What's the difference in flying performance between optical flow and Lidar lite?
It's been a month or so since I've messed with the px4flow. I was at a very similar place with OF that you are now, Wes. It took me a while before someone over on the Px4 Groups on Google told me that the only sure fire way to confirm the OF Data is through enabling the full log bitmask and viewing the log, using FlightPlot or LogMuncher to view the OF Data.
My first mistakes were; Not having a distance sensor working in sync with the OF sensor (bought a LIDAR-Lite), after that I found out I was using Mission Planner Stable and not the Dev/Beta loaded in the Hawk, then I was told that QGroundControl w/ the PX4 Firmware is the preferred firmware for OF. So that brings me here, I've uploaded logs onto log muncher which didn't help me much more than FlightPlot.(Log from test flight). I'm breaking out multiple SD cards tomorrow and starting over with different firmware's and settings. Hopefully I'll uncover something to contribute.
I think it depends upon who you talk to.. so if you talk with the px4 developers they'll lead you the way that they know (i.e. QGC+px4stack), while Paul and I would steer you towards ardupilot + mission planner. So this thread is really for the ardupilot+MP method that hopefully Paul and I can help you with.
Just in case it might be useful to someone trying to get OF to work, here's a copy of my notes on getting OpticalFlow working with Copter v3.3.
I have it kinda/sorta working (with some intermittent issues), and I'm not 100% sure if everything is setup correctly and I'm sure I've missed something, so any feedback will be greatly appreciated.
Download the APM's version of PX4FLOW Firmware from: http://ardupilot.com/downloads/?did=118
(The expanded firmware should be
NOTE: Some versions of QGroundControl are missing the menu to upload custom firmware from local filesystem. Use the latest version (v2.8.0) in order to upload the custome firmware to PX4FLOW. v2.8.0 also has PX4FLOW specific settings menu with auto-video streaming. If you want to run an older version of QGroundControl, use v2.5.2 or earlier in order to be able to load custom firmware to PX4FLOW.
All release versions of QGroundControl can be found here
Change the following parameters:
EKF_GPS_TYPE -> 3
FLOW_ENABLE -> 1
FLOW_FXSCALER -> 0
FLOW_FYSCALER -> 0
FLOW_ORIENT_YAW -> 0 if you've mounted PX4FLOW's x axis facing forward (xyz axis marker is printed on the backside of PX4FLOW PCB board). If x is not facing forward, adjust this. Value Must be between -18000 and 18000 centidegrees.
# Disable GPS pre-arm check
GPS_HDOP_GOOD -> 9999
# Enable Pre-ARM Logging (All + FastATT, including pre-arm logging)
LOG_BITMASK -> 131071
# If you want to use built-in barometer instead of external range finder (NOT recommended).
EKF_ALT_SOURCE -> 0 # Set this to 1 if you have external range finder (LiDAR, etc.)
RNGFND_GNDCLEAR -> set this according to your rangefinder's spec.
Check mount orientation and tweak the scaler parameters according to the instructions in the wiki
Check dataflash logs (NOT telemetry logs) and make sure:
NOTE: OF.flowX and OF.flowY don't get updated in the telemetry log, so make sure to check the dataflash logs.
NOTE: Don't use OF_LOITER mode as they've been removed a long time ago from the firmware. APM Planner 2.0 still has this mode in the drop-down menu, presumably in order to support older versions.
px4flow statuscommand to see if the PX4FLOW module is detected on I2C and the driver is loaded. You should see a bunch of readouts if it's functioning correctly and error message otherwise.