AP_Airspeed: Converted library to be stand-alone from APM:Plane.

Additional changes:
   ARSPD_FBW_MIN and ARSPD_FBW_MAX renamed to ARSPD_MIN and ARSPD_MAX
   ARSPD_MIN and ARSPD_MAX changed to floats

libraries/AP_Airspeed/AP_Airspeed.cpp

@@ -132,17 +132,37 @@ const AP_Param::GroupInfo AP_Airspeed::var_info[] = {
     // @Description: This parameter allows you to to set the PSI (pounds per square inch) range for your sensor. You should not change this unless you examine the datasheet for your device
     // @User: Advanced
     AP_GROUPINFO("PSI_RANGE",  8, AP_Airspeed, _psi_range, PSI_RANGE_DEFAULT),
-    
+
+    // @Param: ARSPD_FBW_MIN
+    // @DisplayName: Minimum Airspeed
+    // @Description: This is the minimum airspeed you want to fly at in modes where the autopilot controls the airspeed. This should be set to a value around 20% higher than the level flight stall speed for the airframe. This value is also used in the STALL_PREVENTION code.
+    // @Units: m/s
+    // @Range: 5 100
+    // @Increment: 1
+    // @User: Standard
+    AP_GROUPINFO("FBW_MIN", 9, AP_Airspeed, _airspeed_min, 9),
+
+    // @Param: ARSPD_FBW_MAX
+    // @DisplayName: Maximum Airspeed
+    // @Description: This is the maximum airspeed that you want to allow for your airframe in auto-throttle modes. You should ensure that this value is sufficiently above the ARSPD_MIN value to allow for a sufficient flight envelope to accurately control altitude using airspeed. A value at least 50% above ARSPD_MIN is recommended.
+    // @Units: m/s
+    // @Range: 5 100
+    // @Increment: 1
+    // @User: Standard
+    AP_GROUPINFO("FBW_MAX", 10, AP_Airspeed, _airspeed_max, 22),
+
     AP_GROUPEND
 };
 
 
-AP_Airspeed::AP_Airspeed(const AP_Vehicle::FixedWing &parms)
+AP_Airspeed::AP_Airspeed()
     : _EAS2TAS(1.0f)
-    , _calibration(parms)
+    , _calibration()
+    , analog(_pin, _psi_range)
+    , digital(_psi_range)
 {
     AP_Param::setup_object_defaults(this, var_info);
-}
+};
 
 
 /*

libraries/AP_Airspeed/AP_Airspeed.h

@@ -16,7 +16,7 @@ class Airspeed_Calibration {
 public:
     friend class AP_Airspeed;
     // constructor
-    Airspeed_Calibration(const AP_Vehicle::FixedWing &parms);
+    Airspeed_Calibration(void);
 
     // initialise the calibration
     void init(float initial_ratio);
@@ -32,14 +32,13 @@ private:
     const float Q1; // process noise matrix bottom right element
     Vector3f state; // state vector
     const float DT; // time delta
-    const AP_Vehicle::FixedWing &aparm;
 };
 
 class AP_Airspeed
 {
 public:
     // constructor
-    AP_Airspeed(const AP_Vehicle::FixedWing &parms);
+    AP_Airspeed();
 
     void init(void);
 
@@ -124,6 +123,16 @@ public:
         return _EAS2TAS;
     }
 
+    // get the min set airspeed
+    float get_airspeed_min(void) const {
+        return (float)(_airspeed_min);
+    }
+
+    // get the max set airspeed
+    float get_airspeed_max(void) const {
+        return (float)(_airspeed_max);
+    }
+
     // update airspeed ratio calibration
     void update_calibration(const Vector3f &vground);
 
@@ -156,6 +165,8 @@ private:
     AP_Int8         _autocal;
     AP_Int8         _tube_order;
     AP_Int8         _skip_cal;
+    AP_Int16        _airspeed_min;
+    AP_Int16        _airspeed_max;
     float           _raw_airspeed;
     float           _airspeed;
     float			_last_pressure;

libraries/AP_Airspeed/Airspeed_Calibration.cpp

@@ -13,9 +13,10 @@
 #include "AP_Airspeed.h"
 
 extern const AP_HAL::HAL& hal;
+AP_Airspeed arspd;
 
 // constructor - fill in all the initial values
-Airspeed_Calibration::Airspeed_Calibration(const AP_Vehicle::FixedWing &parms)
+Airspeed_Calibration::Airspeed_Calibration()
     : P(100,   0,         0,
         0,   100,         0,
         0,     0,  0.000001f)
@@ -23,7 +24,6 @@ Airspeed_Calibration::Airspeed_Calibration(const AP_Vehicle::FixedWing &parms)
     , Q1(0.0000005f)
     , state(0, 0, 0)
     , DT(1)
-    , aparm(parms)
 {
 }
 
@@ -39,7 +39,7 @@ void Airspeed_Calibration::init(float initial_ratio)
   update the state of the airspeed calibration - needs to be called
   once a second
  */
-float Airspeed_Calibration::update(float airspeed, const Vector3f &vg)
+float Airspeed_Calibration::update(float aspeed, const Vector3f &vg)
 {
     // Perform the covariance prediction
     // Q is a diagonal matrix so only need to add three terms in
@@ -54,7 +54,7 @@ float Airspeed_Calibration::update(float airspeed, const Vector3f &vg)
     // invariant plus process noise
     // Ignore vertical wind component
     float TAS_pred = state.z * norm(vg.x - state.x, vg.y - state.y, vg.z);
-    float TAS_mea  = airspeed;
+    float TAS_mea  = aspeed;
 
     // Calculate the observation Jacobian H_TAS
     float SH1 = sq(vg.y - state.y) + sq(vg.x - state.x);
@@ -101,8 +101,8 @@ float Airspeed_Calibration::update(float airspeed, const Vector3f &vg)
     P.b.y = MAX(P.b.y, 0.0f);
     P.c.z = MAX(P.c.z, 0.0f);
 
-    state.x = constrain_float(state.x, -aparm.airspeed_max, aparm.airspeed_max);
-    state.y = constrain_float(state.y, -aparm.airspeed_max, aparm.airspeed_max);
+    state.x = constrain_float(state.x, -arspd.get_airspeed_max(), arspd.get_airspeed_max());
+    state.y = constrain_float(state.y, -arspd.get_airspeed_max(), arspd.get_airspeed_max());
     state.z = constrain_float(state.z, 0.5f, 1.0f);
 
     return state.z;

libraries/AP_Airspeed/examples/Airspeed/Airspeed.cpp

@@ -25,11 +25,9 @@
 
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
-static AP_Vehicle::FixedWing aparm;
-
 float temperature;
 
-AP_Airspeed airspeed(aparm);
+AP_Airspeed airspeed;
 
 void setup()
 {