How to ride an electric unicycle - understanding the dynamics

[rcgldr]

1 hour ago, Eucner said:

I'm a great fan of Hirsute, but not sure if everything he does translates to normal. Here we can see wheel going straight and turning by on it's own. Both shots last only few seconds and might have needed several takes. It is fun to see dog riding a wheel. At the first it is carving deeply and then it straightens up. I wouldn't rule out dog actively balancing it.

Speed is a factor as mentioned in this video "the faster you go ... the unicycle ... stay level". At the end of the video in the bonus scenes, the EUC is "hiked" at a faster speed to another rider (since a rider isn't trying to jump back on, it could be launched at a higher speed) and it is more stable (stays vertical and goes straight).

https://www.youtube.com/watch?v=VYDZ6FzUEGY&t=922s

I doubt the dog knows how to balance an EUC. This is a case of a lone running EUC with the center of mass a bit higher due to the dog being on the EUC. 

My beginner experience with my V8F was that at 3 to 4 mph, I had to steer for balance, but at 6 to 8 mph, the V8F became self-stable, and I didn't have to steer for balance. My guess is that some beginners get the impression that something just clicked allowing them to be balanced on an EUC, when I suspect in many cases that they just started riding fast enough for the EUC to become self-stable.

In Kuji Roll's how to ride EUC video, where a girl learns how to ride an EUC for the first time, he emphasizes that she needed a bit more speed to ride the V8.

https://www.youtube.com/watch?v=t6o8ZMlo5ko&t=298s

At 8:05 into the video, the girl is going faster and is much more stable.

Edited December 15, 2021 by rcgldr

[Eucner]

1 hour ago, rcgldr said:

Speed is a factor as mentioned in this video "the faster you go ... the unicycle ... stay level". At the end of the video in the bonus scenes, the EUC is "hiked" at a faster speed to another rider (since a rider isn't trying to jump back on, it could be launched at a higher speed) and it is more stable (stays vertical and goes straight).

https://www.youtube.com/watch?v=VYDZ6FzUEGY&t=922s

These were much longer shots, but for me it still was just delayed falling. When the wheel starts to turn it doesn't straighten up again by itself, which would show it being self-correcting.

[rcgldr]

8 hours ago, Eucner said:

These were much longer shots, but for me it still was just delayed falling. When the wheel starts to turn it doesn't straighten up again by itself, which would show it being self-correcting.

If speed is sufficient, a lone running EUC may turn, but will not fall.

The premise is with a rider on board with no relative (to the rider) foot movement, any small imbalance leans rider and EUC by the same amount, causing the EUC to steer enough (camber effect) to guide it back under the rider, and with no relative (to the rider) foot movement, as the rider returns to vertical, the rider causes the EUC to also return to vertical.

This is something you can try for yourself. At lower speed, a rider senses falling and needs to steer for balance, but at some faster (stable) speed, there is no sensation of falling or having to steer for balance if just riding in a straight line and not trying to turn. At least this is what my experience was when I learned to ride.

Before I learned to ride, in addition to watching several how to ride videos, I also watched the next video as a guide for tilt steering, since the girl on the S18 in the video is almost motionless (Marty Backe style - no arm flailing, no body twisting, no constant carving). The ride looks extremely stable, and there are no perceptible correcting movements when she's going straight. When turning, due to weight, speed, turning radius, she leans more than she tilts the EUC, and this does require the rider to coordinate how much to body lean and an how much to tilt the EUC for a balanced turn. Near the end of the video, she weaves side to side, which I tried to mimic when first learning how to tilt steer.

https://www.youtube.com/watch?v=-hWMwK3Cfs0

 

Edited December 15, 2021 by rcgldr

[Eucner]

2 hours ago, rcgldr said:

...the rider causes the EUC to also return to vertical.

This means the tire is not self-correcting. If there would be a rigid weight instead of the rider, the wheel would make tighter and tighter turn until it would fall. From higher speed it would just take more time, result would be the same.

[rcgldr]

1 hour ago, Eucner said:

This means the tire is not self-correcting. If there would be a rigid weight instead of the rider, the wheel would make tighter and tighter turn until it would fall. From higher speed it would just take more time, result would be the same.

With a rigid weight rigidly attached via a pole to the frame so that the weight is sufficiently above the EUC, then if in response to a small lean angle due to imbalance, the EUC steers back under the weight, then as the pole returns to vertical, since the pole is rigidly attached to the EUC, the pole returns the EUC to vertical as the pole returns to vertical. That would be a self-correcting response for the system of weight, pole, and EUC.

[Eucner]

8 hours ago, rcgldr said:

With a rigid weight rigidly attached via a pole to the frame so that the weight is sufficiently above the EUC, then if in response to a small lean angle due to imbalance, the EUC steers back under the weight, then as the pole returns to vertical, since the pole is rigidly attached to the EUC, the pole returns the EUC to vertical as the pole returns to vertical. That would be a self-correcting response for the system of weight, pole, and EUC.

That theory would be nice to have tested.

[rcgldr]

9 hours ago, Eucner said:

That theory would be nice to have tested.

The known facts are that at sufficient speed, an EUC becomes stable from a rider's perspective, and that tilting an EUC generates enough steering torque to steer both the EUC and rider, as seen in that video of the girl on an S18 I linked to above. The poster of the video commented that she had ridden 200 to 300 miles by the time of that video.

As for evidence of stability, my wife took a video of me on my 10th day of riding my V8F at night on a large pathway. I have the V8F headlight on, and any steering motion can be observed due to the beam from the headlight. From the start of the video, you can see my arm movements and steering motion that diminishes to very little movement and steering motion as speed increases to 8 mph or so. On my way back from the half circle from the back, I'm weaving for tilt steering practice, then stop weaving a bit before I start slowing down to stop and dismount.

https://www.youtube.com/watch?v=keDvRMScO1g

Once I lower my arms and relax them, I can see in the video that I'm making small arm movements, but I'm unaware of these small movements when I'm riding. You can see the girl in the video above making similar small arm movements when the camera is at her side and her arms are relaxed, but at other times, she's holding her arms still, like when she signals for a turn, so the small relaxed arm movements are probably the result of disturbances, while larger movements would be rider induced (for balance). The surface of the road | pathway is probably triggering small disturbances (that pathway I was on has bumpy seams). In the video of the girl above, there are a few spots where a small wobble occurs, but the girl appears to ignore them and they go way on their own, a form of self-correction. 

Over time, I developed a somewhat reflexive tilt | yaw steer response in my feet. I also improved my ability to look around and|or move my arms without upsetting balance. The most impressive case of rider movement while riding an EUC I've seen in a video is a girl (gracexdolly): she takes her backpack off one arm, while holding a cell phone with her other hand, moves the backpack in front of her, speeds up a bit, puts the cell phone into the backpack, puts the backpack back on, and speeds up again, all while riding a very stable EUC:

https://www.youtube.com/watch?v=Q5HB40I4C3g&t=440s

 

Edited December 16, 2021 by rcgldr

[Eucner]

23 minutes ago, rcgldr said:

The known facts are that at sufficient speed, an EUC becomes stable from a rider's perspective, and that tilting an EUC generates enough steering torque to steer both the EUC and rider, as seen in that video of the girl on an S18 I linked to above.

At the higher speed it is easier to correct the balance. Wheel moves faster under the falling rider and catches him/her at the very early stage. Very little corrections are enough. Those little shifts of riders balance are hardly noticeably from a video. Multiple accelerometers and pressure sensors should be used. Or better, rigid weight and no rider. That would give a very little room for doubts.

[rcgldr]

7 hours ago, Eucner said:

At the higher speed it is easier to correct the balance. Wheel moves faster under the falling rider and catches him/her at the very early stage. Very little corrections are enough. Those little shifts of riders balance are hardly noticeably from a video. Multiple accelerometers and pressure sensors should be used. Or better, rigid weight and no rider. That would give a very little room for doubts.

I updated my prior post to note that small disturbances in the road | pathway are the most likely cause of those small movements.

Getting back on point, my learning experience was my V8F became stable the very first time I rode it at 6 to 8 mph. Prior to that, I was riding at 3 to 5 mph, using arm flailing (flail left to steer right and vice versa) for balance (steer into fall), but at 6 to 8 mph, I no longer had to focus on balance, and could relax and lower my arms and focus on speed control and learning to tilt steer. If I was making small corrections, I was unaware of it.

It is possible that I was sub-consciously balancing in the same manner as person standing on the ground: where a person pushes down with their feet to remain vertical, pushing down with the left foot to correct a left lean, pushing down with the right foot to correct a right lean, and on an EUC, this same foot pressure would cause the EUC to steer into fall. The issue here is that I was unaware of making any balance corrections once I was at a stable speed, so I don't what, if anything, that I was doing for balance. 

Edited December 16, 2021 by rcgldr

[Julian Lo]

On 12/16/2021 at 3:09 PM, rcgldr said:

I updated my prior post to note that small disturbances in the road | pathway are the most likely cause of those small movements.

Getting back on point, my learning experience was my V8F became stable the very first time I rode it at 6 to 8 mph. Prior to that, I was riding at 3 to 5 mph, using arm flailing (flail left to steer right and vice versa) for balance (steer into fall), but at 6 to 8 mph, I no longer had to focus on balance, and could relax and lower my arms and focus on speed control and learning to tilt steer. If I was making small corrections, I was unaware of it.

It is possible that I was sub-consciously balancing in the same manner as person standing on the ground: where a person pushes down with their feet to remain vertical, pushing down with the left foot to correct a left lean, pushing down with the right foot to correct a right lean, and on an EUC, this same foot pressure would cause the EUC to steer into fall. The issue here is that I was unaware of making any balance corrections once I was at a stable speed, so I don't what, if anything, that I was doing for balance. 

This fellow in the video didn't have the speed to aid his balance while riding on those rocks.   Neither had he the luxury to ride into the direction of the fall to regain balance.  Did he constantly use his right and left calves to push the wheel to center for balance? or did he use a combination of both?  I tend to think that one has to learn how to balance at a lower speed (e.g. 2 mph) in order to handle balance naturally at a higher speed (6-8 mph).  Surely, at a higher speed, balance is less of an issue, but at a higher speed one loses the opportunity of learning how to balance.   I am just thinking out loud.  

 

Edited January 11, 2022 by Julian Lo
Video failed to dispaly

[Paul A]

Angular momentum increases with speed.

Angular momentum stabilizes the wheel in an upright position.

 

 

[rcgldr]

On 1/11/2022 at 12:04 PM, Paul A said:

Angular momentum increases with speed. Angular momentum stabilizes the wheel in an upright position.

From what I've read, camber effect steering is the primary factor for an EUC to become stable at some speed. Similar to steering geometry (trail) on a bicycle, it steers into the direction of fall (assuming no relative foot movements by the rider so that the EUC tilts as much as the rider leans sideways due to a small imbalance), and also similar to a bicycle, at sufficient speed, it steers enough to correct for small imbalances, but the range of imbalance correction on an EUC is smaller than that of a bicycle. 

Angular momentum resists changes in lean (and steering) angle, but doesn't correct for lean angle. Precession effect steering would be too small or too slow for self-correction. Note how slow the precession response is in the video with the bicycle wheel to a fairly large torque due being suspended well away from the center of mass of the bicycle wheel. Angular inertia of the rotating parts is relatively small compared to mass of EUC plus rider. 

Edited January 13, 2022 by rcgldr

[mrelwood]

1 hour ago, rcgldr said:

From what I've read, camber effect steering is the primary factor for an EUC to become stable at some speed.

I agree. Switching to a knobby tire that has much less camber effect and no difference in gyroscopic forces, it feels like the wheel must be brought back upright manually after a turn. In which situation the gyroscopic forces seem to overcome the forces of the camber effect, which is what would keep the wheel in a tilted position after a turn.

I think for the same reason an EUC with a knobby is much more resistant to wobbles. In which I claim for the camber effect to be the main force in a wobble as well.

[rcgldr]

5 hours ago, mrelwood said:

I think for the same reason an EUC with a knobby is much more resistant to wobbles. In which I claim for the camber effect to be the main force in a wobble as well.

Kuji Rolls also agrees with your comment. He made a video comparing a street tire versus a knobby tire on a Sherman and noted the reduced camber effect of the knobby tire. With the knobby tire, the Sherman has to be tilted more than it does with the street tire to make the same turn. However, he felt the street tire was too sensitive above 30 mph and his conclusion was the knobby tire was better for speeds above 30 mph, while the street tire would be better for speeds at or below 30 mph 

[Julian Lo]

This is the most useful video I have found on how to ride a EUC.  The most inspiring point he made was Riding a EUC is an implicit learning - “What we are figuring out without the awareness of what has been learned.”  Time stamp 2:38.  

 

[.....]

How odd. Knobby is better for speeds above 30mph and street for under 30mph? I found the exact opposite to be true, especially if ANY turning is invloved. Of course, I have a tendency to not overthink it and just ride.  Same with the decades of street and dirt bike use. It never once occured to me to put knobbies on my road track bike and slicks on my dirtbike. Maybe I should have. Altho, at the time I wasnt thinking too hard, I was merely doing what the many professionals before me, had already come to conclude. I guess I must have changed my view when it comes to euc's, as I refuse to simply accept what the 'pros' are spouting. I've come up with my own results thru personal testing rather than intense reading. Strokes for folks as the usual, it seems.

Edited January 13, 2022 by ShanesPlanet

[mrelwood]

 

1 hour ago, ShanesPlanet said:

It never once occured to me to put knobbies on my road track bike and slicks on my dirtbike. Maybe I should have.

Absolutely, as long as you only have one tire on the ground at all times and rely on the camber effect for turning and the lack of it for stability!

The thing about overthinking is that it allows you to understand in which circumstances a certain tip may or may not be useful.  

[rcgldr]

On 1/13/2022 at 7:45 AM, Julian Lo said:

This is the most useful video I have found on how to ride a EUC.  The most inspiring point he made was Riding a EUC is an implicit learning - “What we are figuring out without the awareness of what has been learned.” 

That's not the way it worked for me. I was aware of what I was doing during my entire learning experience. Knowing that I had to steer into fall for balance (counter-steering), and as seen in a few beginner videos, my plan was to use arm flailing, flail left to steer right and flail right to steer left to steer into fall for balance and to direct my V8F at slow speed, 3 to 5 mph. I'm not sure why arm flailing isn't mentioned in a lot of the how to ride EUC videos, since it is useful when first learning to ride at slower speeds. After using a fence for supported mount, and a couple of minutes going back and forth using fence for support to get used to how the V8F would respond to speed control inputs, I ventured away from the fence and was able to do laps around a tennis court on my first attempt. My wife took a video from day 2, but it was essentially the same as my first attempt at arm flailing. The video was helpful in that I didn't realize I was hunched over so much, which I corrected afterwards:

https://www.youtube.com/watch?v=zPyy84EThmM

You are not always falling on an EUC. At some speed, an EUC becomes stable, similar to a bicycle, but due to different physics. Assuming a rider makes no relative foot movement, then the EUC tilts the same as the rider leans sideways, and at sufficient speed, steers enough to correct for small imbalances. After 3 short sessions at the tennis court, I moved to a long straight where I felt comfortable going a bit faster, since many how to ride EUC videos mention speed is beneficial. At around 6 mph I found my V8F to become stable. I didn't have to focus on balance any more (since I was not always falling). Leaning forward | backwards for speed control was instinctive. I then experimented with tilt steering (inner foot down, outer foot up) to see how the V8F would respond, then did some weaves, and then some large radius turns. I had to experiment and consciously estimate how much to body lean and how much to tilt the V8F, depending on speed and turning radius, making mid-turn corrections using conscious counter-steering, tilt|steer more to lean less, tilt|steer less to lean more. I was still using support for mount and launch, so it was time to learn to free mount, my only time on grass. Since I could already ride, there was no need to learn one foot glide, so I just did a couple of steps and hopped on (like a skateboard). Since it was my first time on grass, I didn't lean enough to get it going on the first two tries and had to step off, but got it on the third try. My wife was with me on day 10, and took a video. You can see just how stable the V8F is, since it's night and the headlight is on.

https://www.youtube.com/watch?v=keDvRMScO1g

Some riders are able to ride on their first attempt at riding, after having done some drills. In this case, the rider already knew how to ride a non-powered unicycle. The other guy was having balance issues, until they were switched to a more stable EUC. The entire video is humorous. 

https://www.youtube.com/watch?v=X-dDOxvmzvQ&t=143s

I did weave and turn drills to improve my tilt steering inputs, hoping that eventually it would become reflexive, a transition that occurred between 1 month | 75 miles to 2 months | 150 miles. 

I'm an old guy (70 years old now, 69 1/2 when I received my V8F). An old dog learning a new trick.

Edited January 14, 2022 by rcgldr

[rcgldr]

11 hours ago, ShanesPlanet said:

How odd. Knobby is better for speeds above 30mph and street for under 30mph? I found the exact opposite to be true, especially if ANY turning is invloved. Of course, I have a tendency to not overthink it and just ride.  Same with the decades of street and dirt bike use.

To follow up on mrelwood's response, there is no camber effect on bikes and motorcycles, because any camber effect steering at the rear tire would require the front tire to skid sideways (and vice versa). Instead bikes turns because of tracking, the front wheel is turned inwards of the rear wheel. For a leaned bike, if you were to virtually extend the front and rear wheel axis into the pavement, they would cross at some point below the pavement, and the point on the pavement directly above the point where those lines cross is the center of the circle the bike tends to follow. Due to lateral load deformation (slip angle), the actual turning radius will be a bit larger, and the point above where those lines cross will move in a tiny circle. If a knobby is used instead of a street tire, the lateral load deformation is greater, and it takes a bit more steering to get the same turning radius, assuming speed is the same.

There are two ways to steer an EUC. Yaw steering where the rider directly steers the EUC, and tilt steering, where due to camber effect, the EUC steers the rider. It's a bit more complicated than steering on a bike because tilt steering | camber effect response is not linear, and depends on tire profile, speed, ... . A knobby tire has a reduced camber effect compared to a street tire. You have to tilt a knobby tire more to make the same turn, but at high speed, the reduced camber effect makes the EUC less sensitive to tilt, and also less prone to wobble.

[Julian Lo]

https://youtu.be/77WFrQYfytg

1. The faster you go, the harder you hit the ground as the footage showed.

2. No matter how long you’ve been riding, you will crash when you are stepping out of your comfort zone. 

[Tawpie]

18 minutes ago, Julian Lo said:

No matter how long you’ve been riding, you will crash when you are stepping out of your comfort zone. 

I’ve discovered that I crash even when I’m in my comfort zone. Dress accordingly!

[Paul A]

The crash from time mark 40 secs shows why a full face helmet is needed.

Some cheap full face helmets might not actually have a structurally sound chin bar.

It might just be cheap, plastic moulding that gives the appearance of a full face helmet.

Safety certifications may not be actually good indicators of quality.

Brands like Shoei, Arai and AGV used by moto gp riders are a better indicator of quality.

[HardyM]

A helmet is the most essential safety equipment you will need so it’s imperative to make the right choice. The protection that helmets provide is highly dependent on finding one that fits you well and wearing it correctly. It should give you a snug yet comfortable fit when fastened securely and should not tilt towards the back head or sit low over the forehead.

[Paul A]

https://www.championhelmets.com/

Champion Helmets in the Netherlands are a great retailer of motorcycle protective gear.

Huge range, worldwide shipping, great prices.

[Paul A]