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Some small problems with the VESC 6 and the VESC Tool V 0.87

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JL2579
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Joined: 2017-12-25 21:09
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Some small problems with the VESC 6 and the VESC Tool V 0.87

Hi Guys,
I have discovered the vesc a few months ago and after several failed attempts of soldering my own vesc 4.12 I bought a vesc 6 for my own ebike project, which was finished a few days ago. ( In case anyone wants to see a few pics/specs, I will make a seperate post, unfortunately I am away from the bike for the next few months now and only have very few pictures).

During the project I had to fight with several issues of the vesc and wanted to post them here so they might get fixed or people tell me other workarounds:

-the whole vesc tool layout isn't made for high DPI screens at all. ( maybe there is a setting, but I didn't find it and all the buttons are extremely tiny on my laptop)

- it took me 20 mins to find the keyboard control button. Maybe add one tab to the left for newbies, maybe its just related to the previous issue

- the keyboard control doesn't work at all. My VESC works and both the calibrating of the motor and the thumb throttle works, but keyboard control is only making some noise in the motor. I assume this is due to too low current, but the keyboard control current seems to be not adjustable anywhere ?!

-At one point I had the issue of the vesc locking at full throttle unless some external mechanical brake was applied. After plenty of testing I figured out that this was because I had set the deadband too narrow and the motor wirings were inducing enough voltage into the throttle wire that was partially parallel to keep on spinning at full speed !!. Rewiring , limiting the duty cycle and increasing the deadband did fix it for me, but there is always a serious amount of induced voltage in the throttle wire at full speed no matter how I hold the cable, which leads me to the assumption that the rest happens directly at the port on the board, which is a serious design flaw at the port IMO. Try it yourself, at 95% duty cycle with a turnigy 6374 192KV the ADC1 Voltage alternates at several hertz by about 10% or more. the problem drastically increases with increasing duty cycle, but is even at the default 95% very present.

-when accelerating and hitting the duty cycle limit, there is a very hard cutoff that feels like hitting the rev limiter on a car in a low gear. Maybe include an option for soft current cutoff at duty cycle limit ( or is there one and I didn't find it yet, if so I am sorry).

-I whish I was able to display all data in the real time analysis at once and not have to switch between tabs.

Looking forward to your replies,
JL2579

EDIT: The DPI problem seems to not apply to fonts on linux, only the icons and on windows.

JL2579
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Last seen: 1 year 6 months ago
Joined: 2017-12-25 21:09
Posts: 13

One more feature I would like to see in the next version is to be able to configure a boost current for the motor. What I mean is that for example my 6374 can handle the current limit of 85amps quite well since have a 3d printed fan with an housing around it, but I would like to be able to set boost acceleration current that is adjustable in max length ( i.e. "15 seconds") , Amount ( i.e. "+20%" or "105 amps") and cooldown time ( i.e. "5 x Time_spent_in_boost"), since it doesn't have a temp sensor and I don't want to kill the motor accidentally when going uphill for a longer period, but would like to try some boost acceleration attempts ;D.

 

I am thinking of an internal "boost_meter" . If a is the max boost time, b is the max boost current and c is the cooldown factor, the code would do something like this:

 boost_meter = max(0,  boost_meter + max(0,instant_current- current_limit) -  decay_factor ) in every timestep,

where    decay_factor =  (boost_current_limit - current_limit) / c

and when  boost_meter >=   a*  (timesteps/second) *( boost_current_limit -current_limit -decay_factor) , the boost current is shut off until the boost_meter is at 0 again.

JL2579

JL2579
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Last seen: 1 year 6 months ago
Joined: 2017-12-25 21:09
Posts: 13

So I have to admit that my learning curve regarding the vesc is also steep, and that I initially overlooked some things. As it turns out, one is able to set a soft ERPM limit for the controller, the only downside here I see though is that this means you can either adjust this limit for a full or an empty battery, that means when I always want to use the full voltage of the battery, but just have a soft cutoff at the last 3 km/h , this would not be possible without a soft cutoff duty cycle limit instead of the ERPM limit.

 

JL2579