Dual VESC over CAN - One belt break, the other motor looses power, Why?

ESK8 Electronics
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The title says all

I can’t understand why is this the default behavior, it totally kills one of the main points of dual motor, redundancy

@trampa

Maybe @Deodand also has some insight

Long history, after doing some stupid donuts on the dirt in the middle of nowhere, the belt gets shredded, ok my fault , even more for not bringing my phone or any tools, but it still doesn’t change that the current behavior is bad

Is this the same problem that cause one of the motors to spin slower when they are unloaded? Thought a lot about in my 6 km walk of shame home

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Did you have traction control enabled?

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I had many walk of shames.

Meanwhile I carry every tool and spare part I could need in my backpack.

Was ist the master or slave motor where the belt snapped?

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That’s why you want a BLE dongle and the VESC-Tool app. Maybe your walk of shame could be an inspiration for a new feature, allowing to control the slave via master, but have the master motor switched off.

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Can’t we already do that by setting 0 amps for everything on the master and disabling traction control?

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Maybe the software can just detect the load loss and do that by there own? :thinking: probably the better way, instead of depending on a second device which could have a connection loss or empty battery or what ever…

Edit:

@trampa that’s what I mean. Even the new tool and the BLE dongle wouldn’t have helped him in this case.

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That’s why you prepare for the ride. Phone, spare inner tube, maybe spare belt, some tools. We design our boards to require a minimum of tools. @taz Yes, you can set master to zero amps and only drive slave. That could also be a single button for convenience.

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I see we look from different sides on it and that’s ok. Just there million other ways why a phone could stop to work. I think you know best by your own that it doesn’t matter how good you prepare, you most likely will need the things you don’t have with you. That’s why, if a sw can do that why to relay on a second tool.

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would be nice to be able to instruct a slave to become the master, maybe difficult with canbus

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You would need 2 receivers for that to work because the master Vesc is the one that should be plugged into the remote receiver. Unless you can open your enclosure

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Mmm yes of course :face_with_hand_over_mouth:

maybe possible to have the receiver wired to both ESCs for that scenario, if of course the firmware allowed for the slave to ignore signal until the slave detects no can comms then slave becomes master

Firmware and 3pin cable mod, could be my simplification of a complicated process tho

I use can and not split receiver so gotta say this is of interest personally

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I don’t see a problem the master request the ppm signal from the slave ppm port via can. It’s just not implemented in the sw. If it works in one direction, why it shouldn’t in the other?

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Drawbacks?

Maybe the can cable becomes detached from either ESC, maybe the can chip goes poof on either ESC.

In that case you are now running split receiver(with one dead esc), congratulations you get home on the slave’s back praising Skatan all the way

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My understanding is canbus is bidirectional

@Ackmaniac @Deodand @trampa

What say the F/W peops?

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Sure everything is possible and can fail. Your ppm receiver antenna can break as well or the plug can get lose. As far as I know the latest versions of the CAN connection are pretty stable against any damage.

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Is the receiver is damaged game over typically, nothing to be done there in f/w

Even the dual single pcbs like the unity rely on can, so if the master side dies, you should be able to limp home

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I think the only way to be able to ride home, regardless of what was damaged (apart from a damaged remote), is to use 2 receivers and no can connection.

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Something can always brake, that’s the nature of technology. If you take a 4X4 car off road, you prepare yourself. Spare tire, tools, winch, spare fuses, 10L extra fuel, oil, maybe satellite phone. Before you start your adventure the car gets a proper service and checks.

I never had a VESC 6 fail on me, chance of burning it mid way seams to be very very little. Worst case scenario: Open the lid, plug receiver to slave, re-configure via App. 5V usb jack for phone should be easy to install on any board. Two receivers can be used, even when using can. You can plug it in, but deactivate ppm or NRF. When you need it, switch it back on. Carry a spare 50 $ android Phone if you are totally paranoid of getting stranded.

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It would be nice to have the option not to open it up, some environments are hostile to open electronics.

Just a sugg. on a possible enhancement requiring only software and 3cm of receiver cable

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Thanks for all the input guys

Yeah, traction control would have saved, but never had a need for it so it was off, first thing I did after creating this topic is to turn it on

@trampa my main question is why this is the behavior happening, lets say I’m commanding X amps, why if one motor isn’t able to get to the desired current, the other one doesn’t even try

In my head with traction control off, they should be completely independent, I’m not even talking about the slave turning master or something like that, I would had no problem with the beltless motor spinning at full rpm if that would mean that I had power on the other one

Maybe is something you could bring it to Benjamin

@rich I feel you, I stopped carrying anything in shorter rides due to the board being pretty reliable

It’s the master that snapped, I think if it was the slave I would be fine

1 Like