Takeoff: switch internally to use a ramp progress

src/modules/mc_pos_control/Takeoff/Takeoff.cpp

@@ -72,7 +72,7 @@ void Takeoff::updateTakeoffState(const bool armed, const bool landed, const bool
 	case TakeoffState::ready_for_takeoff:
 		if (want_takeoff) {
 			_takeoff_state = TakeoffState::rampup;
-			_takeoff_ramp_vz = _takeoff_ramp_vz_init;
+			_takeoff_ramp_progress = 0.f;
 
 		} else {
 			break;
@@ -80,7 +80,7 @@ void Takeoff::updateTakeoffState(const bool armed, const bool landed, const bool
 
 	// FALLTHROUGH
 	case TakeoffState::rampup:
-		if (_takeoff_ramp_vz >= takeoff_desired_vz) {
+		if (_takeoff_ramp_progress >= 1.f) {
 			_takeoff_state = TakeoffState::flight;
 
 		} else {
@@ -119,14 +119,14 @@ float Takeoff::updateRamp(const float dt, const float takeoff_desired_vz)
 
 	if (_takeoff_state == TakeoffState::rampup) {
 		if (_takeoff_ramp_time > dt) {
-			_takeoff_ramp_vz += (takeoff_desired_vz - _takeoff_ramp_vz_init) * dt / _takeoff_ramp_time;
+			_takeoff_ramp_progress += dt / _takeoff_ramp_time;
 
 		} else {
-			_takeoff_ramp_vz = takeoff_desired_vz;
+			_takeoff_ramp_progress = 1.f;
 		}
 
-		if (_takeoff_ramp_vz < takeoff_desired_vz) {
-			upwards_velocity_limit = _takeoff_ramp_vz;
+		if (_takeoff_ramp_progress < 1.f) {
+			upwards_velocity_limit = _takeoff_ramp_vz_init + _takeoff_ramp_progress * (takeoff_desired_vz - _takeoff_ramp_vz_init);
 		}
 	}
 

src/modules/mc_pos_control/Takeoff/Takeoff.hpp

@@ -94,9 +94,9 @@ public:
 private:
 	TakeoffState _takeoff_state = TakeoffState::disarmed;
 
-	systemlib::Hysteresis _spoolup_time_hysteresis{false}; /**< becomes true MPC_SPOOLUP_TIME seconds after the vehicle was armed */
+	systemlib::Hysteresis _spoolup_time_hysteresis{false}; ///< becomes true MPC_SPOOLUP_TIME seconds after the vehicle was armed
 
-	float _takeoff_ramp_time = 0.f;
-	float _takeoff_ramp_vz_init = 0.f;
-	float _takeoff_ramp_vz = 0.f;
+	float _takeoff_ramp_time{0.f};
+	float _takeoff_ramp_vz_init{0.f}; ///< verticval velocity resulting in zero thrust
+	float _takeoff_ramp_progress{0.f}; ///< asecnding from 0 to 1
 };