Hello, I’m wondering if someone could explain the AllowDescentSpeedup option in the TECS_OPTIONS parameter to me. I’m trying to increase my aircraft’s descent rate between two waypoints. I’ve tried many parameter changes according to the TECS documentation, without success. My aircraft currently cannot achieve a 12-degree descent between two waypoints, despite a high TECS_SINK_MAX rate (22%) and a low TECS_PITCH_MIN (-45 degrees). I believe this is due to the TECS’s descent rate limitation algorithm, which attempts to maintain the airspeed at AIRSPEED_CRUISE (11 m/s in my case). There should be a solution to this: reducing the TECS_SPDWEIGHT to give more authority to pitch in altitude control, but I’m wondering if the AllowDescentSpeedup option could also improve the descent rate.
Thanks for any explanation regarding this parameter.
Just put TECS_SPDWEIGHT=0
I would be careful with that as it may handle motor loss badly.
Both should be testable in SITL.
Thanks for your replies. Unfortunately SITL does not work since a previous Mission Planner update. I will try to reduce TECS_SPDWEIGHT gradually and check if it improve my descent rate. That being said, I’m still interested if someone can explain the AllowDescentSpeedup parameter.
Thanks
I, I’m still struggling in making my descent rate steeper in auto modes. My plane is capable of pitching down way more than auto mode permit him in missions. My goal is to shorten the land sequence. I tweaked lot of parameters without success so any advice is welcome. Here are my current parameters modified from default :
PTCH_LIM_MIN_DEG = -70 (DEFAULT IS -45) (TECS_PITCH_MIN is 0)
TECS_SINK_MAX = 22 (DEFAULT is 5)
TECS_VERT_ACC = 10 (DEFAULT is 7)
Also tested to modify those without success and revert back to default :
TECS_SPDWEIGHT tested at 0 (DEFAULT is 1)
TECS_OPTIONS Bitmask to 2 (AllowDescentSpeedup checked)
Thrust reversal enables the highest possible rates of descent without overspeed. See Reverse Thrust Setup — Plane documentation
Rolf
Thanks Rolf. Unfortunately I don’t have reversible ESCs on that plane (not sure that said that it is compatible with my VTOL configuration). I just want my plane to pitch down more without worrying about overspeed.
Without thrust reversal, you should set and fly the TECS parameters as accurately as possible according to the instructions: TECS (Total Energy Control System) for Speed and Height Tuning Guide — Plane documentation
Set TECS_SINK_MAX at THR_MIN to a value just enough to descend without overspeeding.
Rolf