Enabling RAW logs to measure vibration

[Jumpy07]

Turning on Raw Logging In order to record the necessary Accelerometer data to your flight logs you will need to enable RAW mode in the "Log" recording function of the APM (which is off by default).

   
• Hook up your APM to you PC with the USB cable.

•Start the Mission Planner Software on your PC.

   
• DO NOT select the connection icon but instead select Terminal mode.
• Type in "logs" and the enter key.
• Type in "enable raw" and the enter key.
• Raw Accelerometer and Gyro information for all 3 axes will now be recorded to the flight log that is produced each time you fly.
• Disconnect from the PC.

Downloading log files

First, ensure that your in CLI mode and that you';ve selected the right Com port for your board in the Mission Planner configuration menu.

Select "Log Download" from the Mission Planner Terminal tab. A list of logs from the onboard memory will be shown. You can either select individual files to download or download all of them. They will be saved in your APMMissionPlanner/logs folder, along with a KML, that can be opened in Google Earth.

Note: It can take a long time (several minutes) to download a big log file. Do not interrupt the process until the software reports that it';s finished.

Analysing log files

Once you';ve downloaded log files, you can analyse them. Click on a log file to analyse, and the Log Browser should open.

You can click on any cell to add that kind of data to the data already graphed.

You can use your mouse';s scroll wheel to zoom in or out on the data, or drag a box around the area of data you';re interested in to have it fill the window.

[neagron]

    very much for this Craig,Marty. :scotland:

[rickp]

Worth turning the frequency down to 20HZ too, as that is the default for 2.9.2 (and is already committed in the main trunk).

[Jumpy07]

Worth turning the frequency down to 20HZ too, as that is the default for 2.9.2 (and is already committed in the main trunk).

Agree.. detailed in the PID guide Faq already.. although worth pointing out depends on your frame.. some people finding better results at 40 who have very stiff vibration free setups.

[Gaza07]

Excellent info Craigs thanks for posting 

[rickp]

Just to add to Craig';s fine procedure - in 3.0, it will be ';enable IMU'; rather than ';raw'; to turn on the appropriate logs. May also be worth enabling ';compass'; to see how thats doing.

[Srocupado]

Thanks for that info Rickp.

[Hands0n]

Important Note - Downloading Logs Change In 3.2

As of version 3.2 of ArduCopter the CLI is no longer used in APM 2.x hardware.

To download logs do the following

1. Navigate to the Flight Data panel
2. On the bottom left, select the "DataFlash Logs" tab and push the "Download DataFlash Log Via Mavlink" button


Then, select the log you want to download. This will save that log to your MissionPlanner/logs directory, in a folder named after the vehicle type, such as QUADCOPTER.


Full details are now on the ArduPilot wiki --> http://planner.ardupilot.com/wiki/downloading-and-analyzing-data-logs-in-mission-planner/

[james]

Worth mentioning - in newer firmwares (currently only master and I think possibly 3.3 when it';s released) there';s full IMU logging support. This logs the raw data from the IMUs, requires a fast uSD card and the bitmask setting to All+FullIMU.

There';s now an FFT button in most MPs Ctrl+F menu. In there you can load a log with FullIMU logging enabled and see peaks that correspond to different sources of mechanical vibration, eg ~100Hz (6000rpm) for motor rotation, ~200Hz for blade passage (when the blade passes over the arm), etc.

Potentially very useful when tuning and debugging vehicles.

[Revs]

James, is that on APM and Pix or just Pix? I assume that';s just the Pix as the APM had no mSD card..

[james]

James, is that on APM and Pix or just Pix? I assume that';s just the Pix as the APM had no mSD card..

Just Pixhawk - anything new in APM is for 32-bit hardware only, there';s no new (official, at least) build activity for 8-bit given how cheap 32-bit is these days.