Strange issue with motor PWM output
I'm using a homemade Quad with the beta3 code following the guide for a clean setup but I'm having major issues getting the PWM output to work right or at all. I though it may be H/W at first so I calibrated my ESCs, tried them directly (from receiver) and they work fine. So I then tried the example pde for the RC and that drives the motors fine through the ACM. But even after a clean rebuild of the code and setup the ACM code doesn't drive the motors. The motors arm (green light goes from solid to flashing) but no RPM.
After a trying a few things I managed to get it working but had to move the line, "set_servos_4();" which outputs the servo values,
down to the 50Hz loop (from the 160Hz loop). With that changed the code works perfectly, all be it requiring a little tunning as its oscillatory. Has anyone got any ideas what this is about or why it happening? I haven't seen anyone report the same issue, so it makes me think it is bad H/W or something I've done wrong. The ESCs don't complain about no signal, so it makes me think the PWM is almost good or really high frequency some thing must be getting outputted; I'll try to get an oscilloscope trace.
I currently have my quad in a rig allowing pitch only +-50deg so I can tune the controller on the bench. Hence why I was willing to try the drastic code hack!!
BTW, great project guys, it's my childhood dream come true. Just wish I had a bit more time so I could contribute and give something back. Maybe one day.
After a trying a few things I managed to get it working but had to move the line, "set_servos_4();" which outputs the servo values,
down to the 50Hz loop (from the 160Hz loop). With that changed the code works perfectly, all be it requiring a little tunning as its oscillatory. Has anyone got any ideas what this is about or why it happening? I haven't seen anyone report the same issue, so it makes me think it is bad H/W or something I've done wrong. The ESCs don't complain about no signal, so it makes me think the PWM is almost good or really high frequency some thing must be getting outputted; I'll try to get an oscilloscope trace.
I currently have my quad in a rig allowing pitch only +-50deg so I can tune the controller on the bench. Hence why I was willing to try the drastic code hack!!
BTW, great project guys, it's my childhood dream come true. Just wish I had a bit more time so I could contribute and give something back. Maybe one day.
Replies to This Discussion
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DeveloperPermalink Reply by Michael Oborne on -
Whats escs are you using. id suggest your escs cant handle that update rate. whereas the kit ones can
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Permalink Reply by Scott Findlay on -
Ah, I hadn't realized that there are ESCs that are non-I2C that can handle greater than 50Hz period PWM, I thought it was all standard servo 1-2ms pulse, 50Hz period. I'm using Scorpion Commander 25A, so non-standard and I guess that is the issue. Can't see any data online to tell what period the ESCs support.
Ok, that sounds like the issue. Thanks for the help. I just hope 50Hz is fast enough.
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Permalink Reply by Sebastian Gralla on -
most brushless ESC can handle greater update rates...
but it seems that you got one of these which can't..
can you post which ones you are using please?
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Permalink Reply by Scott Findlay on
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Scorpion commander 25A
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Permalink Reply by Flávio Henrique P. de Oliveira on -
is Turnigy 25A BASIC recomended? Thanks
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Permalink Reply by Sebastian Gralla on
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turnigy plush is recommended, don't know the turnigy basic.
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Permalink Reply by Flávio Henrique P. de Oliveira on
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its is stange because I have both, turnigy basic and turnigy plush, it works fine with basic, but when I connect plush it keeps beeping rapidly
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