torque steer

General Discussion about large electric scooters and motorcycles and other things with no pedals.
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pellicle   100 mW

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torque steer

Post by pellicle » Jul 22 2019 11:45pm

I recently bought an eScooter that has dual motors (500W) and have noted that torque steer is ... surprisingly observable.

Obviously its more of a whack at lowest speeds and takes quite some getting used to for a lad with more experience on scooters which are rear wheel drive and dirt bikes.

Basically my questions are:
"does one eventually get used to this"
"should I stop using the single wheel scooter because its hard to adjust to the dualie on the weekends"
"does anyone else have this sort of issue"

Thanks

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amberwolf   100 GW

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Re: torque steer

Post by amberwolf » Jul 23 2019 12:34am

Torque steer is something you see on things like trikes with two powered wheels in parallel with each other (like having motors on a tadpole trike's front wheels, or a delta trike's rear wheels), and you apply more power to one wheel than the other--then you get pulled toward teh side with more power (really, more torque).

I am not sure what problem you're encountering if your wheels are in line with each other, but I think if you post a pic of what you have, and describe exactly what is happening, we might be more able to help figure something out.

pellicle   100 mW

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Re: torque steer

Post by pellicle » Jul 23 2019 2:56am

amberwolf wrote:
Jul 23 2019 12:34am
Torque steer is something you see on things like trikes with two powered wheels in parallel
...
I am not sure what problem you're encountering if your wheels are in line with each other, but I think if you post a pic of what you have, and describe exactly what is happening, we might be more able to help figure something out.
strangely I don't have a pic on the ready for it, although I do the single motor variant, there is a quick n dirty vid I did with no editing (about 9min long) so you'll see my reference to that in the beginning (after I climb the drive way) as well as an examination of it later

https://www.youtube.com/watch?v=sCHxqpQ4Efg

most notable when the power is engages when the front wheel is orientd for a corner as the wheel is dragged to be straigh (IIRC)

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stan.distortion   10 W

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Re: torque steer

Post by stan.distortion » Jul 23 2019 4:47am

Have you tried reversing things, swapping controller outputs (and sensors) or motors/controllers if cables are too short? If you can get a logging output from the controllers it should show what's happening but if not then swapping things over will tell you if the issue is with motor or controller (torque steer will be in opposite direction).

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DogDipstick   10 W

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Re: torque steer

Post by DogDipstick » Jul 23 2019 7:04am

amberwolf wrote:
Jul 23 2019 12:34am
Torque steer is something you see on things like trikes with two powered wheels in parallel with each other (like having motors on a tadpole trike's front wheels, or a delta trike's rear wheels), and you apply more power to one wheel than the other--then you get pulled toward teh side with more power (really, more torque).

I am not sure what problem you're encountering if your wheels are in line with each other, but I think if you post a pic of what you have, and describe exactly what is happening, we might be more able to help figure something out.
Tourque moments and Tourqe steering is possible on any vehicle with one or more than one wheel in track. Slip angle of tire and direction of travel, and 30m/sec ^2 ( gravity) acceleration downward makes this unavoidable. Can absolutely happen on a 2 inline wheeled vehicle... even unpowered, it in motion... It has to do with the length of the track, wheelbase, power application.... ( or power dissipation, like deceleration.. ) and even braking on a single sided disk brake can cause significant torque steering polar moments. Any sideways force ( affecting the slip angle... )

Ride height rake and trail all affect this.

However, what you may be feeling is tourque induced gyroscopic precession... a lil different concept. I think. Dont quote me.
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pellicle   100 mW

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Re: torque steer

Post by pellicle » Jul 23 2019 6:10pm

DogDipstick wrote:
Jul 23 2019 7:04am

However, what you may be feeling is tourque induced gyroscopic precession... a lil different concept. I think. Dont quote me.
could be ... but I'm sure feeling something strongly in the steering, and not only when its not straight, but then it doesn't pull it off line ;-)

Either way its unsettling till you get used to it (and catches you when you swap out and back to a front powered scoot)

pellicle   100 mW

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Re: torque steer

Post by pellicle » Jul 23 2019 6:12pm

stan.distortion wrote:
Jul 23 2019 4:47am
Have you tried reversing things, swapping controller outputs (and sensors) or motors/controllers if cables are too short? If you can get a logging output from the controllers it should show what's happening but if not then swapping things over will tell you if the issue is with motor or controller (torque steer will be in opposite direction).
I'm not sure I understand how this can even be done

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neptronix   100 GW

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Re: torque steer

Post by neptronix » Jul 23 2019 7:18pm

You could lower the power on the front motor to eliminate some of the torque steer. Safety at the expense of acceleration.

If the controller is not programmable, then the trick would be to shave the shunt in it ( given that it uses a shunt! )
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pellicle   100 mW

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Re: torque steer

Post by pellicle » Jul 24 2019 5:08am

neptronix wrote:
Jul 23 2019 7:18pm
You could lower the power on the front motor to eliminate some of the torque steer. Safety at the expense of acceleration.
not a bad idea, but I'm ok with it now ... I guess its only when moving between the two that its an issue.

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