I’ve got a YRRC Mini PX4 for a flight controller, flying a Volantex Phoenix 2000mm glider. In RTL mode it circles with a radius of 120 meters, regardless of parameter settings. RTL_RADIUS is 0, WP_RADIUS is 60 and WP_LOITER_RAD is set to 90. Unfortunately these values do not seem to have any impact on the actual loiter radius. When I initially put it in RTL mode it will do a much narrower turn at a 45’ bank angle to return to the home point, so this does not appear to be a limitation. Any ideas?
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I have an F3B glider with a wing size of 2.6 metres, a weight of 3.2 kg. My parameters RTL_RADIUS -85 metres LIM_ROLL_CD 35 degrees. As you can see on the screenshot of my flight, this radius is 94 metres with a roll angle of 32 degrees. I think I need to change the LIM_ROLL_CD parameter to 40 degrees.
I have ROLL_LIMIT_DEG set to 45, but my plane never rolls more than about 23-25 degrees. I think it may be the stall prevention.
I cannot understand this from your log file: WP_LOITER_RAD is 60 and has not been changed during the flight, i.e. the plane does not need to bank more than about 20° even on the leeward side of the circle to maintain the WP_LOITER_RAD of 60 metres.
By the way: If you set RTL_RADIUS to zero, the WP_LOITER_RAD is also used in RTL.
Rolf
Hi Rolf,
Thank you for your response. The problem is the vehicle does not maintain a 60 meter radius, it circles at 120 meters from the home location.
Compare my graph with your logs, pay attention to the coincidence of CTUN parameters. ROLL and CTUN. NAVROLL – the desired and achieved roll angle. By their coincidence, you can see if there is a problem with your glider to perform RTL with a smaller radius.
Good idea. That all seems to be fine though. The plane will do a small-radius turn at max bank (45’) when I initially flick it into RTL mode (2nd pic), only when it arrives at the home location it does the large radius circle.
I did some more testing. Disabled stall prevention and set WP_LOITER_RAD from 60 (1st image) to -50 (2nd image). This had the result of it maintaining a 100 meter radius instead of 120 meters. So for some reason it seems to be doubling the WP_LOITER_RAD value.
I had a plane that was consistently off it’s loiter radius, however not this far. I dialed it in with the NAVL1_LIM_BANK.
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