LPS with Flow Deck and uneven terrain
Posted: Tue Oct 02, 2018 1:01 am
Hello,
We are working on a research project where a group of UAVs will plan a path overflying obstacles in order to reach certain areas. At the moment we are only flying one UAV at a time, we are using the Loco Positioning System with 8 anchors to provide global positioning for the crazyflies v2. We are also using the flow deck in combination with the LPS deck on the CF's as it provides greater stability vs relying on LPS alone.
We have discovered that if the Crazflie is fitted with a Flowdeck then the laser rangefinder is used to return Z relative to whatever is directly below. If the Flowdeck is removed then the LPS is used to estimate the absolute position of Z within the coordinate system. Thus if the Flowdeck is fitted and the Crazyflie goes over an obstacle then it shoots upwards as the relative value of Z drops by the height of the obstacle – this makes the task of flying over obstacles in a caged arena near impossible. Removing the Flowdeck makes waypoint navigation much easier but less stable especially while hovering.
Ideally we would like to use the absolute altitude derived from the LPS instead of the relative altitude taken from the laser range finder of the flow deck.
1. Is there a way to choose what altitude estimation takes precedence? (LPS vs Flowdeck)
2. Is there a way to completely disable the laser range finder (or ignore its readings) on the flow deck while maintaining the use of the flow sensor?
3. Is there a way to switch altitude estimation to absolute altitude so that the crazyflie can overfly obstacles without shooting up?
Thank you for your help,
Note: I tried to find a solution on the forums with not much success. The closest possible answer was to select the choice of barometer described in links below. This is not the solution we are after since the error from the barometer is relatively high in comparison to the estimation available from the LPS.
viewtopic.php?f=16&t=2725&p=13662
and
viewtopic.php?f=6&t=2592&p=13131
We are working on a research project where a group of UAVs will plan a path overflying obstacles in order to reach certain areas. At the moment we are only flying one UAV at a time, we are using the Loco Positioning System with 8 anchors to provide global positioning for the crazyflies v2. We are also using the flow deck in combination with the LPS deck on the CF's as it provides greater stability vs relying on LPS alone.
We have discovered that if the Crazflie is fitted with a Flowdeck then the laser rangefinder is used to return Z relative to whatever is directly below. If the Flowdeck is removed then the LPS is used to estimate the absolute position of Z within the coordinate system. Thus if the Flowdeck is fitted and the Crazyflie goes over an obstacle then it shoots upwards as the relative value of Z drops by the height of the obstacle – this makes the task of flying over obstacles in a caged arena near impossible. Removing the Flowdeck makes waypoint navigation much easier but less stable especially while hovering.
Ideally we would like to use the absolute altitude derived from the LPS instead of the relative altitude taken from the laser range finder of the flow deck.
1. Is there a way to choose what altitude estimation takes precedence? (LPS vs Flowdeck)
2. Is there a way to completely disable the laser range finder (or ignore its readings) on the flow deck while maintaining the use of the flow sensor?
3. Is there a way to switch altitude estimation to absolute altitude so that the crazyflie can overfly obstacles without shooting up?
Thank you for your help,
Note: I tried to find a solution on the forums with not much success. The closest possible answer was to select the choice of barometer described in links below. This is not the solution we are after since the error from the barometer is relatively high in comparison to the estimation available from the LPS.
viewtopic.php?f=16&t=2725&p=13662
and
viewtopic.php?f=6&t=2592&p=13131