same effort?

[Rawnei]

12 minutes ago, techyiam said:

But how would you rank them?

Are you saying the Sherman S accelerates as well as the Patton off the line with the same effort?

Read the original post.

[okvp]

I draw the basic forces which are creating torque around wheel center point, inclinatig the EUC balance sensor and making EUC controller to turn the wheel to counter the effect. (forces in the picture are not in the scale)

Some of the forces help rider input making it easier to accelerate or decelerate and some will make it harder (rider must lean more).

To move forward rider is moving his balance to the front and riders mass gravity force is creating the torque which is rider mass X riders CG point on the pedals, pedal length (pivot point distance from center point) is limiting the torque.  With power pads you can shift the riders pivot point further and thus add torque.

Rider’s Inertial force (vertical force) is helping create to torque if the pedals are below center point (CP). If pedals are higher than CP it starts to create counter torque. The lower the pedals are (from CP) easier is to accelerate or brake.

EUC Inertial force (EUC mass center) is higher than wheel CP (with all the current EUCs) so it’s creating counter torque. The lower the mass or mass center of EUC body is (from CP) easier is to accelerate or brake.

Inertial forces are present only when accelerating or decelerating during constant speed they are zero.

Air drag force of rider is of course making rider harder to lean forward, but it is also helping rider to create input torque if pedals are lower than wheel CP.

If you want to make really fast EUC you should put pedals as low as possible to make the pedals distance from CP as long as possible with a bigger diameter wheel you can make distance longer. So fast wheel should have large wheel and low pedals.

Air drag force of EUC is creating counter torque because force vector is above wheels CP (with current EUCs)

Adding ‘softness’ of pedals will increase rider’s inertial force, because it dips pedal edge lower, but it will also decrease riders G force decreasing horizontal distance (if pads are not used).  But whit soft pedal setting there is a delay because of movement of pedals. All in all I think that real effect is quite small, it is more how things are feeling.

Like Rawnei already stated Different EUC controllers has a very little to do with actual acceleration or deceleration it is actually coming from rider input. Motor torque makes harder input from rider possible thus faster acceleration. There is so much marketing bullshit going on!  

Edited December 5, 2023 by okvp

[The Brahan Seer]

21 hours ago, Rawnei said:

The only thing it can really do is spin the motor to keep itself balanced

When we switch on the wheel it balances from front to back when stationary, so is the motor spinning then too? What is keeping us from falling forward or back when stationary? Ie keeping the pedals horizontal. 

Edited December 5, 2023 by The Brahan Seer

[Rawnei]

9 minutes ago, The Brahan Seer said:

When we switch on the wheel it balances from front to back when stationary, so is the motor spinning then too? What is keeping us from falling forward or back when stationary? Ie keeping the pedals horizontal. 

Spinning is just another word for applying power to the motor to adjust the angle and keep the wheel balanced, when it's upright it's using power to keep it at that balanced angle.

If you sit still on your wheel with your body without moving and look with an app such as EUC World or Darknessbot you can see that the wheel can use quite a lot of power to keep you balanced depending on how far front or back on the wheel you are positioned, temperature will also rise as a result.

[Chriull]

2 hours ago, Rawnei said:

Spinning is just another word for applying power to the motor to adjust the angle and keep the wheel balanced, when it's upright it's using power to keep it at that balanced angle.

Using "Spinning" is regarding physics a bit unfortionate.

Balancing occurs by the forces the motor and the rider applies to the wheel. Regarding the radius of the "attack point" of these two forces one has two torques.

Once these two torques sum up to zero the wheel is in balance and the tire has no angular acceleration. But the wheel can have "whatever" angular velocity.

In the stages of acceleration between "equilibrium" the speed is changed by the acceleration and stays while in balance.

One could argue that riding and controlling the speed with an euc is just a byproduct of the self balancing.

PS: as mechanical power is torque times angular velocity the same is more or less true for the use of the term power