Aircraft position control system, aircraft, and aircraft position control method

Abstract

This aircraft position control system makes the position of an aircraft follow movement in a target landing point due to oscillatory motion, and comprises: an oscillatory motion quantity estimation process unit that estimates a first oscillatory motion quantity of the target landing point, on the basis of attitude correction acceleration obtained by correcting acceleration of the aircraft and a relative position between the aircraft and the target landing point; an oscillatory motion quantity prediction process unit that predicts a future second oscillatory motion quantity of the target landing point, on the basis of the estimated first oscillatory motion quantity; a filtering process unit that performs filtering process on the second oscillatory motion quantity predicted by the oscillatory motion quantity prediction process unit such that the relative position becomes zero; and a model prediction control unit that performs model prediction control based on the estimated first oscillatory motion quantity and the filtering-processed future second oscillatory motion quantity and that outputs a control quantity for controlling flight of the aircraft.

Description

Aircraft position control system, aircraft, and aircraft position control method

[0001] The present disclosure relates to an aircraft position control system, an aircraft, and an aircraft position control method, and in particular to target point tracking hovering position control that tracks the position of an aircraft in accordance with movement of a target landing point due to vibration.

[0002] Conventionally, there has been known a takeoff and landing control system for causing an aircraft to take off and land on a moving body, such as a ship (see, for example, Patent Document 1). The takeoff and landing control system of Patent Document 1 includes a hull motion prediction device that predicts the hull motion of the ship, a takeoff and landing condition instruction device that receives the output of the hull motion prediction device and calculates the takeoff and landing condition of the aircraft on the ship, an instruction transmitting device that transmits the output of the takeoff and landing condition instruction device, an instruction receiving device that receives the output of the instruction transmitting device, and a flight motion control device that controls flight motion in response to the output of the instruction receiving device. The hull motion prediction device, takeoff and landing condition instruction device, and instruction transmitting device are provided on the ship, and the instruction receiving device and flight motion control device are provided on the aircraft.

[0003] Japanese Patent Application Publication No. 4-71998

[0004] Patent Document 1 relates to a technique for docking fixed-wing aircraft, but for rotary-wing aircraft, docking is performed as follows.

[0005] When a rotorcraft lands on a ship in a situation where there is significant turbulence, it hovers at a predetermined position without following the movement of the deck caused by the turbulence, and lands when the turbulence subsides. In this case, landing is only possible for about 10 seconds, for example, about once every five minutes. It was necessary to aim for such a short time to land the rotorcraft. If the rotorcraft was unable to land, it would have to wait for the next time the turbulence subsided. As such, it was difficult to repeatedly take off and land rotorcraft on a ship at any desired time, which was an operational limitation.

[0006] Therefore, an object of the present disclosure is to provide an aircraft position control system, an aircraft, and an aircraft position control method that can enable the aircraft to suitably track a target landing point even when the target landing point is unstable.

[0007] The aircraft position control system disclosed herein is an aircraft position control system that tracks the position of the aircraft in accordance with movement of a target landing point due to turbulence, and includes: a turbulence amount estimation processing unit that estimates a first turbulence amount of the target landing point based on an attitude-corrected acceleration that corrects the acceleration of the aircraft and a relative position between the aircraft and the target landing point; a turbulence amount prediction processing unit that predicts a second turbulence amount of the future target landing point based on the estimated first turbulence amount; a filtering processing unit that filters each of the first turbulence amount and the second turbulence amount predicted by the turbulence amount prediction processing unit so that the relative position becomes zero; and a model predictive control unit that performs model predictive control based on the estimated and filtered first turbulence amount and the filtered future second turbulence amount, and outputs a control amount for controlling the flight of the aircraft.

[0008] The aircraft of the present disclosure includes the above-mentioned aircraft position control system and a flight control unit that controls flight based on the control amount output from the position control system.

[0009] The aircraft position control method disclosed herein is a method for controlling the position of an aircraft that tracks the position of the aircraft in accordance with the movement of a target landing point due to turbulence, and includes the steps of: estimating a first amount of turbulence of the target landing point based on attitude-corrected acceleration corrected for the acceleration of the aircraft and the relative position between the aircraft and the target landing point; predicting a second amount of turbulence of the future target landing point based on the estimated first amount of turbulence; filtering each of the first amount of turbulence and the predicted second amount of turbulence so that the relative position becomes 0; and performing model predictive control based on the estimated first amount of turbulence and the future second amount of turbulence after filtering, and outputting a control amount for controlling the flight of the aircraft.

[0010] According to the present disclosure, even if the target landing point is subject to vibration, the aircraft can be made to suitably follow the movement of the target landing point due to the vibration.

[0011] FIG. 1 is a schematic configuration diagram showing an example of an aircraft position control system according to a first embodiment. FIG. 2 is an explanatory diagram showing a state in which an aircraft according to the first embodiment heads toward a target landing point. FIG. 3 is an explanatory diagram showing an example of a marker provided at a target landing point. FIG. 4 is a block diagram showing an example of a motion amount estimation process, a motion amount prediction process, a filtering process, and a model predictive control. FIG. 5 is a graph related to position control of an aircraft with respect to a target landing point. FIG. 6 is a block diagram showing an example of a motion amount estimation process, a motion amount prediction process, a filtering process, and a model predictive control of an aircraft position control system according to a second embodiment.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, this disclosure is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical. Furthermore, the components described below can be combined as appropriate, and when there are multiple embodiments, the respective embodiments can also be combined.

[0013] [First Embodiment] Fig. 1 is a schematic configuration diagram showing an example of an aircraft position control system according to a first embodiment. Fig. 2 is an explanatory diagram showing a state in which an aircraft according to the first embodiment heads toward a target landing point.

[0014] As shown in Figures 1 and 2, aircraft 1 is a rotary-wing aircraft (e.g., a helicopter, a drone, etc.). In this embodiment, aircraft 1 is an unmanned aircraft. Note that aircraft 1 may be any aircraft capable of forward, backward, sideways, turning, and hovering, and may also be a manned aircraft. Aircraft 1 is equipped with a portion of a position control system 100, and its flight is controlled by the position control system 100, causing it to land at a target landing point 2 shown in Figure 2.

[0015] (Target Landing Point) In the first embodiment, the target landing point 2 is provided on a ship 5, as shown in Fig. 2. Therefore, the aircraft 1 lands (landed) on the ship 5, which is a mobile body that moves on water. Although not shown, the ship 5 is provided with a restraining device for restraining the aircraft 1 when it lands at the target landing point 2. However, the target landing point 2 is not limited to the ship 5, and may be provided on a vehicle or the like, which is a mobile body that moves on the ground, or on stationary equipment or the ground.

[0016] A marker 7 is provided at the target landing point 2 so that the aircraft 1 can capture the position of the target landing point 2. FIG. 3 is an explanatory diagram showing an example of a marker provided at the target landing point. As shown in the figure, the marker 7 is an AR marker, for example, color-coded in two colors, black and white, and is a square marker. Note that the marker 7 is not limited to an AR marker and may be any marker that can capture the position of the target landing point 2 through image processing, such as an H mark or R mark indicating a landing point of a heliport. Furthermore, the marker 7 may be a plurality of markers of different shapes provided on the ship 5, and the aircraft 1 may be guided to the target landing point 2 corresponding to one of the different markers 7. Furthermore, in this embodiment, the marker 7 is provided on the ship 5 to capture the position of the target landing point 2, but is not particularly limited as long as it is configured to be able to acquire the position of the target landing point 2.

[0017] (Position Control System) The aircraft position control system 100 according to this embodiment is a system that controls the position of the aircraft 1 in flight so as to land the aircraft 1 at a target landing point 2. The position control system 100 is installed both on the aircraft 1 and on the ship 5. As shown in FIG. 1 , the aircraft 1 includes a camera 10, a navigation device 20, an altitude sensor 25, an image processing unit 32, a guidance calculation unit 34, a flight control unit 36, and a data transmission device 40. The ship 5 includes the marker 7, a navigation device 70, a data transmission device 80, and an operation and display unit 90. The position control system 100 includes the camera 10, the image processing unit 32, the guidance calculation unit 34, and the data transmission device 40 in the aircraft 1, and the marker 7, the navigation device 70, the data transmission device 80, and the operation and display unit 90 in the ship 5.

[0018] (Ship) As shown in Fig. 1 , the ship 5 includes a navigation device 70, a data transmission device 80, and an operation display unit 90. The navigation device 70 is, for example, an inertial navigation system (INS), and acquires the pitch and roll attitude angles of the ship 5, heading, speed, acceleration, and position coordinates in a global coordinate system. In this embodiment, the navigation device 70 is described as being an inertial navigation system, but is not particularly limited, and any navigation device 70 may be used. In this embodiment, the navigation device 70 is an inertial navigation system that includes a global positioning system (GPS) as a position measurement unit in order to improve the position measurement accuracy. In this embodiment, the present invention will be described as being applied to an inertial navigation system including a GPS. However, the present invention is not limited to a GPS system and any position measurement unit capable of measuring the position with high accuracy may be used. For example, a quasi-zenith satellite system may be used. Alternatively, if the position can be measured with high accuracy using the navigation device 70 alone, a position measurement unit such as a GPS may be omitted. The navigation device 70 may also acquire at least some of the various data using a sensor. The data transmission device 80 is included in the position control system 100 and exchanges various signals with the data transmission device 40 installed on the aircraft 1 via wireless communication. The operation and display unit 90 is a user interface through which an operator on board the ship 5 grasps the control status and inputs various instructions. The instructions input via the operation and display unit 90 are transmitted from the data transmission device 80 to the data transmission device 40. The control status of the aircraft 1 is also transmitted from the data transmission device 40 to the data transmission device 80. In other words, the data transmission devices 40 and 80 are capable of two-way communication.

[0019] (Aircraft) As shown in Figures 1 and 2, the aircraft 1 includes a camera 10, a navigation device 20, an altitude sensor 25, an image processing unit 32, a guidance calculation unit 34, a flight control unit 36, and a data transmission device 40.

[0020] The camera 10 is an imaging device mounted on the aircraft 1 via a gimbal (not shown). The camera 10 may be a monocular camera, a compound eye camera, an infrared camera, or the like, as long as it can capture an image of the marker 7. The camera 10 is provided to capture an image of the marker 7 provided at the target landing point 2 from the aircraft 1. The imaging direction of the camera 10 is adjustable via a gimbal (not shown). In this embodiment, the camera 10 is controlled so that its imaging range B (see FIG. 2 ) faces directly downward in the vertical direction, for example. Note that the camera 10 may also be controlled so that the imaging range B faces diagonally forward with respect to the vertical direction. Alternatively, the gimbal may be omitted, and the camera 10 may be fixed directly below the body of the aircraft 1 so that the imaging direction faces downward in the vertical direction.

[0021] The navigation device 20 is, for example, an inertial navigation system (INS), similar to the navigation device 70. Note that, similar to the navigation device 70, the navigation device 20 may be an inertial navigation system including a position measurement unit such as a GPS, or an inertial navigation system omitting a position measurement unit such as a GPS, and is not particularly limited.

[0022] The navigation device 20, which includes a GPS, acquires the attitude angles in the roll, yaw, and pitch directions of the aircraft 1, the aircraft speed, inertial velocity, aircraft acceleration, heading, and position coordinates in the Earth coordinate system of the aircraft 1. The navigation device 20 may also include an attitude angle sensor that detects the attitude angle of the aircraft 1, a speed sensor that detects the aircraft speed of the aircraft 1, an acceleration sensor that detects the aircraft acceleration of the aircraft 1, and a sensor that detects the heading of the aircraft 1. The navigation device 20 outputs the acquired attitude angle, aircraft speed, inertial velocity, aircraft acceleration, heading, and position coordinates of the aircraft 1 to the flight control unit 36.

[0023] As shown in FIG. 1 , the position control system 100 also includes an altitude sensor 25 that detects the altitude of the aircraft 1 above the ground or water surface. The altitude sensor 25 is, for example, a laser altimeter, and measures the relative altitude Δh (see FIG. 2 ) from the aircraft 1 to the target landing point 2. The altitude sensor 25 may be a radio altimeter, a barometric altimeter, or any other altimeter. These altimeters may be used in combination depending on the usage environment, i.e., to measure the altitude above the ground or the altitude above sea level. The altitude sensor 25 outputs the detected relative altitude Δh of the aircraft 1 to the flight control unit 36. The altitude sensor 25 may measure the altitude of the aircraft 1 and output it to the flight control unit 36, and the guidance calculation unit 34 (described later) may calculate the relative altitude Δh to the target landing point 2 based on the altitude of the aircraft 1. Furthermore, the position control system 100 may calculate the relative altitude Δh between the aircraft 1 and the ship 5 by performing image processing on an image including the marker 7 captured by the camera 10 in the image processing unit 32 described later, instead of using the altitude sensor 25.

[0024] The image processing unit 32 performs image processing on the image captured by the camera 10 to calculate the center (Cx, Cy) of the marker 7, i.e., the target landing point 2 (see FIG. 3 ). The center (Cx, Cy) here is a coordinate point in a camera-fixed coordinate system with the center of the image captured by the camera 10 as the origin, and can be calculated based on the number of pixels from the center of the image. Specifically, as shown in FIG. 3 , the image processing unit 32 identifies two diagonal lines Ld extending between the corners of the marker 7 through image processing, and determines the intersection of the two identified diagonal lines Ld as the center (Cx, Cy) of the marker 7. Note that the target landing point 2 is not limited to the center (Cx, Cy) of the marker 7, but may be one of the four corners of the marker 7 or a position offset from the center of the marker 7. The image processing unit 32 outputs the calculated center (Cx, Cy) of the marker 7 to the guidance calculation unit 34.

[0025] Furthermore, the image processing unit 32 may perform image processing on the image including the marker 7 captured by the camera 10 to identify the orientation of the marker 7, and may calculate the heading direction of the ship 5 by correlating it with the heading direction of the aircraft 1 acquired by the navigation device 20. Note that, as described above, the image processing unit 32 may calculate the relative altitude Δh between the aircraft 1 and the ship 5 by performing image processing on the image including the marker 7 captured by the camera 10.

[0026] The guidance calculation unit 34 calculates control variables for the aircraft 1 to guide the aircraft 1 to the target landing point 2. The control variables are variables for adjusting the aircraft speed, attitude angle, rate of change of attitude angle, etc. of the aircraft 1. In order to calculate the control variables, the guidance calculation unit 34 calculates the relative coordinate position between the aircraft 1 and the target landing point 2. Specifically, the guidance calculation unit 34 calculates the relative position (X, Y) between the aircraft 1 and the target landing point 2 and the relative altitude Δh between the aircraft 1 and the target landing point 2 as the relative coordinate position. The guidance calculation unit 34 also calculates the relative speed between the aircraft 1 and the target landing point 2, etc. The relative position (X, Y) is the distance between the aircraft 1 and the target landing point 2 in the horizontal direction. The relative altitude Δh is the distance between the aircraft 1 and the target landing point 2 in the vertical direction.

[0027] The guidance calculation unit 34 calculates the relative position (X, Y) between the aircraft 1 and the target landing point 2 based on the center (Cx, Cy) of the marker 7 calculated by the image processing unit 32, the orientation of the camera 10 (i.e., the heading of the aircraft 1), and the altitude of the aircraft 1 (relative altitude Δh with respect to the target landing point 2). In this embodiment, the orientation of the camera 10 and the heading of the aircraft 1 are made to coincide, but this is not particularly limited, and the orientation of the camera 10 and the heading of the aircraft 1 do not have to coincide. In this way, the image processing unit 32 and the guidance calculation unit 34 acquire the relative position between the aircraft 1 and the target landing point 2.

[0028] Furthermore, the guidance calculation unit 34 calculates the relative altitude Δh to the target landing point 2 based on the altitude of the aircraft 1 detected by the altitude sensor 25. Therefore, the altitude sensor 25 and the guidance calculation unit 34 acquire the relative altitude Δh between the aircraft 1 and the target landing point 2. Note that the image processing unit 32 may calculate the relative altitude Δh between the aircraft 1 and the ship 5 by performing image processing on an image including the marker 7 captured by the camera 10.

[0029] The guidance calculation unit 34 also calculates the relative speed between the aircraft 1 and the target landing point 2. Therefore, the guidance calculation unit 34 acquires the relative speed between the aircraft 1 and the target landing point 2. More specifically, the guidance calculation unit 34 executes a relative speed estimation process to calculate the relative speed (ΔVx, ΔVy) between the aircraft 1 and the target landing point 2 based on the relative position (X, Y) and the aircraft speed (Vx, Vy). Therefore, the guidance calculation unit 34 acquires the relative speed (ΔVx, ΔVy) between the aircraft 1 and the target landing point 2.

[0030] The guidance calculation unit 34 then calculates the control variable C' by model predictive control based on the relative position (X, Y), relative altitude Δh, relative velocity (ΔVx, ΔVy), and aircraft acceleration. The guidance calculation unit 34 outputs the calculated control variable C' to the flight control unit 36.

[0031] The flight control unit 36 ​​controls each component of the aircraft 1 in accordance with the control amount calculated by the guidance calculation unit 34, thereby flying the aircraft 1. The flight control unit 36 ​​controls the blade pitch angle, rotation speed, etc. of each rotor in accordance with the control amount, and adjusts the aircraft speed, attitude angle, rate of change of attitude angle, etc. of the aircraft 1. In this way, the aircraft 1 is guided to the target landing point 2. Note that in this embodiment, the image processing unit 32 and the guidance calculation unit 34 are described as functional units separate from the flight control unit 36, but the flight control unit 36, image processing unit 32, and guidance calculation unit 34 may be an integrated functional unit. In other words, the processing of the image processing unit 32 and the guidance calculation unit 34 may be performed in the flight control unit 36.

[0032] The data transmission device 40 exchanges various signals with a data transmission device 80 mounted on the ship 5 via wireless communication.

[0033] (Aircraft Position Control) Next, position control of the aircraft 1 according to this embodiment will be described with reference to Fig. 4. Fig. 4 is a block diagram showing an example of vibration amount estimation processing, vibration amount prediction processing, filter processing, and model predictive control. In the position control of the aircraft 1, the guidance calculation unit 34 performs position control related to target point tracking hovering, which causes the position of the aircraft 1 to track in accordance with the movement of the target landing point 2 due to vibration, based on the block diagram shown in Fig. 4. For this reason, the guidance calculation unit 34 calculates a control amount C' of the aircraft 1 for performing target point tracking hovering.

[0034] As shown in FIG. 4, the guidance calculation unit 34 includes a motion amount estimation processing unit 51, a motion amount prediction processing unit 52, a filter processing unit 53, and a model prediction control unit 54.

[0035] The vibration amount estimation processing unit 51 performs processing to estimate the vibration amount (first vibration amount) of the target landing point 2 that changes due to vibration. The vibration amount estimation processing unit 51 estimates the vibration amount based on the attitude corrected acceleration and the relative position (X, Y). The vibration amount estimation processing unit 51 includes a Kalman filter 61, a smoothing processing unit 62, a low-pass filter 63, and a subtraction circuit unit 66.

[0036] The Kalman filter 61 performs estimation based on the relative position (X, Y) and outputs the estimated relative position (X, Y) after estimation. Specifically, the relative position (X, Y) calculated by the guidance calculation unit 34 is input to the Kalman filter 61. When the relative position (X, Y) is input, the Kalman filter 61 calculates an estimated relative position (X, Y) by estimating a change in the relative position (X, Y) over time. The Kalman filter 61 outputs the calculated estimated relative position (X, Y) to the smoothing processing unit 62 and the subtraction circuit unit 66.

[0037] The smoothing processing unit 62 performs processing to calculate a smoothed relative position, which is an average relative position, even when the target landing point 2 changes due to shaking. The smoothing processing unit 62 outputs a smoothed relative position (X, Y) obtained by smoothing the estimated relative position (X, Y) based on the attitude-corrected acceleration and the estimated relative position (X, Y). Specifically, the attitude-corrected acceleration and the estimated relative position (X, Y) calculated by the Kalman filter 61 are input to the smoothing processing unit 62. The attitude-corrected acceleration is obtained by correcting the acceleration of the aircraft 1 based on the acceleration of the aircraft 1 and the attitude of the aircraft 1 acquired by the navigation device 20. When the attitude-corrected acceleration and the estimated relative position (X, Y) are input, the smoothing processing unit 62 calculates the smoothed relative position (X, Y). The smoothing processing unit 62 then outputs the calculated smoothed relative position (X, Y) to the subtraction circuit unit 66.

[0038] The subtraction circuit unit 66 outputs the amount of fluctuation based on the estimated relative position (X, Y) and the smoothed relative position (X, Y). Specifically, the subtraction circuit unit 66 calculates the difference between the estimated relative position (X, Y) and the smoothed relative position (X, Y) and outputs the calculated amount of fluctuation to the low-pass filter 63.

[0039] The low-pass filter 63 is a filter that attenuates frequencies equal to or higher than a predetermined cutoff frequency of the fluctuation amount input from the subtraction circuit unit 66. The low-pass filter 63 removes high-frequency components from the fluctuation amount and outputs low-frequency components included in the fluctuation amount to the fluctuation amount prediction processing unit 52 and the model prediction control unit 54.

[0040] The fluctuation amount prediction processing unit 52 predicts a future fluctuation amount based on the fluctuation amount output from the fluctuation amount estimation processing unit 51. The fluctuation amount prediction processing unit 52 uses a prediction logic 67 and processes the input fluctuation amount using the prediction logic 67 to calculate a fluctuation amount that will be a predicted value. The fluctuation amount prediction processing unit 52 outputs the calculated fluctuation amount that will be a predicted value to the filter processing unit 53.

[0041] The filter processing unit 53 filters the vibration amount (second vibration amount) output from the vibration amount prediction processing unit 52 so that the relative position (X, Y) between the aircraft 1 and the target landing point 2 becomes zero. The filter processing unit 53 includes a high-pass filter 68 and a gain 69. The filter processing unit 53 is equipped with a high-pass filter 68 and a gain 69 for the first vibration amount, and a high-pass filter 68 and a gain 69 for the second vibration amount. The high-pass filter 68 and the gain 69 may be common to the first vibration amount and the second vibration amount.

[0042] The high-pass filter 68 is a filter that attenuates, with a predetermined time constant, frequencies equal to or lower than a predetermined cutoff frequency for each of the fluctuation amount input from the fluctuation amount estimation processing unit 51 and the fluctuation amount input from the fluctuation amount prediction processing unit 52. The high-pass filter 68 removes low-frequency components from the fluctuation amount and outputs high-frequency components included in the fluctuation amount to a gain 69.

[0043] The gain 69 is a filter that multiplies the fluctuation amount input from the high-pass filter 68 by a predetermined sensitivity coefficient. The gain 69 outputs the fluctuation amount multiplied by the predetermined sensitivity coefficient to the model prediction control unit 54.

[0044] The model predictive control unit 54 calculates the control variable C' by performing model predictive control (MPC) based on the vibration amount. The model predictive control unit 54 receives, as vibration amounts, the vibration amount that is an estimated value filtered by the filter processing unit 53 and the vibration amount that is a predicted value calculated by the vibration amount prediction processing unit 52 and filtered by the filter processing unit 53. The model predictive control unit 54 performs model predictive control based on the vibration amount that is the estimated value and the vibration amount that is the predicted value to calculate the control variable C'. The model predictive control unit 54 then outputs the calculated control variable C' to the flight control unit 36. More specifically, the model predictive control unit 54 calculates and sets target values ​​including a target relative position and a target relative velocity by assigning the vibration amount that is the predicted value to a target vibration amount based on the vibration amount that is the estimated value and the vibration amount that is the predicted value. The model predictive control unit 54 also receives, as input, estimated values ​​including a relative position and a relative velocity calculated using a previously set simple model of the aircraft 1. Specifically, the estimated value input to the model predictive control unit 54 is calculated using a simple model of the aircraft 1 based on the weighted input parameters, with weighting being applied to each of the input parameters including the relative position between the aircraft 1 and the target landing point 2, the relative velocity between the aircraft 1 and the target landing point 2, the attitude angle of the aircraft 1, and the angular velocity of the attitude angle. The model predictive control unit 54 calculates the control variable C' so that the estimated value including the relative position and relative velocity becomes a target value including the relative position and relative velocity.

[0045] The flight control unit 36 ​​executes flight control based on the control amount C'. As an example of flight control by the flight control unit 36, if the aircraft 1 is a helicopter, flight control is performed to tilt the helicopter's main rotor in the vertical and horizontal directions, thereby executing target point tracking hovering in which the relative position with respect to the target landing point 2 is zero.

[0046] (Aircraft Position Control Method) Next, a position control method using the position control system 100 of the aircraft 1 according to the first embodiment will be described with reference to Fig. 4. Note that the following describes the position control method when the aircraft 1 is a helicopter.

[0047] In the position control method for the aircraft 1, first, the relative position (X, Y) is acquired, and attitude corrected acceleration is acquired (step S1) based on the acceleration of the aircraft 1 and the attitude of the aircraft 1. In step S1, since the position control is related to the relative position (X, Y), attitude corrected acceleration in the longitudinal and lateral directions of the helicopter main rotor is acquired.

[0048] Next, in the position control method for the aircraft 1, the vibration amount estimation processing unit 51 calculates and outputs an estimated vibration amount based on the attitude corrected acceleration and the relative position (X, Y) (step S2). In step S2, the difference between the estimated relative position (X, Y) and the smoothed relative position (X, Y) is calculated, and this difference is calculated as the vibration amount.

[0049] Thereafter, in the position control method for the aircraft 1, the motion amount prediction processing unit 52 uses the prediction logic 67 to calculate and output a predicted value of the motion amount based on the estimated value of the motion amount (step S3).

[0050] Next, in the position control method for aircraft 1, after step S3 is executed, the output predicted value of the amount of vibration and the output estimated value of the amount of vibration in step S2 are filtered in the filter processing unit 53 and output (step S4).

[0051] Then, in the position control method for aircraft 1, after executing step S4, model predictive control is performed based on values ​​obtained by filtering the estimated value of the vibration amount output in step S2 and the predicted value of the vibration amount output in step S3, and a control amount C' is calculated and output to the flight control unit 36 ​​(step S5).

[0052] Next, position control of the aircraft 1 relative to the target landing point 2 will be described with reference to Fig. 5. Fig. 5 is a graph relating to position control of the aircraft relative to the target landing point. In Fig. 5, the horizontal axis represents time and the vertical axis represents the amount of oscillation. Fig. 5 illustrates the true value of the amount of oscillation of the ship 5 (target landing point 2), the amount of oscillation calculated by a conventional method, and the amount of oscillation calculated by the method of the present disclosure. An example of the conventional method is feedback control (e.g., PID control).

[0053] 5 shows, from top to bottom, cases where the fluctuation amount changes in 5-second, 10-second, and 20-second cycles, and also shows cases where the fluctuation amount changes slightly and cases where the fluctuation amount changes significantly. In FIG. 5, when the fluctuation amount is in a 10-second cycle, the fluctuation amount obtained by the conventional method and the method of the present disclosure are nearly identical with respect to the fluctuation amount that becomes the true value. On the other hand, when the fluctuation amount is in a 5-second cycle or a 20-second cycle, when the fluctuation amount changes slightly or significantly, the fluctuation amount obtained by the conventional method lags significantly behind the fluctuation amount that becomes the true value compared to the fluctuation amount obtained by the method of the present disclosure. In other words, it was confirmed that the fluctuation amount obtained by the method of the present disclosure lags less behind the fluctuation amount that becomes the true value compared to the fluctuation amount obtained by the conventional method.

[0054] [Second Embodiment] Next, a second embodiment will be described with reference to Fig. 6. In the second embodiment, to avoid redundant description, only parts different from the first embodiment will be described, and parts having the same configuration as the first embodiment will be described using the same reference numerals. Fig. 6 is a block diagram showing an example of a motion amount estimation process, a motion amount prediction process, a filter process, and a model predictive control of an aircraft position control system according to the second embodiment.

[0055] In the position control system 100 of the second embodiment, a motion amount estimation processing unit 110, a motion amount prediction processing unit 52, and a filter processing unit 53 are provided on the ship 5 side, and a model prediction control unit 54 is provided on the aircraft 1 side. The position control system 100 uploads the motion amount calculated on the ship 5 side from the data transmission device 80 of the ship 5 to the model prediction control unit 54 via the data transmission device 40 of the aircraft 1.

[0056] The motion amount estimation processing unit 110 performs processing to estimate the motion amount of the target landing point 2 that changes due to motion. The motion amount estimation processing unit 110 estimates the motion amount based on the attitude corrected acceleration of the ship 5 and the position of the ship 5 (the center (Cx, Cy) of the target landing point 2). The motion amount estimation processing unit 110 outputs the motion amount that is the estimated value to the motion amount prediction processing unit 52 and also to the filter processing unit 53. Note that the motion amount prediction processing unit 52 and the filter processing unit 53 are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0057] On the ship 5 side, the motion amount calculated by the motion amount estimation processing unit 110 and filtered by the filter processing unit 53 to become the estimated value, and the motion amount calculated by the motion amount prediction processing unit 52 and filtered by the filter processing unit 53 to become the predicted value are uploaded from the data transmission device 80 of the ship 5 to the aircraft 1. On the aircraft 1 side, the data transmission device 40 acquires the motion amount to become the estimated value and the motion amount to become the predicted value, and outputs them to the model prediction control unit 54. The model prediction control unit 54 executes model predictive control based on the motion amount to become the estimated value and the motion amount to become the predicted value, calculates a control amount C', and outputs it to the flight control unit 36.

[0058] As described above, the aircraft position control system, aircraft, and aircraft position control method described in the first and second embodiments can be understood, for example, as follows.

[0059] A position control system 100 of an aircraft 1 according to a first aspect is an aircraft position control system that causes the position of the aircraft 1 to track in accordance with movement of a target landing point 2 due to turbulence, and includes: a turbulence amount estimation processing unit 51 that estimates a first turbulence amount of the target landing point 2 based on an attitude-corrected acceleration obtained by correcting the acceleration of the aircraft 1 and a relative position between the aircraft 1 and the target landing point 2; a turbulence amount prediction processing unit 52 that predicts a second turbulence amount of the future target landing point 2 based on the estimated first turbulence amount; a filtering processing unit 53 that filters each of the first turbulence amount estimated by the turbulence amount estimation processing unit 51 and the second turbulence amount predicted by the turbulence amount prediction processing unit 52 so that the relative position becomes zero; and a model predictive control unit 54 that executes model predictive control based on the estimated and filtered first turbulence amount and the filtered future second turbulence amount, and outputs a control amount C′ for controlling the flight of the aircraft 1.

[0060] According to this configuration, by executing model predictive control based on the estimated amount of vibration and the predicted amount of vibration, the amount of vibration can be accurately determined, and the control variable C' corresponding to the amount of vibration can be accurately calculated, thereby making it possible to bring the relative position closer to 0. Therefore, even if the target landing point is vibrating, the aircraft can be made to suitably track the target landing point. In this case, by filtering the predicted amount of vibration, the convergence of the amount of vibration can be improved, and the aircraft can be made to stably track the target landing point.

[0061] As a second aspect, in the position control system 100 of the aircraft 1 according to the first aspect, the filter processing unit 53 has a high-pass filter 68 to which the first vibration amount is input and which has a predetermined time constant, a gain 69 to which the first vibration amount output from the high-pass filter 68 is input, a high-pass filter 68 to which the second vibration amount is input and which has a predetermined time constant, and a gain 69 to which the second vibration amount output from the high-pass filter 68 is input.

[0062] According to this configuration, the convergence of the fluctuation amount can be further improved by using a simple configuration using the high-pass filter 68 and the gain 69 .

[0063] As a third aspect, in the position control system 100 of the aircraft 1 relating to the first or second aspect, the model predictive control unit 54 calculates a target value based on the first amount of vibration and the second amount of vibration, calculates an estimated value based on the relative position, the relative velocity between the aircraft and the target landing point, the attitude angle of the aircraft, and the angular velocity of the attitude angle, and calculates the control variable C' so that the estimated value becomes the target value.

[0064] According to this configuration, the control amount C′ corresponding to the flight operation of the aircraft 1 can be calculated with high accuracy.

[0065] The aircraft 1 according to the fourth aspect includes the position control system 100 for the aircraft 1 described above, and a flight control unit 36 ​​that controls flight based on the control amount C′ output from the position control system 100.

[0066] This configuration allows the flight of the aircraft 1 to be controlled so that it can appropriately follow the target landing point 2 that is vibrating.

[0067] A position control method for an aircraft 1 according to a fifth aspect is a position control method for an aircraft 1 that causes the position of the aircraft 1 to track in accordance with the movement of a target landing point 2 due to turbulence, and includes the following steps: a step S2 of estimating a first amount of turbulence of the target landing point 2 based on an attitude-corrected acceleration obtained by correcting the acceleration of the aircraft 1 and the relative position between the aircraft 1 and the target landing point 2; a step S3 of predicting a second amount of turbulence of the future target landing point 2 based on the estimated first amount of turbulence; a step S4 of filtering each of the first amount of turbulence and the predicted second amount of turbulence so that the relative position becomes 0; and a step S5 of performing model predictive control based on the estimated first amount of turbulence and the future second amount of turbulence after filtering, and outputting a control variable C' for controlling the flight of the aircraft 1.

[0068] According to this configuration, by executing model predictive control based on the estimated amount of vibration and the predicted amount of vibration, the amount of vibration can be accurately determined, and the control variable C' corresponding to the amount of vibration can be accurately calculated, thereby making it possible to bring the relative position closer to 0. Therefore, even if the target landing point is vibrating, the aircraft can be made to suitably track the target landing point. In this case, by filtering the predicted amount of vibration, the convergence of the amount of vibration can be improved, and the aircraft can be made to stably track the target landing point.

[0069] Furthermore, in this embodiment, the processing target is the relative position in the horizontal plane, i.e., the amount of vibration in the XY plane. However, this is not limited to this. The position control system may process the amount of vibration of the relative position in three-dimensional space, including not only the horizontal direction but also the Z direction (direction of distance Δh) perpendicular to the XY plane. Furthermore, the processing target may be the amount of vibration in the XZ plane and the YZ plane based on the relative positions in the XZ plane and the YZ plane. The position control system may process the amount of vibration based on the relative positions on each of the X axis, Y axis, and Z axis. By performing the above processing, the position control system can also evaluate the amount of vibration in the vertical direction, thereby improving the accuracy of position control.

[0070] REFERENCE SIGNS LIST 1 aircraft 2 target landing point 5 ship 7 marker 10 camera 20 navigation device 32 image processing unit 34 guidance calculation unit 36 ​​flight control unit 40 data transmission device 51 motion amount estimation processing unit 52 motion amount prediction processing unit 53 filter processing unit 54 model prediction control unit 61 Kalman filter 62 smoothing processing unit 63 low-pass filter 66 subtraction circuit unit 68 high-pass filter 69 gain 70 navigation device 80 data transmission device 90 operation display unit 100 position control system

Claims

1. An aircraft position control system that tracks the position of an aircraft in accordance with movement of a target landing point due to vibration, a vibration amount estimation processing unit that estimates a first vibration amount of the target landing point based on an attitude corrected acceleration obtained by correcting the acceleration of the aircraft and a relative position between the aircraft and the target landing point; a motion amount prediction processing unit that predicts a second motion amount of the target landing point in the future based on the estimated first motion amount; a filter processing unit that filters the first vibration amount and the second vibration amount predicted by the vibration amount prediction processing unit in order to set the relative position to 0; a model predictive control unit that executes model predictive control based on the first fluctuation amount after filtering and the second fluctuation amount in the future after filtering, and outputs a control amount for controlling the flight of the aircraft.

2. The filter processing unit a high-pass filter to which the first fluctuation amount is input and which has a predetermined time constant; a gain to which the first fluctuation amount output from the high-pass filter is input; a high-pass filter to which the second fluctuation amount is input and which has a predetermined time constant; 2. The aircraft position control system according to claim 1, further comprising: a gain to which the second vibration amount output from the high-pass filter is input.

3. The model prediction control unit calculating a target value based on the first amount of fluctuation and the second amount of fluctuation; calculating an estimated value based on the relative position, the relative velocity between the aircraft and the target landing point, an attitude angle of the aircraft, and an angular velocity of the attitude angle; The aircraft position control system according to claim 1 , wherein the control variable is calculated so that the estimated value becomes the target value.

4. An aircraft position control system according to any one of claims 1 to 3; a flight control unit that controls flight based on the control amount output from the position control system.

5. A method for controlling the position of an aircraft, which controls the position of the aircraft to follow the movement of a target landing point due to vibration, comprising: estimating a first amount of vibration of the target landing point based on an attitude corrected acceleration obtained by correcting the acceleration of the aircraft and a relative position between the aircraft and the target landing point; predicting a second amount of vibration of the target landing point in the future based on the estimated first amount of vibration; filtering the first amount of motion and the predicted second amount of motion to zero the relative position; a step of executing model predictive control based on the first fluctuation amount after filtering and the second fluctuation amount in the future after filtering, and outputting a control amount for controlling the flight of the aircraft.