Any tips for VESC with standard RC transmitter / PPM ?

[benj]

Hey everyone,

Thanks to Marcin my VESC arrived and is all fired up and wired up. Detection worked smoothly and I have great control using the BLDC tool.

However I can't seem to figure out PPM control. It's kind of 'all or nothing'. I've read that Vedder hadn't tested it that much, but hoped that was kind of old news.

I have set the Minimum and Maximum Pulsewidth based on the live display, and now the live display looks great, moving from zero to full with the throttle position.

However, the motor doesn't spin up until about 50% throttle is pressed and when it does,the motor runs at max speed straight away. I tried changing the deadzone but that didn't seem to make much difference.

Releasing the throttle stops the motor dead, almost like the brake is coming on.

This is all on a bench, no load on the motor at all.

Am I missing something? Shouldn't I be able to hold an RPM based on throttle position?

Thanks for any tips.
Ben

 

[Marcin]

Benj, what mode are you running your VESC in? Current, RPM, ..?
If it's in current control mode then it's normal for the motor to spin up to 100% when not under load.
Also, play around with the 'with reverse' and 'with brake without reverse' settings.

 

[benj]

Thanks Marcin.

I was using 'Current no reverse with brake' - and after further reading I now understand that under no-load it does indeed spin up to 100% on any throttle position and I can understand why. It just seems scary to trust it and step on a live board after having had a few accidents in my time :lol:

As for the 50% throttle problem, I also now understand that the minimum pulsewidth should be measured with the brake fully applied. That makes sense.

When I test my pulsewidth it reports from 1.0 (fully braking) to 2.0 (fully accelerating). For some reason I get the best results when I set maximum pulsewidth to 2.6...anything lower and the VESC doesn't respond to throttle anymore, not sure why.

So, tomorrow hopefully I can run some real tests with a fully loaded board and a brave pilot strapped in!

 

[Marcin]

I've made a video for you:
[youtube]OtuofrQr3F8[/youtube]

I hope it helps (and that you can understand my heavy accent hehe)

Regards

 

[vedder]

It is really nice to see that a community is starting to form around the VESC with people helping out. Thanks for making a video

Some comments about the video:
* It is very important that you run detection for the sensorless settings for new motors. If you don't, the motor will run inefficiently if you are lucky and if you are unlucky the VESC will die. So go to the sensorless tab and run the detection for new motors and enter the integrator limit and coupling.
* Reboot is only required when changing application. When changing settings, just writing them is enough.
* The read/write buttons will read/write all application settings under all tabs at once.

 

[Marcin]

It is really nice to see that a community is starting to form around the VESC with people helping out. Thanks for making a video

Some comments about the video:
* It is very important that you run detection for the sensorless settings for new motors. If you don't, the motor will run inefficiently if you are lucky and if you are unlucky the VESC will die. So go to the sensorless tab and run the detection for new motors and enter the integrator limit and coupling.
* Reboot is only required when changing application. When changing settings, just writing them is enough.
* The read/write buttons will read/write all application settings under all tabs at once.

Noted, thanks for the tips. I'll do a in-depth guide in the future
I thought that the automatic detection was meant for hall-effect sensored motors but I clearly was wrong. All my VESCs shipped out with the Turnigy SK3 settings pre-loaded

Regards

 

[benj]

Thanks Marcin, I appreciate the video. My transmitter reports a range from 1.0 to 2.0. When I use that in BLDC, I get no response from the motor. Setting a max pulsewidth to 2.6 makes it all come alive....

I managed to test my VESC a bit today and it worked OK. Acceleration was really slow - perhaps because of the problem I just mentioned?

I guess you can change the Motor Max & Batt Max in Current Limits section for faster acceleration?

 

[benj]

Hey everyone, I solved my problems so thought I'd post the solution for future reference.

I ran the motor detection again and got a much higher number for Integrator Limit. When I used this new number, everything was perfect - the PPM from 1.0 to 2.0 is working well.

Quick test ride and - WOW - so smooth. Very impressed with the VESC so far on acceleration and brakes; very smooth, feels very natural, can't wait for the rain to stop so I can wind it up and get some distance runs Thanks Vedder and Marcin!

 

[Marcin]

No problem whatsoever, Benj. Glad to see you happy with the VESC!
If you could post a small review (Maybe including a picture or two) of your VESC manufactured by us on my sales thread I'd be eternally thankful (https://endless-sphere.com/forums/viewtopic.php?f=31&t=69942&start=25)

Best wishes, Marcin