During the first few seconds after takeoff, the failure detector is allowed to
trigger motor lockdown.
This is done for safety reasons to detect tipping-over or unstable
tuning gains
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.
- Use a low-passed value of the signed innovation test ratio to trigger
the state variance boost. The threshold of 0.2 has been chosen using log
replay and simulation scenarii.
- Do not reset the learned accel noise during a state variance boost.
After a few tests, this does not seem to help at all.
- Continue to learn the accel noise even if the measurement got rejected
to avoid ignoring sudden changes of noise
- Lower the acceleration noise time constant and increase min/max
values to avoid learning quickly a small variance that could temporarly
destabilize the filter
- Update filter time constants. Increasing the speed of the residual lpf
improves the quality of the learned accel noise
This is done to test the recovery function of the estimator in case
of divergence or sudden extreme hover thrust change.
Also specify seed of random generator
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.
* NotchFilter: add NotchFilter template and test for float type
* NotchFilterTest: add test for Vector3f notch filter
* PX4Gyroscope: add notch filter with IMU_GYRO_NF_(FREQ|BW) parameters to
set the notch center frequency and bandwidth
used back in time when no soothing was done to avoid large steps when
the estimator stops sending a maximum velocity (e.g.:GPS gained during
optical flow flight). Since smoothing is applied later, this is not
required anymore.
The constrainAbs function was not prioritizing the minimum value
that produces the autocontinue behaviour. This caused zig-zag
paths when the waypoints were almost -but not exactly- aligned.
dt could drive the alpha filter crazy because of the small dt
approximation during the computation of the coefficient.
- Remove unused bitmask packing of the innovation checks
* ekf2: Add FirstOrderLpf and InnovationLpf classes for innovation lowpass filtering
* ekf2: use InnovLpf filter class in preflight checks
* ekf2: move selection of yaw test limit for pre-flight check in function
* ekf2: Move pre-flight checks into separate function
* ekf2: use static constexpr insetead of inline for sq (square) function
* ekf2: Split pre-flight checks in separate functions
Also use the same check for all the innovations:
innov_lpf < test and innov < 2xtest
* ekf2: Add optical flow pre-flight check
* ekf2: Combine FirstOrderLpf and InnovationLpf in single class
* ekf2: check vel_pos_innov when ev_pos is active as well
* ekf2: transform InnovationLpf into a header only library and pass the
spike limit during the update call to avoid storing it here
* ekf2: Static and const cleanup
- set spike_lim constants as static constexpr, set innovation
- set checker helper functions as static
- rename the mix of heading and yaw as heading to avoid confusion
* ekf2: use ternary operator in selectHeadingTestLimit instead of if-else
* ekf2: store intermediate redults in const bool flags. Those will be used for logging
* ekf2: set variable const whenever possible
* ekf2: create PreFlightChecker class that handle all the innovation
pre-flight checks.
Add simple unit testing
Use bitmask instead of general flag to have more granularity
* PreFlightChecker: use setter for the innovations to check instead of sending booleans in the update function
This makes it more scalable as more checks will be added
* ekf: Use booleans instead of bitmask for ekf preflt checks
Rename "down" to "vert"
part to avoid having to scale its saturation separately. This is
required to avoid premature saturation of the integrator when using
the K term.
Also remove double saturation of the integrator
A NAN is interpreted in the FlightTaskAuto as a non-valid global coordinate and sets a local position.
If a zero is sent instead, the global coordinate is recognized as valid and will be executed.
This is a problem when the global position is gained for the first time after takeoff and that a valid global reference did not exist before
Also split a few functions into smaller ones for readability, fix
formatting, use geters to get the current state of the trajectory
instead of return arguments.
This helps when the current velocity is smaller than the target but that
the acceleration is too large such that the velocity will overshoot.
Without this check, the algorithm increases the acceleration which leads
to an even larger overshoot.
This solves many numerical issues when the trajectory is close to the
primary NE axes (small velocities). It is also more robust when dt is
large and has some jitter.
It was broken because _velocity_setpoint is used for input and output
and was assumed to be the input at a place where it was already overwitten
To clarify this, the input setpoint is renamed "target"
Also remove crosstrack P controller that produces overshoots when the
acceptance radius is large (crosstrack error is suddenly large at
waypoint switch).
This is done to allow proper initialization of the new FlightTask and
give it a chance to continue the setpoints without discontinuity. The
function checkSetpoints replaces the setpoints containing NANs with an
estimate of the state. The estimate is usually the current estimate of
the EKF or zero.
The transition FlightTask also provides an estimate of the current
acceleration to properly initialize the next FlightTask after
back-transition. This avoid having to initialize the accelerations to
zero knowing that the actual acceleration is usually far from zero.
the vehicle yaws towards the next waypoint before accelerating. This is
required for drones with front vision and aerodynamic multicopters such
as standard vtol planes or highspeed multirotors.
The linear mapping from position error to cruise velocity is changed by
a combination of that linear mapping and a nonlinear function containing
the maximum acceleration and jerk to avoid overshoots at waypoints due to
overoptimistic breaking distance.
bresch