How to ride an electric unicycle - understanding the dynamics

[Mono]

16 hours ago, beast@tanagra said:

Anyone have a good technique for short drops other than bending your knees at the right time? I find drops more jarring than bumps, especially with a more inflated tire.

IMHO the right time for bending the knees is before the drop and not (only) after. During the drop I push the wheel down by extending the knees to rejoin contact with the ground as quickly as possible. Getting the body to the final (lower) height before the drop is much less demanding on the material and on the knees. Thinking about it, it's pretty logical, because like this it is not necessary to stop the down motion of the entire body, but only of the wheel itself.

Edited June 30, 2018 by Mono

[Mono]

11 hours ago, mrelwood said:

Perhaps because:

 

(My video is mostly aimed for riders who have challenges with curbs. My way is the only way I can do it, so perhaps it can help someone else as well.)

The three situations as shown in the vid are to me not anymore a challenge, just part of daily riding. Only for the higher curb I would have to think twice when approaching it backwards. For higher curbs I also switch more to the crouching-jumping technique, but this technique is for my taste too unforgivable to timing mistakes, hence I don't use it in daily riding, only when practicing.

[mrelwood]

@Mono, how do you ride over for example the first obstacle, the speed bump? Do you really just bend your knees when the wheel  starts to climb the bump? Nothing else?

[meepmeepmayer]

I do this stuff like @Mono, too.

For bumps, I don't "jump" off the wheel before the bump like in your video, but simply bend the knees in the moment of the bump so the wheel only has to lift itself, not my body weight (body stays at same height). This can also help so the wheel isn't held back by the obstacle and can bounce up. Then after the bump, straighten the legs again.

Same for down curbs, bend knees so I'm on the right riding height after the curb, and simply push down a little while the curb drop happens, so no contact to the pedals is lost.

So essentially, the idea is, the legs deal with the bump/curb/whatever it is, so the wheel only has to deal with its own weight while negotiating the obstacle. Of course it's never perfect, but it does not have to be.

Of course that doesn't work for going up bigger curbs, one has to jump I guess. I never do that, so idk. Didn't think about this consciously, I'm just doing it.

[Mono]

15 hours ago, mrelwood said:

@Mono, how do you ride over for example the first obstacle, the speed bump? Do you really just bend your knees when the wheel  starts to climb the bump? Nothing else?

I would list three actions.

1st, adjusting speed. For the shown speed bump it is probably slowing down to somewhere between 10 and 15km/h to be on a reasonably safe side, and not much below 5km/h to make the climb not too difficult.

EDIT: I also try to get into the free floating situation before I hit the bump. That is, the wheel is right under me and the motor produces only minimal (ideally zero) forces. And the knees need to be as soft as possible now (for this they must be bent).

2nd, bending knees (further) to follow the bump as closely as possible. Sometimes I practice by focussing an object to see whether my head is moving up or down and I am getting pretty close to no head movement at all on speed bumps (that's more difficult on curbs).

3rd, I also use your hint to play with the forefoot pressure thereby leading the wheel over the bump.

The movement idea is pretty close to mogul skiing, I think.

 

Edited July 1, 2018 by Mono

[someguy152]

On 6/24/2018 at 1:33 PM, someguy152 said:

I'm 4 to 5 hrs in and wanted to share my progress on a ks18s.  after a few hrs of trying the drills found mostly here minus the ones with a partner (how to ride a unicycle in about an hr) , I still couldn't go more than 5 ft.  I was thinking it's was because the 50lb monstrosity is almost half my bodyweight.  Then I was instantly able to increase my max distance to probably 50ft by just squeezing my knees together, touching (gripping) the euc (i'm slightly over 5ft).  I was informed not to because of the video below (valgus knee causes many girls to wear knee braces in sports as their hips make them more susceptible to it).  Hopefully in the longrun i won't need to squeeze the wheel so much, but for now it was the critical piece i was missing to get moving. Now I need to learn how to control speed.

The other most helpful things i did was practicing the triangle method for getting on the unit (turn on captions),  the touch and glide, and the   pivoting or swerving practice on a fence first.

Next I'll try going up and down a hill to practice picking up speed and slowing down, respectively 

Do most ppl who ride keep their knees straight or out vs in towards the wheel? If the former, do you remember at first death gripping your euc to get balance?

 

one week later update:

THIS THING IS A BLAST now that i don't waste so much energy getting on and off and trying to balance.  I can do pretty narrow turns and almost go on one leg.

I go outside and spend a lot less time on the computer now.  That's worth the price of admission for me.

I think the most important thing as many others have said is it's better to do 20-40 minute sessions, and call it a day, so your brain has time to rest and build the neural pathways, and also for your small balancing muscles to recover and grow stronger.  I got better every time i stepped on and it was just a lot more encouraging.

also, shinguards have saved me about a dozen times from bruising.

[mrelwood]

1 hour ago, Mono said:

2nd, bending knees to follow the bump as closely as possible.

I don't know if the issue for me is my weight (95kg), using the medium and not the hard pedal mode (16S), perhaps not the best physical balance, or my falldownophobia. But if I only bend my knees at the obstacle without preparation, even the smallest obstacles make me feel like I'm going to fall, flip, explode and die.

Any obstacle will slow down the wheel. If the rider doesn't prepare for the obstacle before the wheel reaches it, the wheel slows down while the rider continues at the same speed. Then it is up for the wheel to catch up. I don't have the guts to offset my balance like that. I have seen a lot of other people do that though, so I believe I'm a wimp in this regard.

I've experienced this dozens of times if I don't see the obstacle. I always ride with soft knees, so while the wheel goes over the obstacle my knees do bend as the wheel climbs up the obstacle. During which I'm having a heart attack and nearly pick a god to pray to for me to survive. When I go back to look at the obstacle, it is usually something very tiny. Told ya, I'm a wimp.

[Mono]

3 hours ago, mrelwood said:

I don't know if the issue for me is my weight (95kg), using the medium and not the hard pedal mode (16S), perhaps not the best physical balance, or my falldownophobia. But if I only bend my knees at the obstacle without preparation, even the smallest obstacles make me feel like I'm going to fall, flip, explode and die.

Any obstacle will slow down the wheel. If the rider doesn't prepare for the obstacle before the wheel reaches it, the wheel slows down while the rider continues at the same speed. Then it is up for the wheel to catch up. I don't have the guts to offset my balance like that. I have seen a lot of other people do that though, so I believe I'm a wimp in this regard.

I've experienced this dozens of times if I don't see the obstacle. I always ride with soft knees, so while the wheel goes over the obstacle my knees do bend as the wheel climbs up the obstacle. During which I'm having a heart attack and nearly pick a god to pray to for me to survive. When I go back to look at the obstacle, it is usually something very tiny. Told ya, I'm a wimp.

I indeed realized another thing I do, which is quite related: before to hit the bump I stop pushing/leaning and I move the wheel under me as if I would try to free float. When decelerating before to hit the bump moving the wheel in front of the body happens anyway automatically, but I think I still go into the "free floating" position with minimal (ideally zero) force demanded from the wheel the moment I hit the bump.

[ir_fuel]

On 6/29/2018 at 11:00 AM, mrelwood said:

Here's a proper video on how I go over curbs and bumps:

 

The speed bump and the low curb, for me they don't even require a special technique. It's like riding over a rough bump in the road. Just keep going at speed (not too close to your device's vmax so you have torque margin and of course make sure you don't get airborne if not expecting it) and use your knees as suspension.

The higher curb requires a bit of a jump. Sometimes my feet let go a bit of the pedals when jumping. I still overcompensate those curbs. I prepare myself as if some kind of big hit is coming but in the end the euc usually takes it with much more ease than I expected.

[ir_fuel]

4 hours ago, mrelwood said:

I've experienced this dozens of times if I don't see the obstacle. I always ride with soft knees, so while the wheel goes over the obstacle my knees do bend as the wheel climbs up the obstacle. During which I'm having a heart attack and nearly pick a god to pray to for me to survive. When I go back to look at the obstacle, it is usually something very tiny. Told ya, I'm a wimp.

Just train. Spend half an hour "curb hopping". I don't even know exactly how I move my balance/euc when riding up a curb. I just started doing it (with a lot of stress in the beginning, that's for sure, you always expect the thing to get stuck while you continue) and it just goes better and better.

[mrelwood]

2 hours ago, ir_fuel said:

Just train. Spend half an hour "curb hopping". I don't even know exactly how I move my balance/euc when riding up a curb. I just started doing it (with a lot of stress in the beginning, that's for sure, you always expect the thing to get stuck while you continue) and it just goes better and better.

Perhaps you read this with a mobile device and didn’t see my signature... I have ridden over 12000km on an EUC, of which 9000 on my 16S. I ride up dozens of curbs, bumps and obstacles both on and off road every day.

2 hours ago, Mono said:

before to hit the bump I stop pushing/leaning and I move the wheel under me as if I would try to free float.

That is indeed quite relevant. I think I use your technique when for example riding over a threshold to and from a bridge (they can be quite harsh at full speed), or when pavement starts without a notable step up, or if there is a larger crack on the pavement. But even on those I usually jump just a little.

I’m not sure if this is a phobia that started at some personal near fall experience, or if I’ve read on too many falls caused by obstacles that ended up being too steep for the rider’s technique. But I prefer to over-compensate every single obstacle rather than have a single surprise even in a week.

[Mono]

6 hours ago, mrelwood said:

I’m not sure if this is a phobia that started at some personal near fall experience, or if I’ve read on too many falls caused by obstacles that ended up being too steep for the rider’s technique. But I prefer to over-compensate every single obstacle rather than have a single surprise even in a week.

Same here, plus I never use protection gear. The good thing with practicing curbs and bumps is that they come in virtually any size and shape here.

[The Wizard]

Question regarding long steep downhill or long sustained hard braking.

My understanding is that an euc generates/charges the battery a little as this occurs. And can even Over Charge a battery.

Why or how come?

The back lean to keep going slow is a function of the motor powerfully resisting the wheel revolutions, correct?

Isn't the motor doing Work to resist this motion? Isn't it consuming electricity?

I do understand that this Resistance results in a by product - some meger amount of electricity being generated.

However, I can just feel the euc laboring hard to stay up or resist falling backward. In hard braking it feels as though it might even Brake and just fall backwards. Like an Extreme amount of power (electrical consumption) is taking place.

Far more than is being generated?

Conclusion? A very long mountain road or steep hill may Not be your friend? We might have a Backward CutOut or failure?

I would like go down longer hills with confidence. Please explain.

 

[Shad0z]

5 minutes ago, The Wizard said:

Question regarding long steep downhill or long sustained hard braking.

My understanding is that an euc generates/charges the battery a little as this occurs. And can even Over Charge a battery.

Why or how come?

The back lean to keep going slow is a function of the motor powerfully resisting the wheel revolutions, correct?

Isn't the motor doing Work to resist this motion? Isn't it consuming electricity?

I do understand that this Resistance results in a by product - some meger amount of electricity being generated.

However, I can just feel the euc laboring hard to stay up or resist falling backward. In hard braking it feels as though it might even Brake and just fall backwards. Like an Extreme amount of power (electrical consumption) is taking place.

Far more than is being generated?

Conclusion? A very long mountain road or steep hill may Not be your friend? We might have a Backward CutOut or failure?

I would like go down longer hills with confidence. Please explain.

 

i dont know much about what actually happens. But the best technique i think would be to let it roll down the hill. Dont push foward dont push backward. Just let it glide

i think @esaj aould know some thing about how all of this actually works

[The Wizard]

I am not exactly inexperianced. Hitting 1000 miles this weekend. I think your very considerate and helpful comment would benefit a new rider in how to relax and better negoiate hills.

No one here just let's their euc free wheel down hills, picking up speed, going faster and faster.

I do feel very compitant in my assent and descent capabilities. Unfortuately, this includes the much sought out Face Plant descent also

My question is not about technique but an Electrical one.

Edited July 6, 2018 by The Wizard
Spelling

[m.s.g.]

I am not anywhere near @esaj's level of electrical expertise, but from what I understand is that in order to create resistance, the electrical motor becomes an electrical generator. Instead of expending energy to drive the wheel, it provides resistance and the forcing of the wheel to rotate generates heat and electricity, which goes to the batteries. If the batteries are at capacity, the BMS will stop the flow of electricity to the batteries which can result in overloading the MOSFETs. This is one of the reasons why it's recommended to not charge the batteries to full capacity. 

Someone please correct me if i'm mistaken. 

[esaj]

1 hour ago, The Wizard said:

Question regarding long steep downhill or long sustained hard braking.

My understanding is that an euc generates/charges the battery a little as this occurs. And can even Over Charge a battery.

Why or how come?

The wheels have what is called "regenerative braking". The wheel (and you) have kinetic energy when moving, and you build up "potential energy" when you go up a hill. Law of conservation of energy says that energy "can neither be created nor destroyed; rather, it can only be transformed from one form to another". What this means is that the energy "stored" in the motion (or "just" plain potential energy when coming down a hill) must go somewhere, it cannot just disappear.

A more technical explanation is given here:  https://electronics.stackexchange.com/questions/56186/how-can-i-implement-regenerative-braking-of-a-dc-motor

Trying to explain it more in layman terms... isn't easy   When you're braking (or coming down a hill, steady speed or braking), the kinetic energy spinning the motor is used to charge the battery by using the motor as a generator. The rotating motor causes a voltage ("back-EMF"), but this voltage by itself isn't high enough to cause current to change direction from "normal" motor driving.

What the stackexchange answer is explaining is that the mosfets and the motor inductances (coils) form a "boost converter", a circuit which "pumps" the voltage up (if you're more electronically inclined, compare this to a boosting switching-mode power supply). During braking (when the motor is actually being slowed down by shorting the phases together), the magnetic fields of the coils are "charged". When the low side mosfet stops conducting, the motor "free wheels" a bit, and then when the high-side mosfet is switched to conducting, the collapsing magnetic field causes the voltage to raise to high enough level for it to become higher than the battery voltage, forcing current to flow in the opposite direction, and thus charging the batteries. After a (very short) while, there's not enough voltage to keep the current flowing "towards" the batteries, and the cycle must be repeated. But as the wheel is turning the mosfets on and off really fast (6000-8000 times per second), you won't notice that it's actually switching between free-wheeling and braking.

EDIT: The 6000-8000 times per second -value comes from the PWM-frequency, which to at least some wheels is around there. It could be that the high- and low-side conducting are changed more infrequently, but anyone who has ridden a wheel knows that you don't feel any "twitching" during braking, and I can't exactly rig an oscilloscope on there while riding the damn thing to see what's going on   

With fully charged packs there's the risk of (at least momentarily) overcharging the batteries, although there are usually large caps in the mainboard next to the battery power lines, which will at least take some of the energy coming from the motor. Overcharging a lithium cell is very stressful for the cell, and can degrade it (and in extreme situations, destroy it). If the battery BMS has overcharge protection also on the discharge side (cutting connection from the discharge side in case of overvoltage), the battery won't be "there" to take the energy, and you'll likely fall.

How much it charges is anyone's best guess. A lot of losses occur along the way (at least resistance of motor coils, mosfets and connectors & batteries), so part of the energy is "lost" as heat (yeah, it doesn't disappear, but changes into "unwanted" form of heat instead of just charging the batteries, thus the power "loss").

There are other ways to slow down an electric motor, like driving the coils in "opposite" (ie. switching it on after it has passed the magnet, attracting it against the direction of the motion) to normal motor driving (I think this was called "plugging braking"), it has been debated before whether wheels could use this method in some situations. The problem with this approach is that the battery and kinetic energy is then transformed only to heat, in the mosfets and motor coils, and it's very taxing to the motor, and could burn the mosfets or the coils (or PCB traces, wiring or connectors). Still, it's possible that the wheels could use this method in some more extreme situations (power braking).

 

Quote

The back lean to keep going slow is a function of the motor powerfully resisting the wheel revolutions, correct?

The "resistance" (opposition) to spinning faster is caused by the phases being shorted together. If you ever for any reason need to disconnect the motor from the mainboard, you can try it: with the motor disconnected from the mainboard, try to spin it with your hand. It should spin relatively easy at this point. Now, take two connectors coming from the motor and press them against each other. Now try to spin the motor. You'll notice it's much harder to spin the motor now. You could also put the motor spinning with your hand, then touch the connectors together. The motor should brake really fast.

 

Quote

Isn't the motor doing Work to resist this motion? Isn't it consuming electricity?

If it's "plain" regenerative braking, the motor is producing, not consuming energy. If it's the "plugging"-type braking, then it would be consuming.

 

Quote

I do understand that this Resistance results in a by product - some meger amount of electricity being generated.

Pretty much all resistance does is mostly causing power dissipation as heat.

 

Quote

However, I can just feel the euc laboring hard to stay up or resist falling backward. In hard braking it feels as though it might even Brake and just fall backwards. Like an Extreme amount of power (electrical consumption) is taking place.

Far more than is being generated?

The momentary power from hard braking can lead to somewhat extreme power being produced. I'm too tired to break open the physics books, but I'd say that a 100+kg of mass being decelerated very quickly can produce quite high momentary power. Enough to even burn the mosfets (that has happened at least in older wheels with heavy riders and strong braking).

 

Quote

Conclusion? A very long mountain road or steep hill may Not be your friend? We might have a Backward CutOut or failure?

I would like go down longer hills with confidence. Please explain.

Unless you try to stop on a dime from fast speed coming down the hill, and your batteries aren't charged to full, at least the more modern wheels should be safe in this regard. I've had the "pleasure" of finding out about the BMS overcharge protection in discharge side & full batteries in a downhill...

Edited July 6, 2018 by esaj

[Demargon]

Thanks for your knowledge @esaj. Worth it to read many times for assimilate the few things I can understand.

I pleased to share my small discovers about euc riding:

For drops of big curbs I think more in pushing the pedals instead to bend my knees, bending it the same but results in more progressive absorption.

When the drop is too big I land with one foot in the floor for euc axis protection.

For climb curbs I approach it slowly, doing a fast push up and forward against the curb, relaxing the knees in the contact for better follow of the euc bounce, that normally makes you jump, so take care.

Finally the wobbles behaviour can be solved riding in slight slalom instead of going perfectly straight.

[The Wizard]

Thank you very much. This is what i was after. I will re-read it several times.

I also now understand how rare a back Cut Out or failure would be. The effort or circumstances to make it happen. This is the confidence I was referring to.

A very Special thank you for your time!

[littlelio]

Hi I am a new bee on the EUC, although I am able to ride a two-wheel version. So I thought at least I am not from scratch.

It was frustrating that the fact is harder than I imagined. But this thread definitely helped, and after some careful reading, and 1 hour practice, now I can ride my S2 without any support on a straightline for more than 20 meters. If I could summerize the points from my experience, hopeful helping others:

1. A strap is very helpful to avoid smashing your EUC again and again. The only warning is that do not pull the strap while you are ride, since ninebot S2 will suddenly stop spinning if you lift the handle. Again, very dangours to pull the strap during moving.
2. Patience. The muscle needs time to learn balance the body, which takes time. Do not expect learn it in one day, pracetise and take a rest, and go on. - of course with other balancing activity background someone may learn very quickly.
3. Use your leg! not only your upper body to get the balance. This advice from this thread is extremely helpful. I am a long time bicycle rider, and I am quite good at it. The mistake is that I used my upper body to balance on EUC, which is not the right way. Of course upper body would help, but most of the central of gravity is controlled by legs.
4. Pyschologically, find your way to balance. Useful advice from here: look ahead and find a target point, then ride to it in straight line. Your muscle will do the work, to keep the central gravity falling on the wheel. It is simple physics, but to get the muscle trained, you have to find a good system to adapt. Looking at the groud or even the wheel will not help. With the help of the strap trick, not too much damage will be done to you or the wheel so just relax.
5. Other basic theory can be found in many online videos, but above I think it is the keys, which should remember repeatedly when practising.

My next step is to teach my 7-year old son ride the EUC. Bless...

[mrelwood]

3 hours ago, littlelio said:

My next step is to teach my 7-year old son ride the EUC.

That should happen in an instant. Kids tend to be unbelievably fast in learning these.

Good luck with this great new hobby!

[Stabio]

I am still learning so I would like to thank everyone who has contributed their good advice. There is invaluable advice that will reduce my frustrations.

What I have learnt so far;

You are training your brain to balance so give it time. I think quality over quantity. 15 minutes of quality practice is better than one hour of frustration. One hour spread over a couple of days is better than one long slog. The brain puts important information into the right slots while you sleep. You learn while you sleep.

Let go of the wall. I struggled learning to ride a non-powered unicycle until a friend told me I need to go straight into the wild. No hand rails. 30hrs after going only 5-10 metres I suddenly could go 100m. Then I bought a EUC and stopped practicing. I can now jump onto a unicycle and go straight but with a struggle. I intend continue learning.

I spent quite a few hours getting the feel of my Ninebot One E within the house. The first time I rode in the open I was horrible. I was scared of destroying my new toy. I did not show bravery for months. I would hop on with intrebitation. My young daughter could ride through the house. I was scared.  Be brave. You can do it. It took me 30 minutes to achieve 100m after I made a real effort. My EUC took a few big tumbles. Next day I practices free mounts. I got it, 1 out of 10 tries. My turns are still bad.

I can now go for a long distance on a nice flat path. If I’m scared I know how to crash but that’s not my desire. I want to control my EUC with safety. Once again I will try to do quality practice. I watched a YouTube video where the veteran  EUC rider spoke about dodging leaves as he rides. He spoke about continuing his learning everything he rides. Yesterday, on netball courts, I tried going in a perfect straight line, doing smooth turns, moving one side of the line to the other lines and dodging leaves. EUC is like an other sport where the fundamentals are important.

My biggest obstacle is fear.

[mrelwood]

18 hours ago, Stabio said:

My biggest obstacle is fear.

Padding up the wheel and the rider usually helps overcome this fear. And practicing on smooth dry grass.

Remove the padding from the wheel once the fear is in control. But leave the padding on the rider!

[Elder Meat]

My progress seems to be going pretty quickly, so I consider myself fortunate.

• Day 1: 15 minutes spinning in a slow circle around one planted foot.
• Day 2: Mount and start moving while holding onto a wall. 20 minutes learning to take large circles in a parking lot.
• Day 3: Mount and start moving while holding onto a wall. 15 minutes learning to take small circles on level and turn around on inclines.
• Day 4: 30 minutes taking wide circles over slightly bumpy asphalt. 20 minutes learning how to mount from a freestanding start. (Two short hops then step on.)

My challenge now is learning how to dismount and keep control of the wheel with my dominant foot. After that I figure it will be just developing balance and muscle memory to improve overall skill. My one "aha" was to clamp onto the wheel with the sides of my feet rather than the inside of my calf. I feel more stable and in control that way mounting the wheel. Any suggestions for learning the controlled stop?

[RockyTop]

 RockyTop's beginner guide  A summery of things to know and expect as a beginner.