LD06/LD19 measured distance stability improvement

[boa-pe]

Fix for Lidar measured distance fluctuations by little transplant from RPLidar driver.

So far tested only on desk with LD19. Test flight as soon as weather is good enough.

[peterbarker]

@boa-pe is this a duplicate of #27045 ?

[boa-pe]

@boa-pe is this a duplicate of #27045 ?

It seems to solve the same issue and I see also some parts of code from RPLidar too. I just started looking into the code just because my LD19 was going crazy.

IMO description is a little missleading, as basically it updates same face multiple times with latest 12 measurements (2deg slice I think would be for default rotation speed only), but still whole 360deg scanning field is handled. Result is that measured distance varies a lot.

[peterbarker]

Sorry, this PR has been made against 4.5 - we don't merge things directly into stable branches, things have to go via master first.

I was unable to distinguish the behaviour of your PR vs that other PR. I've tested that other PR (again) and merged it.

Please create a PR against master with the changes you'd like to make - please make the changes minimal and explain how I should test to see an improvement.

Interestingly my device does not have a cable coming out of the back of the device - but there is an arrow on top of the device and that does indicate the correct orientation. So I'm not sure our documentation for this device is correct (@Hwurzburg) The phrase "lidar should be mounted horizontally on the top or bottom of the vehicle with the black cable pointing towards the rear of the vehicle" was probably copied from the rplidara2 page. The correct phrase should be, "lidar should be mounted horizontally on the top or bottom of the vehicle with the arrow on top of the unit pointing towards the front of the vehicle"

Again, please open with a PR against master. If there's a problem with the logic in here then the same problem may exist in the RPiLIDAR code too...