From 9fcf2b674a401e63ac7fc29d03a1873aaa144141 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Fri, 10 Jan 2025 19:17:06 +1100
Subject: [PATCH] SITL: add plane-redundant

---
 libraries/SITL/SIM_Plane.cpp | 9 +++++++++
 libraries/SITL/SIM_Plane.h   | 1 +
 2 files changed, 10 insertions(+)

diff --git a/libraries/SITL/SIM_Plane.cpp b/libraries/SITL/SIM_Plane.cpp
index 82aa8c659d..4435ef1c57 100644
--- a/libraries/SITL/SIM_Plane.cpp
+++ b/libraries/SITL/SIM_Plane.cpp
@@ -56,6 +56,8 @@ Plane::Plane(const char *frame_str) :
         vtail = true;
     } else if (strstr(frame_str, "-dspoilers")) {
         dspoilers = true;
+    } else if (strstr(frame_str, "-redundant")) {
+        redundant = true;
     }
     if (strstr(frame_str, "-elevrev")) {
         reverse_elevator_rudder = true;
@@ -311,6 +313,13 @@ void Plane::calculate_forces(const struct sitl_input &input, Vector3f &rot_accel
         aileron  = (elevon_right-elevon_left)/2;
         elevator = (elevon_left+elevon_right)/2;
         rudder = fabsf(dspoiler1_right - dspoiler2_right)/2 - fabsf(dspoiler1_left - dspoiler2_left)/2;
+    } else if (redundant) {
+        // channels 1/9 are left/right ailierons
+        // channels 2/10 are left/right elevators
+        // channels 4/12 are top/bottom rudders
+        aileron  = (filtered_servo_angle(input, 0) + filtered_servo_angle(input, 8)) / 2.0;
+        elevator = (filtered_servo_angle(input, 1) + filtered_servo_angle(input, 9)) / 2.0;
+        rudder   = (filtered_servo_angle(input, 3) + filtered_servo_angle(input, 11)) / 2.0;
     }
     //printf("Aileron: %.1f elevator: %.1f rudder: %.1f\n", aileron, elevator, rudder);
 
diff --git a/libraries/SITL/SIM_Plane.h b/libraries/SITL/SIM_Plane.h
index 2a49de12be..a99d8b4b59 100644
--- a/libraries/SITL/SIM_Plane.h
+++ b/libraries/SITL/SIM_Plane.h
@@ -95,6 +95,7 @@ protected:
     bool elevons;
     bool vtail;
     bool dspoilers;
+    bool redundant;
     bool reverse_elevator_rudder;
     bool ice_engine;
     bool tailsitter;