Added "bottom distance" switch, multirotor_pos_control implemented: use bottom distance to surface to control altitde

src/modules/uORB/topics/manual_control_setpoint.h

@@ -60,6 +60,7 @@ struct manual_control_setpoint_s {
 	float return_switch;			/**< land 2 position switch (mandatory): land, no effect */
 	float assisted_switch;			/**< assisted 2 position switch (optional): seatbelt, simple */
 	float mission_switch;		/**< mission 2 position switch (optional): mission, loiter */
+	float dist_bottom_switch;		/**< distance bottom 2 position switch (optional): off, on */
 
 	/**
 	 * Any of the channels below may not be available and be set to NaN

src/modules/uORB/topics/rc_channels.h

@@ -63,20 +63,21 @@
 enum RC_CHANNELS_FUNCTION
 {
   THROTTLE = 0,
-  ROLL     = 1,
-  PITCH    = 2,
-  YAW      = 3,
-  MODE = 4,
-  RETURN = 5,
-  ASSISTED = 6,
-  MISSION = 7,
-  OFFBOARD_MODE = 8,
-  FLAPS   = 9,
-  AUX_1   = 10,
-  AUX_2   = 11,
-  AUX_3   = 12,
-  AUX_4   = 13,
-  AUX_5   = 14,
+  ROLL,
+  PITCH,
+  YAW,
+  MODE,
+  RETURN,
+  ASSISTED,
+  MISSION,
+  DIST_BOTTOM,
+  OFFBOARD_MODE,
+  FLAPS,
+  AUX_1,
+  AUX_2,
+  AUX_3,
+  AUX_4,
+  AUX_5,
   RC_CHANNELS_FUNCTION_MAX /**< indicates the number of functions. There can be more functions than RC channels. */
 };
 

src/modules/uORB/topics/vehicle_control_mode.h

@@ -79,6 +79,7 @@ struct vehicle_control_mode_s
 	bool flag_control_position_enabled;		/**< true if position is controlled */
 	bool flag_control_altitude_enabled;		/**< true if altitude is controlled */
 	bool flag_control_climb_rate_enabled;		/**< true if climb rate is controlled */
+	bool flag_use_dist_bottom;				/**< true if bottom distance sensor should be used for altitude control */
 
 	bool flag_control_auto_enabled;		// TEMP
 	uint8_t auto_state;	// TEMP navigation state for AUTO modes

src/modules/uORB/topics/vehicle_status.h

@@ -106,16 +106,16 @@ typedef enum {
 	ASSISTED_SWITCH_EASY
 } assisted_switch_pos_t;
 
-typedef enum {
-	RETURN_SWITCH_NONE = 0,
-	RETURN_SWITCH_RETURN
-} return_switch_pos_t;
-
 typedef enum {
 	MISSION_SWITCH_NONE = 0,
 	MISSION_SWITCH_MISSION
 } mission_switch_pos_t;
 
+typedef enum {
+	SWITCH_OFF = 0,
+	SWITCH_ON
+} on_off_switch_pos_t;
+
 enum VEHICLE_MODE_FLAG {
 	VEHICLE_MODE_FLAG_SAFETY_ARMED = 128,
 	VEHICLE_MODE_FLAG_MANUAL_INPUT_ENABLED = 64,
@@ -187,9 +187,10 @@ struct vehicle_status_s
 	bool is_rotary_wing;
 
 	mode_switch_pos_t mode_switch;
-	return_switch_pos_t return_switch;
+	on_off_switch_pos_t return_switch;
 	assisted_switch_pos_t assisted_switch;
 	mission_switch_pos_t mission_switch;
+	on_off_switch_pos_t dist_bottom_switch;
 
 	bool condition_battery_voltage_valid;
 	bool condition_system_in_air_restore;	/**< true if we can restore in mid air */