- track and publish validity based on hover thrust variance, innovation test ratio, and hysteresis
- only publish on actual updates or becoming inactive
- fix dt (previous timestamp wasn't being saved)
- use local position timestamp (corresponding) to accel data rather than current time to avoid unnecessary timing jitter
- check local position validity before using
- mc_hover_thrust_estimator: move from wq:lp_default -> wq:nav_and_controllers to ensure the hover thrust estimator runs after the position controller and uses the same vehicle_local_position data
- land_detector: check hover thrust estimate validity and adjust low throttle thresholds if hover thrust is available
- mc_pos_control: only use hover thrust estimate if valid
Before #14212 the velocity control gains used in the multicopter
position controller were defined as a scale between velocity error in
one axis (or it's integral and derivative respectively) and the unit
thrust vector. The problem with this is that the normalization of the
unit thrust vector changes per vehicle or even vehicle configuration
as 0 and 100% thrust get a different physical response. That's why
the gains are now defined as scale between velocity error
(integral/derivative) and the output acceleration in m/s².
- Avoid constantly adjusting the velocity gains with the HTE
- Make sure the hover thrust integral update doesn't break
even though its unit is acceleration and not unit thrust anymore
We need to convert the velocity gains to not contain/depend on the
hover thrust. In horizontal direction it doesn't make sense to scale
them with the hover thrust and in vertical direction the adjustments are
already done in the acceleration to collective thrust conversion.
- create common uORB::PublicationBase
- uORB::PublicationQueued types are now type aliases
- ORB_PRIO use enum type everywhere to avoid accidental misuse
- PX4Accelerometer/PX4Gyroscope/etc driver libs explicitly advertise on construction, unadvertise on destruction. This is a workaround for any potential issues that might appear when accel/gyro cdev and uORB indexing doesn't align.
Because the takeoff ramp is a vertical velocity limit ramp for the
nice user experience but the acceleration feed-forward can
add on top of the output and depending on trajectory generation
result in unwanted thrust changes during the ramp.
- bring in PX4/ecl#795 "EKF: Improve covariance prediction stability"
- the ecl/EKF filter update period has changed from 8 ms to 10 ms
- change default integration period 4000 us -> 2500 us (aligns with new EKF filter update period)
Adjusting the tilt limit can lead to diverging position control
and should only be used by setting a sanity limit for the controller
and not to adjust during the descent phase of a Land or RTL.
Otherwise it leads to flyaways in important failsafe modes when
there's stronger disturbance e.g. wind.
The hover thrust estimator (HTE) starts to run after the first thrust
setpoint is published. Until then, the feedforward of the vertical
velocity controller was unitialized (= 0). This is now set to hover
thrust parameter until the estimate is available.
This mode was just kept as an example after
its usage in a single case. It's basically untested
and doesn't make much sense anymore since it's
incompatible with the jerk limited trajectory
implementations. It's implementation only switched
hte configuration parameter of the velocity resulting
from maximum stick deflection to be
MPC_XY_VEL_MAX instead of MPC_VEL_MANUAL.
This is according to todays understanding undesired
because when hitting that limit the position
controller has no room for corrections anymore.
Also it saves some flash space on omnibus to remove
the task at this point and makes romm for the
acceleration feed-forward.
The landing thrust limit was after the position controller and
could be inconsistent with what the takeoff limit did. This
resulted in different thrust values sequentially getting applied
during landing.
This was only necessary for stabilized mode before #10805.
The unit length thrust setpoint will anyways not be available
anymore soon because it gets replaced with the acceleration
setpoint in m/s².
This function updates the vertical velocity integrator with the change
in hover thrust to avoid propagating discontinuities through the
controller when changing the hover thrust.
This is also important when using the hover thrust estimator as its
estimate has unconstrained dynamics and can cause drops or kicks when
the estimate updates faster than the velocity integrator.
* MC_HTE: unitialize with hover_thrust parameter
* MC_HTE: constrain hover thrust setter between 0.1 and 0.9
* MC_HTE: integrate with land detector and velocity controller
* MCHoverThrustEstimator: Always publish an estimate even when not fusing measurements. This is required as the land detector and the position controller need to receive a hover thrust value.
* MC_HTE: use altitude agl threshold to start the estimator
local_position.z is relative to the origin of the EKF while dist_bottom
is above ground
Co-authored-by: bresch <brescianimathieu@gmail.com>
with measurement noise auto-tuning
The purpose of this estimator is to improve land detection and vertical
velocity feedforward
Recovery strategy:
This is required when the setpoint suddenly changes in air or that the
EKF is diverging. A lowpassed test ratio is used as a trigger for the recovery logic
Also, a lowpassed residual is used to estimate the steady-state value
and remove it when estimating the accel noise to avoid increasing the
accel noise when the redisual is caused by an offset.
These assignments were temporary for correct logging of the input
setpoint which now properly also comes out of the controller again.
This is reverting the hotfix from:
dee8d200d8
Removing the skip_controller and interfaceMapping
concept and replacing it with a single method checking
if the position control update was successful and
return the result in the PositionControl.update().
Matthias Grob