JP2878229B2 - Ground sensor for rotorcraft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground sensor for a rotary wing machine for detecting whether or not the rotary wing aircraft has landed on the ground.

[0002]

2. Description of the Related Art An aircraft equipped with a flight control device such as an autopilot or a fly-by-wire system determines whether the skid or the wheel is in contact with the ground or levitates, and determines whether the aircraft touches or levitates. It is necessary to switch to control according to the state. As a means for realizing this, there is known a grounding sensor for automatically detecting a grounding state by providing a switch to be conducted to a leg portion such as a skid by contact with the ground. With these ground sensors,
The work load during takeoff and landing can be greatly reduced, improving flight safety. In the case of a fixed-wing aircraft having a wheel suspension mechanism, the amount of sinking of the aircraft at the time of landing is detected to detect a ground contact state.

[0003]

However, with a contact-type ground sensor, there is a possibility that the landing surface is not flat and has irregularities, or it may not operate properly due to obstacles such as stones and plants.

[0004] In particular, in a helicopter having a severe weight limit, it is rare for a skid to have a suspension mechanism.

It is an object of the present invention to provide a ground contact sensor for a rotary wing machine capable of detecting a ground contact state safely and reliably without being influenced by the state of the ground.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a flap sensor for detecting a flap angle or a bending moment in a flap direction of a rotor blade is compared with an output signal from the flap sensor and a predetermined level threshold value Ta, and the rotor blade is detected. And a determining means for determining a ground contact state of the machine. According to the present invention, the magnitude of the lift force generated by the rotor blade can be detected by the flap sensor detecting the flap angle or the bending moment in the flap direction of the rotor blade. For example, 1) In a flying state or a hovering state, a lift force substantially equal to the weight of the fuselage is generated, and the entire blade bends to a state in which the tip bounces upward. Become. On the other hand, 2) when the lift force of the rotor blade is not generated in the state of landing, the entire blade is substantially horizontal, and the flap angle or the bending moment in the flap direction becomes zero or a negative value. Further, if the rotation of the rotor blade is stopped in the state of 3) landing, the blade hangs down to the ground side by its own weight. Therefore, various states of the rotary wing aircraft can be determined by analyzing the output signal from the flap sensor, and it can be detected whether or not the rotary wing aircraft has touched down by comparing with a predetermined level threshold value Ta. . The detection target of the flap sensor can be appropriately selected according to the mounting structure of the blade.For example, in the case of a blade with a hinge, it is preferable to detect the flap angle at the hinge portion with a rotation angle sensor or the like, and in the case of a rigid type blade. It is preferable to detect the bending moment in the flap direction with a strain cage or the like.

In the present invention, the judging means may compare the time T during which the output signal from the flap sensor is smaller than the level threshold Ta with a predetermined time threshold Tb, and determine whether the time T is longer than the time threshold Tb. Is determined. According to the present invention, the level threshold value Ta is set as a boundary value between the flight state and the contact state, but when the aircraft repeatedly repeats ascending and descending, deflects in the left and right directions, or fluctuates greatly in the flying state, the flap angle or The flap direction bending moment may become zero or a negative value in a short time. Therefore, by comparing the time T with the predetermined time threshold Tb, it is possible to prevent the erroneous determination during the flight by determining that the ground contact state is established only when the time T lasts for a certain long time, thereby improving the reliability of the determination. improves.

Further, the present invention is characterized in that the time threshold Tb is set in a range of 2 seconds to 5 seconds. According to the present invention, by setting the time threshold Tb in the range of 2 seconds to 5 seconds, the processing from the start of contact to the determination can be completed in a short time, and the contact state can be reliably determined.

[0009]

FIG. 1 is a block diagram showing an embodiment of the present invention. The helicopter 1 includes an airframe 2 and a rotor shaft 3 that is rotationally driven by an engine (not shown).
And a rotor star 4 that rotates together with the rotor shaft 3 and supports the rotor blades 5, a tail rotor 6 attached near the tail fin, and the like.

As a support structure for the rotor blade 5, 1)
All-joint rotor having hinges about three orthogonal axes (flapping hinge, feathering hinge, drag hinge), 2) hinges about two orthogonal axes (flapping hinge,
A typical example is a semi-articulated rotor having a feathering hinge, 3) a non-articulated rotor having a hinge around a single axis (feathering hinge), and the like.

FIG. 1 shows an example of an articulated rotor using a rigid type blade. Since this type has no flapping hinge, a flap sensor 10 composed of a strain gauge or the like is attached near the root of the blade,
The bending moment of the rotor blade in the flap direction (parallel to the paper) is detected.

An output signal from the flap sensor 10 is taken out via a slip ring 11 provided near the lower end of the rotor shaft 3, and is input to a signal processing unit 20 installed in the machine as a judging means. The signal processed by the signal processing unit 20 is transmitted to a display unit 12
And a ground signal for switching the mode of the flight control device 30 such as an autopilot or fly-by-wire from levitation to grounding is supplied to the flight control device.

Incidentally, in a configuration using an all-joint type rotor or a half-joint type rotor having a flapping hinge, a flap sensor 10 comprising a potentiometer, a Hall element, and the like is used.
Is attached to the flapping hinge, and the rotor blade 5
Can be directly detected.

FIG. 2 is a block diagram showing an electrical configuration of an embodiment of the present invention. The signal processing unit 20 includes an integration circuit 21 for integrating the output signal from the flap sensor 10, a comparison circuit 22 for comparing the output of the integration circuit 21 with a predetermined level threshold Ta, and an output signal of the integration circuit 21. A timer circuit 23 for measuring a time T that becomes smaller than the level threshold Ta; a comparison circuit for comparing the measured value of the timer circuit 23 with a predetermined time threshold Tb and outputting a ground signal G when the time T is longer than the time threshold Tb; 24.
The state of the ground signal G is displayed to the pilot by the display unit 12, and is also supplied to the flight control device 30.

An output signal from the flap sensor 10 is input to an integration circuit 21 via a slip ring 11. The integration circuit 21 averages out periodic fluctuations due to the rotation of the rotor, for example, fluctuations due to cyclic pitch control and harmonic control of the blades, and removes noise components of the signal.

The level threshold value Ta and the time threshold value Tb can be arbitrarily set according to the type of the vehicle or the purpose of flight. Processing can be completed in a short time, and the contact state can be reliably determined.

Although an example in which the signal processing unit 20 is constituted by an analog circuit is shown here, the flap sensor 10
After converting the output signal from the A / D converter into a digital signal by an A / D conversion circuit, the digital signal can be processed by a computer including a CPU (Central Processing Unit), a memory, and various interfaces.

FIG. 3 is an explanatory view showing various states of the helicopter. FIG. 3A shows a state in which the rigid type rotor blade 5 flies with a constant lift force and flies, and FIG. 3B shows a state in which the rotor blade 5 with a flapping hinge bends and flies with a constant lift force. FIG. 3C shows a hovering state where the skid 7 is stationary in the air, and FIG. 3D shows a state where the skid 7 is grounded.

In FIG. 3A, since a constant bending moment in the flap direction acts on the rotor blade 5 by the lift force, the flap sensor 10 outputs a signal substantially proportional to the bending moment. In FIG. 3B, since the flap angle β of the rotor blade 5 has a constant value (≠ 0), the flap sensor 10 outputs a signal substantially proportional to the flap angle β. In FIG. 3D, since no lift force is generated,
The bending moment or the flap angle of the rotor blade 5 in the flap direction is zero or a negative value. FIG. 3C shows an intermediate state between the flight state and the landing state.

Next, the operation will be described. Flap sensor 10
Is removed from the output signal by the integrating circuit 21 and is compared with the level threshold value Ta by the comparing circuit 22. The output signal from the flap sensor 10 is a level threshold T
3a or 3b, or the hovering state of FIG. 3C. If the output signal from the flap sensor 10 is smaller than the level threshold value Ta, it is assumed that FIG. It can be inferred that the landing state is (d).

Next, the timer circuit 23 measures the time T during which the output signal from the flap sensor 10 becomes smaller than the level threshold Ta, and the comparison circuit 24 calculates the time T and the time threshold T.
b. Therefore, when the time T is shorter than the time threshold Tb, it is determined that the vehicle is in an instantaneous state during flight, and a low-level determination signal G is output, for example. On the other hand, when the time T is longer than the time threshold Tb, the helicopter steadily determines that it is in the ground state, and outputs a high-level determination signal G, for example.

When the determination signal G is at a high level, the display unit 12 displays characters, symbols, figures, and the like indicating a ground state. It is also possible to emit an alarm sound simultaneously with such display.

When the determination signal G is at the high level, the flight control device 30 switches the control law from the levitation mode to the ground mode.

[0024]

As described above in detail, according to the present invention, the flap sensor detects the flap angle or the bending moment in the flap direction of the rotor blade and analyzes the output signal from the flap sensor to thereby realize various types of rotary wing machine. The state can be determined, and by comparing with a predetermined level threshold value Ta, it can be detected whether or not the rotary wing aircraft has touched the ground.

The time T during which the output signal from the flap sensor becomes smaller than the level threshold Ta and the predetermined time threshold T
Compared with b, by determining that the vehicle is in the ground contact state only when the time T continues for a relatively long time, erroneous determination during flight can be prevented, and the reliability of the determination is improved.

Further, by setting the time threshold value Tb in the range of 2 seconds to 5 seconds, the process from the start of the contact to the determination can be completed in a short time, and the contact state can be reliably determined.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram illustrating an electrical configuration according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing various states of the helicopter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Helicopter 2 Body 3 Rotor shaft 4 Rotor star 5 Rotor blade 6 Tail rotor 7 Skid 10 Flap sensor 11 Slip ring 12 Display part 20 Signal processing part 30 Flight control device

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) B64D 43/00-47/08 B64C 27/04 G01B 21/00

Claims (3)

(57) [Claims] 1. A flap sensor for detecting a flap angle or a flap direction bending moment of a rotor blade, an output signal from the flap sensor and a predetermined level threshold Ta.
And a determination means for determining a ground contact state of the rotary wing machine by comparing the above-mentioned conditions. 2. The method according to claim 1, wherein the determining unit compares the time T when the output signal from the flap sensor is smaller than the level threshold Ta with a predetermined time threshold Tb, and determines that the grounding state is established when the time T is longer than the time threshold Tb. 2. The method according to claim 1, wherein
A ground sensor for a rotary wing machine according to the above. 3. The ground sensor for a rotary wing machine according to claim 2, wherein the time threshold value Tb is set in a range of 2 seconds to 5 seconds.