Motor testing failure; Command was denied by autopilot

ArduCopter Copter 4.2
1

Hello,

I am trying to debug my quadcopter. I am using a brand new Cube Orange flight controller. It is connected by USB to a laptop. The controller is not connected to a battery, GPS, or safety switch, and I have disabled all of the arming checks. I have updated to the most recent 4.2.3 firmware for copters (quadcopter configuration).

I am trying to test the motors using Mission Planner. I would like to adjust the Motor 1 throttle in Mission Planner’s “Motor test” and see the corresponding change in the PWM signal in an oscilloscope. However, I receive the error “Command was denied by autopilot” for any test I try (ex: 20% for 10 seconds).

I can see 3.3 V pulses from MAIN 1 output of the CubeOrange, but they obviously don’t change. They are at a higher frequency and amplitude than the 5 V pulses I see from a servo tester. I wasn’t expecting that.

Am I forgetting any configuration step? I am new with quadcopters and Ardupilot and would appreciate any advice.

2

Did you disable the Safety Switch? Not connecting it doesn’t do that :slight_smile:

2 Likes
3

Complementing @dkemxr response, if I am not mistaken, the FC will deny this command if you are sending it by USB (it is a safety concern about someone being close enough to a propelled motor and being injured during the test). Always perform it via telemetry radio.

4

Set these parameters and you should be OK

BRD_SAFETYENABLE,0
MOT_SAFE_DISARM,0

1 Like
5

You can run it via USB, no issue with that.

1 Like
6

This worked! Thank you.

1 Like
7

I can confirm that I ran it with a USB once I followed @xfacta advice.

1 Like
8

Agreed. Worked for me as well. Thanks @xfacta!

9

I have the same problem… dont see the param BRD_SAFETYENABLE

10

was
BRD_SAFETYENABLE,0
now
BRD_SAFETY_DEFLT,0
BRD_SAFETYOPTION,0

1 Like
11

I am only a student, so take this with a grain of salt, but in class it appeared we fixed this problem by raising the throttle from 5% to 20%. That seemed to be the minimum threshold at which the motors could be tested.

12

You use the MissionPlanner motor test to find and set the minimum percentage for MOT_SPIN_ARM first, then add about 0.03 and set MOT_SPIN_MIN

So if motor test can reliably spin all motors at 9 percent (0.09) but is not so reliable at 7 or 8 percent, then set MOT_SPIN_ARM,0.09 and set MOT_SPIN_MIN,0.12

With the newer ESCs, BLHELI_32 and similar, that ARM spin can be very low and that is good for a pre-flight check to see if all the motors are spinning correctly. But if MOT_SPIN_ARM is very low like 0.04 for example, then you probably still need to have MOT_SPIN_MIN up around 0.10 or just over, or the motors could be stopped by wind or descents - you dont want that to happen.

13

hello,
I have the same problem but I don’t have MOT_SPIN_x parameters. How could I do ?

Thanks !

14

This is a Copter V4.2 thread. Is this the firmware you are using?

15

I just received a Pixhawk 6c sans the GPS. I could not remove the safety switch in the paramators. I ended up picking up a new GPS 10 and I could arm and calibrate. Go figure.

16

BRD_SAFETY_DEFLT = 0 Should do that.

17

The hud said that safety was disabled but unlike the PRP it did not engage. Not sure if there is some type of internal programing was involved.