EP-4738042-A1 - METHOD AND SYSTEM FOR LANDING A VTOL AIRCRAFT

EP4738042A1EP 4738042 A1EP4738042 A1EP 4738042A1EP-4738042-A1

Abstract

System and related operating method are provided for landing an aircraft. An exemplary method involves determining that an amount of available energy associated with an energy source onboard the aircraft is less than a predicted amount of energy required to land the aircraft in accordance with a flight plan or other procedure currently being flown. Thereafter, the method automatically operates the aircraft to descend using an unregulated vertical speed and regulates an orientation of the aircraft to a reference orientation. Thereafter, when the altitude of the aircraft is below a threshold, the method automatically operates the aircraft to descend using a different control scheme to regulate a lateral position of the aircraft to a lateral trajectory to a landing location while regulating a velocity of the aircraft using a cost function.

Inventors

CHEN, SHUAI
DING, Jiankun
HE, YINGYING
ZHU, Xukai

Assignees

Honeywell International Inc.

Dates

Publication Date: 20260506
Application Date: 20251013

Claims (15)

A method of landing an aircraft, the method comprising determining an amount of available energy associated with an energy source onboard the aircraft is less than a predicted amount of energy required to land the aircraft in accordance with a procedure based on a current state of the aircraft; and thereafter: automatically operating one or more actuators associated with the aircraft to descend using an unregulated vertical speed using a first control scheme to regulate an orientation of the aircraft to a reference orientation; and thereafter, when an altitude of the aircraft is below a threshold, automatically operate the one or more actuators associated with the aircraft to descend using a second control scheme different from the first control scheme to regulate a lateral position of the aircraft to a trajectory to a landing location while regulating a velocity of the aircraft using a cost function.
The method of claim 1, further comprising autonomously operating the one or more actuators associated with the aircraft to descend using a reference vertical speed associated with the procedure prior to determining the amount of available energy associated with the energy source onboard the aircraft is less than the predicted amount of energy while autonomously operating the one or more actuators associated with the aircraft to descend using the reference vertical speed.
The method of claim 1, wherein the cost function is configured to minimize a three-dimensional velocity of the aircraft at touchdown at the landing location.
The method of claim 1, wherein the cost function is configured to minimize energy consumption.
The method of claim 1, wherein the first control scheme comprises a closed-loop control scheme configurable to regulate the orientation of the aircraft to a level flight orientation.
The method of claim 5, wherein the closed-loop control scheme comprises a proportional-integral-derivative (PID) control scheme configurable to regulate a pitch of the aircraft to a zero pitch orientation and regulate a roll of the aircraft to a zero roll orientation.
The method of claim 1, wherein the second control scheme comprises a model predictive control (MPC) scheme configurable to regulate a predicted position of the aircraft to the trajectory while minimizing a predicted vertical speed of the aircraft at the landing location.
The method of claim 1, wherein the second control scheme comprises a model predictive control (MPC) scheme configurable to regulate a predicted position of the aircraft to the trajectory while regulating a predicted velocity of the aircraft to zero at touchdown at the landing location.
The method of claim 1, wherein the procedure comprises a flight plan or a fixed speed forced landing strategy.
The method of claim 1, further comprising determining the threshold based on a terminal velocity of the aircraft.
An aircraft system comprising: an actuation system associated with one or more flight control components of an aircraft; one or more avionics systems onboard the aircraft to provide data indicative of a current state of the aircraft; one or more sensor systems to provide measurement data indicative of an amount of available energy associated with an energy source onboard the aircraft; and a flight control module coupled to the actuation system, the one or more avionics systems and the one or more sensor systems to: detect when the amount of available energy associated with the energy source onboard the aircraft is less than a predicted amount of energy required to land the aircraft based on the current state of the aircraft; and thereafter: automatically operate the actuation system in accordance with an unregulated descent operating mode configurable to regulate an orientation of the aircraft to a reference orientation; and after detecting a transition condition, automatically operate the actuation system in accordance with a controlled slow-down operating mode configurable to regulate a lateral position of the aircraft to a trajectory to a landing location while regulating a velocity of the aircraft using a cost function.
The aircraft system of claim 11, wherein the transition condition comprises an altitude of the aircraft is less than or equal to a threshold altitude influenced by a terminal velocity of the aircraft in the unregulated descent operating mode.
The aircraft system of claim 11, wherein the cost function is configured to minimize a three-dimensional velocity of the aircraft at touchdown at the landing location.
The aircraft system of claim 11, wherein the cost function is configured to minimize energy consumption.
The aircraft system of claim 11, wherein the unregulated descent operating mode comprises a proportional-integral-derivative (PID) control scheme configurable to regulate the orientation of the aircraft to a level flight orientation.

Description

TECHNICAL FIELD The subject matter described herein relates generally to aircraft systems, and more particularly, embodiments of the subject matter relate to control systems and methods for landing aircraft, such as vertical take-off and landing (VTOL) aircraft and other rotorcraft. BACKGROUND In some modern aircraft, traditional mechanical flight control systems have been replaced with electrically controlled actuators, often referred to as fly-by-wire. Instead of mechanical linkages between cockpit controls and flight control surfaces, propulsion systems and/or lift systems, electrical signals are utilized to communicate movements of cockpit controls to the controllers associated with the appropriate flight control components or systems. For example, vertical take-off and landing (VTOL) aircraft, such as unmanned aerial vehicles (UAVs), rotorcraft or other non-conventional aircraft, may include any number of different actuators or effectors arranged or distributed at various locations throughout the body of the aircraft and operated independently of one another to provide lift, propulsion, and/or attitude control for the aircraft (e.g., propellers, lift fans, rotors, flight control surface actuators, and/or the like). Unlike fixed-wing aircraft, VTOL aircraft and other rotorcraft rely on rotors or other actuators or effectors to provide lift, which, in turn, can increase energy consumption. In particular, due to different payloads or meteorological conditions, there is a greater likelihood of rotorcraft having insufficient available energy or fuel required to provide sufficient lift to complete execution of a particular flight plan. For commercial applications, such as film shooting, aerial modeling, and agricultural observation, and the like, such as loss of lift could risk damaging cameras, film equipment or other expensive or fragile payloads. To avoid risk of damage to aircraft or payload, some approaches force landing of an aircraft using a fixed speed when the remaining energy may be insufficient to complete a flight. However, most existing approaches are conservative or inefficient from an energy consumption perspective while still suffering from potential vulnerability in response to an unexpected drop in the remaining available energy or other dynamic flight conditions. Accordingly, it is desirable to provide control methods and systems for improved efficiency when forcing landing of an aircraft without compromising viability of the aircraft or payload. Other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. BRIEF SUMMARY This summary is provided to describe select concepts in a simplified form that are further described in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Aircraft systems and related operating methods are provided. An exemplary method of landing an aircraft involves determining an amount of available energy associated with an energy source onboard the aircraft is less than a predicted amount of energy required to land the aircraft in accordance with a procedure based on a current state of the aircraft, thereafter automatically operating one or more actuators associated with the aircraft to descend using an unregulated vertical speed using a first control scheme to regulate an orientation of the aircraft to a reference orientation, and thereafter, when an altitude of the aircraft is below a threshold, automatically operate the one or more actuators associated with the aircraft to descend using a second control scheme different from the first control scheme to regulate a lateral position of the aircraft to a trajectory to a landing location while regulating a velocity of the aircraft using a cost function. An apparatus is also provided for a non-transitory computer-readable medium having computer-executable instructions stored thereon that, when executed by a processing system, cause the processing system to determine an amount of available energy associated with an energy source onboard an aircraft is less than a predicted amount of energy required to land the aircraft based on a current state of the aircraft, thereafter automatically operate the aircraft to descend in an unregulated descent operating mode configurable to regulate an orientation of the aircraft to a reference orientation, and after detecting a transition condition, automatically operate the aircraft in a controlled slow-down operating mode configurable to regulate a lateral position of the aircraft to a trajectory to a landing location while regulating a velocity of the aircraft using a cost function. An exemplary embodiment of an aircraft system is also provided. The air