Hello,

after setup the heli with the APM 2.6,I tried to run my nitro machine.

The motor didn't work for about 5 years, but works nice afte some minutes.

I only have a problem with the throttle control.

I made a small movie, you can see the problem.

The radio does not change the throttle. The radio has a prop channel with potentiometer input.

I set the throttle servo position to about half and then you can see what happens without moving the slider potentiometer.

The nitro machine is off in the video.

The APM is not armed.

Here a short video link: http://www.vidup.de/v/bNYaT/

Here a little longer video link: http://www.vidup.de/v/2zurK/

Is this a parameter fault? I still have default parameter setup.

The parameter list is included.

Armin

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Hi Armin, I cannot understand what it is you're doing.  All I see is a servo moving.  I would need to understand how you have wired it up, etc. What are your control inputs?

Hello Rob,

I have a frsky radio system in a 7 channel JR transmitter mode 2. Because of wrong order of the ppm sum signal, I made a single wire of the channels to the APM. All servos are moving on the correct radio stick. I load the newest stable APM Helicopter software 3.2.1 to the APM. I benchmarked the helicopter without engine on. That means I armed the APM and moved the helicopter by hand in the 3 axis. The APM controlled the correct servos to change back to the previous position. I mean that's working o.k. The helicopter position change was nice corrected by the APM. Next step was to start and test the nitro engine.

I start the motor, but the motor goes always off after about 10 to 15 sec. In the movies you can see the throttle servo move. I didn't touch the radio. This happens every time after, radio on, receiver on and start sequence of APM finished. The throttle servo makes this moves and I don't know why. If the APM is armed or not, makes no difference.All other servos stay in the actual position and only move, if I move a radio stick or move the helicopter.

This happens all in stabilize mode of the APM.

Does the GPS have any influence, because this is still in progress, I made a ftd connection today for checking the parameters with u-center. Just now I get 6 satelites inside my house and HDOP of 1.3

What is my servo problem? Hardware or software. The 3.3 V regulator chip on the APM I changed to a stronger version. It was broken before with 0 V in the output.

In the attached file is my wiring to/from the APM.

Any more information necessary? Please tell me.

Armin

 

Attachments:

I disconnected the telemetrie and the gps, but the throttle servo is still moving every 10 to 15 sec. Goes to low throttle stay for 1, or 2 sec and moves back to the setpoint of the radio.

Armin

Armin,  If you post a log on the Arducopter support forum I'm sure some of the people here will have some answers for you.  I thought at first that maybe your system was disarming in 10 or 15 seconds causing your servo to move. I'm not sure but if your not armed the throttle servo should not move at all.

Regards,

David R. Boulanger

Hello Robert + David,

The arming system is in function now. The problem was totally crazy. If, in full parameter list you set channel 8 pass through (RC8_FUNCTION = 1), you have always control of channel 8 output, not looking for arming. In the case you setup (H_RSC_MODE = 1) channel 8 input, you have double reading of channel 8, once because of the pass through and one because of the channel 8 input set value. If stick is higher than zero in pass through the servo moves to this position, then come the arming check and push the throttle servo down, next passthrough and so on. This is a double writing of exit pwm to channel 8. I switched of (RC8_FUNCTION = 0) and now it works.

Today I got a second APM which made the absolutely same prob. Now I have one spare, let's see what for.

If anybody is interested my parameter file it is attached. All flight parameters are untested, I didn't  try until now.

Next prob is my GPS, but I will get a new one by warranty. What is to say about the LEA-6H?

Regards

Armin

Attachments:

Armin,  I actually forgot what GPS I am using but it is the one commonly sold by 3DR.  Read the Wiki regarding Traditional Helicopter tuning.  Some of your initial parameters are way off I think.  Pay attention to the FF parameters.  The Heli needs them. Attached are my latest Parameters.

Regards

David R. Boulanger

Attachments:

@David,

I took mainly your parameters, should be better than parameters from any default. I'll look for a parameter setup how to.

My throttle / gas servo is now only moving in armed mode. It's going same as my prop channel position and don't move any more crazy.

I have one more question: I use a 2s LiFePo flight battery with min. 5 V and max 7,2 V. Is this voltage too low for the power modul? I have only 4.7 V on the APM / receiver power rails. JP 1 is not in use, so separate power supply for APM and servos. The power modul should be set to 5.3 V normally. I cannot find any description with minimum voltage supply, there is only max. voltage written.

A lot of things to test and setup, but thats our hobby isn't.

Next I will also install a RPM measuring with a small arduino pro mini and openXsensor software. I already tested with my frsky telemetrie receiver.

Regards

Armin

Armin,  I use a LiFePo 2 cell for my power module without problems.  It's a 2100Mah and it will run the Pixhawk, receiver, GPS, and telemetry for 2 hours easy if not longer.  Servo rail is powered by a BEC set at 5.7 volts.

Be careful with my parameters.  Everything effects them.  Headspeed, servo's and servo geometry, weight, type of blades, and even if you are using an APM or Pixhawk.  I had to change my Throttle Accel parameters when I switched from an APM to a Pixhawk.  I think it has something to do with how fast the Flight controller processes everything but I am not sure. Your biggest problem will be isolating your APM from the vibrations caused by the combustion motor.  Mine is electric so my vibrations are easily managed.  Good luck and take it slow

Regards,

David R. Boulanger

David, you're using a 2S LiFE pack through the power module to power the flight controller?  This is not recommended.  When the battery voltage drops below... I think it was 6.4V, the output of the PM regulator is undefined.  You may be getting away with it, but it's below specification.  I wouldn't risk it.  Use a 3S battery minimum, or go to an extremely low drop-out regulator.  That's what I do.  Mine will supply stable 5V down to 5.1V input. 

Rob,  Thanks for the heads up.  I will get a 3s tomorrow.

Regards,

David R. Boulanger

Thanks, that is what i thought. The LiFePo voltage goes down to minimum 5 V, depending on the dropout voltage the controller has too low voltage. My power modul has a high dropout voltage, with charged LiFePo I get maximum 4.9 V for the controller. I will change to 3s too.

Regards

Armin

Its my understanding, maybe I'm wrong, that a LiFePo ( 2 cell ) should give 6.6 volts until it is nearly dead.  Its not like other batteries that slowly lose voltage as the charge is used up.

Regards,

David R. Boulanger

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