Measuring pressure on pedals in addition to EUC tilt (?)

[.....]

For the low price of $1299, I will happily install pressure sensitive pads to each side of ShanesPads. I'll leave them unwired so you can install a NOS bottle set or just uncork the bottle of lightning (sold seperately). The harder you lean the less resistance will be given between the wires sets on front and rear nubs. NOW you can use the foot pressure on the pedals OR you can use leg pressure on the pads. Sorry, no warranty and you gotta find your own controller and go juice...

Think of it as 'aftertouch' as you would find on a quality synthesizer or midi controller...

Edited August 7, 2021 by ShanesPlanet

[Planemo]

1 minute ago, mrelwood said:

What I think should work is a completely separate mechanism that only moves the pedals (or just the pedal plates) forward/backward.

I know we are only thinking out loud here but I think that would add a whole new level of mechanical complexity.

Pressure sensors are cheap, reliable and solid state. No real moving parts to speak of. Add pressure to the front of the pedal and it proportionally adds a mix signal to the gyro saying that the wheel is leaning forward more than just what the gyro is saying.

A gyro will always be needed because a zero reference will always be required. And for those occasions when no one is standing on the wheel of course

 

 

 

[Planemo]

3 minutes ago, ShanesPlanet said:

For the low price of $1299, I will happily install pressure sensitive pads to each side of ShanesPads. I'll leave them unwired so you can install a NOS bottle set or just uncork the bottle of lightning (sold seperately). The harder you lean the less resistance will be given between the wires sets on front and rear nubs. NOW you can use the foot pressure on the pedals OR you can use leg pressure on the pads. Sorry, no warranty and you gotta find your own controller and go juice...

Think of it as 'aftertouch' as you would find on a quality synthesizer or midi controller...

Make a shopping channel style video of it like you did with your pads and I'm sure they will sell like hot cakes 

[conecones]

For anyone still having trouble visualizing why the concept of using pressure sensor as a force multiplier or even to trick the gyro into thinking the wheel is off balance when its not - is not going to work, try this physical experiment:

Turn on your wheel, stand on it and roll forward into a wall/door (hold onto a wall or something beside you too obviously). Now press hard on the front of the pedals - you will notice the EUC tilt up. Because an EUC can only balance itself and not go forward/backwards, it is in equilibrium with your pedal pressure, the harder you press down the pedal, the harder the motor will press up on the pedal. If you try to cheat this system by asking the motor to go faster (ie: press up harder) than you are pressing down on the pedal, you will just be thrown backwards and the gyro will kick in and start to slow you down. The only reason an EUC moves forward is due to the resultant work(force x displacement) from the motor trying to stay balanced and friction of tire on ground - notice how if you slip on mud/sand while leaning forward you will fall over?

Hopefully the example above can shed some light...or muddle the waters more 

[mrelwood]

 

24 minutes ago, Planemo said:

Add pressure to the front of the pedal and it proportionally adds a mix signal to the gyro saying that the wheel is leaning forward more than just what the gyro is saying.

What would happen then?

[Menace]

Yeah, I am not sure about the pedal pressure sensors. The little Mip robot seems to be able to accelerate without leaning forward, which makes me think that it would be possible to use an input other than leaning to accelerate an EUC. Maybe you could have different modes (lean, pedal pressure, remote, or different combinations of these).

Here's another idea: two speed euc. What if you had two stators with different KV ratings so you could have ridiculous torque at the low end (and really powerful breaks) and then a high cruising speed (although less torque). Stator 1 and 2 could work together up to about 25 mph where the high torque stator would shut off and the high speed stator would keep working and take the euc up to top speed. When you need to break the high torque stator would engage and give you stronger breaking. For that you could use pressure sensors such that when trying to stop really suddendly, the EUC will know based on pedal pressure to engage the high torque stator. 

Also what about using super capacitor banks as a fail safe to save you from over leans? They could provide a huge push of extra current if you hit an unexpected bump (of course the controller would have to be able to handle it). Or, if one can use a remote, the capacitors could charge up and then you could have a "boost" button that would dump the capacitors and give you some crazy acceleration.

Just throwing ideas out there.

[mrelwood]

6 minutes ago, Menace said:

Or, if one can use a remote, the capacitors could charge up and then you could have a "boost" button that would dump the capacitors and give you some crazy acceleration.

That would be so cool! One wouldn’t have to lean at all, and still accelerate like crazy!

[yoos]

On 8/6/2021 at 12:35 AM, null said:

I’m still not sure if there is some logic flaw here (feedback loop?), but throwing out the idea as it would be fairly simple to implement.

The point would be: the firmware taking into consideration the EUC tilt, but also the actual user pressure input.

There is a flaw here indeed: the wheel already has all the neccessary information to calculate pressure input. It knows tilt, velocity, acceleration and motor torque at any given moment, and prior moments which allows it to calculate the torque (i.e. rotational force) resulting from rider pressure on the pedals. Thus, the changes in wheel response that you desire should be implementable algorithmically. 

There are caveats to the above. The wheel indeed knows the total torque that the rider exerts on the pedals at any moment. However, it can not tell how exactly the rider achieves it: is he standing on his toes, or is he pushing against some powerpads or is he pulling with his hands on the rollcage etc? Perhaps, your idea is to identify pressure applied to a particular part of the wheel/pedals to indicate a particular command. Such a system is known as a button or trigger system  In this case I would suggest to simply use a handheld remote instead of buttons operated by ones toes.

However, even more important and fundamental is the self-balancing single-point-contact nature of the wheel. Basically, the argument that @mrelwood never grows tired reminding everyone of. If you want to accelerate at a certain rate, you have to lean to a certain degree - no way around it. For example, if you want to reach 36kmh in 3 seconds, you need to accelerate at roughly g/3 (where g=9.8m/s²), and the forward lean has to be arctan(1/3) = 20^o at least, without even accounting for air drag. And strictly speaking it's the requirement on the incline of the line that connects the wheel's contact point with your center of mass, so your lean from feet to center of mass would be even steeper. This is why lower pedals should make acceleration slightly easier geometrically. 

Still, I think ideas like shifting pedals work theoretically but seem unrealistically difficult/cumbersome to implement properly. By adding more and more additional degrees of freedom we could slowly evolve the EUC into a fully-fledged robot-on-top-of-EUC which would cradle you in its hands and accelerate on command by moving its massive appendages to create the appropriate lean for its center of mass. However, at some point adding more wheels would become the most sensible solution for achieving stability and balance.