JP2955699B2 - Remote flight control system for unmanned helicopter. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote flight control system for an unmanned helicopter and, more particularly, to a system for preventing an aircraft from being damaged by self-excited vibration during takeoff and landing.

[0002]

2. Description of the Related Art Currently, commercially available radio-controlled helicopters and industrial unmanned helicopters (hereinafter collectively referred to as unmanned helicopters) used for spraying pesticides, etc. are used to stabilize the nose azimuth from disturbance during flight. Like a manned helicopter, a gyro (rate of rotation of the azimuth azimuth in the body fixed coordinate system is referred to as a yaw axis, so the gyro is simply referred to as a yaw rate gyro) is mounted. I have.

FIG. 10A is a block diagram of a heading control system in a conventional remote flight control system for an unmanned helicopter, and a mixing amplifier 4 shown in FIG.
As shown in the figure, the signal processing unit 4a and the mixing processing unit 4b are configured. An angular velocity signal (yaw rate signal) Sy of the nose azimuth detected by the yaw rate gyro 3y is input to the mixing amplifier 4, and is filtered.
Then, various filtering processes for removing noise components and separating frequency components necessary for aircraft control are performed.
In a2, a process of amplifying the filtered signal by a predetermined gain magnification is performed, and in a conversion processing unit 4a3, a pre-process for mixing the amplified signal with the steering signal Sb is performed. Part 4
b, mixing processing is performed together with the control signal Sb for controlling the heading sent from the remote control device 1, and then output as a servo control signal Sc to finally control the tail rotor 7 to control the heading. It is a mechanism to stabilize.

However, the heading control system in the remote flight control system as described above is very effective in increasing the stability of the aircraft during flight, but in addition to the large aircraft motion (motion) generated during takeoff and landing, various other operations are required. Since the yaw rate gyro 3y picks up the body vibration as an angular velocity signal, the servo control signal Sc is generated and output in response thereto.
The servo actuator 5 and the linkage 6 are operated in accordance with c, so that the body is inadvertently shaken in order to change the generated thrust of the tail rotor 7. This phenomenon is not limited to the above-mentioned heading system, but is a phenomenon that is observed in all body control systems. In particular, the effect is large in the heading control system, and the thrust fluctuation of the tail rotor 7 causes the body 8 to have a large moment arm L (See FIG. 3A), and the self-excited vibration (resonance phenomenon) that swings the tail boom T right and left occurs. This means that the aircraft vibration is amplified by the tail rotor thrust and the aircraft is forcibly vibrated. Therefore, the original purpose is to increase the aircraft stability from disturbances (S
AS) does not act at all.

The self-excited vibration varies in form depending on the type and structure of the body, as well as the mounting method of the sensor. However, in some cases, the vibration diverges to cause a ground resonance phenomenon, which may cause damage to the body. . For this reason, the current situation is that the operator normally controls the remote control device 1 while observing the state of the airframe, and covers the operation in order to prevent self-excited vibration.

The relationship between the stability increase function of the body control system for suppressing the attitude change during flight based on the detected angular velocity signal and the body vibration has been described above. On the other hand, the self-excited vibration described above is included in the body vibration generated during takeoff and landing. In addition to the above, there is a vibration caused by a posture holding function for keeping the body posture constant (horizontal) during hovering. This is a phenomenon peculiar to the flight control device having the attitude maintaining function. When the aircraft 8 takes off from the inclined ground G as shown in FIG. This is for automatically controlling the servo actuator 5 and performing control (cyclic pitch control) for horizontally rotating the rotational plane (tip path plane) P of the main rotor. In this way, the flapping motion that occurs in the rotating main rotor with cyclic pitch control acts as a vibration to excite the entire aircraft, so it is close to weightlessness where gravity and lift are balanced, especially just before takeoff Under the condition that the skid Lg is constrained by the ground G, even a small vibration may develop into a divergent state (ground resonance phenomenon) and cause a risk of damage to the fuselage. At present.

The above-described mixing amplifier 4 is a flight control device having a circuit used for adding or synthesizing two or more types of signals such as a pulse width modulation signal, but uses a CPU (central processing unit). The same phenomenon occurs even in the flight control device including the digital signal processing circuit, and the same danger exists.

[0008]

As described above, in a conventional remote flight control system having a function of stably increasing the angular velocity (or angle) in the yaw axis, pitch axis or roll axis direction, the vibration of the aircraft during takeoff and landing is controlled. However, there is a disadvantage that self-excited vibration occurs in the airframe because it is detected as an angular velocity due to the vibration. Further, even a remote flight control system having a posture holding function has the same disadvantage.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a remote flight control system which eliminates these conventional drawbacks and prevents ground resonance phenomena such as damaging the airframe during takeoff and landing.

[0010]

SUMMARY OF THE INVENTION The present invention provides a remote control device, a receiving device for receiving the control radio wave, and a rate sensor for detecting angular velocity, or an acceleration sensor for detecting the rate sensor and the acceleration of the body. A signal generated by subjecting an input signal from the above-described rate sensor or the motion measuring device to signal processing necessary for stabilizing or maintaining the attitude of the aircraft, and performing a mixing signal with a control signal. A control signal that is output as a control signal, a flight control device, a servo actuator that generates a driving force for controlling the aircraft based on the servo control signal, and a transmission of the driving force to a main rotor or a tail rotor of the aircraft. A conventional unmanned helicopter remote flight control system consisting of a linkage for In addition, a means for detecting the take-off and landing state of the aircraft is provided, and when the aircraft is in the grounding state based on the detection signal, the signal transmission route is turned off so that the signal processed as described above is not mixed with the control signal. Also, when mixing, reduce the amount of mixing, or take measures such as reducing the gain of the amplification processing unit at the stage of processing the signal from the rate sensor described above, just before the aircraft takes off and immediately after landing. Since the function of stabilizing the attitude or the attitude holding function can be cut off, and those functions can be further suppressed, the occurrence of self-excited vibration can be suppressed, and the damage to the body due to the ground resonance phenomenon can be prevented.

[0011]

FIG. 1 is a block diagram showing a hardware configuration when the present invention is applied to a heading control system of a remote flight control system, and the same reference numerals are given to portions corresponding to those in FIG. In the mixing amplifier 4 in FIG. 1A, as shown in FIG. 1B, a filtering processing unit 4a1, an amplification processing unit 4a2 for adjusting the gain magnification, and a control signal output from the control radio wave reception device 2. A signal processing unit 4a including a conversion processing unit 4a3 for performing preprocessing so that Sb and the filtered and amplified yaw rate signal can be mixed, and a switch unit 4c for turning on or off an output Se of the conversion processing unit 4a3; , A mixing processing unit 4b for mixing the control signal Sb and the output of the switch means 4c.

Next, the interaction between the components will be described. First, the yaw rate gyro 3y detects the angular velocity (yaw rate) of the nose azimuth of the aircraft and detects the yaw rate signal Sy.
Is output to the mixing amplifier 4. On the other hand, the mixing amplifier 4 performs desired filtering processing, amplification processing, conversion processing, and the like on the input yaw rate signal Sy (see FIG. 1B). The signal Se obtained by performing the above-described processing on the yaw rate signal Sy is supplied to the mixing processing unit 4b via the switch unit 4c that is turned on or off by the detection signal Sd from the takeoff / landing detection unit 9. Therefore, when the aircraft is on the ground, the takeoff / landing detection signal Sd becomes L (low level), the switch means 4c is controlled to be turned off, and the output Se of the signal processing unit 4a is not mixed. On the other hand, when the airframe takes off and the takeoff / landing detection signal Sd becomes H (high level), the switch means 4c is controlled to be turned on, and the output Se of the signal processing unit 4a is mixed with the control signal Sb, and becomes the servo control signal Sc. Servo actuator 5
As a result, the nose heading is always stabilized during flight. (The polarities of H and L may be reversed.) The switch unit 4c of FIG. 1B is a signal processing unit 4a.
May be provided on the input side, or may be provided between each functional block in the signal processing unit 4a. Alternatively, as shown in FIG. 2A, the amplification factor of the amplification processing unit 4a2 can be reduced to zero or small by control using the takeoff / landing detection signal Sd.

Further, the switch means 4c has a fade- in state.
Or a fade-out circuit is provided to turn on or off the signal Se.
It is also possible to prevent an excessive signal from being input to the mixing processing unit 4b when the switch is turned off , and to prevent a transient phenomenon from occurring. On the other hand, when suppressing the function of stabilizing the heading, first and second signal processing units 4a-1 and 4a-2 having different stabilization conditions are provided as shown in FIG. 2B. What is necessary is just to switch the movable contact a of the switch means 4c to the fixed contact b or c side according to L or H of the takeoff / landing detection signal Sd.

FIG. 3A shows an example in which a mechanical take-off and landing switch 9a is provided on the landing gear (skid) Lg of the fuselage to constitute the take-off and landing detection means 9. However, since the helicopter generally hovers with the aircraft leaning to the right or left depending on the direction of rotation of the rotor, the take-off and landing switch 9a is attached to the skid on the inclined side of the fuselage. It is desirable to set as follows. Further, the position where the skid first touches and takes off and the position where it touches the ground to the end during takeoff and landing may differ depending on the weight distribution (center of gravity position) of the aircraft and the state of the inclined ground. Therefore, the takeoff and landing switch 9a is shown in FIG. 3B. As shown in the figure, a plurality of skids are attached to the front, rear, left and right, and the takeoff / landing state detected by each switch is divided into a case of takeoff and a case of landing, and a determination process is performed by a logic circuit 9e. As shown in FIG. Sd can be obtained. With this configuration, it is possible to accurately detect the takeoff and landing state without being affected by the inclination of the ground contact surface or the weight distribution (center of gravity position) of the aircraft.

As shown in FIG. 5, a plurality of pressure sensors 9b1 to 9b4 are used to constitute the takeoff / landing detecting means 9, and their output signals (ground pressure values) are sent to respective comparators (comparators) 9d1 to 9d4. input. Since the set pressure level is input as a threshold value to the above-mentioned comparator, if the ground pressure falls below the set value, it is determined that the aircraft has taken off at the pressure sensor mounting position, and a signal is sent to the logic circuit 9e. Is output. Then, the logic circuit 9e determines the takeoff / landing state based on the output signal of each comparator, and as shown in FIG. 5B, the takeoff / landing detection signal Sd of the whole body
You can also get In this way, the take-off and landing state of the aircraft can be detected more accurately even on a bumpy ground, a snowy place, a soft ground, or the like where the take-off and landing switch does not easily function as a switch.

Although the embodiment of the present invention has been described above with reference to stabilization of the nose azimuth, the remote flight control system according to the present invention is not limited to the pitch control system (mainly the vertical length of the aircraft) which is another aircraft control system. The present invention can also be applied to a control system related to movement (pitching) and a roll control (mainly a control system related to lateral movement (rolling) of the aircraft). FIG. 6 is a block diagram showing a hardware configuration when the present invention is applied to a pitch system and a roll system in addition to the heading system.
1 and parts corresponding to those in FIG. 1 are denoted by the same reference numerals. FIG.
As shown in B, the switch means of each control system can be automatically turned on or off according to the take-off and landing state of the aircraft.

The remote flight control system according to the present invention can also be realized by using a digital signal processing circuit using a CPU. FIG. 7 shows a remote control having a flight control device 4 'using a CPU using a strap-down type motion measuring device 3' for measuring a motion state such as an angular velocity and an attitude angle of a fuselage, a nose azimuth angle, a speed and an acceleration. It is a block diagram of a structure of a flight control system. In the figure, angular velocity signals Sp, Sr, and Sy corresponding to the pitch axis, roll axis, and yaw axis of the aircraft output from the motion measuring device 3 'and acceleration signals in the respective axis directions are A / D converters 4a4 shown in FIG. 7B. The data is taken into the CPU 4a5 via the D / A converter 4 and subjected to various filtering processes and amplification processes.
The data is output to the conversion processing unit 4a7 via a6. Midway CP
U4a5 converts takeoff / landing detection signal Sd to A / D converter 4a.
Since the signal has been read from the D / A converter 4, the signal subjected to the various processes described above is output to the D / A converter 4a6 as it is, or the output is stopped, depending on the state of the signal Sd. Further, since the output signal is converted by the processing of the conversion processing unit 4a7 so that mixing processing can be performed, the output signal is mixed with the control signal Sb by the mixing processing unit 4b and the corresponding servo control signals Scp, Scr, Scy are output.
Is output to the servo actuators 5 and 5M.

FIG. 8A shows an example of a main routine of the arithmetic processing flowchart of the CPU 4a5 in FIG. 7B, and FIG. 8B shows an example of a subroutine.

[0019]

As described above, according to the present invention, the take-off and landing detecting means 9 is provided, and the servo control signal for stabilizing the body by the take-off and landing vibration detected by the rate sensor 3 or the motion measuring device 3 '. The self-excited vibration of the aircraft is controlled by controlling the level of the signal component to zero or small before mixing with the control signal Sb so that the signal is not output as a servo control signal for further holding the attitude. And the effect of preventing damage to the fuselage due to the ground resonance phenomenon can be obtained.

[Brief description of the drawings]

FIG. 1A is a block diagram showing a configuration of an embodiment in which the present invention is applied to a heading control system of an unmanned helicopter, and FIG. 1B is a block diagram showing an example of a mixing amplifier 4 of A.

FIG. 2 is a block diagram showing another example of the mixing amplifier 4 of FIG. 1A.

FIG. 3A is a front view of a helicopter in which a takeoff / landing switch is provided on a landing gear (skid) of an airframe to constitute a takeoff / landing detection means, and FIG. 3B is provided with four takeoff / landing switches at front, rear, left and right of the skid. The bottom view of the skid in the case.

4A is a block diagram showing an example of the take-off and landing detecting means 9 of FIG. 3B, and FIG. 4B is a waveform diagram thereof.

5A is a block diagram showing another example of the take-off and landing detection means 9 of FIG. 3B, and FIG. 5B is a waveform diagram of a main part thereof.

FIG. 6A is a block diagram showing an embodiment in which the present invention is applied to all body control systems, and FIG. 6B is a block diagram showing an example of the mixing amplifier 4 of A.

FIG. 7A is a block diagram showing another embodiment of the present invention, and FIG.
FIG. 3 is a block diagram showing an example of a flight control device 4 'of FIG.

FIG. 8 is a flowchart illustrating an example of a calculation process of the CPU in FIG. 7B;

FIG. 9 shows a servo control signal addition operation output process S _{5 of} FIG. 8A.
5 is a flowchart showing an example of the process.

10A is a block diagram of a conventional remote flight control system for an unmanned helicopter, and FIG. 10B is a block diagram showing an example of the mixing amplifier 4 of FIG.

FIG. 11 is a diagram showing a state in which a tip path plane of a main rotor of a helicopter is horizontally held by cyclic pitch control.

Claims (7)

(57) [Claims] 1. A remote control device for transmitting a control signal on a radio wave to an unmanned helicopter, and a control signal mounted on the unmanned helicopter, receiving and detecting a control radio wave transmitted from the remote control device, and outputting a control signal. And a motion sensor having a rate sensor for detecting a rotational angular velocity of a body of the unmanned helicopter in one, two or three axes, or an acceleration sensor for detecting acceleration of the rate sensor and the body of the unmanned helicopter. A signal processing required for stabilizing or maintaining the attitude of the aircraft is performed on an input signal from the apparatus and the rate sensor or the motion measuring apparatus described above, and the signal processed signal is output to the output (steering signal) of the steering radio wave receiving apparatus. A mixing amplifier or flight control device for mixing and outputting as a servo control signal, A remote flight control system for an unmanned helicopter, comprising at least: a servo actuator for generating a driving force for controlling; and a linkage for transmitting an output (driving force) of the servo actuator to a tail rotor or a main rotor of the airframe. Newly adding take-off and landing detection means for detecting whether the aircraft is in a take-off state or a landing state, and when the output of the take-off and landing detection means is in a take-off state, the signal processed signal is directly used as the control signal. A remote flight control system for an unmanned helicopter, wherein the mixing amplifier or the flight control device is provided with a function of reducing the level of the signal processed to be mixed to zero or to reduce the level of the signal to be mixed when in a landing state. . 2. A remote control device for transmitting a control signal on a radio wave and transmitting the control signal to an unmanned helicopter. The control device is mounted on the unmanned helicopter and receives and detects a control radio wave transmitted from the remote control device and outputs a control signal. And a motion sensor having a rate sensor for detecting a rotational angular velocity of a body of the unmanned helicopter in one, two or three axes, or an acceleration sensor for detecting acceleration of the rate sensor and the body of the unmanned helicopter. A signal processing required for stabilizing or maintaining the attitude of the aircraft is performed on an input signal from the apparatus and the rate sensor or the motion measuring apparatus described above, and the signal processed signal is output to the output (steering signal) of the steering radio wave receiving apparatus. A mixing amplifier or flight control device for mixing and outputting as a servo control signal, A remote flight control system for an unmanned helicopter, comprising at least: a servo actuator for generating a driving force for controlling; and a linkage for transmitting an output (driving force) of the servo actuator to a tail rotor or a main rotor of the airframe. A take-off / landing detection means for newly detecting whether the aircraft is in a take-off state or a landing state, and a signal processing unit for performing the signal processing, wherein a plurality of signal processing units having different signal processing characteristics are provided. An unmanned helicopter, wherein a function of switching and selecting the outputs of the plurality of signal processing units according to the output of the takeoff / landing detection means and mixing the control signals is provided in the mixing amplifier or the flight control device. Remote flight control system. 3. The remote flight control of an unmanned helicopter according to claim 1, wherein the takeoff / landing detection means has a mechanical switch attached to a skid or a fuselage side of the helicopter and turned on or off by takeoff / landing. system. 4. The take-off / landing detection means according to claim 3, wherein the take-off / landing detection means is attached to four or more places at the front, rear, left and right of the skid of the helicopter, and from take-off to take- off or take-off at takeoff.
Off to on or off to on or on to off when landing.
Has first to fourth switches off and that Do, when all of the switches which takeoff is switched from off to on or from on to off in a state determination takeoff, from one initially off at the time of landing them switch A remote flight control system for an unmanned helicopter, which outputs a detection signal for judging a landing state when being switched on or from on to off . 5. The remote flight control system for an unmanned helicopter according to claim 1, wherein the take-off and landing detection means has a pressure sensor attached to a skid of the helicopter and pressed by the weight of the fuselage. 6. The take-off / landing detection means according to claim 5, wherein said take-off / landing detection means is provided with a plurality of pressure sensors mounted on a ground surface of a skid of a helicopter or over the entire surface and pressed by the weight of an airframe. The output is compared with the threshold value, and the take- off state is set when the detection outputs of all pressure sensors are below the threshold value at takeoff , and the landing state is set when one of the pressure sensors first exceeds the threshold value at landing. A remote flight control system for an unmanned helicopter, which outputs a detection signal. 7. The signal processing method according to claim 1, wherein the signal processed to be mixed and the control signal are mixed in the takeoff / landing mode, and the signal processed to be mixed is faded in at the time of on / off switching.
Or a remote flight control system for an unmanned helicopter, characterized by fading out .