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Rider222

Minipro intermittently LIFE-THREATENING unsafe, veering right

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When the problem happened to me, my gut feeling was that either it was an "edge case" algorithmic problem, or, more likely an actual physically bad component/connection/trace.  When the unit has acted up, there was always a vibration/bump involved, but always your normal fairly common minimal bump.  I typically ride (hundreds of hours of experience) over extremely bumpy off roading/dirt/gravel roads with no sign of any problem.  So having this errant Minipro randomly veer right, while riding full speed on an otherwise common smooth sidewalk with the vibrations only being somewhat normal expansion joints is what makes it this issue so randomly odd, and scary.  And, I could never repeat the problem in a controlled manner.  I spent hours trying to repeat the problem and never could.  The problem would only repeat under normal riding,  when I would least expect it.

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Posted (edited)
4 hours ago, Rider222 said:

When the unit has acted up, there was always a vibration/bump involved, but always your normal fairly common minimal bump.

Exactly! Even though I have a ledge at the end of my driveway which always causes problems it is just 2cm high. But there is a slight down-slope from the bitumen  getting to it, and a slight up-slope on the other side. In my case the problem is repeatable. We can take bigger bumps (pine cones and tree roots are common around here, for example) but it is this innocuous one which causes trouble... Interestingly, the entrance to our local park is shaped exactly the same, and it also throws me in exactly the same way... But other driveway ramps are not a problem...

Edited by trevmar

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Posted (edited)
16 hours ago, Rider222 said:

When the problem happened to me, my gut feeling was that either it was an "edge case" algorithmic problem, or, more likely an actual physically bad component/connection/trace.  When the unit has acted up, there was always a vibration/bump involved, but always your normal fairly common minimal bump.  I typically ride (hundreds of hours of experience) over extremely bumpy off roading/dirt/gravel roads with no sign of any problem.  So having this errant Minipro randomly veer right, while riding full speed on an otherwise common smooth sidewalk with the vibrations only being somewhat normal expansion joints is what makes it this issue so randomly odd, and scary.  And, I could never repeat the problem in a controlled manner.  I spent hours trying to repeat the problem and never could.  The problem would only repeat under normal riding,  when I would least expect it.

The first time I encountered this bug it was exactly as you described: a minimal undulation in the sidewalk that’s commonplace and should never cause an issue. The second time I had the bug was just a few meters later on a more gradual ‘bump’ (in quotes because it barely qualified as a bump). If those bumps I rode over are likely to cause issues then the MP simply can’t be ridden outdoors...but I know that’s not the case.

The subsequent times I encountered the bug were on  perfectly flat tiles AND immediately after powering up. Now, about 50% of the time the thing just spins clockwise upon boot-up

I’ll upload a video once I export.

 

—edited for spelling

Edited by Zephyrzone

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Please, everyone who has experienced the bug where the MiniPro shoots right at a tiny bump, if you haven’t already, contact Ninebot/Segway support. They really need to know about this issue, and that it’s not an isolated incident.

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To me a mini-pro is just a glorified hover board (no offence) When you have two computers controlling two different wheels independently and something unexplained happens (like this ) or even something explained like running one wheel over an unobserved rock You're going down hard. I feel your frustration.  Maybe you should have sent that wheel back to Amazon.  Is it too late for that?

Appologies if this has already been covered, I didn't read the whole thread.

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Posted (edited)
1 hour ago, Smoother said:

When you have two computers controlling two different wheels independently 

Don’t know about hoverboards, but the MiniPro has a single mainboard with a single processor chip running a single software. Just like my seated Airwheel A3.

On the A3 the motors do have their own power distributing boards with their own  MosFets, and IIRC MiniPro has them separated as well. Either way the single firmware controls the whole vehicle.

During the winter I noticed several times when one wheel got stuck or started skidding, that rather than trying to stay upright with the remaining wheel (your scenario), the MiniPro tries to stay facing forward even if it means falling down. Which is of course the only sane way to make a vehicle like this to behave.

Edited by mrelwood

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3 hours ago, mrelwood said:

Don’t know about hoverboards, but the MiniPro has a single mainboard with a single processor chip running a single software. Just like my seated Airwheel A3.

Ah, ok.  What I meant was two wheels driven and one encounters a problem.  I remember in my (original) segway days, if one wheel hit a patch of mud it would spin up to speed wildly, even though the computer knew the other wheel was still only crawling forward.  If the wild wheel suddenly found grip, the inertia of the wheel would jerk the whole machine, often followed by a fall.  Why the wheels didn't share their relative speed info, I have no idea.  But regardless of that firmware fail, a lot of the segway/hoverboard fails show one wheel suddenly having a different idea of speed (usually rider induced (not the OPs issue) or by riding over something, or clipping something, with one wheel. It's basically a flawed design concept IMHO.

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In my case the MP is now spinning to the right without provocation; it’s happening half the time I boot it up without even standing on it. It wasn’t doing that prior to the sudden veering. Could be coincidence, but I doubt it.

Ninebot didn’t see anything unusual in the black box data, which is disconcerting. I’m suspecting a hardware malfunction of the steering mechanism.

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3 hours ago, Zephyrzone said:

In my case the MP is now spinning to the right without provocation; it’s happening half the time I boot it up without even standing on it. It wasn’t doing that prior to the sudden veering. Could be coincidence, but I doubt it.

Ninebot didn’t see anything unusual in the black box data, which is disconcerting. I’m suspecting a hardware malfunction of the steering mechanism.

So in your case, did your Minipro always have noticeably odd issues, or, does it seem to be getting worse over time?  Did your issues only become noticeable after a firmware upgrade?  What I'm asking is if a "logical" change (programming) could be causing your issue, or, is some component is gradually (or instantly) failing.

I feel MY Minipro probably always had this issue, firmware upgrades over time, didn't change anything.  Again; MY "veering right" issue happened extremely rarely,  and, possibly (see my original post) very early on.  And, MY veering issue was ALWAYS extreme; instant 90deg veer right, during my riding high speed straight ahead on smooth/fairly smooth surface, hitting slight bump.  After I was certain a problem existed, I tested for hours riding slow in an empty asphalt parking lot paying full attention to oddities, and twice I might have felt it "twitch" right".  That's when I called it quits on that unit.  That unit is now stripped down to it's bare parts in which I did full visual inspection of all parts/traces/solder joints using magnifying glass and could find nothing odd.

I have never felt any oddities on my other two Minipros [yet].  But we haven't had the opportunity to ride them anywhere near as much lately.

 I'll post if I feel anything odd.

 

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My MP has seemed a little odd since first run, but nothing obvious- much more in line with your ‘did it happen or didn’t it?’ twitchiness. Nothing noticeable by someone who isn’t hyper sensitive. 

The overall performance and stability never changed, regardless of firmware. The sudden veering- and now constant spinning- came on suddenly unrelated to a software update. I get the distinct impression that whatever sensors are used for steering have been ‘gracefully’ degrading until a final failure point. 

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I still think some thing is going on with the hall sensor.

Mine did the same spinning while idle.

Bouncing the unit around would sometimes stop it.

I believe the bouncing would make the cold solder joint re connect

for a short time until the next bump or jarring.

Reflowing the solder on the hall sensor board fixed it.

There are solder connections on both sides of the board.

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10 hours ago, 68bugboy said:

I still think some thing is going on with the hall sensor.

Mine did the same spinning while idle.

Bouncing the unit around would sometimes stop it.

I believe the bouncing would make the cold solder joint re connect

for a short time until the next bump or jarring.

Reflowing the solder on the hall sensor board fixed it.

There are solder connections on both sides of the board.

Oh, really? That’s interesting. I’m going to test bouncing it, this very well could be the root cause on mine. Would you happen to have pics or be able to describe the location of the Hall effect sensor so I know what I’m looking for?

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