A helicopter half-roll maneuver control method

Abstract

The present invention provides a helicopter half-roll maneuver control method, comprising: 1) maneuver process decomposition: based on the characteristics of the helicopter half-roll maneuver mechanism, the method is decomposed into four stages: entry, half-roll, dive and pull-up, and recovery; 2) maneuver control mode and control instruction design: corresponding control modes are designed according to different flight stages, roll angular velocity is designed to be maintained in the half-roll stage, and the collective pitch input is adjusted according to the roll angle; pitch angular velocity is designed to be maintained in the dive and pull-up stage, and the collective pitch input is adjusted according to the pitch angle; 3) visual simulation verification: a joint simulation environment of Matlab and FlightGear is constructed based on the UDP network communication mechanism, and a data protocol for maneuver instruction input and flight parameter feedback is formulated to realize visual simulation verification of the maneuver process. Visual simulation shows that the present invention can effectively complete the helicopter half-roll maneuver flight. During the confrontation process, altitude is exchanged for speed, reverse direction is quickly achieved, and the passive lock state is switched to the active attack state, providing a theoretical basis for further engineering tests of helicopter half-roll maneuvers.

Description

Technical Field

[0001] The present invention relates to the field of large maneuvering flight of helicopters, and in particular to a method for controlling half-roll and reverse maneuvering of helicopters. Background Art

[0002] Due to their advantages of rapid response and maneuverability, helicopters are increasingly being used in complex environments such as battlefields, mountainous areas, and plateaus. Improving helicopter maneuverability is an effective means of ensuring their battlefield survivability. Helicopter maneuverability allows them to track and target fast-moving targets in complex environments, and rapidly change flight path and altitude to evade attack, significantly enhancing mission capabilities and survivability. Helicopter maneuverability has long been a hot research topic. Maneuvering allows helicopters to track and target fast-moving targets in complex environments, and rapidly change flight path and altitude to evade attack, significantly enhancing mission capabilities and survivability. Maneuverability is a highly complex process, involving multiple fields such as aircraft design, flight dynamics, flight control, and intelligent decision-making. Currently, maneuverability design, maneuverable aircraft modeling, and maneuverable controllers remain challenging research challenges and hot topics in this field. While most helicopter research has focused on stable flight, in recent years, increasing research has focused on helicopter maneuverability. Existing research methods include simulation, flight simulation, and actual flight maneuver testing. The difficulty of helicopter maneuver flight control lies in the serious aerodynamic and control coupling during maneuver flight, the significant increase in modeling uncertainty and disturbance factors, and the severe test of the helicopter's own structural strength. Therefore, it is necessary to design a control strategy with a reasonable control structure and smooth maneuver command switching.

[0003] This patent investigates a control method for helicopter half-roll maneuvers. The goal is to rapidly achieve reverse flight maneuvers by converting the helicopter's current altitude to forward flight speed in combat situations on the battlefield, effectively mitigating the shift from passive attack to active strike. Because this maneuver involves extreme maneuvers such as 180-degree rolls, dives, and pull-ups, designing a practical control method for helicopter half-roll maneuvers is crucial. Summary of the Invention

[0004] In order to solve the problems in the existing technology, this application analyzes the mechanism of the helicopter's half-roll and inverted maneuver, designs corresponding control modes and control instructions according to the maneuvering state, and uses visual simulation to carry out half-roll and inverted maneuver flight simulation for a certain type of helicopter, providing an effective technical approach for further conducting helicopter maneuver flight tests.

[0005] Technical Solution

[0006] The present application provides a method for controlling a helicopter half-roll maneuver, the method comprising the following steps:

[0007] S1, decomposing the helicopter half-roll inversion maneuver into four stages, including: entry stage, half-roll stage, dive and pull-up stage, and recovery stage;

[0008] S2, design the control mode for each stage respectively, and design the control mode and control instructions according to the real-time flight status and flight trajectory of each stage in the maneuvering process.

[0009] Furthermore, in the entry section, the four-channel control modes are: the longitudinal channel adopts speed keeping control, the lateral channel adopts position keeping control, the heading channel adopts yaw angle keeping control, and the vertical channel adopts altitude keeping control.

[0010] Furthermore, the control instructions for entering the segment four channel are:

[0011]

[0012] Where θ c Enter the command for the desired pitch angle, is the longitudinal speed PID control gain; u c is the longitudinal speed setting value, u is the longitudinal speed, θ trim is the pitch angle trim value; φ c Input command for roll angle, is the lateral position PID control gain, Y c is the lateral position command, Y is the lateral position, v is the lateral velocity; ψ c is the yaw angle command, h c For height instructions.

[0013] Furthermore, in the half-roll segment, the real-time roll angle status is divided into two stages: in the first stage, when the roll angle changes from 0 degrees to 90 degrees, the longitudinal direction adopts pitch angle hold control, the lateral channel adopts roll angle velocity tracking control, the heading channel adopts yaw angle hold control, and the vertical channel adopts collective pitch direct control;

[0014] In the second section, when the roll angle changes from 90 degrees to 180 degrees, the longitudinal channel adopts pitch angular velocity maintenance control, the lateral channel adopts roll angular velocity maintenance control, the heading channel adopts yaw angular velocity maintenance control, and the vertical channel adopts direct control of the total distance.

[0015] Furthermore, in the half-roll segment, when the roll angle changes from 0 degrees to 90 degrees, the half-roll segment control instruction is:

[0016]

[0017] When the roll angle changes from 90 degrees to 180 degrees, the half-roll segment control instructions are:

[0018]

[0019] Where p0 is the initial roll angular velocity, p c is the desired roll angular velocity, q c is the desired pitch angular velocity, δ c is the collective distance command, δ c0 is the total distance during hovering, δ c1 is the total distance in inverted flight and hovering, and φ is the roll angle.

[0020] Furthermore, in the dive and pull-up phase, the aircraft is divided into two stages according to the pitch angle value: in the first stage, when the pitch angle changes from 0 degrees to -90 degrees, the longitudinal direction adopts pitch angle velocity tracking control, the lateral channel adopts roll angle velocity maintenance control, the heading channel adopts yaw angle velocity control, and the vertical channel adopts collective pitch direct control;

[0021] In the second stage, when the pitch angle changes from -90 degrees to 0 degrees, the longitudinal channel adopts pitch angle velocity maintenance control, the lateral channel adopts roll angle tracking control, the heading channel adopts yaw angle tracking control, and the vertical channel adopts collective distance direct control.

[0022] Furthermore, in the dive and pull-up phase, when the pitch angle changes from 0 degrees to -90 degrees, the input command is:

[0023]

[0024] When the pitch angle changes from -90 degrees to 0 degrees, the command is:

[0025]

[0026] Where θ is the pitch angle.

[0027] Furthermore, in the recovery phase, the four-channel control modes are: speed control in the longitudinal direction, speed control in the lateral channel, yaw angle control in the heading channel, and altitude control in the vertical channel.

[0028] Furthermore, in the change-out section, the input instruction is:

[0029]

[0030] Where, is the expected altitude after recovery from a half-roll maneuver, u′ c 、v′ c They are respectively the longitudinal speed command after correction and the lateral speed command after correction.

[0031] Beneficial effects

[0032] The implementation plan of this application analyzes the half-roll inversion maneuver, determines the flight status of the helicopter in each stage, and divides it into four stages: entry stage, half-roll stage, dive and pull-up stage, and recovery stage. The corresponding flight mode is then selected for each of the four stages. The flight mode is decomposed to obtain the control mode of the four channels, and then the control instructions for the maneuvering flight are designed based on the real-time flight status and flight trajectory. A helicopter maneuvering flight simulation environment based on Matlab and FlightGear is constructed, and the control method is verified by visual simulation, which can intuitively grasp the real maneuvering flight process of the helicopter.

[0033] The present invention has the following advantages: (1) the half-roll reverse maneuver is segmented, which is convenient for designing control modes and control instructions and simplifies the design process; (2) the roll angular velocity is designed to be maintained in the half-roll segment, and the collective pitch input is adjusted according to the roll angle; the pitch angular velocity is designed to be maintained in the dive pull-up segment, and the collective pitch input is adjusted according to the pitch angle, thereby reducing the coupling between channels during the control mode switching process and the influence of factors such as state jump caused by the control instruction switching; (3) the helicopter maneuver flight simulation environment constructed using Matlab and FlightGear can not only intuitively grasp the real maneuver flight process of the helicopter, but also avoid aircraft damage caused by unreasonable control mode design, thereby improving design efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the overall block diagram of the simulation system;

[0035] Figure 2 This is a schematic diagram of a half-roll inverted maneuver;

[0036] Figure 3 This is a schematic diagram of the control strategy for the half-roll maneuver;

[0037] Figure 4 This is a simulation diagram of the half-roll segment visual scene of the half-roll inverted maneuver;

[0038] Figure 5 This is a visual simulation diagram of the pull-up phase of a half-roll maneuver;

[0039] Figure 6 is the height response curve;

[0040] Figure 7 is the roll angle response curve;

[0041] Figure 8 is the roll angular velocity response curve;

[0042] Figure 9 is the pitch angle response curve;

[0043] Figure 10 is the pitch angular velocity response curve;

[0044] Figure 11 is the ground speed response curve;

[0045] Figure 12 This is a three-dimensional trajectory diagram of the entire half-roll maneuver process. DETAILED DESCRIPTION

[0046] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0047] This embodiment describes a helicopter half-roll maneuver control method and verification, and its overall framework diagram is as follows: Figure 1 As shown. The control structure includes position loop, speed loop, attitude loop, angular velocity loop and trim limit control loop module, control instruction acquisition module, data receiving and sending module, three-dimensional trajectory drawing module, real-time time acquisition module and flight status display module; the input and output XML protocol for simulation interaction is customized, and the input parameters mainly include: position, speed, angle and angular rate, etc. The output instructions include: collective pitch, longitudinal cyclic pitch, lateral cyclic pitch, tail rotor pitch and external wind disturbance, etc. These two files are placed in the Protocol folder under the FlightGear installation directory; FlightGear establishes a data connection with Matlab through the command line; Matlab uses UDP communication and customized input XML protocol to input control instructions into the built-in model machine of FlightGear to drive the visual simulation module. FlightGear exports flight data to Matlab through UDP communication and customized output XML protocol. The specific implementation method is as follows:

[0048] Control modal design of half-roll inversion maneuver

[0049] like Figure 2 The figure shows a schematic diagram of a half-roll maneuver. The entire process can be described as follows: the helicopter enters in level flight, then rolls 180 degrees, then dives and pulls up, recovers after reaching the desired pitch angle, achieves a 180-degree change in flight direction, and quickly decreases altitude while gaining a high forward speed, finally entering an active attack state in level flight. The entire process can be decomposed into the entry phase, the half-roll phase, the dive and pull-up phase, and the recovery phase. The control strategy for the entire maneuver process is as follows: Figure 3 shown.

[0050] Approach phase: The helicopter maintains its current altitude and flies forward at a certain speed, while using position hold control in the lateral direction. This means that the longitudinal channel uses speed hold control; the lateral channel uses position hold control; the heading channel uses yaw hold control; and the vertical channel uses altitude hold control.

[0051] Half-roll phase: This process can be broken down into two phases for control mode design. In the first phase, when the roll angle changes from 0 to 90 degrees, pitch hold control is used in the longitudinal direction; roll rate tracking control is used in the lateral channel; yaw hold control is used in the heading channel; and direct collective pitch control is used in the vertical channel. In the second phase, when the roll angle changes from 90 to 180 degrees, pitch rate hold control is used in the longitudinal direction; roll rate hold control is used in the lateral channel; yaw rate hold control is used in the heading channel; and direct collective pitch control is used in the vertical channel.

[0052] Dive and pull-up phase: This process is divided into two phases for control mode design. In the first phase, when the pitch angle changes from 0 to -90 degrees, pitch velocity tracking control is used in the longitudinal direction; roll velocity control is used in the lateral channel; yaw velocity control is used in the heading channel; and direct collective pitch control is used in the vertical channel. In the second phase, when the pitch angle changes from -90 to 0 degrees, pitch velocity control is used in the longitudinal direction; roll angle tracking control is used in the lateral channel; yaw angle tracking control is used in the heading channel; and direct collective pitch control is used in the vertical channel.

[0053] Recovery Phase: Since the half-roll phase generates lateral velocity, it is necessary to eliminate it during the recovery phase. Therefore, velocity control is used in the longitudinal direction, velocity control in the lateral channel, yaw angle control in the heading channel, and altitude control in the vertical channel.

[0054] Enter the segment control instruction design

[0055] The main purpose of the entry phase is to make the helicopter reach the desired altitude and speed. The flight mode of this phase is decomposed to obtain the control mode of the four channels. The control instruction expression is:

[0056]

[0057] Where θ c Enter the command for the pitch angle, is the longitudinal speed PID control gain; u c is the given value of longitudinal velocity, u is the longitudinal velocity, θ trim is the pitch angle trim value. c Input command for roll angle, is the lateral position PID control gain, Y c is the lateral position command, Y is the lateral position, and v is the lateral velocity. c is the yaw angle command. c is the height instruction, The desired initial altitude for the half-roll maneuver.

[0058] Design of half-roll segment control instructions

[0059] During this phase of flight, the helicopter rolls by spiraling forward. Because changes in the thrust direction of the main rotor can lead to changes in lateral speed and altitude, the vertical path must be compensated based on the roll angle throughout the maneuver. Lateral speed must be reduced as quickly as possible after the roll is completed. The half-roll maneuver command is divided into two parts based on the roll angle.

[0060] When the roll angle changes from 0 degrees to 90 degrees, the control instruction expression is:

[0061]

[0062] When the roll angle changes from 90 degrees to 180 degrees, the control instructions are:

[0063]

[0064] Where p0 is the desired roll angular velocity; δ c It is the collective pitch command, which is calculated based on the roll angle. When the roll angle is between -90 degrees and 90 degrees, positive rudder is given. When the roll angle is between 90 degrees and 180 degrees and -180 degrees and -90 degrees, negative rudder is given. c0 is the total distance during hovering, δ c1 It is the total distance when hovering in inverted flight.

[0065] Design of control instructions for the dive and pull-up phase

[0066] The dive-and-pull phase primarily uses longitudinal cyclic pitch control to reduce altitude, gain speed, and achieve a 180-degree shift in roll and yaw angles. Faster dive-and-pull speeds enhance maneuverability, while smaller altitude changes and speed increments also decrease. This maneuver primarily focuses on the helicopter's maneuverability in the vertical plane, but due to the lateral velocity generated during the half-roll phase, the actual position of the maneuver can deviate. The dive-and-pull phase maneuver commands are divided into two parts, depending on the pitch angle.

[0067] When the pitch angle changes from 0 degrees to -90 degrees, the control instruction expression is:

[0068]

[0069] When the pitch angle changes from -90 degrees to 0 degrees, the command is:

[0070]

[0071] Where q0 is the desired pitch angular velocity; δ c It is the collective pitch command, calculated based on the pitch angle. When the pitch angle is between 0 and 90 degrees, positive rudder is given, and when the pitch angle is between -90 and 0 degrees, negative rudder is given.

[0072] Modify the design of segment control instructions

[0073] Since the half-roll section generates lateral velocity, it is necessary to eliminate the generated lateral velocity in the recovery section. The control instruction expression is:

[0074]

[0075] Visual simulation verification

[0076] The feasibility of the proposed control strategy was verified through visual simulation in a helicopter maneuvering flight simulation environment constructed using Matlab and FlightGear. Matlab generated control instructions and viewed flight data and status curves, while FlightGear solved the flight dynamics model, drove visual module updates, and transmitted flight data.

[0077] A digital simulation system was built in Matlab, consisting of a data receiving module, a control module, and a data sending module. The data receiving module receives data from the visual module and unpacks it according to the file format. The control module generates maneuvering instructions based on the designed maneuvering flight strategy, converts coordinates into control instructions, and then generates control variables through a control loop. It also outputs the specified wind disturbance data to the data sending module. The data sending module packages the control instructions derived from the control law solution and sends them to the visual module.

[0078] This paper uses the UH-60 helicopter built into FlightGear as a verification platform, primarily utilizing the Plib component of FlightGear that provides external communication capabilities for data exchange, and employing the high-speed UDP communication method to implement helicopter maneuver flight visual simulation. In this mode, the workflow is as follows:

[0079] 1) Data protocol customization: customize the XML files for input and output data and place them in the Protocol folder under the FlightGear installation directory;

[0080] 2) Set the aircraft type, airport, runway, time, etc., and open a data connection with the outside world by using a predefined communication interface and communication protocol. The internal mode requires two command lines, one corresponding to the output XML file data format and the other corresponding to the input XML file data format;

[0081] 3) The aircraft enters the ready-to-fly state, realizing the two-way data transmission function of digital simulation.

[0082] The output XML file (com_output.xml) called in this invention mainly includes the flight data such as the position, speed, attitude, angular velocity, etc. of the helicopter. The data is as follows:

[0083] Serial number Output data Data Type unit 1 latitude double Spend 2 longitude double Spend 3 high double rice 4 Roll angle double Spend 5 Pitch angle double Spend 6 Heading angle double Spend 7 Northbound speed double m / s 8 Eastbound speed double m / s 9 Ground speed double m / s 10 Ground speed double m / s

[0084] The input XML file (com_input.xml) used in this invention mainly includes the control variables and wind disturbance data of the helicopter, and the data is as follows:

[0085] Serial number Input Data Data Type unit 1 lateral cyclic pitch variation float radian 2 Longitudinal cyclic pitch float radian 3 Tail rotor pitch float radian 4 Total distance float radian 5 wind direction float Spend 6 wind speed float m / s

[0086] The specific steps of half-roll maneuver flight scene simulation are as follows:

[0087] 1) Maneuver preparation visual simulation: Add the airport and time in the FlighrGear command line window and start data communication with the Matlab simulation model in the form of command line. The command line is as follows:

[0088] --airport=ZSNJ

[0089] --generic=socket,in,100,127.0.0.1,5501,udp,com_input

[0090] --generic=socket,out,100,127.0.0.1,5502,udp,com_output

[0091] --timeofday=noon

[0092] 2) Click "Start Flight" to enter the interface, switch the view to "Helicopter View," and start the helicopter by pressing "Shift+}." The simulation will begin once the main rotor speed reaches the rated value. The helicopter will first climb vertically and then fly forward, reaching the desired altitude and speed.

[0093] 2) Based on the designed control modes and control commands, the helicopter completes the entry and half-roll phases, then switches to the dive and pull-up phase. During the dive and pull-up phase, the helicopter pitches close to -90°, with a significant altitude change. After the dive and pull-up phase, the helicopter transitions to the recovery phase, flying forward at a shallow angle, completing the half-roll maneuver.

[0094] The FlighrGear software interface allows real-time observation of the helicopter's motion. After the simulation is complete, the received flight data can be viewed and the state curve can be plotted in Matlab.

[0095] Simulation test verification

[0096] To verify the effectiveness of the proposed helicopter half-roll maneuver control method, a simulation test was conducted using the UH-60 helicopter built into FlightGear. The simulation parameters were set as follows: an initial desired altitude of 200 meters, an initial desired ground speed of 10 meters per second, a desired roll velocity of 50 degrees per second during the half-roll phase, and a desired pitch velocity of 50 degrees per second during the pull-up phase. Figure 4 and Figure 5 This is a visual simulation diagram during the half-roll maneuver. Figure 4 It can be seen that the half-roll flight has a large angle change; Figure 5 It can be seen that the helicopter pitch angle is close to -90° and has obvious height changes. Figure 6 The height response curve shown in the figure shows that the height change during the half-roll maneuver dive pull-up phase is about 93.7m. After the dive pull-up phase is completed, the total channel cut height is kept under control, and the height response can achieve stable tracking. Figure 7 、 8 The roll angle and roll angular velocity response curves shown in the figure show that the half-roll segment is completed in about 3.6 seconds, and the roll angular velocity response is relatively fast during this process. Figure 9 、 10 From the response curves of pitch angle and pitch angular velocity, we can see that the response of pitch angle and pitch angular velocity is fast and stable tracking can be achieved. Figure 11 The ground speed response curve shows that after the dive and pull-up phase, the ground speed increases from 10m / s to about 41.9m / s, achieving the goal of "exchanging altitude for speed" in the half-roll maneuver while also achieving stable tracking. The three-dimensional trajectory of the flight during the entire half-roll maneuver is shown in the figure below. Figure 12 As shown in the figure, it can be seen that the flight trajectory during the helicopter's vertical climb and forward flight phases is essentially error-free. However, during the half-roll maneuver, the above analysis shows that lateral velocity is generated during the half-roll phase and eliminated during the recovery phase. Therefore, the entire process exhibits a certain amount of lateral offset, and a significant change in altitude can also be observed. In summary, the effectiveness of the maneuvering flight control method proposed in this invention has been verified.

[0097] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and adjustments can be made without departing from the principles of the present invention. These improvements and adjustments should also be regarded as the scope of protection of the present invention.

Claims

1. A method for controlling a helicopter half-roll maneuver, characterized by: The control method includes the following contents: S1, decomposing the helicopter half-roll inversion maneuver into four stages, including: entry stage, half-roll stage, dive and pull-up stage, and recovery stage; S2, design the control mode for each stage respectively, and design the control mode and control instructions according to the real-time flight status and flight trajectory of each stage during the maneuver; In the entry phase, the four-channel control modes are: the longitudinal channel adopts speed hold control, the lateral channel adopts position hold control, the heading channel adopts yaw angle hold control, and the vertical channel adopts altitude hold control; The control instructions for entering the segment four channel are: Where θ c Enter the command for the desired pitch angle, is the longitudinal speed PID control gain; u c is the longitudinal speed setting value, u is the longitudinal speed, θ trim is the pitch angle trim value; φ c Input command for roll angle, is the lateral position PID control gain, Y c is the lateral position command, Y is the lateral position, v is the lateral velocity; ψ c is the yaw angle command, h c For height instructions; In the half-roll segment, the system is divided into two stages according to the real-time state of the roll angle: in the first stage, when the roll angle changes from 0 to 90 degrees, the longitudinal direction adopts pitch angle hold control, the lateral channel adopts roll angle velocity tracking control, the heading channel adopts yaw angle hold control, and the vertical channel adopts direct collective distance control; In the second section, when the roll angle changes from 90 degrees to 180 degrees, the longitudinal channel adopts pitch angular velocity maintenance control, the lateral channel adopts roll angular velocity maintenance control, the heading channel adopts yaw angular velocity maintenance control, and the vertical channel adopts direct control of the total distance.

2. A helicopter half-roll maneuver control method according to claim 1, characterized in that: In the half-roll segment, when the roll angle changes from 0 degrees to 90 degrees, the half-roll segment control instruction is: When the roll angle changes from 90 degrees to 180 degrees, the half-roll segment control instructions are: Where p0 is the initial roll angular velocity, p c is the desired roll angular velocity, q c is the desired pitch angular velocity, δ c is the collective distance command, δ c0 is the total distance during hovering, δ c1 is the total distance in inverted flight and hovering, and φ is the roll angle.

3. A helicopter half-roll maneuver control method according to claim 1, characterized in that: In the dive and pull-up phase, the aircraft is divided into two stages according to the pitch angle value: in the first stage, when the pitch angle changes from 0 degrees to -90 degrees, the longitudinal channel adopts pitch angle velocity tracking control, the lateral channel adopts roll angle velocity maintenance control, the heading channel adopts yaw angle velocity control, and the vertical channel adopts collective pitch direct control; In the second stage, when the pitch angle changes from -90 degrees to 0 degrees, the longitudinal channel adopts pitch angle velocity maintenance control, the lateral channel adopts roll angle tracking control, the heading channel adopts yaw angle tracking control, and the vertical channel adopts collective distance direct control.

4. A helicopter half-roll maneuver control method according to claim 3, characterized in that: In the dive and pull-up phase, when the pitch angle changes from 0 degrees to -90 degrees, the input command is: When the pitch angle changes from -90 degrees to 0 degrees, the command is: Where θ is the pitch angle.

5. A helicopter half-roll maneuver control method according to claim 1, characterized in that: In the recovery phase, the four-channel control modes are: speed control in the longitudinal direction, speed control in the lateral channel, yaw angle control in the heading channel, and altitude control in the vertical channel.

6. A helicopter half-roll maneuver control method according to claim 5, characterized in that: In the recovery section, the input instruction is: Where, is the expected altitude after recovery from a half-roll maneuver, u' c 、v' c They are respectively the longitudinal speed command after correction and the lateral speed command after correction.

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