AP_Parachute: added a released() function

used to help with throttle suppression in plane

libraries/AP_Parachute/AP_Parachute.cpp

@@ -91,7 +91,7 @@ void AP_Parachute::update()
     uint32_t time_diff = hal.scheduler->millis() - _release_time;
 
     // check if we should release parachute
-    if ((_release_time != 0) && !_released) {
+    if ((_release_time != 0) && !_release_in_progress) {
         if (time_diff >= AP_PARACHUTE_RELEASE_DELAY_MS) {
             if (_release_type == AP_PARACHUTE_TRIGGER_TYPE_SERVO) {
                 // move servo
@@ -100,6 +100,7 @@ void AP_Parachute::update()
                 // set relay
                 _relay.on(_release_type);
             }
+            _release_in_progress = true;
             _released = true;
         }
     }else if ((_release_time == 0) || time_diff >= AP_PARACHUTE_RELEASE_DELAY_MS + AP_PARACHUTE_RELEASE_DURATION_MS) {
@@ -111,7 +112,7 @@ void AP_Parachute::update()
             _relay.off(_release_type);
         }
         // reset released flag and release_time
-        _released = false;
+        _release_in_progress = false;
         _release_time = 0;
         // update AP_Notify
         AP_Notify::flags.parachute_release = 0;

libraries/AP_Parachute/AP_Parachute.h

@@ -49,6 +49,9 @@ public:
     /// release - release parachute
     void release();
 
+    /// released - true if the parachute has been released (or release is in progress)
+    bool released() const { return _released; }
+    
     /// update - shuts off the trigger should be called at about 10hz
     void update();
 
@@ -69,7 +72,8 @@ private:
     // internal variables
     AP_Relay   &_relay;         // pointer to relay object from the base class Relay. The subclasses could be AP_Relay_APM1 or AP_Relay_APM2
     uint32_t    _release_time;  // system time that parachute is ordered to be released (actual release will happen 0.5 seconds later)
-    bool        _released;      // true if the parachute has been released
+    bool        _release_in_progress:1;  // true if the parachute release is in progress
+    bool        _released:1;    // true if the parachute has been released
 };
 
 #endif /* AP_PARACHUTE_H */