Plane: suppress rate D terms in ground mode

this prevents a common oscillation issue on the ground

ArduPlane/Attitude.cpp

@@ -141,7 +141,8 @@ float Plane::stabilize_roll_get_roll_out(float speed_scaler)
     if (control_mode == &mode_stabilize && channel_roll->get_control_in() != 0) {
         disable_integrator = true;
     }
-    return rollController.get_servo_out(nav_roll_cd - ahrs.roll_sensor, speed_scaler, disable_integrator);
+    return rollController.get_servo_out(nav_roll_cd - ahrs.roll_sensor, speed_scaler, disable_integrator,
+                                        ground_mode && !(plane.g2.flight_options & FlightOptions::DISABLE_GROUND_PID_SUPPRESSION));
 }
 
 /*
@@ -197,7 +198,8 @@ float Plane::stabilize_pitch_get_pitch_out(float speed_scaler)
         demanded_pitch = landing.get_pitch_cd();
     }
 
-    return pitchController.get_servo_out(demanded_pitch - ahrs.pitch_sensor, speed_scaler, disable_integrator);
+    return pitchController.get_servo_out(demanded_pitch - ahrs.pitch_sensor, speed_scaler, disable_integrator,
+                                         ground_mode && !(plane.g2.flight_options & FlightOptions::DISABLE_GROUND_PID_SUPPRESSION));
 }
 
 /*
@@ -402,7 +404,7 @@ void Plane::stabilize_acro(float speed_scaler)
         // 'stabilze' to true, which disables the roll integrator
         SRV_Channels::set_output_scaled(SRV_Channel::k_aileron, rollController.get_servo_out(roll_error_cd,
                                                                                              speed_scaler,
-                                                                                             true));
+                                                                                             true, false));
     } else {
         /*
           aileron stick is non-zero, use pure rate control until the
@@ -426,7 +428,7 @@ void Plane::stabilize_acro(float speed_scaler)
         nav_pitch_cd = acro_state.locked_pitch_cd;
         SRV_Channels::set_output_scaled(SRV_Channel::k_elevator, pitchController.get_servo_out(nav_pitch_cd - ahrs.pitch_sensor,
                                                                                                speed_scaler,
-                                                                                               false));
+                                                                                               false, false));
     } else {
         /*
           user has non-zero pitch input, use a pure rate controller

ArduPlane/Parameters.cpp

@@ -1075,7 +1075,7 @@ const AP_Param::GroupInfo ParametersG2::var_info[] = {
     // @Param: FLIGHT_OPTIONS
     // @DisplayName: Flight mode options
     // @Description: Flight mode specific options
-    // @Bitmask: 0:Rudder mixing in direct flight modes only (Manual / Stabilize / Acro),1:Use centered throttle in Cruise or FBWB to indicate trim airspeed, 2:Disable attitude check for takeoff arming, 3:Force target airspeed to trim airspeed in Cruise or FBWB, 4: Climb to ALT_HOLD_RTL before turning for RTL, 5: Enable yaw damper in acro mode, 6: Surpress speed scaling during auto takeoffs to be 1 or less to prevent oscillations without airpseed sensor., 7:EnableDefaultAirspeed for takeoff, 8: Remove the TRIM_PITCH_CD on the GCS horizon, 9: Remove the TRIM_PITCH_CD on the OSD horizon, 10: Adjust mid-throttle to be TRIM_THROTTLE in non-auto throttle modes except MANUAL
+    // @Bitmask: 0:Rudder mixing in direct flight modes only (Manual / Stabilize / Acro),1:Use centered throttle in Cruise or FBWB to indicate trim airspeed, 2:Disable attitude check for takeoff arming, 3:Force target airspeed to trim airspeed in Cruise or FBWB, 4: Climb to ALT_HOLD_RTL before turning for RTL, 5: Enable yaw damper in acro mode, 6: Surpress speed scaling during auto takeoffs to be 1 or less to prevent oscillations without airpseed sensor., 7:EnableDefaultAirspeed for takeoff, 8: Remove the TRIM_PITCH_CD on the GCS horizon, 9: Remove the TRIM_PITCH_CD on the OSD horizon, 10: Adjust mid-throttle to be TRIM_THROTTLE in non-auto throttle modes except MANUAL, 11:Disable suppression of fixed wing rate gains in ground mode
     // @User: Advanced
     AP_GROUPINFO("FLIGHT_OPTIONS", 13, ParametersG2, flight_options, 0),
 

ArduPlane/Plane.h

@@ -601,6 +601,9 @@ private:
     // time since started flying in any mode in milliseconds
     uint32_t started_flying_ms;
 
+    // ground mode is true when disarmed and not flying
+    bool ground_mode;
+
     // Navigation control variables
     // The instantaneous desired bank angle.  Hundredths of a degree
     int32_t nav_roll_cd;
@@ -684,7 +687,6 @@ private:
         uint32_t time_max_ms;
     } loiter;
 
-
     // Conditional command
     // A value used in condition commands (eg delay, change alt, etc.)
     // For example in a change altitude command, it is the altitude to change to.

ArduPlane/defines.h

@@ -165,6 +165,7 @@ enum FlightOptions {
     GCS_REMOVE_TRIM_PITCH_CD = (1 << 8),
     OSD_REMOVE_TRIM_PITCH_CD = (1 << 9),
     CENTER_THROTTLE_TRIM = (1<<10),
+    DISABLE_GROUND_PID_SUPPRESSION = (1<<11),
 };
 
 enum CrowFlapOptions {

ArduPlane/is_flying.cpp

@@ -174,6 +174,9 @@ void Plane::update_is_flying_5Hz(void)
 
     // tell AHRS flying state
     set_likely_flying(new_is_flying);
+
+    // conservative ground mode value for rate D suppression
+    ground_mode = !is_flying() && !hal.util->get_soft_armed();
 }
 
 /*