PreArm: Throttle (RC3) is not neutral during Motor Test

Hi all

I’ve just started with my first ArduRover project. Your documentation is great and leads me quite well, thanks alot!

My setup is a “skid steered” boat with only two motors (reverse should be possible) and no rudder. I have got:

  • a Frsky X10s with a binded xm+ plus receiver
  • a Pixhawk 4 with the PM07 board and GPS Module
  • two preinstalled ESC (which I know little about but it got a PWM input)

So far, I made my way through till the point where I want to run a motor test (Motor and Servo Configuration — Rover documentation). Means that I have setup my radio control and calibrated the GPS and accelerometer.

As Soon as I change to manual mode and select the any motor test feature in Mission Planner, the test is rejected with to following message:

15.11.2021 18:18:46 : PreArm: Roll (RC1) is not neutral
15.11.2021 18:18:45 : PreArm: Throttle (RC3) is not neutral
15.11.2021 18:18:45 : PreArm: Roll (RC1) is not neutral
15.11.2021 18:18:34 : IMU0: fast sampling enabled 8.0kHz/2.0kHz
15.11.2021 18:18:34 : RCOut: PWM:1-16
15.11.2021 18:18:34 : Pixhawk4 0020002C 3756500F 20373658
15.11.2021 18:18:34 : ChibiOS: 08877972
15.11.2021 18:18:34 : ArduRover V4.1.1 (7b9f15d8)
15.11.2021 18:18:34 : IMU0: fast sampling enabled 8.0kHz/2.0kHz
15.11.2021 18:18:34 : RCOut: PWM:1-16
15.11.2021 18:18:34 : Pixhawk4 0020002C 3756500F 20373658
15.11.2021 18:18:34 : ChibiOS: 08877972
15.11.2021 18:18:34 : ArduRover V4.1.1 (7b9f15d8)
15.11.2021 18:18:34 : IMU0: fast sampling enabled 8.0kHz/2.0kHz
15.11.2021 18:18:34 : RCOut: PWM:1-16
15.11.2021 18:18:34 : Pixhawk4 0020002C 3756500F 20373658
15.11.2021 18:18:34 : ChibiOS: 08877972
15.11.2021 18:18:34 : ArduRover V4.1.1 (7b9f15d8)

I looked up similar topics. One conclusion was:

Virtual Joystick in QGC is the one that occurred. Please uncheck the auto center throttle.

Is this also my case? If so: Where can I find this checkbox.

Thanks for giving a greenhorn a hand and sorry if I created this topic at the wrong place.

In the meanime I proceeded with the following steps:

  • I set up an AUX function for arming my boot (according to Arming / Disarming — Rover documentation).
  • Changed my Tx to Taranis QX7 and another a Receiver (XM+). This has not changed anything.
  • Checked all my switches whether the limits are reached (LOW <1200us and HIGH >1800us).
  • Set the following parameter:
    • BRD_SAFETYENABLE = 0
    • SERVO1_FUNCTION = 73 (Throttle Left)
    • SERVO3_FUNCTION = 74 (Throttle Right)
    • MOT_PWM_TYPE = 0 (Normal)
    • FRAME_CLASS = 2 (Boat)
    • FRAME_TYPE = 0 (Undefined)

This changed nothing about the listed problem. This is my current log:

19.11.2021 20:01:16 : PreArm: Roll (RC1) is not neutral
19.11.2021 19:56:19 : PreArm: Roll (RC1) is not neutral
19.11.2021 19:56:11 : PreArm: Roll (RC1) is not neutral
19.11.2021 19:53:46 : AHRS: EKF3 active
19.11.2021 19:53:46 : EKF3 IMU1 is using GPS
19.11.2021 19:53:46 : EKF3 IMU0 is using GPS
19.11.2021 19:53:46 : EKF3 IMU1 origin set
19.11.2021 19:53:46 : EKF3 IMU0 origin set
19.11.2021 19:52:12 : PreArm: Roll (RC1) is not neutral
19.11.2021 19:51:02 : PreArm: Roll (RC1) is not neutral
19.11.2021 19:50:15 : PreArm: Roll (RC1) is not neutral
19.11.2021 19:49:47 : PreArm: Roll (RC1) is not neutral
19.11.2021 19:49:38 : IMU0: fast sampling enabled 8.0kHz/2.0kHz
19.11.2021 19:49:38 : RCOut: PWM:1-16
19.11.2021 19:49:38 : Pixhawk4 0020002C 3756500F 20373658
19.11.2021 19:49:38 : ChibiOS: 08877972
19.11.2021 19:49:38 : ArduRover V4.1.1 (7b9f15d8)
19.11.2021 19:49:38 : IMU0: fast sampling enabled 8.0kHz/2.0kHz
19.11.2021 19:49:38 : RCOut: PWM:1-16
19.11.2021 19:49:38 : Pixhawk4 0020002C 3756500F 20373658
19.11.2021 19:49:38 : ChibiOS: 08877972
19.11.2021 19:49:38 : ArduRover V4.1.1 (7b9f15d8)
19.11.2021 19:49:37 : IMU0: fast sampling enabled 8.0kHz/2.0kHz
19.11.2021 19:49:37 : RCOut: PWM:1-16
19.11.2021 19:49:37 : Pixhawk4 0020002C 3756500F 20373658
19.11.2021 19:49:37 : ChibiOS: 08877972
19.11.2021 19:49:37 : ArduRover V4.1.1 (7b9f15d8)

It seems (to me as a beginner) that Roll gets a wrong signal or is not configured correctly. When I look at radio calibration everything looks fine to me (see screenshot). I assume, that 1495us is fine for a neutral position, am I wrong? It also corresponds to my LCD display of my Tx, where Roll jitters around -0.1 and 0.1.

.

Another observation is that Servo Output shows 1500 on Position 1 and 3, which seems fine. But: I does not move at all when I move the sticks around. Is this only moving when armed?

Furthermore I do not manage to assign my error message accordingly, since it is not listed here: Pre-Arm Safety Checks — Rover documentation

Have I left out something essential? I am afraid that I am behaving like an idiot. frankly I might not be the brightest but I have spent now already to full days on understanding my issue.

Some pieces of advice would be appreciated alot… thanks!