Enhanced take-off system

Patent metadata

Field	Value
Publication number	US-11226639-B2
Application number	US-201615273986-A
Country	US
Kind code	B2
Filing date	Sep 23, 2016
Priority date	Sep 23, 2016
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

An automatic takeoff flight control system controls an aircraft to automatically follow a predetermined set of control parameters upon taking off from the ground using both longitudinal and lateral control laws. The control system provides takeoff speed reduction to thereby reduce the takeoff distance (TOD) and, as a consequence, increase the takeoff weight (TOW). The control system sets the horizontal stabilizer (HSTAB) in a non-trimmed condition—named “mistrim”; and provides beta for optimum climb at takeoff, through lateral-directional surfaces commands.

First claim

The invention claimed is:

1. An automatic takeoff system configured to reduce takeoff distance of an aircraft of the type including control surfaces and a tail having a horizontal stabilizer thereon, the system comprising:
a fly-by-wire system connected to control the control surfaces and the horizontal stabilizer, the fly-by-wire system comprising at least one processor coupled to receive input signals from at least one air data measuring sensor and at least one inertial sensor, the at least one processor accessing takeoff speed values VR and V 2 to automatically provide, via the fly-by-wire system, both longitudinal and lateral-directional control surface control to provide automatic takeoff of the aircraft during ground roll through rotation up to a screen height, the fly-by-wire system configured to:
(a) use data from the at least one air data measuring sensor to automatically rotate the aircraft in response to airspeed of the aircraft achieving a pre-defined rotation speed,
(b) automatically apply non-neutral horizontal stabilizer trim control to mistrim the horizontal stabilizer in a pitch-up mistrimmed position during automatic rotation of the aircraft, the pitch-up mistrim of the type that produces a non-zero force at pilot controls; and
(c) compute longitudinal control surface deflection and use the computed longitudinal control surface deflection to automatically control amount of pitch of the aircraft up to the aircraft screen height, which controlled pitch amount does not cause a tail strike as the aircraft automatically rotates and once the aircraft is airborne does not cause the aircraft to stall.

2. The automatic takeoff system of claim 1 wherein the at least one processor prevents the aircraft maximum angle of attack from exceeding the aircraft stall limits up to a predefined climb speed.

3. The automatic takeoff system of claim 2 wherein the at least one processor controls longitudinal control surface actuators connected to actuate the control surfaces to keep the airspeed of the aircraft at a reference level upon detecting the aircraft has reached the predefined climb speed.

4. The automatic takeoff system of claim 1 wherein the at least one processor controls lateral control surfaces to maintain an aircraft wing leveled during a ground roll segment.

5. The automatic takeoff system of claim 1 wherein the at least one processor is further configured to automatically command the aircraft to a bank angle, and to limit the bank angle to avoid the wing tips hitting the ground.

6. The automatic takeoff system of claim 1 wherein the at least one processor computes directional control surface deflection in order to automatically augment stability and controllability during a ground roll segment.

7. The automatic takeoff system of claim 1 wherein the system reduces takeoff distance by setting the horizontal stabilizer in a pitch-up mistrimmed position during rotation, thereby enabling increase in takeoff weight.

8. The automatic takeoff system of claim 1 wherein the at least one processor is configured to supply a beta indication to minimize drag when the aircraft is in-air but has not yet attained the aircraft screen height, all engines are operating, landing gear is not down-locked, thrust levers are in takeoff configuration, and flaps are in takeoff position, and the at least one processor is further configured to also provide a predetermined Beta and Phi value beginning when the aircraft lifts off the ground.

9. The automatic takeoff system of claim 8 wherein the automatic takeoff system provides asymmetrical drag reduction upon takeoff by controlling control surfaces responsible for yaw and roll including at least some of ailerons, rudder, spoilers, spoilerons, ailevators, and flaperons.

10. The system of claim 1 wherein the at least one processor closes a control feedback loop around pitch angle.

11. The system of claim 10 wherein the at least one processor is further configured to implement an additional control loop for a lateral axis to use the lateral control surfaces to maintain the aircraft wing leveled during a ground roll segment.

12. The system of claim 1 wherein the at least one processor is further configured during the automatic takeoff to operate for automatic rotation outside of Federal Aviation Administration mandated speed margins for the aircraft.

13. The system of claim 1 wherein the at least one processor is further configured to automatically provide wings level operation during the ground roll and automatically prepare bank angle for climb before the aircraft ascends to screen height.

14. An automatic takeoff method for achieving reduced takeoff distance of an aircraft including control surfaces and a tail having a horizontal stabilizer thereon, the method comprising:
automatically provide longitudinal and lateral-directional control surface control during ground roll of the aircraft while automatically applying non-neutral horizontal stabilizer trim control to mistrim the horizontal stabilizer in a pitch-up mistrimmed position during automatic rotation of the aircraft, the pitch-up mistrimmed position producing a non-zero force at pilot controls;
automatically rotate the aircraft without pilot intervention to provide automatic takeoff of the aircraft while still applying the non-neutral horizontal stabilizer trim control to mistrim the horizontal stabilizer in the pitch-up mistrimmed position; and
use computed longitudinal control surface deflection to control pitch of the aircraft to prevent the aircraft tail from striking the ground as the aircraft automatically rotates and once the aircraft is airborne to ensure the aircraft does not exceed stall limits.

15. The method of claim 14 further including preventing aircraft maximum angle of attack from exceeding the aircraft stall limits up to a predefined climb speed.

16. In an aircraft including an inceptor that controls control surfaces and a tail having a horizontal stabilizer thereon, an automatic takeoff system comprising:
a fly-by-wire controller connected to actuate the control surfaces and the horizontal stabilizer, the fly-by-wire controller being configured to automatically provide longitudinal and lateral-directional control surface control during ground roll of the aircraft while automatically applying non-neutral horizontal stabilizer trim control to mistrim the horizontal stabilizer in a pitch-up mistrimmed position that produces a non-zero force at the inceptor;
the fly-by-wire controller being further configured to automatically rotate the aircraft without any pilot intervention to provide automatic takeoff of the aircraft while still applying the non-neutral horizontal stabilizer trim control to mistrim the horizontal stabilizer in the pitch-up mistrimmed position producing the non-zero force at the inceptor;
the fly-by-wire controller being further configured to use computed longitudinal control surface deflection to automatically control pitch of the aircraft as the aircraft automatically rotates to prevent the aircraft tail from striking the ground and once the aircraft is airborne to prevent the aircraft from exceeding stall limits.

Assignees

• Embraer Sa
• Yabora Ind Aeronautica S A

Inventors

• De Tarso Ferreira Daniel Paulo
• Kestenbach Thomas
• Carneiro Luiz Gustavo Medeiros
• Guedes Patrice London
• De Camargo Clark Reis Jose Roberto Ferreira

Classifications

• B64C2009/005

  Ailerons · CPC title

• B64C13/506

  overriding of personal controls; with automatic return to inoperative position · CPC title

• G05D1/0808

  specially adapted for aircraft · CPC title

• B64C13/18 Primary

  using automatic pilot · CPC title

• G05D1/0661 Primary

  specially adapted for take-off · CPC title