JP2524712B2 - Equipment for controlling aircraft - Google Patents

Description

Description: BACKGROUND OF THE INVENTION a. Field of the Invention This invention relates to aircraft control, and more particularly to aircraft control by deflecting a wing through the controlled movement of a wing control surface. Is.

b. Description of the Prior Art Controlling high speed aircraft has been a major issue for aircraft designers. An aircraft with a swept wing at the very rear of the aircraft has poor control effectiveness, especially roll control, in the high dynamic pressure regime. The roll control difficulty of high speed aft swept aircraft results from aeroelastic torsion caused by trailing edge controlled surface deflection. Normal,
When differentially deflected, the wing control surface creates a differential lift on the wing panel, resulting in a roll moment. However, since the vanes are flexible, the increased differential lift caused by the trailing edge controlled surface deflection will also cause each vane to twist in a direction that reduces the differential lift. In high dynamic pressure flight conditions, the torsion is large due to the effects of aeroelasticity. As a result, the roll control surface must be highly deflected to obtain the desired roll, thereby increasing the drive requirements and power system requirements that add to the weight of the aircraft. At some point, the effect may result in roll reversal, or what is commonly known as aileron reversal. (The aircraft will actually roll in the opposite direction from the pilot's command.) To maintain the effectiveness of roll control, the wings are traditionally stiffened and a rolling tail is utilized. The addition of rolling tails and increased wing hardness result in heavier aircraft, reduced aerodynamic performance, and increased observable laser detectability).

U.S. Pat. No. 821,393, issued May 2, 1906 to O. and W. Wright, discloses a maze of ropes and pulleys twisting two sides of a wing to provide lateral stability. . The wings, made of wood and covered with cloth, were sufficiently flexible to allow the desired twist. The pilot was positioned on a movable platform, to which a rope was attached. Thus, the pilot was able to cause the rope movement and the resulting twisting of the wings by his lateral movement. Wright Brothers
The purpose of s) was to keep the wings horizontal and control the lateral turbulence caused by the gusts. This practice has been obsoleted by the current practice of aircraft control forces resulting from deflection of the control surface with minimal wing deflection.

Another problem with high speed aircraft is the need to compromise on wing design for effectiveness over flight range. Aerodynamic requirements for different flight conditions are changing. For example, the optimal wing configurations for transonic maneuvering and ultrasonic cruising are quite different. Variable aeroelastic torsion seldom solves this problem, as modern aircraft wings typically must be stiff to provide roll control effectiveness. Machines that change the leading and trailing cambers have been used in this regard,
The balance of the wings remains unchanged, and until the weight, cost, and complexity of the aircraft increases, it can only be an inefficient compromise.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a system for controlling an aircraft through aeroelastic deflection of the aircraft wing.

Another object of this invention is to provide a system that minimizes drag of the aircraft during cruise and maneuvering.

Another object of the present invention is to provide an aircraft control system that provides improved control effectiveness during high dynamic pressure conditions and overcomes control surface reversal.

Still another object of the present invention is to determine the weight, drag force,
The observable is to provide an aircraft control system that is reduced as a result.

Yet another object of the present invention is to provide an aircraft control system that automatically compensates for damaged control surfaces.

Yet another object of the present invention is to provide an aircraft control system that alters its configuration by aeroelastically deflecting the wings of the aircraft to what is desired for flight conditions.

Briefly, in accordance with the present invention, there is provided a system for controlling an aircraft through aeroelastic deflection of wings in all flight modes. The movement of the leading and trailing wing control surfaces results in aircraft control, optimal cruise, and aeroelastic deflection of the flexible wing for specific maneuvers. The system may also achieve gust load reduction, flutter suppression, and maneuver load control. The load control of maneuvering is to control the aerodynamic force distribution in the spanwise direction of the main wing by steering on the control surface, while ensuring the lift necessary for a predetermined motion, while preventing an increase in the main wing load,
It means to reduce the weight of the structure. For example, if the auxiliary wings are raised and the flaps are lowered, the lift distribution can be changed so that the total lift is the same and the center of the span is large and the tip is small. It has the effect of reducing the bending moment at the base. The system is responsive to pilot control signals and signals from sensors representative of selected aircraft flight parameters. Processing means responsive to the command and sensor signals provide control signals to the actuators which move the leading and trailing edge control surfaces to cause selected aeroelastic deflections of the airfoil so that each of the airfoil is desired. Has an overall shape that results in a particular aircraft control. The system preferably incorporates adaptive capabilities into the processing means to compensate for control surface damage. For example, if the control surface becomes disabled, the remaining control surface will immediately adapt to the loss and achieve the desired aeroelastic wing deflection to maintain control of the aircraft with minimal drag.

Other objects and advantages of the present invention will become apparent upon reading the following detailed description and upon reviewing the drawings.

While the present invention is described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the other hand,
It is intended to include all such changes, modifications and equivalents included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIGS. 1 and 2, blade 12 and
An aircraft, generally designated 10, is shown having 14 and a fuselage 16. Engine inlets 13 and 15 are provided in the fuselage. Wing 1 on the right side, ie starboard side
The 2 employs leading edge control surfaces 18 and 20 and trailing edge control surfaces 22 and 24. The left or port side wing 14 has leading edge control surfaces 26 and 28 and trailing edge control surfaces 30 and 32.
To use. Also shown in FIG. 1 are body control surfaces 34 and 35 which provide primarily pitch control and vertical tail control surfaces 42 and 44 which provide yaw control. In this example, the yaw control surface is conventional. The control surface is mechanically movable in the conventional manner. However, the wing control surface can be deflected above and below the corresponding wing.

It should be noted that aircraft 10 does not include a horizontal tail. This is not necessary in this invention, thereby saving considerable weight and reducing the observables of the aircraft. The tail structures 41 and 43 are shown somewhat tilted with respect to the aircraft's vertical axis, however, they are much closer to vertical than the sailors, and their primary function is as a vertical tail for yaw control. Yes, not as a horizontal tail. Thus, no horizontal tail is meant to be a tail structure that is substantially horizontal with respect to the fuselage and has the first purpose of acting as a horizontal tail.

Aircraft 10 preferably does not have a horizontal tail, but this is not a requirement. The system will also provide many of the advantages discussed herein for aircraft with a horizontal tail. Similarly, aircraft 10 does not use a tail. However, the present invention may be used to advantage with or without aircraft having such surfaces.

The wings of all aircraft are somewhat flexible. However, even with active control, the wings must have sufficient hardness and strength to withstand design loads, maneuver loads, and gusts, and prevent flutter. Composite materials have recently been provided for wings because of their strong weight-to-weight ratio and their ability to modify aeroelasticity. For these reasons, the preferred embodiment includes blade 12 of the present invention and
14 is made from a composite material such as graphite epoxy. However, other materials can be used if desired. Optimal use of blade material will provide a significant degree of blade flexibility with sufficient strength and hardness to meet the design requirements described above with active control.

Referring now to FIG. 3, there is shown a block diagram of a control system according to the present invention. When the pilot wants the aircraft to perform a particular control action, command signal 48
Are generated (such as by maneuvering a control rod) and are transmitted to the computer 50. The instructions may be manual from a pilot or by an automatic pilot. Computer 50 also receives signals from sensors 46 located on aircraft 10. Sensor 46 provides a signal indicative of aircraft motion. A number of parameters will be sensed in this regard. These will preferably include aircraft attitude, fuselage movement (accelerometer readout), hardness and Mach number. Gain scheduling for a particular aircraft contained in computer memory, after proper shaping, filtering, switching, adjustment, conversion, surface command limiting, and combination, command and sensor signals are calculated to optimize flap operation. To cause a deflection of the aeroelastic wing that will result in the desired control action. Computer 50
The control signal from each flap 18, 20, 22, 2
Subsequent transmission to actuators (not shown) for each of 4, 28, 26, 30, 32, 34 and 36, which cause them to rotate from their current position. These flap movements create an aerodynamic load on wings 12 and 14, which causes the blades to deflect, and thus wings 12 and 14.
Each of the 14 has a general shape (in combination with a control surface on it) that produces the desired control action. The controlled surface deflections are calculated by computer 50, thus obtaining the optimum wing shape of wings 12 and 14 for minimum drag for a given flight condition, providing the desired control action. It should be understood that the control surface is not used as the primary force-generating device, but as an aerodynamic surface for controlling the aeroelastic deformation of the airfoil. The overall deflected shape of the wing produces the desired control action.

The control system can also be used to provide the aircraft 10 with active vertical stability enhancement, which is particularly advantageous in the absence of a horizontal tail. This is accomplished in a manner similar to that described above, except that the computer 50 calculates its control signal solely based on the signal from the sensor 46 to maintain stability. However, when stability and flight control are required at the same time, computer 50 processes all input signals to arrive at the control signals that most effectively accomplish both functions. Thus
The computer 50 transmits the control signal to the actuator,
The control surface produces the aircraft's longitudinal stability and desired flight control behavior under current flight conditions, or a wing shape (with minimal drag) that provides the aircraft's longitudinal stability or desired flight control behavior. . Tail control surfaces 42 and 44 are preferably used to provide lateral stability to aircraft 10.

As an alternative to, or in addition to, gain scheduling in computer 50, the self-adaptive concept may be used. This attempt uses incremental movements of selected control surfaces, and the resulting movements of the aircraft are monitored and fed back to computer 50. Based on these feedback signals, the computer 50 continually recalculates the optimum positions of the various control surfaces, causing the wing deflection that results in the desired aircraft control. This can be combined with the gain scheduling used for initial positioning of the control surface.

The self-adaptive concept also allows the system to compensate for damaged or dead control surfaces. Since such a control surface does not provide the expected control effect, the computer searches for the combination of control surface actions that will result in it. Conversely, loss of control surfaces, such as ailerons on conventional aircraft, usually severely impact aircraft controls.

With the ability to compensate for damaged or non-acting control surfaces, the invention results in yet another advantage: less control redundancy is required. This allows additional reductions in weight, complexity and cost.

Referring again to FIGS. 1 and 2, if the pilot issues a roll command intended to cause a certain roll rate, the computer 50 sends control signals to the various wing flaps (and optionally A wing 12 which transmits a control signal to the flap of the body and combined with the wing control surface
And the aeroelastic shape of 14 is, for example, for wing 12
Causing the desired behavior to result, such as by increasing the attack angle of 14. This control technique would not be affected by the reversal of the aileron. In this regard, the present invention makes use of wing flexibility rather than countering it. The control surface twists each wing to obtain the desired wing shape, as opposed to being the first control surface that must overcome the twisting of the opposing aeroelastic wings to achieve the desired motion. Used to achieve the desired control. This allows for a lighter weight wing (since less stiffness is required), and also the elimination of rolling tails, which also save weight and reduce the observable of the aircraft.

FIG. 4 posts an illustration of the graph for a particular design for a blade 12 with a roll rate of 66 degrees per second at various dynamic pressures. Controlled surface deflection was obtained based on achieving the desired roll rate with minimal drag. It should be noted that the trailing edge controlled surface deflection reverses direction as the dynamic pressure increases. Control surfaces are used in addition to conventional aileron reversals. It should also be noted that the maximum deflection of any control surface is never more than 5 degrees. Typical trailing edge controlled surface deflections for conventional "hard" airfoil designs are in the 30 to 40 degree range to maintain the same roll rate. Thus, the present invention produces a much lower drag during maneuver than conventional designs. Also, since less control surface deflection is required, surface hinge motion is reduced, resulting in smaller, lighter and lower power actuators.

Pitch control for aircraft 10 includes flaps 34 and 36,
Alternatively, it may be accomplished by wings 12 and 14, or a combination of body flaps and wings 12 and 14. When the blades 12 and 14 are used for pitch control, the blade control surfaces (and optionally flaps 34 and 36) are positioned causing the deflection of the blades 12 and 14 to provide the desired pitch. The blade deflection to produce the desired pitch motion is optimally based on the form of minimum drag.

The invention can also be used to provide yaw control, which allows for overall control of the aircraft. This is illustrated in the embodiment shown in FIGS. 5 and 6. Aircraft, generally designated 60, have wings 62 and 64.
And a body 66. The fuselage is provided with engine inlets 63 and 65. Wing 62 employs leading edge control surfaces 68 and 70 and trailing edge control surfaces 72, 74 and 75. Wings
64 is a leading edge control surface 76 and 78 and a trailing edge control surface 80,
Adopt 82 and 83. Optional body control surfaces 84 and 86 that primarily provide pitch control are also illustrated. The control surfaces are all movable in the conventional manner. However, the aircraft
Similar to 10, the wing control surface can be deflected above and below the corresponding wing. Also, like aircraft 10, aircraft 60 does not include a horizontal tail. Further, aircraft 60 does not include a vertical tail. This again saves the entire aircraft weight and reduces the aircraft's observables.

Yaw control for aircraft 60 is provided by wings 62 and 64. In this regard, it should be noted that wings 62 and 64 are permanently bent upwards in a crescent shape (span-wise). Wings 62 and 64 are still flexible according to the invention, but generally maintain a crescent shape regardless of any deflection. Wings 62 and 64 may instead be permanently bent down into a crescent. The crescents have vertical components for achieving yaw control, particularly at tips 90 and 92, respectively, at wings 62 and 64. Thus wings 62
And 64 are wing control surfaces (and optionally body control surfaces 84 and 84, as in the embodiment of FIGS. 1-3).
86) utilizing roll and pitch control, for longitudinal stability, and for aeroelastic deflection to achieve yaw control, for example by differentially deflecting blade tips 90 and 92. Can be done. In this example, wings 62 and
64 is also used to provide active lateral stability increase for aircraft 60 as well.

A significant advantage of this invention is the ability to shape an aircraft wing for substantially optimal performance under different flight conditions. Thus, the optimal wing shape for transonic maneuvering, ultrasonic cruise, landing and takeoff, and high speed acceleration is substantially altered. The present invention is based on pilot or computer control and sensor signals to provide the wing as desired.
By greatly changing the shapes of 12 and 14, this problem can be dealt with. In this regard, the wings 12 and 14 may be aeroelastically modified for increased wing flexibility as the extra stiffness of the wings specified by conventional high speed aircraft designs is eliminated. As such, the present invention provides a great deal of freedom in changing the wing configuration as desired for a particular flight condition.

Referring now to FIG. 7, a diagram of the aircraft 10 of FIG. 1 is shown illustrating an example of various sensor arrangements. While aircraft 10 is illustrated, this approach also applies to aircraft 60. Sensors 120, 122, 124 and 126 are located near the leading edge of wing 12. Sensors 128, 130, 132 and 134
Is located near the trailing edge of wing 12. Sensor 136, 138, 140
And 142 are located near the leading edge of wing 14 and sensor 144,
146, 148, and 150 are located near the trailing edge of wing 14. The sensors on wings 12 and 14 measure the motion of the respective portions of the wings where they are located. The wing sensor is preferably a linear accelerometer and is positioned to measure vertical acceleration. Aircraft 10 also employs fuselage sensors 152 and 154, which are located on the right and left sides of the fuselage, respectively. Sensors 152 and 154, which are also preferably linear accelerometers, are equidistantly spaced from the fuselage centerline and measure vertical fuselage acceleration so that the load on wings 12 and 14 is It can be separated (from the movement of the torso and from the state of interest).

A number of other sensors, indicated at 156, are also provided for aircraft roll, pitch and yaw motions, lateral fuselage motions,
Provided on the aircraft to measure Mach number and altitude. An aircraft nominal cg164 is also illustrated. The term “nominal” is used because in flight the actual center of gravity of the aircraft shifts, ie due to fuel usage. So what is meant by "nominal" is the mean position of the center of gravity in flight.

FIG. 8 illustrates a block diagram of an enhanced control system for aircraft 10, which incorporates maneuver load control, gust unloading, and the ability to compensate for flutter control.
Such a system allows for further reductions in wing weight and hardness. Computer 200 (when transmitted by pilot or autopilot)
A pilot command signal 48 is received, as well as signals from overall sensor 156, vertical fuselage sensor 202 and wing sensor 204. Vertical fuselage sensor 202 includes sensors 152 and 154 illustrated in FIG. 7, while wing sensor 204 includes sensors 120, 122, 124, 126, 128, 13 also illustrated in FIG.
0, 132, 134, 136, 138, 140, 142, 144, 146, 148 and 150.

When neither mobile load control, gust offloading, or flutter suppression is required, computer 200 will use sensor 1
In response to 56 and pilot command signal 48, it performs the functions listed to calculate the optimal flap motion, causing wing deflection, which maintains stability, produces the desired control motion, and, for example, ultrasonic cruise. Results in optimal wing morphology for certain flight conditions. The control signal from the computer 200 is applied to each flap 18, 2
Subsequent transmission to actuators (not shown) for each of 0, 22, 24, 28, 26, 30, 32, 34 and 36, which are rotated from their current position. As previously discussed, the action of these flaps creates an aerodynamic load on wings 12 and 14, which causes wings 12 and
Causes the wings to deflect so that each of the 14 has an overall shape that produces the optimum morphology of the wing for the desired control action (or increased stability) and flight conditions. Computer
Gain scheduling by 200 is preferably based on providing optimal wing shapes for wings 12 and 14 with minimal effectiveness for a given flight condition (and to achieve any stable increase and desired control action). Is).

Wing 12 and Wing 14 or Wing 12 or Wing 14 are sensors for maneuver load control, gust load mitigation, or flutter suppression, such as when deflected due to flutter, gusts and maneuver loads, or flutter, gusts or maneuver loads. Computer 200 also determines the signal from overall sensor 156 and pilot command signal 4 when determined necessary by computer 200 based on the signals from 202 and 204.
Combine the signals from 8 and process such signals to calculate the behavior of the flaps. Thus, the increased stability and desired control action, or the flap action calculated to achieve the increased stability or desired control action, is
Combined with the calculated flap action required to compensate for maneuver load control, gust mitigation or flutter suppression.
When flutter control, maneuver load control or gust mitigation is required, the flaps can be used to simply offset detected maneuver loads, gusts or flutter because no control action or increased stability is required at a given time. 200
Will be moved by.

The self-adaptive concepts discussed with reference to FIG. 3 may be used instead of, or preferably in combination with, gain scheduling of computer 200. The computer 200 will use the resulting feedback of the motion of the aircraft for the desired control motion or optimal form for a given flight condition. For gusts, flutter and maneuver loads, computer 200 will use feedback from wing sensors to determine the impact of flap movements.

Thus, in accordance with the present invention, it is apparent that an aircraft control system has been provided which fully satisfies the previously stated objectives, aims and advantages. Although the present invention has been described in relation to particular embodiments thereof, it will be apparent that many variations, modifications and variations thereof will become apparent to those skilled in the art in light of the foregoing description.
It is therefore intended to include all such changes, modifications and variations that fall within the spirit and scope of the appended claims.

[Brief description of drawings]

FIG. 1 is a plan view of an aircraft according to the present invention having an active, flexible adaptive wing. FIG. 2 is a front view of the aircraft of FIG. FIG. 3 is a block diagram of a control system according to the present invention. FIG. 4 is a graph of power pressure versus selected control surface deflection to maintain a selected roll rate with minimal drag under the particular conditions of the aircraft of FIG. FIG. 5 is a plan view of another embodiment according to the present invention of an aircraft having an active flexible adaptive wing. FIG. 6 is a front view of the aircraft of FIG. FIG. 7 is a plan view of the aircraft of FIG. 1 showing the placement of various sensors. FIG. 8 is a block diagram of a control system that incorporates gust load reduction, stability increase, flutter suppression, and mobile load control. In the figure, 10 is an aircraft, 12 and 14 are wings, and 13 and 15
Is the engine inlet, 16 is the fuselage, 18, 20, 26 and 28 are leading edge control surfaces, 22, 24, 30 and 32 are trailing edge control surfaces,
34 and 36 are body control surfaces, 42 and 44 are vertical tail control surfaces, 41 and 43 are tail structures, 46 are sensors, 48 are command signals, 50 are computers, 60 are aircraft, 62 and 64 are wings,
66 is the fuselage, 63 and 65 are engine inlets, 68, 70, 76 and 78 are leading edge wing control surfaces, 72, 74, 75, 80, 82 and 83
Is a trailing edge wing control surface, 84 and 86 are body control surfaces, 90 and 92 are wing tips, 120, 122, 124, 126, 128, 130, 132, 13
4, 136, 138, 140, 142, 144, 146, 148, 150, 152 and 154 are sensors, 156 is a plurality of other sensors, 164 is a nominal cg, 200 is a computer and 202 and 204 are sensors.

Claims (22)

(57) [Claims] 1. A flexible wing; a flight control surface mounted on the flexible wing; an aircraft sensor for providing a signal indicative of the overall motion of the aircraft; and the signal from the aircraft sensor. In response, determine the motion of the control surface that aeroelastically causes the desired deflection of the wing to achieve the desired control of the aircraft, and selectively generate control signals that cause the motion of the control surface. Processing means; receiving the control signal from the processing means and moving the control surface according to the control signal to cause the desired deflection of the flexible wing to produce the desired control of the aircraft. For controlling the aircraft in one axis or two axes or more. 2. An apparatus according to claim 1 wherein said processing means is responsive to signals for flight control of the aircraft. 3. The processing means also selectively generates a control signal to aeroelastically induce a desired wing deflection to maintain aircraft stability in relation to control surface movement, The control means also moves the control surface according to the control signal such that the desired wing deflection is aeroelastically induced to maintain aircraft stability. apparatus. 4. The apparatus of claim 1, wherein the leading and trailing edges of the wing have at least one of the flight control surfaces provided thereon. 5. The apparatus of claim 2 wherein said apparatus is provided for roll control of an aircraft, said roll control being provided to begin under and beyond the conditions of aileron reversal. The device according to. 6. The leading and trailing edges of the wing have at least one of the flight control surfaces provided thereon, and the flight control surfaces alter above and below the wing on which they are provided. The device according to claim 5, wherein the device is provided such that it is possible. 7. The apparatus of claim 1 wherein the aircraft does not have a horizontal tail or aft. 8. The apparatus of claim 6 wherein the aircraft does not have a horizontal tail or aft. 9. The control signal causes the control means to move the control surface to aeroelastically deflect the wing such that desired aircraft control is achieved with substantially minimal drag. An apparatus according to claim 1. 10. The control signal causes the control means to move the control surface to cause aeroelastic deflection of the wing such that desired aircraft control is achieved with substantially minimal drag. An apparatus according to claim 6. 11. The processing means also relates to the motion of the control surface with an execution signal that aeroelastically causes the desired blade deflection to substantially optimize the shape of the blade for flight conditions. Selectively occurring, said control means also move said control surface in response to said execution signal to cause said wing to be aeroelastically deflected to a substantially optimal shape for flight conditions. The device according to claim 1. 12. The aircraft has a fuselage, the fuselage is provided on the wing, and also includes a fuselage flight control surface and second control means, the fuselage flight control surface being provided on the aircraft fuselage, The processing means also generates a second control signal, and the second control means moves the fuselage flight control surface in response to the second control signal, the fuselage flight control surface being the desired one of the aircraft. Working in combination with the flight control surface of the wing to provide control of the
Control signal in combination with the first control signal such that control of the aircraft is achieved with substantially minimal drag.
The device according to claim 9. 13. The apparatus of claim 10, wherein the aircraft sensor senses Mach number, aircraft attitude and altitude. 14. The apparatus of claim 10 further including a wing sensor for providing a signal indicative of movement of said wing, said processing means also being responsive to said signal from said wing sensor. 15. The control means also moves the control surface to cause the flexible wings to aeroelastically deflect in a desired manner to provide gust load relief. The device according to paragraph. 16. The method of claim 14 wherein said control means also moves said control surface causing said flexible wings to aeroelastically deflect in a desired manner to provide flutter control. The device according to. 17. The control means of claim 14 further comprising moving the control surface to cause the flexible wings to aeroelastically deflect in a desired manner to provide maneuvering load control. The device according to. 18. The control means also moves the control surface to cause the flexible wings to aeroelastically deflect in a desired manner to provide gust load relief, flutter suppression and maneuver load control. A device according to claim 14. 19. The apparatus of claim 1 wherein said processing means compensates for a damaged or inactive control surface that cannot cause the blade to deflect in a desired manner. 20. The apparatus of claim 14 wherein said processing means compensates for damaged or inactive control surfaces that cannot cause the blade to deflect in a desired manner. 21. The apparatus of claim 6 wherein the aircraft does not have a vertical tail. 22. The apparatus of claim 7 wherein the aircraft does not have a vertical tail.