Understanding the real world considerations and implications of Speed VS Torque models

[Chriull]

1 hour ago, on one said:

I hope over lean wheel failure can be prevented with firmware and hardware solutions. I know not how to do this, but am optimistic.

Optimism is great but science is more realistic

 

[on one]

Well, that should be enough to make me want to stop riding. That seems so risky according to the graph and since nobody seems to think it possible to produce a proper wheel that does not fail. I'm not going to stop riding though.

I can tell how much power my wheels have in reserve by if my pedals start to dip forward, so I don't push it.

[Rawnei]

14 minutes ago, on one said:

Well, that should be enough to make me want to stop riding. That seems so risky according to the graph and since nobody seems to think it possible to produce a proper wheel that does not fail. I'm not going to stop riding though.

I can tell how much power my wheels have in reserve by if my pedals start to dip forward, so I don't push it.

The take-away is to not overlean, not to stop riding, unless you have some uncontrollable urge to overlean?

[on one]

It's just that @Chriull has been around here so long that I know he's seen a lot of riders get injured and I wonder if he thinks it's just not worth the risk. That's what concerns me more than that graph.

[rcgldr]

An EUC does not balance a rider. Assuming a hard pedal setting, an EUC only tries to remain vertical (with respect to gravity). If the rider exerts a torque, that will tilt the EUC, and the EUC will exert a torque to return the EUC back to vertical, and continue to exert whatever torque is needed to maintain its vertical orientation. The bottom line here is a rider is doing the balancing, by the amount of torque the rider exerts onto the EUC, which the motor will match, exerting an opposing torque onto the EUC frame to counter the torque from the rider, and exerting a torque in the same direction as the rider's torque onto the wheel+tire. Once the EUC is no longer tilting then the motor torque matches the riders torque.

In a true overlean, the rider exerts more torque than the motor can compensate for, resulting in the EUC tilting and the rider losing balance. An EUC can beep, or pedal dip as a warning, while the motor still has enough torque | power to recover. Tilt-back is normally used for approaching maximum speed.

With a soft pedal setting, the motors response is delayed and|or reduced to allow the EUC to tilt, before increasing torque to hold a steady tilt angle. In the case of the V13, there is a speed related issue with a soft mode setting. At 100% ⇔ hard pedal mode setting, the V13 has a top speed of 52 mph GPS, but at 0% ⇔ soft mode pedal setting, top speed is limited to 33 mph GPS.

There is always the possibility of electronic failure. Marty Backe was riding at about 12 mph when his A2 just stopped balancing, breaking his ankle. Roger EUC took it, never figured out what cause the failure, and the failure never occurred again. Roger EUC still has that A2.

 

[on one]

11 minutes ago, rcgldr said:

If the rider exerts a torque, that will tilt the EUC, and the EUC will exert a torque to return the EUC back to vertical, and continue to exert whatever torque is needed to maintain its vertical orientation.

I never had a problem keeping a vertical orientation, and I'm really not overly worried because I don't ride on low battery power and if my nose starts to dip forward then I level off and pump my legs a bit if I want to go faster.

14 minutes ago, rcgldr said:

There is always the possibility of electronic failure. Marty Backe was riding at about 12 mph when his A2 just stopped balancing, breaking his ankle.

Yes, that was concerning and it's happened to a lot of riders who are members here, fallen off and broke something.

I enjoy my KS14D and I'm careful not to over lean, its a lot of fun.

 

[alcatraz]

10 hours ago, EUCzero said:

Begode HAVE implemented PWM tiltback. Not sure why you belive they have not.
That is also one of the reasons why Ronnie say moders EUC are more safe than old like 14D.

PWM tiltback is the sollution fro overlean cutouts. But for it to work the riders MUST use the function, and they MUST respect the tiltback.
There is only one more way to eliminate overlean cutouts, and that is to make the EUSs infinte powerful.

Not sure why "on one" seems to think preventing overlean is as simple as a programming thing. Overleaning is done by the rider, but by the machine.
WHEN the rider overlean it means that the rider continue to lean forward even if the EUC already is at 100% power. And then the EUC can't accelerate more to keep the rider in balance, and the rider will tilt more and more forward until the EUC has to cut due to it believing the rider has fallen off (angle to high).

 Not sure if "on one" actually understand what happenes during overlean. As others have written allready. Only thing the EUC can do is to try to tiltback the rider before reaching 100%. And that is what 80% PWM tiltback is. But remember, sometimes the time between 80% and 100% is too short for the tiltback to actually kick in.
 

That's cool. Do you mean that in the official Begode app the primary safety setting is now a pwm percentage value?

I'd love to see some screenshots. Which models/firmware versions were the first to implement this with factory firmware? I always buy older models and it would be cool to have this feature.

Edited August 2 by alcatraz

[Rawnei]

9 hours ago, on one said:

It's just that @Chriull has been around here so long that I know he's seen a lot of riders get injured and I wonder if he thinks it's just not worth the risk. That's what concerns me more than that graph.

How to get through to you? It's in your own control to not overlean, it's the rider overleaning it doesn't happen by itself, ride within what your wheel is capable of and it doesn't happen, push harder than what the wheel can handle and it happens, it's 100% something that you can control.

[Bizra6ot]

4 hours ago, alcatraz said:

That's cool. Do you mean that in the official Begode app the primary safety setting is now a pwm percentage value?

I'd love to see some screenshots. Which models/firmware versions were the first to implement this with factory firmware? I always buy older models and it would be cool to have this feature.

The three main changes compared with previous models in terms of safety are as follows:

-Beeps now have 3 levels within a 10% range (alarm set at 80% pwm: one beep at 70%, 2 beeps at 75% and the classic sequence of 5 beeps at 80%).

-The pwm alarm/tiltback value is no longer locked at 80%, but is now adjustable from 50% to 90%.

-Pwm tiltback
 

There are some screenshots in this topic 

 

[Rawnei]

4 minutes ago, Bizra6ot said:

The three main changes compared with previous models in terms of safety are as follows:

-Beeps now have 3 levels within a 10% range (alarm set at 80% pwm: one beep at 70%, 2 beeps at 75% and the classic sequence of 5 beeps at 80%).

-The pwm alarm/tiltback value is no longer locked at 80%, but is now adjustable from 50% to 90%.

-Pwm tiltback
 

There are some screenshots in this topic 

 

Are you sure about PWM alarm being adjustable? Usually it's the tiltback that is adjustable and PWM alarm being fixed, I think maybe you interpreted @EUCzero text as such but it was more an example that this fixed alarm is usually between the ranges he specified but you can not change it, it's a last resort alarm that you can not change or turn off.

[Bizra6ot]

8 minutes ago, Rawnei said:

Are you sure about PWM alarm being adjustable?

Yep, in the 2nd screenshot "power alarm" 

[alcatraz]

Thank you @Bizra6ot

Is Power Alarm available on T4, Master v1, RS?

[EMA]

41 minutes ago, alcatraz said:

Thank you @Bizra6ot

Is Power Alarm available on T4, Master v1, RS?

dynamic tilt is avaible on all wheels after Master

RS can change the % within 5% step but does not have dynamic tilt

[on one]

4 hours ago, Rawnei said:

It's in your own control to not overlean, it's the rider overleaning it doesn't happen by itself, ride within what your wheel is capable of and it doesn't happen, push harder than what the wheel can handle and it happens, it's 100% something that you can control.

I want to believe you. However, that doesn't address @Marty Backe's wheel report on his wheel failure. What you are contributing @Rawnei makes me doubt if Marty's report is accurate, not that he would lie, he might just not remember what really happened because of the trauma of his accident.

[on one]

2 hours ago, Bizra6ot said:

The three main changes compared with previous models in terms of safety are as follows:

-Beeps now have 3 levels within a 10% range (alarm set at 80% pwm: one beep at 70%, 2 beeps at 75% and the classic sequence of 5 beeps at 80%).

So, that means basically, stop accelerating when you hear your wheel beep once. I might miss that warning. I mean, it's just one little beep. Like a little sparrow could have made that sound and I don't know if it was my Begode or my imagination?

[alcatraz]

The third party begode firmware with pwm tiltback, is that just the addition of tiltback onto the existing 80% pwm alarm?

I thought the firmware did something more special.

[techyiam]

1 hour ago, on one said:

6 hours ago, Rawnei said:

It's in your own control to not overlean, it's the rider overleaning it doesn't happen by itself, ride within what your wheel is capable of and it doesn't happen, push harder than what the wheel can handle and it happens, it's 100% something that you can control.

I want to believe you. However, that doesn't address @Marty Backe's wheel report on his wheel failure

You mean his A2? Rewatch Marty's video on that. Marty's recount of the incident was that the wheel turned off by itself. 

 

 

[on one]

Okay then, it was a Begode wheel failure that caused Marty's very serious accident. Begode looses 10 points, but they are still in the game.

[Planemo]

2 hours ago, on one said:

I might miss that warning.

You might, yes.

So you listen for it like a hawk. And you don't blare out music. And you get used to what speed the beeps are likely to occur at, at what battery percentages.

If you can't do any of that you either crash and learn the hard way or you don't ride near beep speeds to start with. It's a big reason why I bought an EX30 - my ride speeds are very rarely anywhere near beep speeds and to be quite frank I don't even listen for them anymore. That said, I do run PWM tiltback just in case.

[on one]

@Planemo, there is most certainly something to be said about making sure that your wheel is actually equipped with minimum the hardware required to provide a safe ride.

[Planemo]

Well it does help but I've yet to overlean any wheel (V5F/Z10/MSX/Sherman/EX30) so I would suggest the best help is the rider knowing the limits of the wheel. I've always regarded any in-built wheel safety measures as backup, not a primary to avoid crashes.

[timmytool]

I've over leaned/torqued my T4 twice at speed, once resulting in a crash.

Think about a euc over torque like driving a underpowered car up a hill. If you stay in a high gear you will lose speed, and eventually stall the car. This is a over torque, the change in environmental variables has asked the motor for more torque then it can provide. In that same underpowered car on the same hill, if you go down in speed and/or pick a lower gear you will have the touque to maintain that speed and still have throttle control to accelerate. Now the same scenario but with a better spec'ed car, it can go faster up that same hill befor it maxes out its motors torque capabilities, it might not ever exceed its torque capabilities. In euc terms a better more powerfull wheel will be safer and will operate at the same speed with more safety margin.

Over lean is the same but your the one asking for more torque not the environment(hill pothole wind etc). Unlike a hill over torque, over leans often happen at faster speeds as the motors ability to generate torque diminishes as it approaches its kv limit. A motors kv limit is similar to a cars rpm redline but on electric motors the torque drop off is more pronounced, a cars torque will drop off but its more about the engine self disassembling. Over leans make you more susceptible to over torques and at the max speed/torque limits the two are the same. Over leans at lower speeds are doable but modern eucs will lose tyre traction even on flat ground first. Old eucs can over lean at low speeds due to their low powered motors/controllers and batteries hence the opinion of them being less safe then modern euc.

In a euc safety is not accelerating as you approach your top speed and backing off up hills etc. Unlike a car that you can pin the throttle to the floor eucs cant operate at 100% throttle(lean) and road imperfections hills wind gusts etc can affect your lean and torque demands on the motor. On older eucs safety limits you even more, as motor, controller, and battery limits on torque can affect the rider at easier to access riding scenarios.

On my lynx I am 70% the limit with the tyre being the other 30%. I've gone over 75 km/h (45 mph) and only made it beep on road imperfections. Off road and up stairs grip is the limit, better rider control can aid in keeping grip and I'm backing off befor the tyres limit more often then not.

In my rider group others can make it beep past the first beeps with and without hi speed mode (increases the motors kv limit at cost of less torque) but that does not take away from it being more capable and in turn providing a highter safety threshold.

[on one]

7 hours ago, timmytool said:

Think about a euc over torque like driving a underpowered car up a hill. If you stay in a high gear you will lose speed, and eventually stall the car. This is a over torque, the change in environmental variables has asked the motor for more torque then it can provide. In that same underpowered car on the same hill, if you go down in speed and/or pick a lower gear you will have the touque to maintain that speed and still have throttle control to accelerate.

Totally, that's how I think of it too. Once my pedals begin to dip, then I bend until my pedals level off, then I rise and increase my speed as I rise back up. I always try to keep my pedals horizontal, not nose dipping. Is heel dipping okay when going downhill?

 

Edited August 6 by on one
further question

[rcgldr]

12 hours ago, timmytool said:

on electric motors the torque drop off is more pronounced

They're DC motors, peak power occurs at 50% max rpm, which would be free spin speed on an EUC. Torque drops off faster than rpm increases after that. Torque decreases to zero at free spin speed.