A flight control method for unmanned aerial vehicle with terminal guidance capability

Abstract

The present application discloses a flight control method for a UAV with terminal guidance capability, which divides the flight process of the UAV into three stages: initial guidance, intermediate guidance, and terminal guidance. In the initial guidance stage, the UAV takes off and enters the cruise stage, including the ground inspection stage, the ground waiting stage, the launch and takeoff stage, and the takeoff and climb stage; in the intermediate guidance stage, the UAV is guided to the attack target airspace and completes the search, capture, and tracking of the attack target in real time, including the climb stage, the level flight stage, and the command flight stage; in the terminal guidance stage, the attack on the attack target is completed through homing guidance, including the initial adjustment stage, the attack preparation stage, the terminal attack stage, and the go-around pull-up stage. The present application proposes a set of systematic flight stage control methods for UAVs with terminal guidance capability, realizes the comprehensive flight management of UAVs, and also provides corresponding guiding suggestions and measures for the conversion of conventional UAVs into UAVs with terminal guidance capability.

Description

Technical Field

[0001] The present application relates to the field of unmanned aerial vehicles, specifically to the field of unmanned aerial vehicle electronic countermeasure technology, and in particular to a flight phase control method of a unmanned aerial vehicle with terminal guidance capability. Background Art

[0002] The development of UAVs with terminal guidance capability is an important expansion of the application of UAVs in the field of electronic warfare in the future. UAVs with terminal guidance capability are a new generation of UAVs developed by integrating the advantages of anti-radiation missiles and UAVs and improving them. They are an autonomous defense system that uses electromagnetic wave signals radiated by enemy radars and other radiation sources to search, track and destroy enemy radiation sources. They are a special type of unmanned attack aircraft. Compared with anti-radiation missiles, UAVs with terminal guidance capability have the following advantages: (1) Strong long-range attack capability and long hovering time. They can be launched outside the coverage of the enemy's air defense system and rely on navigation equipment to fly to the target area. The range of anti-radiation missiles is only tens of kilometers, and they need to be launched by the carrier aircraft, which greatly limits their attack distance; (2) Strong suppression capability against enemy radiation sources. Anti-radiation missiles have a fast flight speed and basically do not have cruising capability, making it difficult to achieve continuous suppression of enemy radiation sources. In contrast, UAVs with terminal guidance capability can patrol and search over the target for a long time, and then launch an attack when the enemy radar is turned on. They can continuously suppress enemy radars and other radiation sources and suppress enemy radars and other radiation sources. The operator has a deterrent effect; (3) The requirements for launch conditions are relatively low. UAVs with terminal guidance capabilities can be launched outside the defense zone, which is convenient and flexible to use in combat. In contrast, before launching anti-radiation missiles, the reconnaissance equipment on the carrier aircraft must be used to determine the parameters of the target radiation source. In order to improve the real-time strike effect, the launching carrier aircraft must be equipped with a corresponding high-precision radiation source detection system. Therefore, anti-radiation missiles have very high requirements for launch conditions, especially the carrier aircraft; (4) The cost-effectiveness is high and the combat use is more flexible. UAVs with terminal guidance capabilities are similar to missiles or cruise missiles outside the defense zone in terms of combat effectiveness. They have their own autonomous detection, target positioning and attack capabilities, and can stay in the air to cruise and search for and attack targets when the enemy's air defense system radar is turned off.

[0003] Although drones with terminal guidance capabilities have the advantages of both drones and missiles, their control strategies are more complex, especially in the terminal stage. Unlike conventional drones that patrol and return, drones with terminal guidance capabilities need to perform corresponding attack tasks in the terminal stage. Therefore, the control and management of drones during the attack process is very complex. However, for drones with terminal guidance capabilities, the existing technology has not formed a systematic management and control method for the entire flight stage. Summary of the invention

[0004] In order to overcome the problems and shortcomings of the above-mentioned prior art, this application proposes a UAV flight control method with terminal guidance capability.

[0005] In order to achieve the above-mentioned invention object, the technical solution of this application is as follows:

[0006] A flight phase control method for an unmanned aerial vehicle with terminal guidance capability is disclosed. The entire flight process of the unmanned aerial vehicle is divided into three phases: an initial guidance phase, a mid-guidance phase and a terminal guidance phase. In the initial guidance phase, the unmanned aerial vehicle takes off and enters a cruising phase, including a ground inspection phase, a ground waiting phase, a launch and takeoff phase and a takeoff and climb phase. In the mid-guidance phase, the unmanned aerial vehicle is guided to an attack target airspace and searches, captures and tracks the attack target in real time, including a climb phase, a level flight phase and a command flight phase. In the terminal guidance phase, the attack on the attack target is completed through homing guidance, including an initial adjustment phase, an attack preparation phase, a terminal attack phase and a go-around and pull-up phase.

[0007] Furthermore, the initial guidance stage includes:

[0008] a. The drone receives the ground inspection command on the ground, completes the corresponding ground inspection operation, and sends the ground inspection data to the comprehensive inspection equipment;

[0009] b. The drone receives the command to exit ground inspection and enters the ground to wait, with the deflection of each rudder surface at a constant value;

[0010] c. The UAV receives the launch and take-off command, the aircraft launches and takes off, controls the UAV to accelerate, reaches a safe altitude, the throttle maintains a certain proportion of the maximum continuous available speed, controls the pitch angle longitudinally to maintain the launch attitude, and controls the wing level laterally;

[0011] d. Control the UAV to climb quickly and determine whether the difference between the UAV's flight altitude and the expected flight altitude meets the navigation segment threshold requirement for entering the mid-range guidance phase. If so, the UAV enters the navigation segment of the mid-range guidance phase, otherwise it continues to climb.

[0012] Furthermore, the intermediate guidance stage includes:

[0013] e. The UAV enters the navigation phase. According to the difference between the UAV's flight altitude and the expected flight altitude, the UAV chooses to enter one of the climbing phase, the level flight phase, and the descending phase. If the UAV receives a flight command from the ground station, it enters step f, otherwise it directly goes to step g;

[0014] f. The UAV performs command flight, including command level flight, command climb, command descent, left turn, right turn and point flight. After the UAV completes the command flight mission, it enters step g;

[0015] g. The UAV cruises in the target airspace. Once an attack target is found, if the UAV's flight status meets the conditions for executing the terminal attack, it will enter the terminal guidance phase. Otherwise, it will continue to cruise in the target airspace and adjust the UAV's attitude, position and speed according to the conditions for entering the terminal attack.

[0016] Furthermore, the final guidance stage includes:

[0017] h. Obtain the angle between the sight line direction and the speed direction of the UAV. If the angle between the sight line direction and the speed direction is greater than the sight line inclination angle of the critical attack, determine the turning direction according to the current flight state of the UAV, and turn with the limit overload until the attack target is located in the front hemisphere of the attack, and then enter step i; if the angle between the sight line direction and the speed direction is less than the sight line inclination angle of the critical attack, but the guidance solution overload setting exceeds the limit, continuously adjust the guidance law output parameters until the requirements are met, and enter step j; if the angle between the sight line direction and the speed direction is less than the sight line inclination angle of the critical attack, and the guidance solution overload setting does not exceed the limit, directly enter step j;

[0018] i. Obtain the radar beam of the attack target. If the radar beam of the attack target stably falls into the tracking field of view and the guidance law output parameters are within the limit, directly enter step j; if the radar beam of the attack target stably falls into the tracking field of view, but the guidance law output parameters exceed the limit, continuously adjust the guidance law output parameters until the requirements are met, and enter step j;

[0019] j. The UAV flies stably at the desired flight altitude and controls the transmitter speed to the optimal attack speed. If the UAV maintains the above state for more than 2 seconds, it proceeds to step k, otherwise it maintains the current flight state;

[0020] k. The drone performs an attack mission and attacks the target.

[0021] Furthermore, the step e comprises:

[0022] When the difference between the UAV's flight altitude and the expected flight altitude is greater than the set altitude for entering the climb phase, the UAV enters the climb phase, the UAV controls the indicated speed longitudinally through the pitch angle, the engine uses the continuous maximum throttle available, and the aileron controls the UAV to track the flight route;

[0023] When the drone is in the climbing phase, if the difference between the drone's flight altitude and the expected flight altitude is less than the tolerance band for transitioning from climbing to level flight, the drone enters the level flight phase, the drone maintains altitude longitudinally, the engine controls the speed indicator, and the aileron controls the drone to track the flight route; when the drone is in the descending phase, if the difference between the drone's flight altitude and the expected flight altitude is less than the tolerance band for transitioning from descending to level flight, the drone enters the level flight phase, the drone maintains altitude longitudinally, the engine controls the speed indicator, and the aileron controls the drone to track the flight route;

[0024] When the difference between the UAV's flight altitude and the expected flight altitude is less than the set altitude for entering the descent phase, the UAV enters the descent phase, the UAV controls the indicated airspeed longitudinally through the pitch angle, the engine uses the continuously available minimum throttle, and the aileron controls the UAV to track the flight route.

[0025] Furthermore, in step k, if a system failure or external interference causes the drone to deviate from the line of sight, or the attack target is lost, and the drone's flight altitude is greater than or equal to the decision altitude, the drone exits the terminal guidance stage, returns to the mid-guidance stage, and maintains cruising mode flight; otherwise, the drone continues to maintain the terminal guidance stage flight and executes the attack mission.

[0026] Furthermore, when the UAV enters the terminal guidance stage, if the UAV meets the terminal guidance stage exit conditions and the flight altitude is greater than or equal to the decision altitude, the UAV exits the terminal guidance stage and returns to the intermediate guidance stage, maintaining cruise mode flight; if the UAV meets the terminal guidance stage exit conditions and the flight altitude is less than the decision altitude, the UAV directly attacks the target.

[0027] Furthermore, the decision altitude refers to the lowest altitude that can be safely pulled up based on the current UAV flight altitude, flight speed and maximum overload capacity.

[0028] Furthermore, after the UAV leaves the airfield, if the difference between the UAV's flight altitude and the expected flight altitude is greater than or equal to 150m, the UAV enters the navigation segment of the mid-guidance phase, otherwise it continues to climb.

[0029] Beneficial effects of this application:

[0030] This application specifically proposes a systematic flight phase control process method for UAVs with terminal guidance capabilities, which can not only realize the comprehensive flight management of UAVs, but also provide corresponding guiding suggestions and measures for converting conventional UAVs into UAVs with terminal guidance capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of the application method;

[0032] Figure 2 This is a schematic diagram of the search circle for the guidance head in this application;

[0033] Figure 3 This is a schematic diagram of the critical line of sight angle for the drone to attack in this application;

[0034] Figure 4 This is a schematic diagram of the sight angle adjustment for this application;

[0035] Figure 5This is a schematic diagram of setting the advance amount for entering the attack state for this application;

[0036] Figure 6 A schematic diagram of virtual waypoint selection for this application;

[0037] Figure 7 This is the final guidance exit diagram for this application;

[0038] Figure 8 This is a schematic diagram of the best attack position for this application. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions in this application, the following will further illustrate the technical solutions for achieving the invention purpose of this application through several specific embodiments. It should be noted that the technical solutions claimed for protection in this application include but are not limited to the following embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0040] Although UAVs with terminal guidance capabilities have the advantages of both UAVs and missiles, their control strategies are also more complicated, especially in the terminal stage. Unlike conventional UAVs that patrol and return, UAVs with terminal guidance capabilities need to perform corresponding attack missions in the terminal stage. Therefore, the control and management of UAVs during the attack process is very complicated, and the existing technology has not formed a systematic management and control method for the entire flight stage.

[0041] Based on this, this application proposes a systematic flight control method for UAVs with terminal guidance capabilities during their full flight phase, which can not only realize the comprehensive flight management of UAVs, but also provide corresponding guiding suggestions and measures for converting conventional UAVs into UAVs with terminal guidance capabilities.

[0042] The present embodiment discloses a flight control method for a UAV with terminal guidance capability. The present embodiment defines the entire flight process of the UAV from ground waiting to attack execution into three major flight stages according to different guidance methods, namely, the initial guidance stage, the intermediate guidance stage, and the terminal guidance stage; in the initial guidance stage, the UAV successfully takes off and enters the cruise stage of the intermediate guidance stage, and the initial guidance stage is provided with control of the take-off stage including the ground inspection stage, the ground waiting stage, the launch and take-off stage, and the take-off and climb stage; in the intermediate guidance stage, the UAV is guided to the attack target airspace, and the search, capture, and tracking of the attack target are completed in real time, and cruise control management including the climb stage, the level flight stage, and the descent stage and control management of the command flight stage are provided; in the terminal guidance stage, the UAV completes the attack on the attack target through homing guidance, and terminal attack control management including the initial adjustment stage, the attack preparation stage, the terminal attack stage, and the go-around pull-up stage are provided.

[0043] Refer to the instruction manual Figure 1 , the method mainly comprises the following steps:

[0044] S101. Initial guidance stage

[0045] a. The UAV waits on the ground. After receiving the ground inspection command, it completes the corresponding ground inspection operation and sends the ground inspection data to the comprehensive detection equipment. During the ground inspection, the UAV switches the flight phase to ground inspection, sends data to the comprehensive detection equipment periodically, and performs corresponding actions according to the instructions issued by the comprehensive detection equipment.

[0046] b. The UAV receives the command to exit ground inspection and enters ground waiting. The deflection of each rudder surface is constant; the elevator controls the rudder surface to return to zero; the engine speed is initialized to ground slow speed. If the UAV enters ground waiting from other stages, the engine command remains the engine command of the previous stage; aileron control: the rudder surface returns to zero; rudder control: the rudder surface returns to zero.

[0047] c. The UAV receives the launch and take-off command, the aircraft launches and takes off, controls the UAV to accelerate, reaches a safe altitude, the throttle maintains a certain proportion of the maximum continuous available speed, controls the pitch angle longitudinally to maintain the launch attitude, and controls the wing level laterally.

[0048] d. Control the UAV to climb quickly and determine whether the difference between the UAV's flight altitude and the expected flight altitude meets the threshold requirement for entering the mid-range guidance phase. If so, the UAV enters the mid-range guidance phase, otherwise it continues to climb. The elevator controls the pitch angle. When the UAV reaches a certain altitude, the speed indicator is controlled by the pitch angle. The engine is controlled by the throttle, and the throttle target can be interpolated according to the altitude. The aileron controls the roll angle. When the UAV reaches a certain altitude, it follows the route. The rudder uses rudder preset and inner ring stabilization control.

[0049] In the embodiment of the present application, it should be noted that in step b, if the drone is in the following state, the drone also enters the ground waiting state:

[0050] (1) The drone enters this stage by default when it is powered on;

[0051] (2) The UAV is in the recovery phase and the grounding mark has been in the grounding state for a certain period of time;

[0052] (3) The UAV receives a valid abort takeoff command;

[0053] (4) The communication between the UAV flight manager and the integrated detection equipment was interrupted for a period of time.

[0054] In the embodiment of the present application, it needs to be further explained that in step d, if the difference between the UAV's flight altitude and the expected flight altitude is greater than or equal to 150m, the UAV enters the navigation segment of the mid-guidance phase, otherwise it continues to climb.

[0055] In the embodiment of the present application, it needs to be further explained that the throttle control target can be controlled by the "climb throttle binding" instruction of the ground station. When the binding parameters are valid, the throttle control target is executed according to the parameters of the "climb throttle binding".

[0056] S102. Mid-range guidance phase

[0057] e. The UAV enters the navigation section. According to the difference between the UAV's flight altitude and the expected flight altitude, or according to the route planning altitude, the UAV chooses to enter one of the stages of climbing, level flight and descending. After that, if the UAV receives a flight instruction from the ground station, the UAV enters step f for command flight according to the corresponding flight instruction, otherwise it directly goes to step g from the navigation section.

[0058] 1) Climb

[0059] When the difference between the UAV's flight altitude and the expected flight altitude is greater than the set altitude for entering the climb phase, the UAV enters the climb phase. The UAV controls the indicated airspeed longitudinally through the pitch angle, the engine uses the continuous available maximum throttle, and the aileron controls the UAV to track the flight route.

[0060] 2) Level flight

[0061] When the UAV is in the climbing stage, if the difference between the UAV's flight altitude and the expected flight altitude is less than the tolerance band for transitioning from climbing to level flight, the UAV enters the level flight stage, the UAV maintains altitude longitudinally, the engine controls the speed indicator, and the aileron controls the UAV to track the flight route; when the UAV is in the descending stage, if the difference between the UAV's flight altitude and the expected flight altitude is less than the tolerance band for transitioning from descending to level flight, the UAV enters the level flight stage, the UAV maintains altitude longitudinally, the engine controls the speed indicator, and the aileron controls the UAV to track the flight route.

[0062] 3) Decline

[0063] When the difference between the UAV's flight altitude and the expected flight altitude is less than the set altitude for entering the descent phase, the UAV enters the descent phase, the UAV controls the indicated airspeed longitudinally through the pitch angle, the engine uses the continuously available minimum throttle, and the aileron controls the UAV to track the flight route.

[0064] f. The UAV performs command flight, including command level flight, command climb, command descent, left turn, right turn and point flight. After the UAV executes the command flight, it goes to step g;

[0065] g. The UAV cruises in the target airspace. Once an attack target is found, if the UAV's flight status meets the conditions for executing the terminal attack, it will enter the terminal guidance phase. Otherwise, it will continue to cruise in the target airspace and adjust the UAV's attitude, position and speed according to the conditions for entering the terminal attack.

[0066] In the embodiment of the present application, it should be noted that the common difference point of the UAV climbing to level flight can be interpolated according to the lifting speed. The greater the lifting speed, the larger the tolerance band. For subsonic UAVs, the maximum should not exceed 200, and the minimum should not be less than 50; similarly, the tolerance band of the UAV descending to level flight can be obtained.

[0067] In the embodiments of the present application, it needs to be further explained that the command level flight means that the UAV maintains its altitude longitudinally, maintains its track angle laterally, and the engine controls the indicated speed; the command climb means that the UAV controls the indicated speed longitudinally through the pitch angle, the engine uses the continuously available minimum throttle, and maintains the track angle laterally; the command descent means that the indicated speed is controlled through the pitch angle, the engine uses the continuously available maximum throttle, and maintains the track angle laterally; the left and right turns refer to controlling the aircraft to fly in a circling manner by calculating the circling slope based on the circling radius and the speed at entry with the current position as the tangent point. The altitude is maintained longitudinally, the arc track is tracked laterally, and the engine controls the indicated speed; the latitude and longitude parameters of the point-to-point flight are the position target of the flight, the longitudinal control is consistent with the navigation segment call logic, the lateral heading control is consistent with the navigation segment when the distance to be flown from the set waypoint is greater than a certain distance, and the control law call is consistent with the navigation segment. After the distance to be flown from the set waypoint is less than a certain distance, the current track is maintained for straight flight, and the control law call is consistent with the commanded level flight; Engine control: indicated speed control, with the speed parameter entering the point-to-point flight instruction (the indicated speed is calculated by the performance management module) as the indicated speed control target.

[0068] In the embodiment of the present application, it should be noted that when the UAV is cruising in the mid-guidance phase, a corresponding search circle is formed with the center of the attack area as the center and the detection distance of the seeker as the radius. When the UAV enters the search circle, its seeker is turned on, and the UAV searches and captures the attack target by detecting the radar of the attack target.

[0069] In the embodiment of the present application, it is necessary to further explain that after the drone captures the attack target, it is necessary to further determine whether the drone's seeker meets the conditions for entering the terminal guidance stage, and then determine whether the flight state of the drone meets the requirements; the conditions for the drone's seeker to meet the conditions for entering the terminal guidance stage are specifically:

[0070] (1) The seeker is in tracking mode

[0071] Since the seeker's working state is the signal search state by default during takeoff, the seeker's working state should be set to the tracking state at the preset time or waypoint after it is turned on, and it starts to receive the electromagnetic signal parameters emitted by the radar of the attack target and finally locks the attack target.

[0072] (2) The seeker continuously and stably obtains information about the attack target

[0073] The overload and roll angle solved at the moment the seeker obtains the guidance information may have large jumps, but the information output by the seeker converges after the seeker continues to work stably.

[0074] In the embodiments of the present application, it should be further explained that the UAV flight state meets the conditions for executing the terminal attack, which means that the UAV enters a stable level flight state, and its flight attitude, flight altitude and flight speed all meet the requirements of the attack attitude, attack altitude and attack speed.

[0075] In the embodiment of the present application, it is further explained that the UAV needs to meet the following conditions to enter the final guidance phase:

[0076] (1) The UAV meets the attack performance envelope.

[0077] The UAV is in a stable level flight state. If the attack performance envelope is met, it can enter the terminal guidance stage to perform the attack mission. Otherwise, it needs to be adjusted first, and then enter the terminal guidance stage to perform the attack after the attack conditions are met. The main goal of the adjustment stage is to make the flight state meet the handover conditions between mid-range guidance and terminal guidance.

[0078] (2) The target is located within the angle q0 of the front hemisphere of the aircraft, that is, the angle between the line of sight and the velocity direction is no greater than q0.

[0079] is the velocity vector (ground speed), is the sight vector

[0080]

[0081] (3) The UAV overload setting is within the limit

[0082] Overload setting is Nz min ~Nz max Between, Nz min To allow the minimum overload available, Nz min The maximum overload allowed.

[0083] In the embodiment of the present application, it is necessary to further explain that the attack performance envelope in the terminal guidance phase mainly considers the following aspects:

[0084] (1) The miss distance at each altitude meets the requirements, and the limit speed does not exceed the terminal attack performance of the right boundary. The miss distance is in the single digit order of magnitude and does not exceed 10m.

[0085] (2) A critical state of miss at each height and speed, wherein the critical state of miss is a state where the miss amount is greater than a preset miss amount.

[0086] (3) The critical attackable line of sight corresponding to the maximum fall angle at each height, where the maximum fall angle is 65±15.

[0087] In the embodiment of the present application, it needs to be further explained that in the mid-guidance stage, when the UAV tracks the radar of the attack target in real time through the seeker, if the attack target is lost, the UAV will continue to maintain cruising flight in the mid-guidance stage, otherwise the UAV enters the terminal guidance stage from the mid-guidance stage, and the UAV is guided to the virtual waypoint for performing the terminal attack.

[0088] In the embodiment of the present application, it is necessary to further explain that the intersection of the line between the drone and the attack target and the circle with the attack target as the center and the attack radius as the radius is used as a virtual waypoint, and the current position of the drone is used as the starting point to guide the drone into the optimal attack position.

[0089] In the embodiment of the present application, it is necessary to further explain that the process of guiding the drone to enter the optimal attack position can be achieved in the following ways:

[0090] (1) After detecting the sight angle deflection and sight inclination information, control the heading of the UAV to align with the sight direction and adjust the sight angle deflection within a small range, i.e. within 10°;

[0091] (2) After aligning the sight, control the drone to fly towards the attack target, and pre-set the sight angle advance amount Δq. The critical sight angle corresponding to the optimal attack state is q e0 , when the line of sight angle is greater than q e0 When -Δq, the UAV enters the terminal guidance stage. The selection of the lead time is related to the attack speed. The lead time should not be too large. It is recommended to select within 5°. The selection of the lead time is to protect the line of sight angle at the moment of attack from exceeding the critical line of sight angle.

[0092] (3) When the line of sight inclination angle is greater than the critical line of sight inclination angle q e0 After that, give up the attack and adjust the aircraft's waiting point to the set virtual waypoint. The virtual waypoint is selected as the point before the critical line of sight inclination angle, and the corresponding line of sight angle is q e0 -Δq', the UAV re-enters the attack state; the selection of the virtual waypoint is to ensure that the UAV has time to adjust the aircraft attitude after reaching the virtual waypoint to achieve the best attack state and meet the best attack position.

[0093] S103. Final Guidance Phase

[0094] h. Obtain the angle between the sight direction and the speed direction of the drone. If the angle between the sight direction and the speed direction is greater than the sight angle of the critical attack, determine the turning direction according to the current flight state of the drone, give a turn with the limit overload, control the drone to turn until the attack target is located in the front hemisphere of the attack, and then enter step i; if the angle between the sight direction and the speed direction is less than the sight angle of the critical attack, but the guidance solution overload is given to exceed the limit, the drone needs to continuously adjust the guidance law output parameters until the requirements are met and the limit is not exceeded, and then enter step j; if the angle between the sight direction and the speed direction is less than the sight angle of the critical attack, and the guidance solution overload is given to not exceed the limit, directly enter step j;

[0095] i. Obtain the radar beam of the attack target. If the radar beam of the attack target falls stably into the tracking field of view and the guidance law output parameters are within the limit, directly enter step j; if the radar beam of the attack target falls stably into the tracking field of view, but the guidance law output parameters are within the limit, the UAV needs to continuously adjust the guidance law output parameters until the requirements are met and the limit is not exceeded, then enter step j;

[0096] j. The UAV flies stably at the desired flight altitude and controls the transmitter speed to the optimal attack speed. If the UAV maintains the above state for more than 2 seconds, it proceeds to step k. Otherwise, it maintains the current flight state until the requirements are met and then proceeds to step k;

[0097] k. The drone performs an attack mission and attacks the target.

[0098] In the embodiment of the present application, it should be noted that a given turn with an extreme overload, and controlling the UAV to turn means determining the turning radius with the current speed and the maximum use roll angle, and ultimately controlling the UAV to turn.

[0099] In the embodiments of the present application, due to the constraints of the terminal guidance stage plan and the control system response overload capacity limit and other conditions, the terminal guidance stage may experience overload setting limit, flight speed limit and disappearance of the attack target, which may cause the UAV to be unable to continue to perform the attack mission. At this time, the UAV needs to start the terminal guidance stage exit judgment, that is, to judge whether the UAV meets the exit attack conditions at this time.

[0100] The exit conditions of the UAV terminal guidance phase are subject to the constraints of the decision altitude. According to the current flight altitude, speed, maximum overload capacity and other information, the lowest altitude that can be safely pulled up is determined as the decision altitude. When the UAV is in the terminal guidance phase, if the UAV meets the exit conditions of the terminal guidance phase, and the UAV flight altitude is greater than or equal to the decision altitude, the UAV exits the terminal guidance phase, returns to the mid-guidance phase, and enters the navigation phase; if the UAV meets the exit conditions of the terminal guidance phase, the UAV flight altitude is less than the decision altitude, and the UAV directly attacks the target. In other words, as long as the UAV successfully enters the terminal guidance phase and its UAV flight altitude is less than the decision altitude, the UAV will directly attack the target.

[0101] In the embodiment of the present application, it needs to be further explained that the drone meeting the terminal guidance phase exit condition specifically refers to:

[0102] (1) The seeker operating mode is in search mode.

[0103] After the attack target is lost for a period of time, the working state of the seeker changes from tracking mode to search mode, and at this time it is impossible to give an overload setting through solution.

[0104] (2) The instantaneous overload cannot exceed the maximum overload limit.

[0105] (3) The speed during the process does not exceed the speed limit.

[0106] The speed when entering a dive attack is the left boundary of the current altitude. Speed ​​protection is set during the attack if the speed still exceeds the right boundary.

[0107] (4) The angle of attack cannot exceed the current angle of attack limit.

[0108] (5) Some systems of the drone fail.

[0109] (7) The radar beam of the attack target does not stably fall into the tracking field of view.

[0110] (7) The UAV is within the attack range of the target radar.

[0111] (8) The rotation angular rate of the target line of sight angle cannot be greater than the tracking angular rate of the guidance antenna.

[0112] (9) The impact angle cannot exceed the allowable impact range.

[0113] In the embodiments of the present application, it needs to be further explained that when the UAV meets the conditions for exiting the terminal guidance stage and the UAV's flight altitude is greater than or equal to the decision altitude, if the UAV's current flight speed is greater than the pull-up speed, the UAV executes a go-around and pulls up, and successfully returns from the terminal guidance stage to the intermediate guidance stage. However, if the UAV's current flight speed is less than or equal to the pull-up speed, the UAV will not exit from the terminal guidance stage, but will continue to fly in the terminal guidance stage to perform the corresponding attack mission.

[0114] In the embodiment of the present application, it is further explained that the decision height is estimated by using the following algorithm, as follows:

[0115] Assume the aircraft is overloaded with Nz c Normal overload pull up

[0116]

[0117] Assume the limiting speed is V limit , get Nz c The rate of change of the track inclination angle corresponding to the overload is approximately

[0118] In order to obtain a more conservative calculation result, the generated Nz c The overload process is set as a linear link, and its rise time is set as T s , you can get

[0119]

[0120] in

[0121]

[0122] Track angle

[0123]

[0124] When the track angle rises to 0,

[0125]

[0126] Therefore, the track angle can be calculated in two parts:

[0127]

[0128] If the track angle rises to 0 in the first stage, then the solution is

[0129]

[0130] Then t2 can be obtained;

[0131] During the time t2, the total height decreases

[0132]

[0133] The initial value of the track inclination rate of change can be estimated by the current overload. By substituting different initial values ​​of the track inclination and the track inclination rate of change into the decision altitude, the decision altitude can be obtained by calculation.

[0134] In the embodiment of the present application, when the attack target is stationary, the heading of the virtual waypoint can be specified to ensure that the drone adjusts its heading to the line of sight. If the attack target is on the left, roll to the right; if the attack target is on the right, roll to the right; if the attack target is at the rear, turn around; and when the attack target rotates, the drone can be guided to a circular cruise with the same line of sight angle as the virtual waypoint, and then execute the attack mission after aligning with the attack target. The best attack position is different at different heights and speeds. Taking a certain height H0 as an example, the best attack position is as shown in the attached figure. Figure 8 As shown, V3>V2>V1.

[0135] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0136] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0137] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present application shall fall within the protection scope of the present application.

Claims

1. A flight phase control method for an unmanned aerial vehicle with terminal guidance capability, characterized in that: The entire flight process of the UAV is divided into three stages: the initial guidance stage, the intermediate guidance stage and the terminal guidance stage. In the initial guidance stage, the UAV takes off and enters the cruise stage, including the ground inspection stage, the ground waiting stage, the launch and takeoff stage, and the takeoff and climb stage; in the intermediate guidance stage, the UAV is guided to the attack target airspace and completes the search, capture and tracking of the attack target in real time, including the climb stage, the level flight stage and the command flight stage; in the terminal guidance stage, the UAV completes the attack on the attack target through homing guidance, including the initial adjustment stage, the attack preparation stage, the terminal attack stage and the go-around pull-up stage; The intermediate guidance stage includes: e. The UAV enters the navigation phase. According to the difference between the UAV's flight altitude and the expected flight altitude, the UAV chooses to enter one of the climbing phase, the level flight phase, and the descending phase. If the UAV receives a flight command from the ground station, it enters step f, otherwise it directly goes to step g; f. The UAV performs command flight, including command level flight, command climb, command descent, left turn, right turn and point flight. After the UAV completes the command flight mission, it enters step g; g. The UAV cruises in the target airspace. Once the attack target is found, if the flight status of the UAV meets the conditions for executing the terminal attack, it will enter the terminal guidance phase. Otherwise, it will continue to cruise in the target airspace and adjust the UAV's attitude, position and speed according to the conditions for entering the terminal attack; The step e specifically comprises: When the difference between the UAV's flight altitude and the expected flight altitude is greater than the set altitude for entering the climb phase, the UAV enters the climb phase, the UAV controls the indicated speed longitudinally through the pitch angle, the engine uses the continuous maximum throttle, and the aileron controls the UAV to track the flight route; When the drone is in the climbing phase, if the difference between the drone's flight altitude and the expected flight altitude is less than the tolerance band for transitioning from climbing to level flight, the drone enters the level flight phase, the drone maintains altitude longitudinally, the engine controls the speed indicator, and the aileron controls the drone to track the flight route; when the drone is in the descending phase, if the difference between the drone's flight altitude and the expected flight altitude is less than the tolerance band for transitioning from descending to level flight, the drone enters the level flight phase, the drone maintains altitude longitudinally, the engine controls the speed indicator, and the aileron controls the drone to track the flight route; When the difference between the UAV's flight altitude and the expected flight altitude is less than the set altitude for entering the descent phase, the UAV enters the descent phase, the UAV controls the indicated airspeed longitudinally through the pitch angle, the engine uses the continuously available minimum throttle, and the aileron controls the UAV to track the flight route.

2. A flight control method for a UAV with terminal guidance capability according to claim 1, characterized in that: The initial guidance stage includes: a. The drone receives the ground inspection command on the ground, completes the corresponding ground inspection operation, and sends the ground inspection data to the comprehensive inspection equipment; b. The drone receives the command to exit ground inspection and enters the ground to wait, with the deflection of each rudder surface at a constant value; c. The UAV receives the launch and take-off command, the aircraft launches and takes off, controls the UAV to accelerate, reaches a safe altitude, the throttle maintains a certain proportion of the maximum continuous available speed, controls the pitch angle longitudinally to maintain the launch attitude, and controls the wing level laterally; d. Control the UAV to climb quickly and determine whether the difference between the UAV's flight altitude and the expected flight altitude meets the navigation segment threshold requirement for entering the mid-range guidance phase. If so, the UAV enters the navigation segment of the mid-range guidance phase, otherwise it continues to climb.

3. The flight control method of a UAV with terminal guidance capability according to claim 1, characterized in that: The terminal guidance stage includes: h. Obtain the angle between the sight line direction and the speed direction of the UAV. If the angle between the sight line direction and the speed direction is greater than the sight line inclination angle of the critical attack, determine the turning direction according to the current flight state of the UAV, and turn with the limit overload until the attack target is located in the front hemisphere of the attack, and then enter step i; if the angle between the sight line direction and the speed direction is less than the sight line inclination angle of the critical attack, but the guidance solution overload setting exceeds the limit, continuously adjust the guidance law output parameters until the requirements are met, and enter step j; if the angle between the sight line direction and the speed direction is less than the sight line inclination angle of the critical attack, and the guidance solution overload setting does not exceed the limit, directly enter step j; i. Obtain the radar beam of the attack target. If the radar beam of the attack target stably falls into the tracking field of view and the guidance law output parameters are within the limit, directly enter step j; if the radar beam of the attack target stably falls into the tracking field of view, but the guidance law output parameters exceed the limit, continuously adjust the guidance law output parameters until the requirements are met, and enter step j; j. The UAV flies stably at the desired flight altitude and controls the transmitter speed to the optimal attack speed. If the UAV maintains the above state for more than 2 seconds, it proceeds to step k, otherwise it maintains the current flight state; k. The drone performs an attack mission and attacks the target.

4. A flight control method for a UAV with terminal guidance capability according to claim 3, characterized in that: In step k, if a system failure or external interference causes the drone to deviate from the line of sight, or the attack target is lost, and the drone's flight altitude is greater than or equal to the decision altitude, the drone exits the terminal guidance stage, returns to the mid-guidance stage, and maintains the cruise mode flight. Otherwise, the drone continues to maintain the terminal guidance stage flight and executes the attack mission.

5. The flight control method of a UAV with terminal guidance capability according to claim 3, characterized in that: When the UAV enters the terminal guidance stage, if the UAV meets the terminal guidance stage exit conditions and the flight altitude is greater than or equal to the decision altitude, the UAV exits the terminal guidance stage and returns to the intermediate guidance stage, maintaining cruise mode flight; if the UAV meets the terminal guidance stage exit conditions and the flight altitude is less than the decision altitude, the UAV directly attacks the target.

6. A method for controlling a UAV flight with terminal guidance capability according to any one of claims 4 or 5, characterized in that: The decision altitude refers to the lowest altitude that can be safely pulled up based on the current UAV flight altitude, flight speed and maximum overload capacity.

7. The flight control method of a UAV with terminal guidance capability according to claim 2, characterized in that: When the UAV leaves the field, if the difference between the UAV's flight altitude and the expected flight altitude is greater than or equal to 150m, the UAV enters the navigation segment of the mid-guidance phase, otherwise it continues to climb.

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