In this section, it will be explained the Hybrid typical mission profile and the mission phases will be detailed. The common phases of Quadcopter and Plane are:
- Transition Quad to Plane
- Transition Plane to Quad
For all the other phases, the flight type will be specified.
Standby phase is a preliminary phase of the operation. The guidance is simply a “Hold” with no change. Normally, the automation which allows the system to pass to Standby phase requires the GPS signal.
Standby phase panel
QUAD TO PLANE TRANSITION
This transition phase allows the aircraft to maintain attitude using the quadcopter control and increase its horizontal IAS until reaching the requested speed to perform a plane flight avoiding stall condition.
The guidance of this phase is a Hold which allows maintaining Pitch, Roll and Ground Speed Down at 0 and the Yaw angle at the current one.
Quad to Plane guidance
The only difference with a classical Hover phase is the Thrusting control of the Plane. As showed in the following image, this control increases the thrust value from 0 to 1 in 4 [s] with a delay of 0.5 [s]. This action allows reaching the necessary speed to flight horizontally and, when the IAS is reached, the system will pass automatically to Plane phases (an automation definition is necessary).
Quad to Plane thrusting control
PLANE TO QUAD TRANSITION
This transition phase allows the aircraft to maintain attitude using the quadcopter control and decrease its horizontal speed until reaching a 0 value of Ground Speed and enter in a Hover phase.
The guidance of this phase is a Hold which allows maintaining Roll angle and Ground Speed Down at 0 and the Yaw angle at the current one. The Front Ground Speed is controlled in order to decrease it from the initial value to o [m/s] in 15 seconds.
Plane to Quad guidance
Plane to Quad thrusting control
The previous image shows the thrusting control which is brought to 0 in 1 second. In this way, the aircraft stops to control horizontal IAS and the multicopter motors start breaking the platform.
TAKE OFF – QUAD
Take-off phase is composed by two Guidances: VTol and Yaw. The first one is a vertical guidance and where following parameters are set:
- Line attraction: 15.0 m.
- Speed: 0.4 m/s.
- Horizontal Hover Gain: 0.3.
- Vertical Hover Gain: 0.5.
- Relative Vertical Distance: -200.0 m (Positive down).
Yaw guidance allows choosing the Hybrid orientation during takeoff and in this case is set to Current with a limited rotation speed of 0.6 rad/s.
HOVER – QUAD
Hover phase is configured to allow the multicopter maintain the position in the air.
Hover phase panel
The Guidance is a VTol as the one in Take Off phase but, in this case, the Relative vertical distance is set at zero. Another change between TO phase is the Hover gain which is set at 0.3 and 0.4 for Horizontal and Vertical respectively.
The Yaw guidance is the same of the Take Off phase.
LANDING – QUAD
This phase has the same settings of the Take-off with some changes.
Landing phase panel
In Landing phase are set:
- Line Attraction kept at 20.
- Set Speed fixed at 0.3 [m/s].
- Hover gains as in the Take-off phase.
- -100.0 [m] of Absolute vertical position. In this case, we are supposing that at the instant when the Landing phase starts, the hybrid is flying at AGL > -100m (it means all positive values).
Yaw Guidance is configured in order to let the quadcopter with the Current yaw angle and limiting the yaw rate at 0.6 [rad/s].
FLY TO LANDING POINT – QUAD
When the Plane to Quad transition is complete, the platform will stay into a Hover phase until the user changes its phase. The successive flight phase will be a Go Home phase which allows the Hybrid to reach the landing point in a Quadcopter flight mode.
The guidance, in this case, is a Cruise with the following parameters:
- Line Attraction kept at 20.
- Set Speed fixed at 2.0 [m/s], with a Waypoint reach of 1.0 [m/s].
- Hover gains as in the Hover phase.
- Acceleration limits configured to 0.5 [m/s²]
HOLD – QUAD
Hold phase is used to perform a Stick controlled flight. The phase guidance is composed by Hold and Yaw guidances. It is a Hold which allows maintaining:
- Desired pitch at 0.0 [rad]
- Desired roll at 0.0 [rad]
- Desired Ground Speed Down at 0.0 [m/s]
In this way, if the stick control is not active, the quadcopter will keep its position in the air. The Yaw Guidance is set on Current. In this phase, the Arcade allows controlling the platform depending on the set gains.
Hold phase panel
Hold phase Arcade gains
CLIMBING – PLANE
The climbing phase, in this case, is used to make the airplane reach the cruise altitude after the Quad to Plane transition.
Climbing phase panel
Set speed is the speed that will have the airplane during the climb.
Finally, in the “Route” options are configured the parameters that define the path during the climb phase.
- Flight path angle: angle at which the aircraft climbs.
- Radius of the circle trajectory made by the aircraft while is climbing.
- Distance: length from the lift-off point to the beginning of the circular trajectory.
- Altitude: height to be reached by aircraft during the circular climb.
WAYPOINTS – PLANE
The waypoint phase is the main one of this kind of mission. During this phase, the aircraft follows a route marked by a set of waypoints, which are defined by the user in the “Mission” menu.
Landing phase panel
The parameters are similar to the ones from the climbing phase. It is possible to set a cruise speed, limit the accelerations or set the line attraction parameter. Moreover, there is another option related to the gains used to recover the hover point in a multicopter flight. In this case, the platform configured is an airplane so this one will not be used.
APPROACH – PLANE
The Approach phase is configured in order to make the plane flying into the landing zone at the correct altitude and speed. When the platform enters into the polygon, the system will pass to Plane to Quad transition phase.
In this case, the guidance is a Landing and the following parameters are defined.
Approach phase panel
LANDING – PLANE
Landing phase is a safety phase. The platform is defined to have a VTol behavior and it is performed using electrical motors. In a Low Battery situation, the aircraft must land in a plane flight mode and it can be performed only if a Landing phase was previously defined.
Landing-Plane phase panel
The guidance of this phase is a Landing and the parameters are the same of the Approach phase with a landing runway definition. For more info about Failsafe automation, see section 11.2 of this manual.