Copter: AltHold limits lean angle to maintain altitude

get_pilot_desired_lean_angles function now takes angle max parameter but
all flight modes except AltHold simply pass in the ANGLE_MAX parameter
meaning no functional change for them

ArduCopter/Attitude.cpp

@@ -11,12 +11,16 @@ float Copter::get_smoothing_gain()
 
 // get_pilot_desired_angle - transform pilot's roll or pitch input into a desired lean angle
 // returns desired angle in centi-degrees
-void Copter::get_pilot_desired_lean_angles(float roll_in, float pitch_in, float &roll_out, float &pitch_out)
+void Copter::get_pilot_desired_lean_angles(float roll_in, float pitch_in, float &roll_out, float &pitch_out, float angle_max)
 {
-    float angle_max = constrain_float(aparm.angle_max,1000,8000);
-    float scaler = (float)angle_max/(float)ROLL_PITCH_INPUT_MAX;
+    // sanity check angle max parameter
+    aparm.angle_max = constrain_int16(aparm.angle_max,1000,8000);
 
-    // scale roll_in, pitch_in to correct units
+    // limit max lean angle
+    angle_max = constrain_float(angle_max, 1000, aparm.angle_max);
+
+    // scale roll_in, pitch_in to ANGLE_MAX parameter range
+    float scaler = aparm.angle_max/(float)ROLL_PITCH_INPUT_MAX;
     roll_in *= scaler;
     pitch_in *= scaler;
 

ArduCopter/Copter.h

@@ -567,7 +567,7 @@ private:
     void set_using_interlock(bool b);
     void set_motor_emergency_stop(bool b);
     float get_smoothing_gain();
-    void get_pilot_desired_lean_angles(float roll_in, float pitch_in, float &roll_out, float &pitch_out);
+    void get_pilot_desired_lean_angles(float roll_in, float pitch_in, float &roll_out, float &pitch_out, float angle_max);
     float get_pilot_desired_yaw_rate(int16_t stick_angle);
     void check_ekf_yaw_reset();
     float get_roi_yaw();

ArduCopter/control_althold.cpp

@@ -34,7 +34,7 @@ void Copter::althold_run()
 
     // get pilot desired lean angles
     float target_roll, target_pitch;
-    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch);
+    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch, attitude_control.get_althold_lean_angle_max());
 
     // get pilot's desired yaw rate
     float target_yaw_rate = get_pilot_desired_yaw_rate(channel_yaw->control_in);

ArduCopter/control_autotune.cpp

@@ -273,7 +273,7 @@ void Copter::autotune_run()
     update_simple_mode();
 
     // get pilot desired lean angles
-    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch);
+    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch, aparm.angle_max);
 
     // get pilot's desired yaw rate
     target_yaw_rate = get_pilot_desired_yaw_rate(channel_yaw->control_in);

ArduCopter/control_drift.cpp

@@ -55,7 +55,7 @@ void Copter::drift_run()
     }
 
     // convert pilot input to lean angles
-    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch);
+    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch, aparm.angle_max);
 
     // get pilot's desired throttle
     pilot_throttle_scaled = get_pilot_desired_throttle(channel_throttle->control_in);

ArduCopter/control_land.cpp

@@ -153,7 +153,7 @@ void Copter::land_nogps_run()
             update_simple_mode();
 
             // get pilot desired lean angles
-            get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch);
+            get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch, aparm.angle_max);
         }
 
         // get pilot's desired yaw rate

ArduCopter/control_poshold.cpp

@@ -185,7 +185,7 @@ void Copter::poshold_run()
         return;
     }else{
         // convert pilot input to lean angles
-        get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch);
+        get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch, aparm.angle_max);
 
         // convert inertial nav earth-frame velocities to body-frame
         // To-Do: move this to AP_Math (or perhaps we already have a function to do this)

ArduCopter/control_stabilize.cpp

@@ -40,7 +40,7 @@ void Copter::stabilize_run()
 
     // convert pilot input to lean angles
     // To-Do: convert get_pilot_desired_lean_angles to return angles as floats
-    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch);
+    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch, aparm.angle_max);
 
     // get pilot's desired yaw rate
     target_yaw_rate = get_pilot_desired_yaw_rate(channel_yaw->control_in);

ArduCopter/heli_control_stabilize.cpp

@@ -51,7 +51,7 @@ void Copter::heli_stabilize_run()
 
     // convert pilot input to lean angles
     // To-Do: convert get_pilot_desired_lean_angles to return angles as floats
-    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch);
+    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch, aparm.angle_max);
 
     // get pilot's desired yaw rate
     target_yaw_rate = get_pilot_desired_yaw_rate(channel_yaw->control_in);