Hello all,
I'm a new user so forgive me if I'm a moron for some element of the following question, but my issue is this: My Pixhawk seems to refuse to enter ESC calibration mode.
Background: I am building a flying wing UAV for mapping missions. I am using a PX4 pixhawk with arduplane v3.5.2, with MissionPlanner as the computer interface. I am using a Taranis Plus with an X8R receiver. Upon startup of the pixhawk, I immediately get a "no RC receiver" message from mission planner if the unit was still connected prior to being turned off. However, this message goes away after a few moments, and the X8R's LED indicates that everything is fine there. Additionally, I am not getting a GPS fix, but I'm working in the 3rd floor of a 6-story building so this isn't surprising. I have disabled pre-flight checks to get around this issue during startup so that I can get on with ESC calibration.
Approach: With the pixhawk connected to the computer using PC telemetry, I unplug the LiPo (3s, 5200 mAh). Power down the Taranis, then turn it back on and put throttle at 100%. Plug in battery to power up the pixhawk and ESC. Pixhawk flashes yellow, then BRIEFLY cycled red blue and yellow LED's before simply flashing yellow (this is when I get the "no rc receiver" and "bad gps health" messages). Then the pixhawk beeps, and everything turns blue as the RC connection is made with the pixhawk.
Problem: From here, the pixhawk never enters esc calibration mode (indicated by a cycle of red, blue, and yellow LED's. I had tried to proceed with the process described here (http://diydrones.com/group/arducopterusergroup/forum/topics/esc-calibration-all-at-once-procedure-on-pixhawk) and here (http://ardupilot.org/copter/docs/esc-calibration.html) but the ESC never makes any noises! And despite using two different ESC's - both of which are HobbyKing 40A SBEC's suitable for 2-6s LiPo's... One has been used in a previous airframe, so I really don't think it's a problem with the ESC itself.
I can't get the motor to do anything. However, when I up the throttle on the Taranis, the control flaps get jittery - as if they're receiving a pulsed signal somehow - and yet everything is mounted properly onto the Pixhawk (elevon servos are in ports 1 and 2 and the ESC is in port 3).
Any suggestions?
Replies
For anyone who may share the problem I describe above, the solution is a simple one:
It was a rookie mistake. Because the pixhawk has a default two-step arming protocol, you need to be sure to perform BOTH arming actions before you can expect the throttle to do anything! The arming button will suffice to check control surface movement, but in order to arm the throttle one must also arm using the RC transmitter control sticks (hold both sticks to the bottom center).
After going through the full suite of arming stages the motor worked no problem.
ESC calibration only works on copters, not planes. You were looking at the copter wiki manual, not the plane one. Planes do not require ESC calibration.
Oh - well that answers that question; thanks! In followup, then - my motor is failing to function when the pixhawk is armed and I increase throttle. MissionPlanner detects the change in the throttle stick, but nothing happens with the motor... Yet the control flaps react as I described above. Any ideas of what might be wrong?
Have you armed your ESC? Depending on the make, that might require moving the throttle to full in manual mode, waiting for the beeps, and then dropping it back to the bottom. Then it should be armed.
(This is standard RC stuff, BTW. It's very old-fashioned, but that's a legacy of the RC world. In copters, most of the RC stuff is now obsoleted by end-to-end computer control, which is much better)
Thanks, Chris. I tried the arming sequence you suggested, still to no avail. As arming isn't standard across esc's, I looked into my model specifically (HobbyKing 40A SBEC; manual here http://www.hobbyking.com/hobbyking/store/uploads/811103388X7478X20.pdf). Unfortunately it seems that this model doesn't require an arming sequence, leaving me a little beleaguered.
My only thought is relevant to the taranis. While MissionPlanner suggests that the RC receiver is interpreting the throttle and yaw with channels 3 and 4, NEITHER use of the throttle stick yields a response from the armed pixhawk. I would expect moving yaw back and forth should activate the control flap servos, but nothing happens there.
Yaw (ch4) will not move flaps. It only moves the rudder, if you have one, and only in manual mode (rudder is automatically controlled in auto modes). Roll (ch 1) controls ailerons.
WOAH. Reversing the throttle in radio calibration causes the motor to turn on at what seems to be max - but the pixhawk isn't even armed (safety switch still blinking)!!! Plus i'm in FBWA and not auto!!!
FBWA *is* an auto mode. Start by setting up in Manual.
I tried calibrating the radio in manual mode, with the motor unplugged so I could reverse the throttle setting and recalibrate the transmitter before supplying power to the motor. After that, I unplugged the battery, replugged in the esc, and finally replugged in the battery. A series of regularly-timed beeps followed by a cascading series of beeps followed - catastrophic failure or success? or somewhere in between...?
No idea, I'm afraid. I don't have a Taranis nor those ESCs and don't know what that means. Perhaps you've got it reversed again and it doesn't want to start up in full-throttle mode? Or perhaps it's complaining that it has no ESC signal at all, in which case you need to press the safety switch.
My sympathies: this old RC stuff is nuts. Can't wait until planes are as simple as copters.