AC_Avoid: disable AltHold based avoidace by default

Co-authored-by: Randy Mackay <rmackay9@yahoo.com>

libraries/AC_Avoidance/AC_Avoid.cpp

@@ -112,14 +112,16 @@ const AP_Param::GroupInfo AC_Avoid::var_info[] = {
     // @User: Standard
     AP_GROUPINFO("BACKZ_SPD", 10, AC_Avoid, _backup_speed_max_u_ms, 0.75),
 
+#if AP_AVOIDANCE_ALTHOLD_ENABLED
     // @Param{Copter}: ANG_MAX
     // @DisplayName: Avoidance max lean angle in non-GPS flight modes
-    // @Description: Max lean angle used to avoid obstacles while in non-GPS modes
+    // @Description: Max lean angle used to avoid obstacles while in non-GPS modes.  Set to zero to disable lean-based avoidance
     // @Units: deg
     // @Increment: 0.1
     // @Range: 0 45
     // @User: Standard
     AP_GROUPINFO_FRAME("ANG_MAX", 11,  AC_Avoid, _angle_max_deg, 10.0, AP_PARAM_FRAME_COPTER | AP_PARAM_FRAME_HELI | AP_PARAM_FRAME_TRICOPTER),
+#endif
 
     AP_GROUPEND
 };
@@ -135,6 +137,7 @@ AC_Avoid::AC_Avoid()
 // convert parameters
 void AC_Avoid::convert_params()
 {
+#if AP_AVOIDANCE_ALTHOLD_ENABLED
     // PARAMETER_CONVERSION - Added: Feb 2026 ahead of ardupilot-4.7
 
     // exit immediately if ANG_MAX has already been configured
@@ -147,6 +150,7 @@ void AC_Avoid::convert_params()
         { 95, 2, AP_PARAM_INT16, "AVOID_ANG_MAX" },   // AVOID_ANGLE_MAX moved to AVOID_ANG_MAX
     };
     AP_Param::convert_old_parameters_scaled(conversion_info, ARRAY_SIZE(conversion_info), 0.01, 0);
+#endif
 }
 
 /*
@@ -512,6 +516,7 @@ void AC_Avoid::adjust_velocity_z(float kP, float accel_cmss, float& climb_rate_c
 #endif
 }
 
+#if AP_AVOIDANCE_ALTHOLD_ENABLED
 // adjust roll-pitch to push vehicle away from objects
 // roll and pitch value are in radians
 // veh_angle_max_rad is the user defined maximum lean angle for the vehicle in radians
@@ -560,6 +565,7 @@ void AC_Avoid::adjust_roll_pitch_rad(float &roll_rad, float &pitch_rad, float ve
     roll_rad = rp_out_rad.x;
     pitch_rad = rp_out_rad.y;
 }
+#endif // AP_AVOIDANCE_ALTHOLD_ENABLED
 
 /*
  * Note: This method is used to limit velocity horizontally only 
@@ -1501,6 +1507,7 @@ float AC_Avoid::get_stopping_distance(float kP, float accel_cmss, float speed_cm
     }
 }
 
+#if AP_AVOIDANCE_ALTHOLD_ENABLED
 // convert distance (in meters) to a lean percentage (in 0~1 range) for use in manual flight modes
 float AC_Avoid::distance_m_to_lean_norm(float dist_m) const
 {
@@ -1554,6 +1561,7 @@ void AC_Avoid::get_proximity_roll_pitch_norm(float &roll_positive_norm, float &r
     }
 #endif // HAL_PROXIMITY_ENABLED
 }
+#endif // AP_AVOIDANCE_ALTHOLD_ENABLED
 
 // singleton instance
 AC_Avoid *AC_Avoid::_singleton;

libraries/AC_Avoidance/AC_Avoid.h

@@ -79,10 +79,12 @@ public:
     void adjust_velocity_z(float kP, float accel_cmss, float& climb_rate_cms, float& backup_speed_cms, float dt);
     void adjust_velocity_z(float kP, float accel_cmss, float& climb_rate_cms, float dt);
 
+#if AP_AVOIDANCE_ALTHOLD_ENABLED
     // adjust roll-pitch to push vehicle away from objects
     // roll and pitch value are in radians
     // veh_angle_max_rad is the user defined maximum lean angle for the vehicle in radians
     void adjust_roll_pitch_rad(float &roll_rad, float &pitch_rad, float veh_angle_max_rad) const;
+#endif
 
     // enable/disable proximity based avoidance
     void proximity_avoidance_enable(bool on_off) { _proximity_enabled = on_off; }
@@ -199,18 +201,22 @@ private:
      * methods for avoidance in non-GPS flight modes
      */
 
+#if AP_AVOIDANCE_ALTHOLD_ENABLED
     // convert distance (in meters) to a lean percentage (in 0~1 range) for use in manual flight modes
     float distance_m_to_lean_norm(float dist_m) const;
 
     // returns the maximum positive and negative roll and pitch percentages (in -1 ~ +1 range) based on the proximity sensor
     void get_proximity_roll_pitch_norm(float &roll_positive, float &roll_negative, float &pitch_positive, float &pitch_negative) const;
+#endif
 
     // Logging function
     void Write_SimpleAvoidance(const uint8_t state, const Vector3f& desired_vel, const Vector3f& modified_vel, const bool back_up) const;
 
     // parameters
     AP_Int8 _enabled;
+#if AP_AVOIDANCE_ALTHOLD_ENABLED
     AP_Float _angle_max_deg;            // maximum lean angle in degrees to avoid obstacles (only used in non-GPS flight modes)
+#endif
     AP_Float _dist_max_m;               // distance (in meters) from object at which obstacle avoidance will begin in non-GPS modes
     AP_Float _margin_m;                 // vehicle will attempt to stay this distance (in meters) from objects while in GPS modes
     AP_Int8 _behavior;                  // avoidance behaviour (slide or stop)

libraries/AC_Avoidance/AC_Avoidance_config.h

@@ -23,8 +23,10 @@
 #define AP_OAPATHPLANNER_DIJKSTRA_ENABLED AP_OAPATHPLANNER_BACKEND_DEFAULT_ENABLED
 #endif
 
-
-
 #ifndef AP_OADATABASE_ENABLED
 #define AP_OADATABASE_ENABLED AP_OAPATHPLANNER_ENABLED
 #endif
+
+#ifndef AP_AVOIDANCE_ALTHOLD_ENABLED
+#define AP_AVOIDANCE_ALTHOLD_ENABLED 0
+#endif