hi,
i am building my arducopter.
I have it on the same flat surface that it was calibrated on.
I have calibrated the ESC's
I have calibrated the quad.
It do not have the props on yet. I already have a quad (x650) that flies fine.
When i give the arducopter minimum throttle to get the motos spinning , the output is not the same on all the channels. Some or all of the motors also increase in speed slowly, whining up to speed over 10 seconds. I dont want to put on the props as i think it wont fly.
Surely the outputs on a flat surface should increase equally (with no props on)
I have attached the outputs at 0%,min to get motors going,50% and 100% throttle.
It looks like not all the motors are not being driven to spinning at the same speed.
Note i am using the stock configuration file.
Why not?
Also the motors spin very fast (or so it seems to me) at minimum throttle - i have changed the THR_MIN value from 130 to 100,70,30 but when i then go to the minimum throttle not all motors spin or they spin and then one or 2 may stop after 2-3 seconds.
Replies
Hi,
I had a similar issue with my quad in the beginning. The issue had been found by Randy at the time : my Rate_P parameter was wrongly configured and was way too high.
This caused the motors, like your symptom, to turn very fast at low throttle and practically not increase between 0% stick and 100% stick.
What are your rate PID parameters configured like ?
When you give it power on a flat surface it can feed back and build up in strange ways. Eg it might want to yaw a few degrees clockwise but increasing the power on the CCW props doesn't have any effect, so it increases that input.
Unless you we're in a pure rate-only control mode (eg pure acro mode) I wouldn't expect all motors to increase in perfect synchronization.
My motors run with Thr_min set at 15% as I recall. Try calibrating each ESC individually. Also I do not believe the THR_Min means that is the minimum rpm with throttle at "idle." It simply means that when you move your throttle up with the motors stopped, there is enough PWM for them all to start all together. Correct me on this if I am wrong. In stabalize or acro and on the ground and armed, I can stop the motors at any time by simply pulling the throttle to my belly. BTW - using the auto calibration of ESCs it works fine with the Turnigy AE-<xx> that I use. But the manual method calibrating one at a time also works fine too.
Jim
I've had similar problems when I used the auto calibration method (i.e., when all four ESCs are calibrated together). However, I was always able to correct the problem by individually calibrated each ESC individually (by plugging the ESC directly to the throttle channel and running through the throttle range calibration procedure).
Did you use the auto method or calibrate them individually?