Im Ray, live in NM. THis is my first setup using APM. Im not new to helis, been flying for about 6 years, just new to trying the UAV thing.
Im setting up a APM 2.5 on a 600E. I get to "Configure Servos' Part of the heli setup and the servos are not moving. Im using a SPectrum DX 8 and AR 9300 reciever. My servos are plugged into the outputs and the signal wire is to the inside of the board. Im getting NO movement at all. Even if they are in the wrong order I should still get movement. I have been through the radio calibration part and i have even hooked the servos to my reciever directly to make sure that everything is working correctly.
I hoooked everything up using the pic below.
THanks in advance for the help.
How are you powering the board? If you're using the Power Module, you must have a BEC/ESC on the output side to power the servos. the JP1 jumper should be off in that case.
Plug the power cable into the PM port on the APM2.5 as shown in the diagram below.
Also have a look at this link http://code.google.com/p/arducopter/wiki/AC2_Current
If you connect your ESC on output channel 8 it should also power the output side of the APM. Remove jumper J1 to ensure the input side and output side are not interconnected. Otherwise connect a BEC to the +ve and -ve terminals at any point along the output side.
Getting your servos to move:
The latest firmware v2.9.1 for the APM has a safety feature to ensure that you "arm" the APM before flying. To arm you move the throttle down and fully to the right and hold it there. In Mission Planner on the Heads-up display you will see the word ARM come up and the red LED on the APM will stop flashing and go to solid on. Now the servos will move.
Read through this part of the manual http://code.google.com/p/arducopter/wiki/TradHeli_Configuration
Hope that helps.
Thanks, that helped alot. I went ahead and installed the jumper and I am using a BEC feeding 5.2 volts to the servo out side of the board. Seems to be working fine. This should be sufficient to feed everything correct?
When i go to do the swash plate setup now, everything works. When I click the "manual" button to do the swash setup, the servos are very jittery! Once back in to normal mode they stop and are fine.
I appreciate the help.
Ok, ive followed the setup, everything seems to be coming along fine. Now the PID. WHen I power up normaly like im going to fly, and arm, the servos are very jittery, and once in awhile they will just move up and then down very rapidly, like a nervous twitch,, LOL for lack of a better explination. Im sure its one of the pids settings is high, but which one? Im using align 610 servos.
It's hard to be sure without seeing the logs but if you're using a futaba tx/rx with 8 or more channels then you should upgrade to the latest ppm encoder by following the instructions here.
Thanks for the reply. No im using a Spektrum DX8 with a AR9300 reciever. This is a 600 size electric heli. I got it to town down some, using the rates both roll and pitch, then brought down the stab settings as well. But it is still jittery. Acts like what you would find on other systems when you use the wrong frequency on the servos.
You can adjust the update rate to the servos by changing the RC_SPEED parameter. It defaults to 125 for helictopers and 490hz for multicopters. Maybe you could try reducing it further by finding and changing it in the Adv Param List of the mission planner.
Thanks Randy, Ill give that a try tonight when I get home from work..
Is the '125' the frequency? If so that may not be high enough for digital servos. Looking at the specs for my servos it is 200 mhz. That might just fix it. Everything else seems to be working well so far. Thanks for the great help.
Yes, that's the frequency in hz. It can go as high as 490hz or as low as 50hz.
Ray, are you indoors with the GPS connected when this jitter is happening?
Try disconnecting the GPS and see if it goes away.
Also note that the way you have your power system setup, using a single BEC to power the servos as well as the APM, you could have brown-outs on the APM. The servos can demand too much power, drag down the voltage, and the APM will go down, which means you crash.
You can get away with this on a 450 with tiny servos, but I really don't recommend it for anything larger. There's a good discussion about this here:
Also, the power rail on the output rail of the APM is not rated to carry the amperage of 4 full-size digital servos. You really should use an external power bus.
Please take this discussion into the main forum where it will have more attention.
If the rate is too high for the servos, that can cause jitter. But if the rate is too low, that will not cause jitter. I don't think this is your problem.