Lucas Alexander Oliver Posted May 12, 2019 Share Posted May 12, 2019 So I have a solowheel glide 3 with 500 miles on it. But I ride a lot and probably too hard the 500 miles are all in two months ... about a week ago it started doing this weird cough like shake when I jump and am going too fast or going too fast and hit a big bump... until today it always caught itself and smoothed out. But today going down a hill On the road no less I hit a pothole going top speed. (18mph) and I started violently sputtering back and forth and then just went off , threw me down on the curb and my wheel ended up 20 yards away in a yard.. so was this oscillation? Is my motor dying or my control board ? I’m riding like an old man now. Lol but I don’t like being unsure. I have Nikola in order. But it’s not getting here quick enough. Lol. This little sg3 is gonna kill me. ? Any thoughts ? 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted May 12, 2019 Share Posted May 12, 2019 (edited) @Lucas Alexander Oliver, Sideway wobbles are just the rider and the spinning wheel, mostly initiated by some bump or starting at higher speeds. Could be some tire/wheel imbalance initiating this (often the tire is seated badly on the rim and can be reseated quite easily). But mostly it's the rider, who has to know his limits and learn how to dampen such wobbles. Like when driving a car on a slippery surface and the back starts slinging from one side to the other. Depending ob the rider such "slinging" overshoots, is under control of obe-two "slings" or never really start... Or is just out of scope to be handled by a human beeing. The other oscillation (from front to back) is determined by the rider and the control algorithm of the wheel. If the control algorithm is too "aggressive" this can lead to overshoots (or gets an uncontrollable increasing oscilation) initiated by some "strong" event like driving over a bump. As seen in this picture https://images.app.goo.gl/NgwTSMqq69HNrNbc6 of this wikipedia article https://en.wikipedia.org/wiki/Step_response a step response to the event can have different "outcomes" - perfectly dampened, overshoot abd/or oscillation. The one possibility with the oscillation going out of control is not beeing shown there. The driver is beside the control algorithm in this feedback loop, too and can cause it to oscillate. The wheel just looks at the angle of the pedal - if it's tilted forward it accelerates, tilted backwards it decelerates. Not strictly proportional, but with some (mostly) nicely adjusted PID controller to allow good balancing. A non hazardous oscillation every rider can (or could) introduce to this system is doing the pendulum (driving the wheel forward and back while the body stays at the same place) Here perfectly demonstrated by hirsute at starting second 5: This rider "introduced" oscillation can be hazardous too by some "wrong muscle reflexes" - i've seen some occasions were beginners on the "normal" segways did some unintended "high frequency pendulums" - some damped this again, some were near to be thrown off. Edit: nicely seen on this youtube video how the "shaking" body lets the sytem oscillate. Seems to be also very common with hoverboards, if one watches the fail conpilations... Edited May 12, 2019 by Chriull Quote Link to comment Share on other sites More sharing options...
Lucas Alexander Oliver Posted May 12, 2019 Author Share Posted May 12, 2019 @Chriull thanks for the information. Yes the problem I’m having is that I was going down a hill and hit a little bump and the wheel starts violently jerking back and forth sort of like a stick shift car when you are driving and accidentally put it in reverse instead of third gear...a violent hiccup. And it had smoothed out mostly. Until yesterday it couldn’t handle it and just shut off. Something in the wheel can’t handle the the sudden change from going forward then being airborne and then trying to go forward again.. it doesn’t like it. Lol Quote Link to comment Share on other sites More sharing options...
Ronko Posted May 14, 2019 Share Posted May 14, 2019 @Lucas Alexander Oliver sometimes this can happen if the pedal mount/chassis is loose on the axle. Therefore there could be play between the axle and the rest of the EUC (has happened to me before). If the motor is applying a constant torque in one direction this won't be apparent, as soon as you hit a bump it will apply torque in the opposite direction and try to stabilize you, but because of the play in the axle you will start getting oscillation while it tries to find a stable point again. Best way to diagnose if this is the problem: Stand still on the EUC while holding on to a wall, and try accelerating forward and backwards on the spot repeatedly, and see if you can feel any play between the axle and the pedal mount (it should be quite obvious if something is not right). If that's the problem, then you need to take the casing off and tighten it back up. 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted May 14, 2019 Share Posted May 14, 2019 And one other posibility would be a "loose" motherboard. 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted May 14, 2019 Share Posted May 14, 2019 (edited) On 5/12/2019 at 9:55 PM, Lucas Alexander Oliver said: @Chriull thanks for the information. Yes the problem I’m having is that I was going down a hill and hit a little bump and the wheel starts violently jerking back and forth sort of like a stick shift car when you are driving and accidentally put it in reverse instead of third gear...a violent hiccup. And it had smoothed out mostly. Until yesterday it couldn’t handle it and just shut off. Something in the wheel can’t handle the the sudden change from going forward then being airborne and then trying to go forward again.. it doesn’t like it. Lol Going down a hill the wheel is normally in braking mode - once one hits a little bump the wheel has to accelerate/lessen braking to catch up with the rider (the way over the bump is longer than the direct way the rider goes), just to break again shortly afterwards. By enough regenerative braking the wheels battery could be at the border or above the maximum charging current and by this "very stressed" - then a sudden peak current in the other direction for accelerating... The same is true looking at the "mechanical system" - going down while breaking the whole riders weight is pushing against the wheel (force = gravity plus the force of the braking deceleration (in riding direction)). While the wheel accelerates a bit to overcome the bump the force is (almost) released to "hammer" again onto the wheel once it brakes again. So sounds like this is about the toughest test for the wheels control algorithm and the riders dampening possibilities! ?There could also be the (additional) possibility, that by the wheel going over the bump one is putting the weight force on the "wrong side" of the pedal (front) causing by this the wheel to "overaccelerate" a bit, which shifts the force of the rider again on the back side of the pedal causing the wheel to "overbreak"? Leading to some oscilation if this situation is above the riders abilities? Edited May 14, 2019 by Chriull Quote Link to comment Share on other sites More sharing options...
Lucas Alexander Oliver Posted May 14, 2019 Author Share Posted May 14, 2019 So my wheel has some play in it when I put force on the pedals. I recently had to replace all the inner casings after a wreck I probably didn’t put something back together right. Ok open it back up tomorrow and see what I can find. Thanks for the info I didn’t think of that. Quote Link to comment Share on other sites More sharing options...
Chriull Posted May 14, 2019 Share Posted May 14, 2019 14 minutes ago, Lucas Alexander Oliver said: So my wheel has some play in it when I put force on the pedals. I recently had to replace all the inner casings after a wreck I probably didn’t put something back together right. Ok open it back up tomorrow and see what I can find. Thanks for the info I didn’t think of that. Here some report of a worst case scenario: Quote Link to comment Share on other sites More sharing options...
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