Hey everyone,
I've recently run into a throttle problem with my Pixhawk (Arducopter 3.1.5) quadrotor.
My throttle signal seems to be internally reversed. (if that makes any sense)
I ran into an issue where when I powered on the quad with throttle at lowest position, it was entering ESC calibration mode.
At first I thought, "no big deal, I guess I'll reverse my throttle channel on my TX"
So I reversed it and re-calibrated.
While I was re-calibrating, I noticed something strange. My throttle position indicator was reversed.
High value (1850) was at the bottom, and the low value (1165) was at the top.
When I attempted to calibrate my ESC's, everything went well up until the point when I moved my throttle down to the lowest position. To my surprise, the motors spun up to full throttle. I stopped them by moving the throttle to the highest position.
When I did an arm test, I started the pixhawk normally, it went through calibrating the gyros, etc... I pressed the arm button, throttle to lowest position + rudder right, and Hey! the motors spun up to the speed specified in the MOT_SPIN_ARMED parameter :)
But, as soon as I moved the throttle the tiniest bit... Bam! instant full throttle :eek:
It would slow to disarm speed it I moved my throttle stick to highest position.
So here's the catch 22:
When my throttle channel is not reversed on my TX, the pixhawk enters esc calibration mode @ lowest position. I've calibrated, calibrated, calibrated and it still insists, that lowest position is (1850).
When my throttle channel is reversed on my TX, the pixhawk does not enter esc calibration mode @ lowest position, But, the throttle is actually reversed. It arms at lowest position (good) but as soon as I slide the throttle off lowest position it instantly spins up to full throttle. (bad)
Has anyone seen this before? Any ideas?
Replies
SOLUTION: I'm not sure how it happened, but the RC3_REV parameter was set to reversed. I know that I didn't change it. I didn't even know it existed until today... Weird.
Thanks everyone!
And now for my next question... What other parameters have magically decided to change? Should I consider doing a factory reset on this thing?
@John,
If you are using a Futaba transmitter and receiver, the throttle channel on the Futaba is the reverse of other brands of R/C equipment.
In other words, when the throttle joystick is at its lowest position, the PWM output on the throttle channel is close to 2000us.
Regards,
TCIII ArduRover2 Developer
I think that may actually be on the status page. There's a tabbed page with basically all the info ( in simple numbers ). I think it's the tab flight data and at the left you have your instruments. Directly below is that is another tabbed area with lots of numbers detailing the entire state of the vehicle. IN there you should find the motor out info per channel, should be 8 I think.
There should be another screen showing the throttle out to the motors. I certainly recommend taking off the props before you hurt yourself and diagnose the issue that way.
If the throttle out of APM is normal, yet your motors spin up, it's an issue with the ESC"s.
Can this be a failsafe issue? When your lowest throttle position is below the failsafe value, maybe the vehicle goes into RTL mode or whatever you configured. Since it's on the ground, it's trying to get to your RTL altitude. Check the failsafe values and compare that to your radio readouts.
For testing, I've disabled throttle and battery failsafe. I'm not sure what my current values are. Do you think it would have an effect even with the failsafe disabled?