Looking for advice on a good indoor navigation option as well as good altitude options for indoor non range finder based.
I am currently looking to do some research regarding confine space inspection drones where the drone is needed to fly in inside pipes, buildings or places that are hard to reach by human, hence having a good Poshold Asist is desirable to ensure that inspection can be done in a easy manner and so that the data produce will be better compared to flying in stabilize mode.
Actually in my case poshold is not really necessary but Althold is, i have been going through a lot of options using different barometers with no good consistent results (as range finder is not possible due to uneven surface) hence have decided perhaps an better option is to use SLAM with the added benefit of Poshold/ Loiter.
i have explored different options by need some advice before committing on purchasing a device. Options include : Voxl cam, Voxl 2 flight deck, 360 lidar, Oak camera. Can anyone with experience comment on their performance ? especially in dark conditions/ murky conditions due to dust (side note drone will be equiped with 8k lumen LEDS )
I think indoor basic you need optical flow sensor to hold xy position to prevent drifting, optical flow sensor needs a lidar height sensor. You may need front and rear lidar sensors for object avoidance. This product probably the benchmark.
Simultaneous Localization and Mapping got nothing to do with height, more for computer navigation.
So, I think firstly you need a loiter flyable drone, hover and lock to position. If you are using for pilot flying, side, rear and front liar sensors to assist the pilot from crashing. If non-pilot flying, a onboard companion computer is needed. Maybe this is something you like to understand further.
Thanks for your response. I think optical-flow is not a good candidate because it needs range finder for it to work. Range finder is a problem because the surface is not even and the flying environment might have objects on the ground which will interfere with the altitude reading and make the drone move up and down while its moving which is not desire able. I have also have tested my drone prototype with optical flow and this is the performance i noticed. Also because the environment might be dark the optical flow is not able to fully track the surface even with lights on the drone (its not able to see the surface if the drone is 2-3 meters from the surface)
As for the bench mark you are correct the Elios 3 is a very good bench mark and i have tested the drone in different conditions and its Z (altitude) hold and xy hold is every good in all conditions we tested.
Going back to SLAM, i know that it is able to also obtain Z value in correlation with X and Y , that is why i am interested in such a system. The hope that it is able to keep its altitude indoor where the surface is not flat while also having the added benefit of keeping its X and Y position
This statement is not valid, yes if you configure for surface tracking. This I may need help from @rmackay9 to iron out the misconception. It is possible to move over object with downward lidar and yet the drone don’t move up and down.
Have you study what is the lowest lighting requirement for optical sensor, for example Hereflow, Ark flow, etc.
You need to form a big team, they are on their 3rd or 4th product cycles, excluding their beta version before first product. Their issue is on flight duration.
I think the best performance will probably come from a VOXL camera but its much more expensive an optical flow. Opticalflow can also work OK and there are some good options on the wiki.
As @Jai.GAY says, it is possible to have a downward facing rangefinder without it affecting the vehicle’s altitude in AltHold, Loiter, PosHold, etc by setting the SURFTRAK_MODE.
To work in a really dark environment a 360 lidar with a companion computer running ROS/ROS2/cartographer would work well but the setup is a challenge and the vehicle will end up larger
interesting can you help to guide me regarding this ? i have tested using rangefinder/ downward facing lidar intensively and cant get it to work without having the drone surface tracking even though surface tracking is off in the params (i have set SURFTRAK_MODE = 0 ). i suspect it is due to the sudden spike/ increase in reading (altitude) caused by the range finder moving above a object.
actually is not that the sensor is not working but some how the flow quality is really bad, i have access to both ark flow and MTF-01, i will try to test it more
Thanks for the reply, and confirmation. Does the VOXL cam actually work automatically without any more setup once initial setup is performed? like will it automatically run the mavlink server and others uppon boot, and supply possition data directly to ardupilot? or do we still need to SSH into the voxl and run the scripts?
can you please elaborate/ guide me on this? because i have set SURFTRAK_MODE= 0 but yet the drone still does surface tracking
Sorry for replying back very late. i just got some time to test after the long holiday. i have done some testing and actually if using rangefinder the drone will hold is altitude very good but when using barometer it does not, i am using 2 barometer and both shows the same problem: directly after take off the reading is at 6m both indoors / outdoors i experience the same issue could it be due to the location of the barometers it self ?
comparison between both barometer vs range finder :
I am using CubeOrange, that is indeed the headache part. I think outdoor with barometer slightly better. Indoor with barometer more challenging. Last time if we do not cover up the Cube, when pitch forward, it will drop height with barometer. Covering up the Cube, we observe improvement without lidar height sensor. It also depends on the wind condition. DJI drones mounted many downward sensor.
Besides covering up to reduce sudden changes sense by barometer, I do not have other idea. Many years ago, we also sticky tape the DJI A3 FCU holes to reduce the sudden changes.
