Hope it’ll be interesting for e-bikes too!!!
Thierry
Oh yes, big time.
Frank
1 Like
Thanks Frank, and special thanks to Benjamin.
Just tested the 0.84 version with all ADC options, works great.
Thierry
I just updated the manuals on the VESC-Project website: http://www.vesc-project.com/node/178
Benjamin added a new important Feature called ATD. “Acceleration Temperature Decrease” is a powerful new safety feature and should be used straight away.
http://www.vesc-project.com/node/221
Please have a look at:
Additional settings: Throttle curves, ERPM limits, safety features etc.
http://www.vesc-project.com/node/183
Frank
1 Like
Updated, working great. Suggestion: programmable delay/interpolation or curve for throttle down. As I improve my riding skills and get used to my board, I noticed it tends to throw me forward a bit if I decrease throttle too quickly, since the rough terrain has a constantly changing impact on the rolling resistance it is still difficult to predict what it will do. Now that I am aware of it, I slowly decrease throttle but it would be nice if you can program it to slowly decrease RPM when the throttle is reduced, instead of instantly targeting the new RPM. Don’t want that for throttle up.
On a different note, could someone explain why my braking strength is poor when using: motor max 70 motor min -70 battery regen -10
and good when just changing motor max and min to 60 and -60 respectively? The difference is massive.
If you use PPM you can drop in softer values for the ramping delay. Default is 0.3 and 0.1s (acceleration and brake). Try 0.9 and 0.3s.
-70 might cause stator saturation. -10 battery min is very low. Battery min determines the max. braking force at speed (high duty cycle).
Frank
Hi Frank,
In the Help inside VESC Tool, we can read this: “Current control. The output is off when the input is at minimum.”
Does it mean that the Output is in High impedance, and/or the controller is in idle/sleep mode?!
I ask this because when in standalone “ADC only App”, when I set the potentimeter to 0, the controller consumption is still high, and the motor seems in braking mode (hard to manually rotate) altough I’ve choosen “simple current mode”, no braking or reverse.
Have a Nice Day.
Thierry
Ramping delay is currently not decoupled for acceleration and braking. Would be a great addition (for me at least). I have -10 battery min x 2 (dual drive), so far it has been sufficient at motor min -60. I will increase it once I throw out the old li-ion.
for <v3.3 I had to double my observer gain in FOC to not get over current faults all the time. Do I still need to do that now that 3.3 says this?
=== FW 3.30 ===
- Activated iterative observer for better operation at high ERPM.
- Check for NAN and truncate some FOC variables.
- Speed controller windup protection improvement
2 Likes
Switched from BLDC to FOC and the brakes behave differently. With BLDC, I could precisely control the brake strength with my remote (current no reverse with brake). The further I would pull the leaver into the negative direction, the stronger the brake was.
With FOC, it just appears to go to 100% brake strength immediately. Firmware 3.31, FOCBOX
Anything I can do to get the old behaviour back whilst using FOC?
edit: just double checked again with BLDC, and the brakes are progressive as opposed to FOC where it’s either 100% or nothing.
@teknoi, you need to post your settings to get a relevant answer. I never experienced anything like that. The brakes should be linear in FOC. It depends on your settings though.
Frank
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dual focbox 3.31
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sk3 149kv
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motor current max 80 A
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motor current max brake -60 A
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Absolute Max current 130 A
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Battery Current Max 50 A
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Battery Current Max Regen -15 A
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PPM current no reverse w brake. Center, min and max correctly configured.
Everything else defaúlt. FOC startup is fine (much better than unsensored BLDC).
Brake test was indoors at very low speed testing startup from a stand still. Just noticed there that the brake strength never changes according to how hard I brake with the controller, where BLDC offers very precise control (not sure if low speed is a determining factor here).
This is the problem. When reaching very low speeds, just before stopping, it shorts two of the phasing wires. Try outside from 5km+ speed and it should be fine.
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The more you spread apart the Motor Max Brake and Battery Max Regen, the less linear the brake will be. The -15A pretty much define the brake force at high speeds, while the -60A Motor Max Braking are getting dominant at low speed. You can compensate that a bit, using the throttle curves, but it is better do use values closer to another. Your battery needs to be able to cope with the currents you shoot towards it. This is why you want many cells in parallel. Try riding your board with motor and battery values being the same, then spread apart the values. You will see how this affects linearity.
Frank
1 Like
Why is it that everyone is complaining about the brakes with VESC Tool, but no one had any issues wth BLDC Tool. I don’t get it. I have the exact same values that i used on bldc tool, and the brakes are not even close to the same strength as they used to be.
Brake strength depends on how many Amps you allow to be generated and how much your battery can eat Amp wise. Whatever energy you generate needs to be stored, since the energy can’t be evaporated into the universe. If you are at top speed and your motor generates at full voltage (e.g. 40V) and your Battery Regen is -15A, that results in 600W braking power. If you want more braking power you need to set higher Battery Regen values. Neither BLDC-Tool, nor VESC-Tool can do magic and evaporate the energy. The amount of braking power is always equivalent to the energy you shoot towards your battery. Since the motor we use are about 85-90% efficient, only a small fraction is converted into heat. VESC-Tool is more precise, so the values you specify resemble the output in real world a lot better.
Frank
This is the same reply you posted over and over again. I’m pretty sure we all understand this. But here’s the catch:
The new firmware has less braking power than the old firmware with the exact same parameters.
That is what i want an answer for.
2 Likes
Will give it a shot during the weekend. Thanks for the help.
so whats different with Vesc tool and the old BLDC tool that brakes changed?
