I’ve just released plane 4.2.3beta1. This is a minor release, but it includes some significant changes. The changes are:
- allow INA2xx battery to init after startup
- fixed healthy check on battery monitors to check all enabled monitors
- added Pixhawk6C and Pixhawk6X support
- fixed alighment of QRTL start in fixed wing circle landing approach
- added Foxeer Reaper F745 support
- added MFE PixSurveyA1 support
- fixed combination of waypoint passby with acceptance distance
- cut throttle on ICE stop when armed
- added ICE option for starting when disarmed
- zero VFWD integrator on ICE override in quadplanes
- don’t failsafe when in fixed wing landing sequence with RTL_AUTOLAND
- improved handling of overshoot in VTOL landing
- added arming check for VTOL_LAND too close to previous WP
- improved choice of target airspeed in VTOL landing approach
- improved ICM42xxx filter settings
- allow for faster sample rates on ICM42xxx
VTOL Landing Changes
The quadplane changes are focussed on two issues that have come up for users. The first is overshoot in VTOL landing. With previous releases if you had a significant overshoot of the landing point (for example if you had a VTOL_LAND very close to the previous waypoint) then the VTOL landing code would handle it very badly and actually fly away from the landing point for some time until the position controller unwound its buildup of target acceleration. The new code has special overshoot handling for this case. You will get a “VTOL Overshoot” message on the GCS and the aircraft will slow down then yaw around to face the landing point before proceeding back to the landing point at a speed limit of Q_WP_SPEED. It will yaw to keep the nose into the wind while moving back to the landing point.
The second key change is the choice of when to start VTOL control on the landing approach. The new code adds some more margin to start VTOL control sooner, which makes overshoot less likely.
The beta also adds a new arming check to ensure the distance from the previous waypoint to a VTOL_LAND is at least 75% of the calculated distance needed for a smooth stop (based on Q_TRANS_DECEL). This is to prevent users having a set of waypoints which lead to a large overshoot.
The final VTOL landing change is to suppress failsafes while you are in a landing sequence with DO_LAND_START. So once the series of waypoints following a DO_LAND_START has started any RC or GCS failsafes are ignored, allowing the landing to continue without forcing a go-around.
VTOL Land Airspeed
This release also changes the airspeed used for the approach to a VTOL landing if you have not specified a TECS_LAND_ARSPD. The airspeed used will be half way between ARSPD_FBW_MIN and TRIM_ARSPD_CM, so that the aircraft does slow down during the VTOL landing approach. Setting a TECS_LAND_ARSPD overrides this with a specific airspeed target.
Fixed Wing Approach Fix
The VTOL land option which uses a fixed wing approach followed by circling the landing point to estimate the wind then turning towards landing into the wind has been fixed to handle the case where the circling radius is smaller than the distance needed for the VTOL landing. We now ensure that we do turn towards the landing point before we transition, so we don’t end up trying to transition while at 90 degrees to the landing direction.
ICE Changes
The second significant set of changes is for ICE setups, where you control an internal combustion engine.
The first ICE change is to ensure you have zero throttle when you disable the ICE subsystem with the ICE control RC channel while armed. Previously we relied on the user having an ignition cut to kill the engine, and the throttle could still be active due to integrator buildup. The change is to help users without an ignition control channel, such as EFI systems that use zero throttle to kill the engine.
The second ICE change is a new ICE_OPTIONS bit to allow starting of the engine while disarmed in MANUAL mode. This can make for safer startup procedures as it ensures that VTOL motors cannot start even if you accidentally change flight modes or get a failsafe while waiting for the engine to startup.
ICM42xxx Filter Changes
The filter configuration on the ICM42xxx Invensense IMUs has been improved to better match the filtering we use on other IMUs. I’d be interested in feedback from users flying with these IMUs if you notice any issues with the new settings. It should be a significant improvement.
Happy flying!