Steering changes from x to + in mid flight

I’m out of ideas here and was hoping to get some experienced eyes on my log file (attached).

My quad is chaning from x to + in mid flight. Here is a typical flight experience:

  • Turn on Tx and ensure the switches are in stabilize. Trims zero’d, etc…
  • Attach battery to quad
  • Wait for GPS led to go solid (blue LED goes solid)
  • Arm the quad with my Tx (red LED goes solid)
  • Give enough throttle to get a food off the ground.
  • Test controls (pitch, roll, yaw) to ensure all is functional
  • At this point I figure I’m good to fly, so I take it up

Soon after, the quad will switch to + mode. That is up on the elevator will no longer make the aircraft nose down, rather it will nose down AND left roll. This extrapolates to all directions. Sometimes, rather than going to + (the pitch and roll shift by 45 degrees) it will shift by 90 degress. So that up elevator make the aircraft roll to the left. Again, extrapolate.

Here is what I’ve done to setup the aircraft (numerous times):

  • Using APM 2.0
  • Installed ArduCopter v3.1.2 firmware
  • Set frame to X style (quad)
  • Entered my declination locaion for the compass
  • Calibrated the accelerometers
  • Calibrated the radio
  • Flight modes
    ** ch5:
    *** stabilize (set at takeoff)
    *** loiter
    *** alt hold
    ** ch 7:
    *** rtl (off at takeoff)
    ** ch 8:
    *** land (off at takeoff)
  • Failsafe to land mode
  • All other params are basically left as defaults

Here is what I have done to debug:

  • Changed receivers. I’m using a Spektrum DX7 and Orange brand receivers. I recenly harvested a receiver that’s been in a fixed wing aircraft for over a year.
  • Reinstalled the firmware
  • Recalibrated
  • Looked over the log files.
  • Rebound my Tx/Rx.

I’m out of ideas here and was hoping to get some experienced eyes on my log file (attached)

Hardware:

  • Tx Spektrum DX7
  • Rx Orange 7 ch full range with satellite Rx
  • Frame: Hobbyking EPP (circual prop guards)
  • ESC: HK cheapies
  • Motors: HK cheapies
  • FC: HKPilot (an APM 2.5 knock off) + GPS

Other information:
I’ve had this quad for maybe a year. It used to have a KK2 and flew great with that FC using the same DX7 Tx. I seem to recall seeing a similar malfunction once with the KK2. It only happened once so I assumed that I just lost the orientation of the aircraft and it was my fault. Looking back I’m not so sure. Still though, if it was the Tx, how could my aircraft switch to a + configuration? I would think that the pitch and roll would fully exchange places.

I’ve attached a log file where this happened mid flight and caused me to slam in the ground to avoid hitting an obsticle. It is very apparent in the logs where this happened. I can’t recall exactly how long before the impact that the steering changed.

Quick question before I look at your log: is simple or super simple mode turned on?

Good question. I’ve tried both with and without.

As you can read in my post, I was suspecting of the Tx. Well, I went ahead an threw in a cheap no-name Tx and Rx that I got with a foamie a long time ago, ran through the calibration and flew through 4 batteries with no issues. This made the Tx/Rx link suspect.

Next, I put in a brand name receiver (Spektrum AR6210). I’ve flow though two batteries now and it seems to be working properly. I’m hesitant to say that it’s resolved just yet, but it’s looking like the Orange RXs aren’t playing nice with my DX7. It’s not the modern DX7 with the roll knob, but the older one sold with servos and a 7 channel RX.

This is strange though. I would think that the steering would shift by a full 90. I don’t’ see how you can get a 45 degree shit from interpreting a PPM incorrectly. That’s what I assume the issue is between the DX7 and Orange. This is also reproducible in that I tried two different models of the Orange Rx.

[quote=“sneeden”]Good question. I’ve tried both with and without.

As you can read in my post, I was suspecting of the Tx. Well, I went ahead an threw in a cheap no-name Tx and Rx that I got with a foamie a long time ago, ran through the calibration and flew through 4 batteries with no issues. This made the Tx/Rx link suspect.

Next, I put in a brand name receiver (Spektrum AR6210). I’ve flow though two batteries now and it seems to be working properly. I’m hesitant to say that it’s resolved just yet, but it’s looking like the Orange RXs aren’t playing nice with my DX7. It’s not the modern DX7 with the roll knob, but the older one sold with servos and a 7 channel RX.

This is strange though. I would think that the steering would shift by a full 90. I don’t’ see how you can get a 45 degree shit from interpreting a PPM incorrectly. That’s what I assume the issue is between the DX7 and Orange. This is also reproducible in that I tried two different models of the Orange Rx.[/quote]

Well, if you’re flying in simple mode it could be a compass problem.

Hi sneeden,

I was wondering if you could help me out. I have the same APM as you and have a Spektrum DX8 with AR6210 receiver. For some reason i cannot get them to talk to each other. I can bind to the receiver and i have checked all of the connections and they seem to be correct. Im wondering whether i have a dodgy APM or is there some trick to getting the Spektrum RX to work with the APM.

I would really appreciate any help that you can give me on this. I have been using the DX8 add the receiver with a Trex 450 pro Heli no probs but it just doesn’t want to play ball on my Hex.

Many thanks in advance
Dave

@dbraiden,
Do you have a genuine 3DR APM or is it a clone?

If you have a genuine 3DR APM, have you connected the AR6210 receiver to the APM per these Wiki instructions: http://copter.ardupilot.com/wiki/connecting-your-rc-input-and-motors/

Does the receiver bind led come on when the APM is powered and the transmitter is on? In other words is the APM powering the receiver when the APM has power?

Have you correctly connected the PWM outputs (-) of the receiver, which are the row of pins closest to the output legends, to the correct APM receiver PWM inputs (S) which are the row of pins closets to the input pin legends?

Regards,
TCIII GM