AP_MotorsHeli: Add parameter checks to Single class

libraries/AP_Motors/AP_MotorsHeli.h

@@ -107,7 +107,7 @@ public:
     virtual bool allow_arming() const = 0;
 
     // parameter_check - returns true if helicopter specific parameters are sensible, used for pre-arm check
-    bool parameter_check() const;
+    virtual bool parameter_check() const;
 
     // has_flybar - returns true if we have a mechical flybar
     virtual bool has_flybar() const { return AP_MOTORS_HELI_NOFLYBAR; }

libraries/AP_Motors/AP_MotorsHeli_Single.cpp

@@ -518,3 +518,20 @@ void AP_MotorsHeli_Single::servo_test()
     _pitch_control_input = _pitch_test;
     _yaw_control_input = _yaw_test;
 }
+
+// parameter_check - check if helicopter specific parameters are sensible
+bool AP_MotorsHeli_Single::parameter_check() const
+{
+    // returns false if Phase Angle is outside of range 
+    if ((_phase_angle > 90) || (_phase_angle < -90)){
+        return false;
+    }
+
+    // returns false if External Gyro Gain is outside of range
+    if ((_ext_gyro_gain < 0) || (_ext_gyro_gain > 1000)){
+        return false;
+    }
+
+    // check parent class parameters
+    return AP_MotorsHeli::parameter_check();
+}

libraries/AP_Motors/AP_MotorsHeli_Single.h

@@ -83,6 +83,9 @@ public:
     // allow_arming - returns true if main rotor is spinning and it is ok to arm
     bool allow_arming() const;
 
+    // parameter_check - returns true if helicopter specific parameters are sensible, used for pre-arm check
+    bool parameter_check() const;
+
     // set_desired_rotor_speed - sets target rotor speed as a number from 0 ~ 1000
     void set_desired_rotor_speed(int16_t desired_speed);