Hi all,
I just got a pixhawk to pilot my tricopter, and I'm having a few issues. For my setup, I've got pixhawk with a turnigy 9x and PPM encoder for the radio, 3DR power module, 3S battery, aftermarket 915 mhz 3DR telemetry, NEO-M8N GPS, and a q brain 20A esc for my motors. The button and buzzer are all wired up too.
I ran through the setup wizard and checked the 3DR website to make sure all my wiring was correct, and it seems like I've got everything connected right, but I'm still having some problems.
1) The pixhawk won't enter prearm sequence, as far as I can tell. The light just keeps blinking blue when I try to arm it. I read that this means no GPS fix, which it also says on mission planner, but I recall when using the APM that mission planner at least told you why it wasn't arming after the prearm sequence. With the pixhawk, though, it's not doing anything when I try to arm it. I've calibrated the compass, accellerometers, and everything I thought would be necessary. I also tried changing the mission planner setting to skip GPS lock when arming, but it still doesn't do anything. However, if I disable prearm sequence in mission planner, the tri will arm just fine and the props will spin. What might be the problem? Do I need to have a GPS fix to arm? Tomorrow I'll try getting a GPS fix, but any info would be appreciated.
2) My yaw servo isn't working. I have it plugged into port 7, but it doesn't move, nor does it twitch or have any indication of being powered up. Does it need external power to work? Is there any way to test to see if the servo is working besides powering up the tri and trying to fly it? I'll try hooking up the servo to a different receiver tomorrow to at least make sure my servo isn't busted.
3) like many people, the aftermarket el-cheapo telemetry isn't working. !ith com port 4 (the telemetry com port) selected in mission planner, and the tri both plugged in via USB and not plugged in, I tried loading settings. It failed to connect. Then, I connected the tri via USB and tried to load settings, and it worked. Then I copied and saved the settings to the remote, and both of those procedures succeeded. The orange lights on the transmitter and receiver were blinking in unison through the process. But when I tried connecting with com port 4 in mission planner, it timed out with no heartbeat packets received. I changed the baud rate to 57600 and it still didn't work. Could someone perhaps link me to a guide on how to set these up? I used a pair of cheap $20 telemetry radios on my quad in the past and they set up so easily. Also, windows says the driver is working properly for the computer radio, but is there a specific driver I should be using? I'm open to any suggestions, obviously lol.
So that's my story. Any help would be appreciated. If you need any info, please ask. I know I'm not giving you much to work with, but I can get you any info necessary. I'll be doing my research as well and keeping you posted. Also, is this the best place to post this? Thanks for everything. I hope I can get flying soon!
Replies
Thank you for the info about the yaw servo. I either wasn't watching it hard enough, or I had it wired up all wrong, but I got it working. Unfortunately, I ended up breaking it too, and I'm on vacation now so I don't really have any spares. Is there any way to trim the yaw servo? I had glued it in place before I tested it, so it was pointing the tail way to the left and it just barely leveled out when I started raising the throttle. Needless to say, the tri just spun, which was kinda fun to look at either way.
Regarding arming, I think I was just being dumb; it turns out I didn't do a proper compass calibration.
References to Rc7_trim are below ... but they require Copter v3.3-rc8.
BUT -RC4_trim did work for adjusting yaw servo trim??
Can also try yaw-Trim on transmitter CAREFUL!! but then it maybe not able to be armed because the yaw is out of range of the arming spec.
Copter 3.3-rc8 25-Jul-2015
Changes from 3.3-rc7
new tricopter's tail servo parameters (MOT_YAW_SV_MIN, MAX, TRIM, REV)
SEE:
http://copter.ardupilot.com/wiki/tricopter/
Copter 3.3-rc8 25-Jul-2015, Changes from 3.3-rc7
•MOT_YAW_SV_MIN: yaw servo’s lowest PWM value before binding occurs.
•MOT_YAW_SV_MAX: yaw servo’s highest PWM value before binding occurs.
•MOT_YAW_SV_TRIM: yaw servo’s PWM value close to what is required to keep the tail from spinning.
•MOT_YAW_SV_REV: yaw servo’s reverse setting. +1 = servo moves in default direction, -1 to reverse direction of movement.
Copter 3.2.1 (and earlier)
•RC7_MIN: yaw servo’s lowest PWM value before binding occurs.
•RC7_MAX: yaw servo’s highest PWM value before binding occurs.
•RC7_TRIM: yaw servo’s PWM value close to what is required to keep the tail from spinning.
•RC7_REV: yaw servo’s reverse setting. +1 = servo moves in default direction, -1 to reverse direction of movement.
Some new info:
For:
1) if the copter is not sitting still, it will not arm.
2) My yaw servo only becomes active with maybe at least 1/3 throttle. (take off the props or unplug motors and use a BEC to power the Pixhawk.) Then the yaw control will go from zero position on the servo for full right, to Max position on full left.
You can test it by connecting directly to transmitter. Also make sure the black wire is up when plugs into Pixhawk.