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KR-20260065748-A - Lift-Priority Omnidirectional Thrust Vector Mixing System and Method

KR20260065748AKR 20260065748 AKR20260065748 AKR 20260065748AKR-20260065748-A

Abstract

The present invention relates to a system and method for implementing omnidirectional propulsion without tilt switching by first allocating the lift required for the total weight and safety margin of the aircraft, and then continuously vector-mixing the remaining surplus thrust in the direction of the control input. The present invention comprises a lift priority allocation unit, a surplus thrust calculation unit, a control input detection unit, an omnidirectional mixing unit, and a dynamic redistribution unit. It generates a horizontal force component while maintaining the aircraft attitude horizontally by tilting the thrust vector of each thrust generation module by a predetermined deflection angle from the vertical axis. During maneuvering, the lift allocation is dynamically updated and the surplus thrust is redistributed in real time according to changes in the lift requirement. In the event of rapid attitude changes, the attitude is restored while maintaining the total lift sum in a moment priority mode. Through this, safe and efficient omnidirectional propulsion is possible without a tilt mechanism, and the lift priority principle is maintained even during complex maneuvers.

Inventors

  • 김영호

Assignees

  • 김영호

Dates

Publication Date
20260511
Application Date
20260120

Claims (14)

  1. A lift-priority omnidirectional propulsion vector mixing system comprising: (a) a plurality of thrust generating modules positioned at multiple locations on the aircraft, each capable of independently controlling thrust magnitude and thrust vector deflection angle; (b) a lift priority allocation unit that calculates the required lift based on the total weight and safety margin of the aircraft and preferentially allocates the required lift from the total available thrust of the plurality of thrust generating modules; (c) a reserve thrust calculation unit that calculates a reserve thrust for each of the plurality of thrust generating modules by subtracting the lift allocation from the available thrust of the corresponding module; and (d) a control input detection unit that detects the direction and magnitude of a control input. and (e) an omnidirectional mixing unit that vector-mixes the excess thrust into a horizontal thrust in the direction of the control input and outputs a thrust command and a deflection angle command to each of the plurality of thrust generating modules; wherein the omnidirectional mixing unit generates a horizontal force component while maintaining the aircraft attitude horizontally by tilting the thrust vector of each thrust generating module by a predetermined deflection angle from the vertical axis, and uses only the excess thrust remaining after securing lift for horizontal propulsion, thereby continuously implementing omnidirectional horizontal propulsion without tilt switching.
  2. A system according to claim 1 further comprising a dynamic redistribution unit that, when the required lift changes due to a change in aircraft attitude, vertical acceleration/deceleration, or weight change during maneuver, recalculates the changed required lift and dynamically updates the lift allocation, and redistributes the surplus thrust and horizontal thrust in real time based on the updated lift allocation; wherein the dynamic redistribution unit includes a moment priority mode that temporarily reduces the lift allocation of some modules and increases the lift of other modules during a sudden change in attitude to restore the attitude while maintaining the total lift sum.
  3. A system according to claim 1, wherein each thrust generating module comprises a variable orientation vane or louver disposed inside or at the outlet of a duct, and the thrust vector deflection angle is formed by adjusting the angle of the variable orientation vane or louver.
  4. A system according to claim 1, characterized in that the thrust vector deflection angle is formed by applying pitch/roll torque to a gyro flywheel or a high-inertia rotor, thereby tilting the rotor disk plane by precession.
  5. A system according to claim 1, characterized in that the plurality of thrust generating modules are four coaxial duct-type modules respectively positioned at the front left, front right, rear left, and rear right of the airframe.
  6. A system according to claim 5, wherein each of the above-mentioned coaxial duct type modules includes an upper rotor and a lower rotor, and the upper rotor and the lower rotor are arranged coaxially to offset anti-torque.
  7. A system according to claim 1, wherein the omnidirectional mixing unit receives target force and moment vectors and calculates the thrust magnitude and deflection angle for each module based on a mixing matrix defined according to the module position and deflection angle.
  8. A system according to claim 1, further comprising a gyro flywheel; wherein the omnidirectional mixing unit corrects thrust distribution by considering the angular momentum and lateral inertia response related to precession induced by the maneuver of the gyro flywheel.
  9. A system according to claim 1, characterized in that the omnidirectional mixing unit generates a yaw moment by applying differential thrust or differential rotational speed (ΔRPM) to a pair of diagonal modules upon a yaw rotation command.
  10. A system according to claim 1, further comprising a safety mode that prioritizes maintaining lift by setting the propulsion budget to 0 or a minimum value when the total available thrust approaches the required lift.
  11. A method for omnidirectional propulsion vector mixing prioritizing lift, comprising: (S1) a step of calculating the required lift based on the total weight and safety margin of the aircraft; (S2) a step of preferentially allocating the required lift from the total available thrust of a plurality of thrust generating modules; (S3) a step of calculating a surplus thrust by subtracting the lift allocation from the available thrust for each thrust generating module; (S4) a step of detecting the direction and magnitude of a control input; and (S5) a step of vector mixing the surplus thrust into a horizontal thrust in the direction of the control input, wherein the thrust vector of each thrust generating module is tilted by a predetermined deflection angle from the vertical axis to generate a horizontal force component while maintaining the aircraft attitude horizontally, and outputting a thrust command and a deflection angle command to each of the plurality of thrust generating modules; wherein the vector mixing is characterized by using only the surplus thrust remaining after securing lift for horizontal propulsion, thereby continuously implementing omnidirectional horizontal propulsion without tilt switching.
  12. The method according to claim 11 further comprises: (S6) a step of detecting a change in aircraft attitude, vertical acceleration/deceleration, or weight change during maneuver; and (S7) a step of recalculating the required lift and redistributing the lift allocation, spare thrust, and horizontal thrust in real time when the change is detected; wherein the step (S7) includes a moment priority mode that temporarily reduces the lift allocation of some modules and increases the lift of other modules to restore the attitude while maintaining the total lift sum during a sudden change in attitude.
  13. A method according to claim 11, wherein in steps (S2) to (S5), a lift priority principle is maintained such that the total lift sum is maintained above the required lift under any maneuvering situation, and even when the lift of an individual module is temporarily reduced to restore attitude, the total lift sum is preserved by increasing the lift of another module.
  14. A method according to claim 11, characterized in that, in step (S5), thrust distribution and deflection angle are corrected by considering the angular momentum of the gyro flywheel and the lateral inertia response related to precession induced by maneuvering.

Description

Lift-Priority Omnidirectional Thrust Vector Mixing System and Method Lift-Priority Omnidirectional Thrust Vector Mixing System and Method The present invention relates to a propulsion control system for an Urban Air Mobility (UAM) and electric Vertical Take-Off and Landing (eVTOL) aircraft, and more specifically, to a lift-priority omnidirectional propulsion vector mixing system and method that implements omnidirectional propulsion (including horizontal and combined maneuvers) without tilt switching by first allocating the lift required for the total weight and safety margin in an aircraft equipped with a plurality of lift/thrust generating modules, and then continuously vector mixing the remaining surplus thrust in the direction of control input. In this specification, the term "lift priority principle" means a principle in which the total lift of an airframe is controlled preferentially to be maintained above the required lift, and does not mean that the thrust of individual modules cannot always be reduced. Even if the lift allocation of some modules is temporarily reduced for attitude restoration, the lift priority principle is satisfied if the lift of other modules is increased to maintain the total lift. Conventional eVTOL aircraft are broadly classified into three types based on the control method between lift generation and horizontal propulsion. First, multicopter types obtain horizontal thrust by tilting the entire airframe. This method has the problem that the vertical lift component decreases as the lift vector tilts, requiring additional power during horizontal maneuvers and reducing ride comfort (e.g., US10689108B2 "Unmanned aerial vehicle with omnidirectional thrust vectoring"). Second, tiltrotor/tiltwing types switch between lift and propulsion modes by mechanically tilting the rotor or wing. However, this switching is discrete, and a trade-off occurs between lift and propulsion during the switching process. Additionally, there are issues such as the complexity of the tilt mechanism, increased weight, and the addition of failure modes (e.g., US8800912B2 "Three wing, six-tilt propulsion unit, VTOL aircraft"; WO2020141513A2 "eVTOL aircraft"). Third, the compound type is equipped with separate rotors for lift and propellers for propulsion. However, this increases weight and complexity, and energy distribution between the two systems can be inefficient (e.g., WO2023136815A1 "eVTOL aircraft"). The aforementioned prior art technologies do not commonly apply the concept of continuously separating and allocating lift and horizontal thrust from the same thrust vector. Although priority (lift > thrust) is considered during actuator saturation, such as in vectored thrust control allocation in the NASA RAVEN project or Airbus Vahana research (e.g., the paper "Full Envelope Control of Over-Actuated Fixed-Wing Vectored Thrust eVTOLs"), a lift-first omnidirectional vector mixing architecture that calculates the required lift based on gross weight and safety margin, allocates it preferentially, and then continuously redistributes the remaining thrust in the direction of control input is not disclosed in the prior art. FIG. 1 is an overall configuration diagram of a lift-priority omnidirectional propulsion vector mixing system according to the present invention. FIG. 2 is a conceptual diagram illustrating the process of lift priority allocation and reserve thrust calculation according to the present invention. FIG. 3 is a conceptual diagram showing omnidirectional vector mixing logic and thrust vector deflection according to the present invention. FIG. 4 is a flowchart illustrating a dynamic redistribution process according to the present invention. FIG. 5 is a plan view showing an embodiment in which the present invention is applied to a quad coaxial duct module. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. 1. Overall System Configuration Referring to FIG. 1, the lift-priority omnidirectional propulsion vector mixing system (100) of the present invention includes a plurality of thrust generating modules (110), a lift-priority allocation unit (120), a spare thrust calculation unit (130), a control input detection unit (140), an omnidirectional mixing unit (150), and a dynamic redistribution unit (160). 2. Lift Priority Allocation Section The lift priority allocation unit (120) receives the total weight of the aircraft (W) and a safety margin (margin, 10~30%) as input and calculates the required lift (L_req = W × (1 + margin)). Example: W=3000 kg, margin=20% → L_req 35,316 N. 8,829 N allocated per module in quad configuration. The above safety margin ranges and numerical examples are for illustrative purposes only and do not limit the scope of the invention. The key point of the present invention is that the required lift is secured first, prioritizing it over any other control objective. 3. Thrust Reservoir Calculation Secti