AirboundInc · vigneshm-debug · Jun 12, 2026 · Jun 12, 2026 · Jun 16, 2026 · Jun 16, 2026
diff --git a/ArduPlane/quadplane.cpp b/ArduPlane/quadplane.cpp
@@ -564,6 +564,27 @@ const AP_Param::GroupInfo QuadPlane::var_info2[] = {
     // @User: Advanced
     AP_GROUPINFO("LND_FRZ_TIM", 40, QuadPlane, q_land_freeze_time, 7.0f),
 
+    // @Param: DARM_WDG_T
+    // @DisplayName: Disarm watchdog timeout
+    // @Description: Time in seconds after landing detection starts in LAND_FINAL before an emergency disarm warning is issued. Set to 0 to disable.
+    // @Units: s
+    // @Range: 0 30
+    // @Increment: 1
+    // @User: Standard
+
+    AP_GROUPINFO("DARM_WDG_T", 41, QuadPlane, landing_detect.wdg_timeout_s, 10.0),
+
+    // @Param: LND_DET_TIM
+    // @DisplayName: Qmode Land detection timeout
+    // @Description: The maximum time allowed for land detection in milliseconds
+    // @Units: ms
+    // @Range: 1000 4000
+    // @Increment: 100
+    // @User: Standard
+    AP_GROUPINFO("LND_DET_TIM", 42, QuadPlane, landing_detect.timeout_ms, 200),
+
+
+
     AP_GROUPEND
 };
 
@@ -1415,6 +1436,10 @@ void QuadPlane::set_armed(bool armed)
     }
     motors->armed(armed);
 
+    if (armed) {
+        landing_detect.wdg_start_ms = 0;
+    }
+
     if (plane.control_mode == &plane.mode_guided) {
         guided_wait_takeoff = armed;
     }
@@ -2852,6 +2877,7 @@ void QuadPlane::vtol_position_controller(void)
             if (tailsitter.enabled()){
                 set_climb_rate_cms(0);
                 last_pos2_ms = now_ms;
+                weathervane->set_gain(tailsitter.wvane_max_gain/3);
             }else{
                 Location loc2 = loc;
                 loc2.change_alt_frame(Location::AltFrame::ABOVE_ORIGIN);
@@ -2862,6 +2888,7 @@ void QuadPlane::vtol_position_controller(void)
         } else {
             if(tailsitter.enabled()){
                 last_pos2_ms = now_ms;
+                weathervane->set_gain(tailsitter.wvane_max_gain/3);
             }
             set_climb_rate_cms(0);
         }
@@ -3486,10 +3513,16 @@ bool QuadPlane::verify_vtol_takeoff(const AP_Mission::Mission_Command &cmd)
 /*
   a landing detector based on change in altitude over a timeout
  */
-bool QuadPlane::land_detector(uint32_t timeout_ms)
+bool QuadPlane::land_detector(void)
 {
-    bool might_be_landed = should_relax() && !poscontrol.pilot_correction_active;
+    const bool relaxed = should_relax();
+    bool might_be_landed = relaxed && !poscontrol.pilot_correction_active;
     if (!might_be_landed) {
+        if (landing_detect.land_start_ms != 0 && poscontrol.get_state() == QPOS_LAND_FINAL) {
+            gcs().send_text(MAV_SEVERITY_INFO, "LandDet: abort relax=%d pilot=%d",
+                            (int)relaxed,
+                            (int)poscontrol.pilot_correction_active);
+        }
         landing_detect.land_start_ms = 0;
         return false;
     }
@@ -3498,23 +3531,24 @@ bool QuadPlane::land_detector(uint32_t timeout_ms)
     if (landing_detect.land_start_ms == 0) {
         landing_detect.land_start_ms = now;
         landing_detect.vpos_start_m = height;
+        gcs().send_text(MAV_SEVERITY_INFO, "LandDet: start h=%.2f timeout=%u",
+                        (double)height, (unsigned)landing_detect.timeout_ms);
     }
 
-    // we only consider the vehicle landed when the motors have been
-    // at minimum for timeout_ms+1000 and the vertical position estimate has not
-    // changed by more than 20cm for timeout_ms
     if (fabsf(height - landing_detect.vpos_start_m) > landing_detect.detect_alt_change) {
-        // height has changed, call off landing detection
+        gcs().send_text(MAV_SEVERITY_INFO, "LandDet: reset dh=%.2f",
+                        (double)fabsf(height - landing_detect.vpos_start_m));
         landing_detect.land_start_ms = 0;
         return false;
     }
 
-    if ((now - landing_detect.land_start_ms) < timeout_ms ||
-        (now - landing_detect.lower_limit_start_ms) < (timeout_ms+1000)) {
-        // not landed yet
+    if ((now - landing_detect.land_start_ms) < landing_detect.timeout_ms ||
+        (now - landing_detect.lower_limit_start_ms) < (landing_detect.timeout_ms+1000)) {
         return false;
     }
 
+    gcs().send_text(MAV_SEVERITY_INFO, "LandDet: done h=%.2f t=%u",
+                    (double)height, (unsigned)(now - landing_detect.land_start_ms));
     return true;
 }
 
@@ -3527,7 +3561,29 @@ bool QuadPlane::check_land_complete(void)
         // only apply to final landing phase
         return false;
     }
-    if (land_detector(4000)) {
+    if (!motors->armed()) {
+        return false;
+    }
+    // ---- disarm watchdog ----
+    const float wdg_t = landing_detect.wdg_timeout_s.get();
+    if (wdg_t > 0 && motors->armed() &&
+        landing_detect.lower_limit_start_ms != 0 &&
+        landing_detect.wdg_start_ms == 0)
+    {
+        landing_detect.wdg_start_ms = AP_HAL::millis();
+        gcs().send_text(MAV_SEVERITY_INFO,
+            "DISARM_WDG: timer started, %.0fs to disarm", (double)wdg_t);
+    }
+
+    if (wdg_t > 0 && landing_detect.wdg_start_ms != 0 && motors->armed()) {
+        const float elapsed = (AP_HAL::millis() - landing_detect.wdg_start_ms) * 0.001;
+        if (elapsed >= wdg_t) {
+            gcs().send_text(MAV_SEVERITY_EMERGENCY,
+                "DISARM_WDG: ARMED %.0fs AFTER LANDING! DISARM NOW", (double)elapsed);
+            landing_detect.wdg_start_ms = AP_HAL::millis();
+        }
+    }
+    if (land_detector()) {
         poscontrol.set_state(QPOS_LAND_COMPLETE);
         gcs().send_text(MAV_SEVERITY_INFO,"Land complete");
 
@@ -3571,7 +3627,7 @@ bool QuadPlane::check_land_final(void)
       also apply landing detector, in case we have landed in descent
       phase. Use a longer threshold
      */
-    return land_detector(6000);
+    return land_detector();
 }
 
 /*
@@ -3866,8 +3922,7 @@ float QuadPlane::forward_throttle_pct()
   get weathervaning yaw rate in cd/s
  */
 float QuadPlane::get_weathervane_yaw_rate_cds(void)
-{
-    /*
+{   /*
       we only do weathervaning in modes where we are doing VTOL
       position control.
     */
@@ -3879,7 +3934,8 @@ float QuadPlane::get_weathervane_yaw_rate_cds(void)
         plane.control_mode == &plane.mode_qautotune ||
 #endif
         plane.control_mode == &plane.mode_qhover ||
-        should_relax()
+        should_relax() ||
+        landing_detect.wdg_start_ms != 0
         ) {
         // Ensure the weathervane controller is reset to prevent weathervaning from happening outside of the timer
         weathervane->reset();
@@ -4249,6 +4305,12 @@ bool QuadPlane::in_vtol_airbrake(void) const
     return false;
 }
 
+//Check if tailsitter is in vtol transition
+bool QuadPlane::tailsitter_in_vtol_transition()
+{
+    return tailsitter.in_vtol_transition();
+}
+
 // return true if we should show VTOL view
 bool QuadPlane::show_vtol_view() const
 {

diff --git a/ArduPlane/quadplane.h b/ArduPlane/quadplane.h
@@ -192,7 +192,7 @@ class QuadPlane
     // Get pilot throttle input with deadzone, this will return 50% throttle in failsafe!
     float get_throttle_input() const;
 
-    void Log_Write_AttRate();
+    bool tailsitter_in_vtol_transition();
 
 private:
     AP_AHRS &ahrs;
@@ -275,7 +275,7 @@ class QuadPlane
     void relax_attitude_control();
 
     bool check_land_complete(void);
-    bool land_detector(uint32_t timeout_ms);
+    bool land_detector(void);
     bool check_land_final(void);
 
     float assist_climb_rate_cms(void) const;
@@ -286,6 +286,7 @@ class QuadPlane
     bool should_relax(void);
     void motors_output(bool run_rate_controller = true);
     void Log_Write_QControl_Tuning();
+    void Log_Write_AttRate();
     void log_QPOS(void);
     float landing_descent_rate_cms(float height_above_ground);
 
@@ -492,6 +493,10 @@ class QuadPlane
 
         // landing detection threshold in meters
         AP_Float detect_alt_change;
+        AP_Float timeout_ms;
+
+        AP_Float wdg_timeout_s;
+        uint32_t wdg_start_ms;
     } landing_detect;
 
     // throttle mix acceleration filter
@@ -742,6 +747,8 @@ class QuadPlane
 
 public:
     void motor_test_output();
+    AC_AttitudeControl_Multi *get_attitude_control() { return attitude_control; }
+    AP_AHRS_View *get_ahrs_view() { return ahrs_view; }
     MAV_RESULT mavlink_motor_test_start(mavlink_channel_t chan, uint8_t motor_seq, uint8_t throttle_type,
                                         uint16_t throttle_value, float timeout_sec,
                                         uint8_t motor_count);

diff --git a/ArduPlane/tailsitter.cpp b/ArduPlane/tailsitter.cpp
@@ -521,7 +521,7 @@ void Tailsitter::output(void)
     tilt_left = 0.0f;
     tilt_right = 0.0f;
     float pitch_cd = 0.0f, weathervane_gain = 0.0f, gain_slope = 0.0f;
-
+    float extra_elevator = 0.0f;
     float pitch_rate_effort = 0.0f, control_effort_gain_slope = 0.0f;
 
     if (vectored_hover_gain > 0) {
@@ -537,7 +537,6 @@ void Tailsitter::output(void)
         int32_t pitch_error_cd = (des_pitch_cd - quadplane.ahrs_view->pitch_sensor) * 0.5;
         float extra_pitch = constrain_float(pitch_error_cd, -SERVO_MAX, SERVO_MAX) / SERVO_MAX;
         float extra_sign = extra_pitch > 0?1:-1;
-        float extra_elevator = 0;
         if (!is_zero(extra_pitch) && quadplane.in_vtol_mode()) {
             extra_elevator = extra_sign * powf(fabsf(extra_pitch), vectored_hover_power) * SERVO_MAX;
         }
@@ -586,16 +585,16 @@ void Tailsitter::output(void)
     quadplane.attitude_control->get_tilt_motor_angle((constrain_float(tilt_left, -4500.0f, 4500.0f) + constrain_float(tilt_right, -4500.0f, 4500.0f)) / 2.0f);
     SRV_Channels::set_output_scaled(SRV_Channel::k_tiltMotorLeft, tilt_left);
     SRV_Channels::set_output_scaled(SRV_Channel::k_tiltMotorRight, tilt_right);
-
-#if HAL_LOGGING_ENABLED
+    float position_pitch_sp = quadplane.pos_control->get_pitch_cd();
     // Add logging for desired thrust vectoring angles
-    AP::logger().WriteStreaming("PHID", "TimeUS,DesL,DesR,AhrsPitch,WVGain,WVGainS",
-            "sddd--", // seconds, degrees
-            "F00000", // micro (1e-6), no mult (1e0)
-            "Qfffff", // uint64_t, float
-            AP_HAL::micros64(), tilt_left/100, tilt_right/100,pitch_cd/100,weathervane_gain,gain_slope);  
-#endif
-
+    #if HAL_LOGGING_ENABLED
+        AP::logger().WriteStreaming("PHID", "TimeUS,DesL,DesR,AhrsPit,WVGain,VHPwEe,PosPit",
+                "sddd--d",
+                "F000000",
+                "Qffffff",
+                AP_HAL::micros64(), tilt_left/100, tilt_right/100, pitch_cd/100,
+                weathervane_gain, extra_elevator/100, position_pitch_sp/100);
+    #endif
     // Check for saturated limits
     bool tilt_lim = _is_vectored && ((fabsf(SRV_Channels::get_output_scaled(SRV_Channel::Aux_servo_function_t::k_tiltMotorLeft)) >= SERVO_MAX) || (fabsf(SRV_Channels::get_output_scaled(SRV_Channel::Aux_servo_function_t::k_tiltMotorRight)) >= SERVO_MAX));
     bool roll_lim = _have_rudder && (fabsf(SRV_Channels::get_output_scaled(SRV_Channel::Aux_servo_function_t::k_rudder)) >= SERVO_MAX);
@@ -1061,8 +1060,6 @@ void Tailsitter_Transition::VTOL_update()
         if (!quadplane.tailsitter.transition_vtol_complete()) {
             return;
         }
-        // To inform the attitude controller that VTOL_DONE
-        quadplane.attitude_control->set_tailsitter_back_transition_done(true);
         // transition to VTOL complete, if armed set vtol rate limit starting point
         if (plane.arming.is_armed_and_safety_off()) {
             vtol_limit_start_ms = now;

diff --git a/ArduPlane/version.h b/ArduPlane/version.h
@@ -6,7 +6,7 @@
 
 #include "ap_version.h"
 
-#define THISFIRMWARE "Airbound ArduPlane V4.6.3.1 - rc7"
+#define THISFIRMWARE "AB ArduPlane V4.6.3.1 - rc9_lte_fix"
 
 // the following line is parsed by the autotest scripts
 #define FIRMWARE_VERSION 4,6,3,FIRMWARE_VERSION_TYPE_DEV