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BigQuad deck ESC PWM signal not changing

Posted: Tue Oct 08, 2019 10:23 am
by dedecun

I have followed all the instructions for updating the firmware and getting the Crazyflie 2.1 ready for the BigQuad deck. However, I seem to have a persistent problem. When powering up, the ESCs beep and then the drone says that it is ready to fly (in the cfclient console) and the ESCs beep again. It also says that the BigQuad deck has been recognized and that the driver switched to brushless motors. However, probing the PWM signal with an oscilloscope (picture attached) going into the ESC from the BigQuad deck, there is a signal there and this signal has whatever frequency I denoted it to have (for example 50Hz, 400Hz or 2kHz), but the duty cycle is not changing at all, no matter the thrust input given through the gamepad. Is there something simple that I am missing? As I have looked through the forum and found similar issues, but no answer.

Re: BigQuad deck ESC PWM signal not changing

Posted: Wed Oct 09, 2019 6:59 am
by arnaud

There can be at least two reason I can think off for the output thrust to stay at 0% (like it is for you, 1ms pulse is 0% thrust):
- The Crazyflie sensors are not calibrated. After POST the M1 LED blinks red slowly during sensor calibration, when the sensor are calibrated it starts blinking faster. For the calibration to work the Crazylfie needs to be stable (ie. put on a stable surface).
- You are using a controller that do not go back to 0 thrust and you are using Crazyradio to control the Crazyflie: the is a locking mechanism in the Crazyflie that looks for one setpoint with thrust = 0 before accepting any setpoint. This was made as a protection mechanism against gamepad like the PS3 gamepad that outputs full thrust when not initialized.

Both case are not specific to the big-quad and would also happen with a Crazyflie with brushed motors. So one advice would be to test your setup with an unmodified Crazyflie first (if you have one) and then try with the big-quad deck.

Re: BigQuad deck ESC PWM signal not changing

Posted: Wed Oct 09, 2019 8:54 am
by dedecun
Hi, thanks for the answer.

None of the two I believe is the cause. As I said, it outputs "ready to fly" in the console after calibration of the sensors. Also I have tested many times the same setup with a pure Crazyflie, even tested right after this one not working.

Any other ideas?


Re: BigQuad deck ESC PWM signal not changing

Posted: Thu Oct 10, 2019 9:28 am
by TheFalconType
Hello There,

This sounds very similar to the issue I currently am having. I've tried the old "power cycle" technique so many times, alas to no avail. If I find out the solution to the similar issue I am having, I will post it here too.