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PX4 / PX4-Autopilot

PX4 Autopilot Software
https://px4.io
BSD 3-Clause "New" or "Revised" License
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No valid local position and velocity with `OPTICAL_FLOW_RAD` messages publishing #10304

Closed okalachev closed 6 years ago

okalachev commented 6 years ago

I'm using 1.8.0 version with EKF2, SITL.

Publish faked optical flow messages with zero integrated_x and integrated_y. The vehicle is not obtaining valid local position nor velocity (vehicle_local_position.xy_valid, vehicle_local_position.v_xy_valid). This happens when staying still, and in air also.

https://review.px4.io/plot_app?log=1e6bf123-38ed-409d-843d-07ef0d331a7a

(Also, there are some issues with time_usec decoding, so I temporarily changed optical_flow message's timestamp to hrt_absolute_time().)

okalachev commented 6 years ago

I found three problems.

First, if there is a zero value in max_flow_rate of optical_flow uORB message, the local position and velocity are not getting valid.

So something like f.max_flow_rate = 2.5f should be added to MavlinkReceiver::handle_message_optical_flow_rad method.

Second, the local position and velocity are not getting valid, if integrated_xgyro, integratedyxgyro, integrated_zgyro are NaNs, although in that case PX4 should get gyro data from the PixHawk's gyro.

Third, f.timestamp = flow.time_usec line works incorrect (gives an incorrect timestamp). I temporarily changed it to f.timestamp = hrt_absolute_time().

@dagar , @mhkabir , @priseborough .

mhkabir commented 6 years ago

Yes, I actually corrected all those three issues in my local branch, however it didn't make much of a difference. I did get valid local position for a while, and then it stopped working in flight.

okalachev commented 6 years ago

Can you please provide a link to this branch?

mhkabir commented 6 years ago

I will have to extract the relevant commits; Will do so soon.

Meanwhile, here is a log : https://review.px4.io/plot_app?log=4b678d25-1317-4e5e-a9ad-47ae900ff6cc

mhkabir commented 6 years ago

OK, I think I just figured out my issue. The vehicle's terrain estimate is completely wrong, and therefore the flow data scaling is wrong, leading to data rejection.

image

As for why the terrain estimate is invalid, I think it's just my rangefinder : https://github.com/PX4/Firmware/issues/10264

okalachev commented 6 years ago

Generally, the issues were resolved. Also #10506.