HereFlow position bounce

HereFlow
1

Hi

I was testing the hereflow, and works very good! But! I have a strange behaivor. To maintain the position the HF works very good, but when I move forward or backwars, or side to side, is like the drone try to come back to the last steady place, like the drone bounce on a imaginary wall. It moves like 3 o 4 meters, and when I release the stick, the drone come back. Beside that, while more far I try to go from the last steady point, seems to be more diificult to the drone keep going, like something try to brake it, like the drone cant leave a perimeter.

Here is a video, where I just move FW and BW, Im not braking, I only release the stick, then the drone brakes, and try to come back

Here is the log.
http://190.100.113.54:16211/archivos/logs/hereflow/hereflow.bin

I saw this manual to check whats its going on:

https://ardupilot.org/copter/docs/common-px4flow-overview.html?highlight=opt_qua

This is the data:

image
image1738Ă—590 112 KB

image
image1733Ă—568 119 KB

So, here I can see the loongg movement I think, there the flowX-Y are too big compare with the bodyX-Y and Gyros.

So, it say I have to change the FLOW_FYSCALER and FLOW_FXSCALER, both are in 0 now. I suppose I have to put negative values, but I dont know how much, may be the degrees of the deviation?

@philip @Anubis can you give me a hand?

1 Like
2

Have you followed these instructions?

https://ardupilot.org/copter/docs/common-hereflow.html

And what mode are you in?

3

Yes!

Loiter flight mode.

4

In this manual (https://docs.cubepilot.org/user-guides/flow-senor/here-flow) it says at the end:

6.After confirming the data are normal, go to “Full parameter list” and change “EKF2_GPS_TYPE” to “3” to disable GPS. This is for testing if the optical flow is working normally. Change ARMING_CHECK" to 15838 to cancel the pre-arm check of optical flow (Otherwise, you will need to rise the aircraft to at lease 50 cm and then put it back to the ground to disarm. After take off, the aircraft can loiter normally in LOITER mode.

So, what is the final setup after the testing?

5

Those instructions were out of date, leave arming checks at 1
I have updated the instructions on the wiki

6

Hi @philip, im looking the instrucctions and still the same. Can you pls give me the link to the new instructions?

Thanks

7

they are definitely updated at the link you posted, as I said, I fixed them.

For details beyond the physical integration, please follow any guides that are from ardupilot on the ardupilot features.

8

Thanks @philip

What about to use the HereFlow without the GPS? As far as I try, as the flight mode to make the HereFlow work is loiter or position hold, I cant use the drone inside a barn for example.

Thanks

9

you can definitely fly indoors, just ensure you are using EKF3 and tell it that you have no GPS.

10

Hi
I made it work without GPS, works better, but still having the “bouncing” break. The drone stays very good, then Im going forward, and when I release the pitch, the drone stop and come back at least 1 meter. The same happened with the roll

here is a video

Here is a telemetry file from the flight
https://we.tl/t-VsUk97PJJ5

11

@philip can ypu give me a hand with this?

thanks

12

Can you try again with less aggressive altitude change? I am thinking if the tilted attitude during the brake may have confused the flow sensor.

image
image856Ă—611 26.6 KB

https://ardupilot.org/copter/docs/common-hereflow.html
As you see in the test video, the angle change was very small.

1 Like
13

Thanks. I will try. I was working with the FLOW_SCALE, and I got an improvement, here is the video

I saw the video you have sent, and yes at the begining the movement were very soft, but at the final, they did a similar movement.

The Flow_ has a lot of parameters, but I dont know how to tune them. What can I change beside the _scale paremeter? thanks

14

None of the parameters in CAN should be changed.

Please use an SF11 or similar high performance lidar.

Other than this, following the Ardupilot guide is all that’s needed.

15

The Flow_rate_Hz and IMU_Rate Hz simply tell the system how often to send data.

Publish flow
Publish IMU
Publish Rangefinder

These turn on or off features

That’s it.

Anything else, is an Ardupilot matter

1 Like
16

Hi @philip ,

What lidars would you recommend other than the SF11? Can the tfmini be used also?

17

for me the TFMini works great, limited by the max alttitud of 12 meters of reading.