Trouble shooting throttle issues APM 2.6 running 3.2.1

ArduCopter Copter 3.2
1

platform setup:
Hexacopter with APM 2.6 running 3.2.1
Ublox GPS, DJI E300 propulsion system, 4S 3300mah
Futaba T7C/R617FS

Originally I built this platform with a CC3D flight controller. Flew very smooth. But I want to get into missions so I purchased an APM. Got it installed and have run into issues. I am continuing to research this forum looking into this issue.

Pre-arm check always gives me an “RC not calibrated” error even though I have gone through the radio calibration steps. I have searched the APM forum but couldn’t find a solution, just the work around of disabling the RC check. So in an effort to see if the thing will fly I disabled the RC check.

This allows me to arm. Successful arming and the motors are engaged. I throttle up and it starts to, for lack of a better term, "sputter’ kinda bouncing around but never lifting. Throttle at max and it doesn’t leave the ground.

I downloaded the dataflash logs from the APM and can review them through the mission planner. I need to do more research on how to read the logs, that is a work in progress.
I also ran a log analysis using the built-in tool in MP, output shown below.
I also uploaded the logs to dropbox if anyone would like to take a look.

https://www.dropbox.com/s/ufc8y4xzkdgmxz6/2015-03-08%2013-08-02.bin?dl=0

Anyone know the meaning of the bolded info below?
Thanks in advance for any help.

Sandy

Vehicle type ArduCopter
Firmware Version V3.2.1
Firmware Hash 36b405fb
Hardware Type
Free Mem 0
Skipped Lines 0

Test: Autotune = UNKNOWN - No ATUN log data
Test: Balance/Twist = GOOD -
Test: Brownout = GOOD -
Test: Compass = GOOD - No MAG data, unable to test mag_field interference

Test: Dupe Log Data = GOOD -
Test: Empty = FAIL - Empty log? Throttle never above 20%
Test: Event/Failsafe = FAIL - ERRs found: FS_BATT GPS
Test: GPS = FAIL - Min satellites: 0, Max HDop: 2.68
Test: IMU Mismatch = UNKNOWN - No IMU log data
Test: Parameters = GOOD -
Test: PM = GOOD -
Test: Pitch/Roll = GOOD -
Test: Thrust = GOOD -
Test: VCC = GOOD

2

The auto log analysis and your described performance appear to match.
If your TX throttle is max, but the log shows <20 throttle that speaks to radio calibration.
Are you seeing full gimbal functionality, when you are connected, and on the MP radio calibration page?

I do seem to remember some http://diydrones.com/forum/topics/dji-opto-30a-esc-lazy-esc?groupUrl=arducopterusergroup&groupId=705844%3AGroup%3A394475&id=705844%3ATopic%3A1566537&page=1#comments with the DJI propulsion.

I would still confirm the radio/MP calibration first. Someone else may have more to add.

[quote=“wisedawg”]platform setup:
Hexacopter with APM 2.6 running 3.2.1
Ublox GPS, DJI E300 propulsion system, 4S 3300mah
Futaba T7C/R617FS

Originally I built this platform with a CC3D flight controller. Flew very smooth. But I want to get into missions so I purchased an APM. Got it installed and have run into issues. I am continuing to research this forum looking into this issue.

Pre-arm check always gives me an “RC not calibrated” error even though I have gone through the radio calibration steps. I have searched the APM forum but couldn’t find a solution, just the work around of disabling the RC check. So in an effort to see if the thing will fly I disabled the RC check.

This allows me to arm. Successful arming and the motors are engaged. I throttle up and it starts to, for lack of a better term, "sputter’ kinda bouncing around but never lifting. Throttle at max and it doesn’t leave the ground.

I downloaded the dataflash logs from the APM and can review them through the mission planner. I need to do more research on how to read the logs, that is a work in progress.
I also ran a log analysis using the built-in tool in MP, output shown below.
I also uploaded the logs to dropbox if anyone would like to take a look.

https://www.dropbox.com/s/ufc8y4xzkdgmxz6/2015-03-08%2013-08-02.bin?dl=0

Anyone know the meaning of the bolded info below?
Thanks in advance for any help.

Sandy

Vehicle type ArduCopter
Firmware Version V3.2.1
Firmware Hash 36b405fb
Hardware Type
Free Mem 0
Skipped Lines 0

Test: Autotune = UNKNOWN - No ATUN log data
Test: Balance/Twist = GOOD -
Test: Brownout = GOOD -
Test: Compass = GOOD - No MAG data, unable to test mag_field interference

Test: Dupe Log Data = GOOD -
Test: Empty = FAIL - Empty log? Throttle never above 20%
Test: Event/Failsafe = FAIL - ERRs found: FS_BATT GPS
Test: GPS = FAIL - Min satellites: 0, Max HDop: 2.68
Test: IMU Mismatch = UNKNOWN - No IMU log data
Test: Parameters = GOOD -
Test: PM = GOOD -
Test: Pitch/Roll = GOOD -
Test: Thrust = GOOD -
Test: VCC = GOOD[/quote]

1 Like
3

FSP2 - Thanks for the quick and informative reply.

I solved the “RC not calibrated” by adjusting the D/R and endpoint on the TX. There was legacy settings that had the yaw highly restricted. I made the changes on the TX and ran calibration again. The pre-arm error is gone now.

It is a bit late tonight so I am going to follow up on testing the throttle tomorrow and will get back with results.

Thanks for taking the time to view the logs and help me with this.

Sandy

4

I had seen referenced in more than one post that the OPTO escs dont require calibration.
I am still looking into that for a definitive answer.
Thanks again
Sandy

5

I was going to suggest calibrating the endpoints on the radio and I see you did. I normally keep them as close to 1000-2000 as I can no matter which flight controller.
You experience lack of power to lift off? I’ve had the same problem with APM on an aircraft I’ve been running another controller on previously.
It seems APM always cuts the power down for what YOU can give it from the sticks. The system can use the rest to compensate for altitude loss, leveling and so on but the user can not get the full punch. This way you can always get more power switching back from APM.
Though in some cases it seems some people have got as little as 50% throttle out. You can confirm this by either measuring the output signal for the motors (can be done just putting a servo on the output) or by measuring the current draw with propellers on holding the copter down which is not recommended.
They are some settings you could look through which I had some luck with. And I can also recommend clearing EEPROM if you have ever used another firmware version on the board or just want to make sure they are no skelettons in the EEPROM.
Quoting some old posts

[quote]I ran into the same issue with APM 3.2. After reading through all available forums I think I found the resolution to this problem.

First, check the PWM input value for Channel 3 and compare it to the output values for Ch1-4 in the status monitor. In my case, Ch1-4 out never exceeded 1500, regardless of the Ch3 input.

Apparently in some installations 2 parameter are st to wrong values, THR_MAX and MOT_TCRV_MAXPCT.

In my case, THR_MAX was preset to 80 (default is 800 -1000) . Resolution: set this value to 1000

Aso in my case MOT_TCRV_MAXPCT was set to 40 (range 0-80). This limits throttle to 50%. I set this value to 80 and suddenly had full power.

Re-check Ch1-4 out at full throttle. Now you should read a PWM value of ~1900 and you should be good.
[/quote]

[quote]Throttle curve was made to try linearize ESC output, that usually has it’s last 7-10% output same value.

Instead of changing MOT_TCRV_MAXPCT to 80 (default is 93) try disabling throttle curve by setting MOT_TCRV_ENABLE to 0.[/quote]

6

The only firmware I have loaded is 3.2.1.
Does the hardware reset button work?

7

Following that road of thought I decided to reset all parameters to default just for grins.

I really wish I had saved the existing parameters off to a file to do a before/after comparison because the default values got the throttle to respond as expected. I had obviously fat fingered a parameter the first go-round.

If it ever stops raining I will get to test this config. Tomorrow maybe.

8

At the front of your logs is all the parameters that were set including the throttle settings and PID’s.

Mike

9

[attachment=0]2015-09-30 12-30-26.log[/attachment]
Hi,
I also got a problem that the motors don’t react simultaneously with the throttle. I use all apm output channels for an octocopter. For a test the octocopter is fixed on the ground. Whe I increase the throttle slowly from zero to maximum and back to zero only one motor goes to a certain maximum. All the others react different. You can see it on the attached log. I calibrated several times the esc but no effect to this problem. I use an apm 2.5. But in effect the esc should’t be a cause for the problem. The problem has i.e. the effect when I test the yaw one or the other motor comes to a stand still and that’s not really flyable.
See also in the log at the beginning when the throttle ist constant for a relative low gas some of the servo outputs slowly increase. Thas seems als faulty to me.

I hope somebody is still looking at this post. :unamused:

Gerd