adjust some limits to prevent divide-by-zero

src/modules/fw_att_control/FixedwingAttitudeControl.cpp

@@ -449,10 +449,15 @@ void FixedwingAttitudeControl::Run()
 				*/
 				float groundspeed = sqrtf(_local_pos.vx * _local_pos.vx + _local_pos.vy * _local_pos.vy);
 				float gspd_scaling_trim = (_param_fw_airspd_min.get() * 0.6f);
-				float groundspeed_scaler = gspd_scaling_trim / ((groundspeed < gspd_scaling_trim) ? gspd_scaling_trim : groundspeed);
 
 				control_input.groundspeed = groundspeed;
-				control_input.groundspeed_scaler = groundspeed_scaler;
+
+				if (groundspeed > gspd_scaling_trim) {
+					control_input.groundspeed_scaler = gspd_scaling_trim / groundspeed;
+
+				} else {
+					control_input.groundspeed_scaler = 1.0f;
+				}
 			}
 
 			/* reset body angular rate limits on mode change */

src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c

@@ -436,7 +436,7 @@ PARAM_DEFINE_FLOAT(FW_LND_THRTC_SC, 1.0f);
  * increase airspeed more aggressively.
  *
  * @unit m/s
- * @min 0.0
+ * @min 0.5
  * @max 40
  * @decimal 1
  * @increment 0.5
@@ -451,7 +451,7 @@ PARAM_DEFINE_FLOAT(FW_AIRSPD_MIN, 10.0f);
  * airspeed more aggressively.
  *
  * @unit m/s
- * @min 0.0
+ * @min 0.5
  * @max 40
  * @decimal 1
  * @increment 0.5
@@ -467,7 +467,7 @@ PARAM_DEFINE_FLOAT(FW_AIRSPD_MAX, 20.0f);
  * no other airspeed setpoint sources are present (e.g. through non-centered RC sticks).
  *
  * @unit m/s
- * @min 0.0
+ * @min 0.5
  * @max 40
  * @decimal 1
  * @increment 0.5

src/modules/mc_pos_control/PositionControl/PositionControl.hpp

@@ -39,6 +39,7 @@
 
 #pragma once
 
+#include <lib/mathlib/mathlib.h>
 #include <matrix/matrix/math.hpp>
 #include <uORB/topics/vehicle_attitude_setpoint.h>
 #include <uORB/topics/vehicle_local_position_setpoint.h>
@@ -114,9 +115,9 @@ public:
 
 	/**
 	 * Set the normalized hover thrust
-	 * @param thrust [0,1] with which the vehicle hovers not acelerating down or up with level orientation
+	 * @param thrust [0.1, 0.9] with which the vehicle hovers not acelerating down or up with level orientation
 	 */
-	void setHoverThrust(const float hover_thrust) { _hover_thrust = hover_thrust; }
+	void setHoverThrust(const float hover_thrust) { _hover_thrust = math::constrain(hover_thrust, 0.1f, 0.9f); }
 
 	/**
 	 * Update the hover thrust without immediately affecting the output
@@ -192,7 +193,7 @@ private:
 	float _lim_thr_max{}; ///< Maximum collective thrust allowed as output [-1,0] e.g. -0.1
 	float _lim_tilt{}; ///< Maximum tilt from level the output attitude is allowed to have
 
-	float _hover_thrust{}; ///< Thrust [0,1] with which the vehicle hovers not accelerating down or up with level orientation
+	float _hover_thrust{}; ///< Thrust [0.1, 0.9] with which the vehicle hovers not accelerating down or up with level orientation
 
 	// States
 	matrix::Vector3f _pos; /**< current position */