rtl state was getting reset on inactive, which meant that the state which triggered resuming e.g. mission landing would be overwritten, and the navigator mode would switch back and forth between rtl and mission. this commit:
1. moves the reset of rtl state to the on activation function (removing it from the on inactive function)
2. functionalizes the rtl state input to the rtl time estimator so that rtl time can still be calculated from state=none while inactive
FW_LND_USETER defaulted to 1 and FW_LND_ABORT terrain based bits all enabled. why? because using a distance sensor is critical to detecting when to flare, and we want to force the user to actively disable these safety settings if they so choose, so that they understand the implications.
- new param, FW_LND_TER_REL
- fixing the glide slope helps keep the landing glide behavior steady (avoiding bumps in the altitude setpoint from e.g. trees)
- flare is still triggered via the distance sensor, if enabled by FW_LND_USETERR
when the vehicle did not track the slope well (e.g. at an offset above the track) and the altitude setpoint flattening on intersection with terrain, the throttle would spool up to smoothly intersect the newly flattened altitude setpoint, this could happen before the flare altitude was reached, which is bad. now the steady state glide behavior will be maintained, and flare can trigger at the appropriate time
- the target_sink_rate param could possibly constrain the maximum commanded sink rate to something less than that of the landing glide slope, which would make it impossible to track. this commit allows opening up the desired max sink rate up to the performance limits of the aircraft, if necessary, for the landing case
- landing slope/curve library removed
- flare curve removed (the position setpoints will not be tracked during a flare, and were being ignored by open-loop maneuvers anyway)
- flare curve replaced by simply commanding a constant glide slope to the ground from the approach entrance, and commanding a sink rate once below flaring alt
- flare is now time-to-touchdown -based to account for differing descent rates (e.g. due to wind)
- flare pitch limits and height rate commands are ramped in from the previous iteration's values at flare onset to avoid jumpy commands
- TECS controls all aspects of the auto landing airspeed and altitude/height rate, and is only constrained by pitch and throttle limits (lessening unintuitive open loop manuever overrides)
- throttle is killed on flare
- flare is the singular point of no return during landing
- lateral manual nudging of the touchdown point is configurable via parameter, allowing the operator to nudge (via remote) either the touchdown point itself (adjusting approach vector) or shifting the entire approach path to the left or right. this helps when GCS map or GNSS uncertainties set the aircraft on a slightly offset approach"
- post takeoff, the aircraft follows the infinite line sourced from the launch point in the direction of the takeoff waypoint
- takeoff waypoint altitude is used as a clearance altitude, set such that once above, the aircraft has cleared all ground occlusions and may proceed with the mission
- runway takeoff state machine simplified to throttle ramp, clamped to runway, climbout, and fly
- throttle ramp must complete before switching to next state to avoid a jump in throttle setpoint just after takeoff if the takeoff airspeed is reached before the ramp is complete
- roll constraints near ground post takeoff removed from runway takeoff class (handled externally now)
- minimum airspeed in TECS is reduced to takeoff speed (if necessary) to lower the underspeed detection bound
- lateral-directional guidance uses a different period parameter during ground roll
- apply constraint only for takeoff and landing modes
- add two params, wing span and wing height, to calculate a reasonable height at which roll limits can be opened
- takeoff situational knowledge removed from all other modes except manual (or actual takeoff mode)
- manual takeoff is marked complete if at a controllable airspeed
- minimum pitch bounds TECS until manual takeoff complete
- remove individual roll constraints during manual takeoff (ground proximity constraints coming in subsequent commit)
- underspeed condition only determined by true airspeed undershoot
- change binary underspeed condition to a continuous percent undersped
- ramp-in max throttle, pitch speed weight, and TAS setpoint reduction during underspeed to avoid jumpy commands at the true airspeed error boundary
- let true airspeed filter reach zero airspeed
- create integral and trajectory generator reset methods
- always run TECS unless in rotary-wing mode (or in transition)
- constantly reset TECS integrals and trajectory generators when landed
- simplify takeoff reset method
- removes _last_manual variable in favor of _skipping_takeoff_detection, which is handled in the control mode setter
- takeoff detection (both launch and runway) is skipped if entering takeoff mode from any other mode while having already been in the air
- added method to runway takeoff class for force setting the fly state when we want to skip the takeoff detection
- documentation of units, params, returns, and descriptions for variables and methods
- rename ambiguous or erroneous state variables
- remove unused or unecessary input arguments to functions
- remove ugly header white space
mathlib: add second order reference model filter with optional rate feedback (#19246)
Reference models can be used as filters which exhibit a particular, chosen (reference) dynamic behavior. This PR implements a simple second order transfer function which can be used as such a reference model, additionally with rate feedback. The system is parameterized by explicitly set natural frequency and damping ratio. Another nice externality is that the output state and rate are kinematically consistent. Forward-euler and bilinear transform discretizations for the state space integration step are available.
Thomas Stastny