JP2009023629A - Stol aircraft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a short take-off and landing (STOL) aircraft capable of takeoff running in a short distance using a combination of the propulsion of drive wheels and the propulsion of a propulsion unit, and of landing running in a short distance using a driving force of the drive wheels. <P>SOLUTION: To overcome the above problem, the present invention applies drive wheels driven by motors of electric vehicles improved in performance dramatically in recent years to aircraft landing gears, and uses drive wheel thrust for taxiing and the combination of propeller thrust and drive wheel thrust for takeoff running, thereby solving a problem of reducing a takeoff run distance. Although an airframe may unfavorably pitch up due to drive wheel thrust in such cases, the present invention dynamically controls the drive wheel torque within a range in which the above pitch-up movement does not occur, thereby avoiding the pitch-up movement and a resulting contact of a tail portion of the airframe with the ground. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is capable of taking off and landing at a short distance by using both a propulsion force of a driving wheel and a propulsion force of a propulsion device, and taking a landing at a short distance by using a braking force of the driving wheel. It relates to short-range take-off and landing aircraft.

Most of Japan's major airports are remote or offshore, so it takes a long time to travel to the airport, and domestic air traffic rarely loses its advantage in speed over railways, cars and ships. Absent. In recent years, airports that are inconvenient to access often cause passengers to leave and not only the number of flights but also the abolition of routes. On remote islands that have only low-frequency means of sea transportation, even if demand for air transport is high as a means of attracting islanders' lives and attracting tourists, there are concerns about the impact on the environment. Generally not easy. On the other hand, passenger demand in the Tokyo metropolitan area is increasing year by year, and airline slots in the metropolitan area are chronically lacking.
In order to solve the problems that exist in the current air transportation in Japan, the ideal solution is to establish a new airport near the city and on the remote islands. Since it is very difficult to secure a site in terms of construction cost and environmental load, the construction of a small airport with a short runway is one solution. However, aircraft that can take off and land at short distances usually achieve their purpose by increasing the power of the engine and equipping the main wing with a special aerodynamic device to generate high lift, This method has a disadvantage in that it tends to sacrifice the cruise performance due to an increase in weight and an increase in air resistance. In addition, special development as a short-range take-off and landing aircraft is required, so it is difficult to have the development and design process compatible with ordinary aircraft that are currently operating on a daily basis. Even short-range take-off and landing aircraft are not widespread.
In order for an airport near the city to be accepted by neighboring residents, not only short-range take-off and landing performance, but also low emission and noise performance during take-off and landing are strongly required.
However, current aircraft use propellers such as propellers or jet engines used during flight as they are when taxiing and taking off and taking off in airports. These are usually designed to achieve maximum efficiency at cruising speed.If the speed is low, such as during taxiing or gliding, the propulsion efficiency is low, which increases fuel consumption and also causes noise. Become.
Regarding this, as shown in US Pat. No. 3,977,631 from Boeing, a method for quietly and highly efficiently performing taxiing by incorporating an electric motor in an landing gear and driving wheels with power has been proposed (for example, (See Patent Document 1).
Even in Japan, a method of rotating a landing gear wheel has been proposed in various forms (see, for example, Patent Documents 2 to 6). However, since the mechanism shown in these patent documents is a mechanism for rotating the wheel immediately before the landing for the purpose of reducing the impact at the time of landing and landing, there is not enough output to accelerate the entire body on the ground. In addition, the aircraft wheel of Patent Document 6 has a drive mechanism on the wheels of the landing gear for the purpose of saving the propellant fuel during taxiing, but the drive is also sufficient to accelerate the entire fuselage to the takeoff speed. In order to have a force, there is a drawback that the weight of the entire drive mechanism becomes unacceptably large for an aircraft.
In recent years, the performance of permanent magnets has improved, and a small and high-power in-wheel motor type electric vehicle shown in Patent Document 7 has been developed. The in-wheel motor used here has an output necessary for take-off of a small aircraft, and at the same time, since it is an in-wheel, the weight of the drive mechanism is small. By applying these to the wheels of an aircraft, it is possible to reinforce not only the taxing but also the propulsive force during take-off run with a slight increase in weight.

U.S. Pat. No. 3,976,761 Japanese Patent Laid-Open No. 09-095299 Japanese Patent Laid-Open No. 09-150796 JP 2004-058978 A JP 2004-203223 A Japanese Patent Laid-Open No. 05-193577 JP 2002-186119 A

An aircraft with a longer take-off run distance requires a longer runway, and the environmental load associated with airport construction or operation is greater. However, even if a short take-off and landing aircraft that requires a short runway is realized by increasing engine power and adding an aerodynamic device as previously proposed, it is difficult to become an aircraft that is widely spread on the market for the reasons described above.
By the way, the in-wheel motor is built in the wheel of the aircraft, and the driving force generated by the engine and the driving force generated by the wheel are used together to reinforce the driving force during take-off and can take off at a short distance. It becomes possible.
However, when the driving force for accelerating the entire aircraft is given to the wheels of the aircraft, the following pitch-up problem occurs. In other words, unlike an automobile, an aircraft has a high center of gravity, so the pitch-up moment that occurs around the center of gravity (the moment that acts to raise the nose) is as large as the pitch-down moment due to gravity. Have Therefore, when the driving driving force of the wheel increases, the pitch-up moment becomes larger than the pitch-down moment, and as a result, there arises a problem that the aircraft pitches up and the aircraft tail comes into contact with the ground.
Therefore, the present invention has been made in view of the problems of the prior art, and its purpose is to add a few devices without changing the parts related to the design of the aircraft body shape and engine of the existing aircraft. It is an object of the present invention to provide a short-range take-off aircraft equipped with means that can easily reduce the take-off and landing run distance.

In order to achieve the above object, a short take-off and landing aircraft according to claim 1 is provided with left and right main landing gears each having one or a plurality of driving wheels arranged obliquely rearward and symmetrically with respect to the axle from the center of gravity of the aircraft, A pitch-up pre-detecting means for detecting a sign that the airframe starts a pitch-up movement, and a detection signal from the pitch-up pre-detecting means And a propulsive force varying means for controlling the propulsive force of the driving wheel based on the above, and using both the propulsive force of the main propulsion device used when cruising the aircraft during takeoff and the propulsive force of each driving wheel. It is characterized by taking off while accelerating.
In the short-range take-off and landing aircraft, the pitch-up pre-detection means quickly detects a sign that the aircraft starts pitch-up movement due to a pitch-up moment generated due to the propulsive force of the left and right drive wheels, and detects the detection signal. While transmitting to the propulsive force variable means, the propulsive force variable means that has received the detection signal controls the propulsive force of the drive wheels within a range in which the airframe does not cause the pitch-up motion, thereby suppressing the pitch-up motion of the airframe. Thereby, the driving force of the driving wheel can be stably contributed to the acceleration of the airframe. As a result, by using the driving force of the driving wheel and the driving force of the main propulsion device in combination, the airframe can be accelerated to the takeoff speed over a short distance.

In the short take-off and landing aircraft according to claim 2, the pitch-up pre-detection means is based on the attitude angle of the aircraft, the angular velocity of the aircraft, the distance between a part of the aircraft and the ground, or the load from the ground acting on the front legs. Thus, it was decided to detect a sign that the aircraft would start pitching up.
In the short-range take-off and landing aircraft, by using the attitude angle, the angular velocity, the ground distance, or the load, it is possible to suitably detect a sign that the aircraft starts a pitch-up motion.

In the short-range take-off and landing aircraft according to claim 3, the driving wheel is driven by an electric motor.
In the short-range take-off and landing aircraft, it is possible to easily control the torque of the left and right drive wheels by adopting an electric motor as the drive means of the drive wheels. Furthermore, in the case of an in-wheel motor in which the electric motor is housed in a wheel, the rotor's rotating shaft and the wheel's rotating shaft are directly connected, which greatly reduces the mechanism and parts related to power transmission and reduces the weight of the fuselage. Will be. Therefore, by using the driving force of the driving wheel and the driving force of the main propulsion device in combination, the airframe can be accelerated more efficiently to the take-off speed over a short distance. In addition, the weight reduction of the fuselage greatly contributes to the improvement of the fuel consumption rate and the shortening of the landing distance described later.

In the short take-off and landing aircraft according to claim 4, the propulsive force varying means generates a braking torque in the electric motor during the landing run.
In the short-range take-off and landing aircraft, by generating a braking torque in the electric motor, it becomes possible to use both the reverse thrust of the main propulsion device and the braking force of the driving wheel proportional to the braking torque of the electric motor at the time of landing. As a result, the landing run distance is shortened.

In the short-range take-off and landing aircraft according to claim 5, the prime mover driving the main propulsion device of the aircraft includes an internal combustion engine.
In the above short-range take-off and landing aircraft, the take-off run distance and landing run distance of an aircraft equipped with an internal combustion engine as a prime mover can be shortened, and further, taxiing can be performed by oneself.

In the short-range take-off and landing aircraft according to claim 6, the prime mover that drives the main propulsion device of the aircraft is an electric motor.
In the above short-range take-off and landing aircraft, the take-off running distance and landing run distance of an aircraft equipped with an electric motor as a prime mover can be shortened, and further, taxiing can be performed by oneself.

According to the short-range take-off and landing aircraft of the present invention, the following effects are expected.
(1) The number of runways that can be used is increased by reducing the take-off and landing run distance of the aircraft, and the size of the airport can be reduced, so it is possible to establish new airports near urban areas where construction was difficult in the past. As a result, passenger convenience is greatly improved.
(2) Since the taxi can be freely controlled by a single aircraft, it is possible to reduce the cost of the tow vehicle and the personnel for that purpose, and it is possible to reduce airport noise and excessive fuel consumption generated during taxiing.

  Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings.

FIG. 1 is an explanatory view showing a short-range take-off and landing aircraft 100 according to the present invention. 1A is a plan view, and FIG. 1B is a side view.
This short-range take-off and landing aircraft 100 includes a front leg 11 having a steering wheel 12 disposed below a nose portion of the fuselage 1 and left and right main legs 21 having left and right driving wheels 22 and 32 disposed below the left and right main wings 2 and 3. 31. As will be described later, in-wheel brushless motors are built in the left and right drive wheels 22 and 32, and these left and right drive wheels 22 and 32 are directly driven by the motors to generate a driving propulsion force that pushes the airframe forward. As a result, the aircraft will take off and run using the propulsive force of the left and right engines 24 and 34 and the propulsive force of the left and right drive wheels 22 and 32, and the aircraft will take off with only the propulsive force of the main engine. Compared to take a short distance. Further, as will be described later, the front leg 11 includes a linear potentiometer 14 as a pitch-up pre-detection means. That is, the linear potentiometer 14 quickly detects a sign that the tail portion is lowered by the pitch-up moment generated due to the propulsive force of the left and right drive wheels 22 and 32, and uses the detected signal as the torque of the left and right drive wheels 22 and 32. Send to control device. On the other hand, the torque control device that has received the detection signal controls the propulsive force of the left and right drive wheels 22 and 32 within a range in which the airframe does not cause pitch-up motion, thereby preventing the tail from contacting the ground and driving left and right. The propulsive force of the wheels 22 and 32 is stably used for accelerating the aircraft, and greatly contributes to shortening the takeoff distance.

  That is, this short take-off and landing aircraft 100 detects a sign of the aircraft pitch-up by a load acting on the front nose of the aircraft, and this load is measured by the linear potentiometer 14 as a damper displacement of the front nose, and the load falls below a certain threshold. It is determined that the aircraft has started to pitch up, and the driving wheel thrust is controlled within a range that does not cause pitch-up motion by controlling the torque of the driving wheel.

Leg 11 before being placed in front of the center of gravity X _G is disposed on the body 1, also a steering wheel 12 having a steering function that does not generate a driving force is provided on the front legs 11. The front leg 11 is provided with a linear potentiometer 14 for detecting the displacement of the damper 13 (see FIG. 2). The steered wheel 12 receives a vertical load Nf from the ground, and the displacement signal Sn of the damper 13 is proportional to the vertical load Nf. Therefore, by acquiring in advance the threshold value ε of the displacement signal Sn immediately before the steered wheel 12 leaves the ground (immediately before the aircraft starts pitch-up movement), the displacement signal Sn is obtained in real time while the aircraft is accelerating. By checking whether or not the displacement signal Sn is equal to or less than the threshold value ε while being taken in, it is possible to detect a sign that the aircraft will start pitching up.

Diagonally behind the center of gravity X _G in the left and right wing 2,3 equipped with left and right main legs 21 and 31 respectively, also provided right engine 24, 34 for generating a propulsive force during cruising or during skid respectively. Further, the left and right main legs 21 and 31 are provided with left and right drive wheels 22 and 32, respectively, for generating a driving propulsion force during takeoff. Therefore, at the time of takeoff run, the propulsive force of the left and right drive wheels 22 and 32 is added to the propulsive force of the left and right engines 24 and 34, and the takeoff speed can be reached with a shorter run distance than before.

  An in-wheel brushless motor is built in each wheel of the left and right drive wheels 22 and 32. Here, by using the in-wheel motor, the parts used in the power transmission mechanism can be omitted, and as a result, the number of parts can be greatly reduced, and current control (torque control) described later of the motor can be achieved. ), The torque of the left and right drive wheels 22 and 32 can be easily controlled. As a result, the propulsive force of the left and right drive wheels 22 and 32 can be controlled within a range in which the aircraft does not cause a pitch-up movement, and the propulsive force of the left and right drive wheels 22 and 32 is prevented while preventing the tail from contacting the ground. Will be used stably to accelerate the aircraft and will greatly contribute to shortening the takeoff distance. In addition, by using a brushless motor, as described later, by applying a DC voltage to each phase or by short-circuiting the terminals of each phase, it is possible to generate braking torque in the motor and brake the machine body, and as a result The landing run distance is shortened, maintenance is not required, and the operation cost can be reduced. The motor for driving the left and right drive wheels 22 and 32 is preferably an in-wheel type in consideration of not only the ease of torque control of each drive wheel but also the reduction in the number of parts and maintenance-freeness described above. If only the ease of torque control of each drive wheel is considered, an out-wheel type via a power transmission mechanism such as a gear or a pulley may be used.

FIG. 2 is an explanatory diagram showing the configuration of the torque control system 200 of the present invention.
This torque control system 200 includes a linear potentiometer 14 that detects the displacement of the damper 13, a throttle 15 that adjusts the output of the propulsion device (left and right engines 24, 34), a throttle operation amount Th, and a linear potentiometer 14. The torque control device 16 that receives the displacement signal Sn and determines the current Im to be fed to the left and right motors 23, 33, a power supply 17 that supplies power to the torque control device 16, and a charging circuit 18. .

  The linear potentiometer 14 outputs a displacement signal Sn proportional to the vertical load Nf acting on the front leg 11. The torque control device 16 detects a sign of the pitch-up motion of the airframe based on the displacement signal.

  The torque control device 16 receives the operation amount Th and the displacement signal Sn and receives power from the left and right motors 23 and 33 which are in-wheel brushless motors for driving the left and right drive wheels 22 and 32 according to the sequence shown in FIG. By controlling the current Im applied to each, the torque of the left and right drive wheels 22 and 32 proportional to the current, and further the drive propulsive force Fw proportional to these are controlled.

FIG. 3 is a flowchart showing an example of a torque control sequence of the left and right motors 23 and 33 by the torque control device 16.
As the driving thrust Fw increases, the vertical load Nf and the displacement signal Sn decrease.However, in this flow chart, when the driving thrust Fw increases, the displacement signal Sn falls below the threshold value ε. The start is determined, and the current supplied to the motor at that time is set as the maximum value of the current. In addition, this flowchart is intended to control the driving propulsion force Fw within a range in which the airframe does not cause a pitch-up motion by a loop that controls the supply current thereafter. Hereinafter, this flowchart will be described in detail.

In step S 1, after the airframe starts to accelerate, the torque control device 16 sets a value obtained by multiplying the throttle operation amount Th by the gain C _th as the supply current Im, and inputs it to the left and right motors 23 and 33.

Next, in step S2, the displacement signal Sn from the linear potentiometer 14 is received, and the magnitude with respect to the preset threshold value ε is checked. That is, between the displacement signal Sn is larger than the threshold value ε, the process returns to step S1, the supply current Im calculated by multiplying the gain C _th to the throttle operation amount Th, continue to enter the left and right motors 23 and 33. On the other hand, when the driving propulsive force Fw increases and the displacement signal Sn falls below the threshold ε, the process proceeds to step S3, where the value of the throttle operation amount Th is Th _ref and the value of the supply current Im at that time is Im _max. And

In step S4, the magnitude of the throttle operation amount Th and Th _ref is checked. That is, if Th ≧ Th _ref , the process proceeds to step S5, and the supply current Im = Im _max is set. On the other hand, if Th <Th _ref , the process returns to step S1 and the throttle operation amount Th is multiplied by the gain C _th . The value obtained in this way is input to the left and right motors 23 and 33 as the supply current Im.

  Further, the torque control device 16 controls the current actually supplied to the motor by adjusting the duty ratio of the pulse voltage applied to the left and right motors 23 and 33 in accordance with the calculated supply current Im. By controlling the maximum value of the current supplied from the power supply 17 to the left and right motors 23 and 33 in this way, the aircraft is controlled while controlling the torque of the drive wheels, and thus the drive propulsion force Fw, within a range in which the aircraft does not cause pitch-up motion. Can be accelerated over a short distance to takeoff speed.

  On the other hand, when the airframe lands, a DC torque is applied to each phase of the coils of the left and right motors 23 and 33 or a terminal of each phase is short-circuited to generate a braking torque in the left and right motors 23 and 33. It is possible to apply braking. Alternatively, when a large braking force is not required, the charging circuit 18 regenerates the rotational energy generated in the left and right motors 23 and 33 to charge the power source 17.

  In the above embodiment, the case where the load acting on the front leg is detected as a sign of the pitch-up motion has been described. However, a method of detecting the angular velocity of the aircraft using a gyroscope or the like, or using an acceleration sensor or an inclinometer Thus, a method of detecting the attitude angle of the aircraft can be considered. Further, as a method for detecting the load acting on the front leg, not only the damper displacement but also a method using a load cell or the like can be considered. As for the torque control method (sequence) of the left and right motors 23 and 33, a method of performing more accurate control by estimating the pitch moment generated in the main wing from the airspeed and incorporating it in the control law is also conceivable.

  Furthermore, the present invention can be applied not only when the prime mover prime mover is an engine but also when the prime mover is an electric motor as shown in FIG.

  Here, FIG. 5 shows the result of quantitatively examining the effect of shortening the take-off run distance (the distance until the aircraft reaches 1.2 times the stall speed) when the present invention is applied to the Cessna Skyhawk172. Here, two in-wheel motors (weight 26 kg, maximum torque 46.73 Nm) of the scale used for electric vehicles were used. As shown in FIG. 5, a numerical analysis result is obtained in which the take-off run distance is expected to be reduced by about 40% as compared with the existing aircraft.

  The short-range take-off and landing aircraft of the present invention can be applied to various types of aircraft take-off and landing devices, but can be suitably applied to small aircraft for which demand growth is expected in the future. Especially in Japan, where the land is small and mountainous, this technology enables the activation of local airports that are currently sluggish and the efficient operation of runways at metropolitan airports.

It is explanatory drawing which shows the short distance take-off and landing aircraft of this invention. It is composition explanatory drawing which shows the torque control system of this invention. It is a flowchart which shows the example of the torque control sequence of the left-right motor by a torque control apparatus. It is composition explanatory drawing which shows the other torque control system of this invention. It is a graph which shows the numerical analysis result of the shortening effect of the take-off run distance by this invention.

Explanation of symbols

1 fuselage 2 left main wing 3 right main wing 4 left horizontal tail 5 right horizontal tail 6 vertical tail 11 front leg 12 steering wheel 13 damper 14 linear potentiometer 15 throttle 16 torque control device 17 power source 18 charging circuit 21 left main leg 22 left drive wheel 23 Left motor 31 Right main leg 32 Right drive wheel 33 Right motor 100 Short-range take-off and landing aircraft 200,300 Torque control system

Claims (6)

  It is an aircraft having left and right main legs that are arranged obliquely rearward from the center of gravity of the fuselage and symmetrically with respect to the axle and each provided with one or more drive wheels, and front legs that are disposed in front of the center of gravity of the aircraft and provided with one or more idle wheels. And a pitch-up pre-detecting means for detecting a sign that the airframe starts pitch-up motion, and a propulsive force varying means for controlling the propulsive force of the drive wheel based on a detection signal from the pitch-up pre-detecting means. A short-range take-off and landing aircraft that takes off and runs while accelerating using both the propulsive force of the main propulsion device used during cruise of the aircraft and the propulsive force of each drive wheel during take-off run.   The pitch-up pre-detection means provides a sign that the aircraft starts pitch-up motion based on the attitude angle of the aircraft, the angular velocity of the aircraft, the distance between a part of the aircraft and the ground, or the load from the ground acting on the front legs. The short-range take-off and landing aircraft according to claim 1 for detection.   The short-range take-off and landing aircraft according to claim 1 or 2, wherein the driving wheels are driven by an electric motor.   The short-range take-off and landing aircraft according to any one of claims 1 to 3, wherein the propulsive force varying means generates a braking torque in the electric motor during landing landing.   The short-range take-off and landing aircraft according to any one of claims 1 to 4, wherein the prime mover that drives the main propulsion device of the aircraft includes an internal combustion engine.   The short-range take-off and landing aircraft according to any one of claims 1 to 4, wherein the prime mover that drives the main propulsion device of the aircraft is an electric motor.

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