Mirror/ardupilot
5
0
Fork 0
mirror of https://github.com/ArduPilot/ardupilot synced 2025-02-22 07:44:03 -04:00
Code Issues Packages Projects Releases Wiki Activity

SITL: Add momentum drag to Z axis to work around thrust model deficiencies

Browse Source
This commit is contained in:
Paul Riseborough 2020-12-06 06:21:59 +11:00 committed by Andrew Tridgell
parent e835da41fa
commit b258cb0539
1 changed files with 6 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
libraries/SITL/SIM_Frame.cpp
View File

@ -561,7 +561,12 @@ void Frame::calculate_forces(const Aircraft &aircraft,
drag_bf.y = -drag_bf.y;
}
drag_bf.z = areaCd * 0.5f * air_density * sq(vel_air_bf.z);
// The application of momentum drag to the Z axis is a 'hack' to compensate for incorrect modelling
// of the variation of thust with vel_air_bf.z in SIM_Motor.cpp. If nmot applied, the vehicle will
// climb at an unrealistic rate during operation in STABILIZE. TODO replace prop and motor model in
// the Motor class with one based on DC motor, mometum disc and blade elemnt theory.
drag_bf.z = areaCd * 0.5f * air_density * sq(vel_air_bf.z) +
model.mdrag_coef * fabsf(vel_air_bf.z) * sqrtf(fabsf(thrust.z) * air_density * model.disc_area);
if (is_positive(vel_air_bf.z)) {
drag_bf.z = -drag_bf.z;
}