Rocket boosting unmanned aerial vehicle launching attitude control method based on active disturbance rejection control

Abstract

The invention discloses a rocket-assisted unmanned aerial vehicle launching attitude control method based on active disturbance rejection control, and belongs to the field of unmanned aerial vehicles. The method specifically comprises the steps that firstly, in the take-off stage of the unmanned aerial vehicle, an engine reaches a specified rotating speed, and a booster rocket starts to ignite When the axial acceleration of the unmanned aerial vehicle is larger than 30 m / s or the ground speed is larger than 5 m / s, it is judged that the rocket is successfully ignited; then, the unmanned aerial vehicle enters the off-ground stage, linear active-disturbance-rejection attitude control is started, in attitude outer ring control, a pitch angle and roll angle control loop adopts a dynamic inverse control structure, and a yaw channel adopts a lateral acceleration control structure; in attitude inner ring control, LADRC is used in a pitch angle rate control loop, a roll angle rate control loop and a yaw angle rate control loop; and after entering the climbing stage, implementing a lateral deviation control mode according to a lateral deviation distance, and adopting a lateral acceleration control mode for course control. And when the indicated airspeed is greater than the safe airspeed, the unmanned aerial vehicle flies according to a preset route. According to the invention, the hardware cost of the unmanned aerial vehicle is effectively reduced while the control performance robustness is ensured.

Description

Technical Field

[0001] The present invention belongs to the field of unmanned aerial vehicles (UAVs), and in particular to a launch attitude control method for a rocket-assisted UAV based on active disturbance rejection control. Background Art

[0002] Rocket-assisted drones, with their rapid response and flexible deployment, play a vital role in military reconnaissance, meteorological monitoring, and geographic mapping. However, launching rocket-assisted drones faces numerous challenges: First, there are uncertainties in the drone model, including inaccurate aerodynamic parameters and mass distribution variations. Second, there are bounded, unsteady external disturbances, including airflow interference, rocket thrust deviation, and sensor noise. These factors can significantly affect the drone's launch attitude, leading to attitude instability and trajectory deviation, reducing launch success rates and compromising flight safety.

[0003] Currently, traditional methods for controlling the launch attitude of rocket-assisted UAVs have significant limitations: simple PID control has poor adaptability to model changes and external disturbances, making it difficult to achieve high-precision control in complex environments; some methods based on robust control theory are insufficiently capable of handling multi-channel coupling and rapidly changing interference, especially when coordinating the pitch, roll, and yaw channels, which can easily lead to response lag or coupled oscillation problems. Some traditional solutions only control a single channel (such as angle or angular rate) and lack comprehensive optimization of multiple channels, making it difficult to meet the control requirements of high-dynamic launch scenarios for rocket-assisted UAVs. In addition, the interference-prone and rapidly changing booster launch scenarios require high precision from sensors and actuators, resulting in high hardware costs for the control system.

[0004] Therefore, there is an urgent need for an advanced method with strong robustness, anti-interference ability and multi-channel collaborative control capability to improve the launch attitude control performance of rocket-assisted UAVs. Summary of the Invention

[0005] The present invention aims to provide a launch attitude control method for a rocket-assisted UAV based on active disturbance rejection control (ADRC). By integrating linear active disturbance rejection control (LADRC) with dynamic inversion control, this method achieves precise and stable control of the launch attitude of a rocket-assisted UAV, enhancing system robustness and anti-interference capabilities, and improving launch success rate and flight safety. Furthermore, by estimating and compensating for the total system disturbance in real time, LADRC reduces the accuracy requirements for sensors and actuators, effectively reducing the hardware cost of the UAV while ensuring robust control performance.

[0006] The launch attitude control method of a rocket-assisted UAV based on active disturbance rejection control has the following specific steps:

[0007] Step 1: The rocket propels the drone into the flight-ready phase. Ground personnel send an engine ignition command, and the engine ignites and starts, entering idle mode.

[0008] Step 2: The ground staff sends the takeoff command, the engine speed increases to the specified speed, and the booster rocket begins to ignite.

[0009] When the axial acceleration of the UAV is greater than 30m / s² or the ground speed is greater than 5m / s, the rocket ignition is considered successful;

[0010] Step 3: After the rocket is successfully ignited, the speed and acceleration of the UAV increase, and it enters the takeoff phase and begins to perform linear active disturbance rejection attitude control;

[0011] The attitude control channel includes three major control channels: pitch, roll and yaw.

[0012] The pitch control channel includes cascade attitude control consisting of pitch angle and pitch angle rate, the roll control channel includes cascade attitude control consisting of roll angle and roll angle rate, and the yaw control channel includes cascade attitude control consisting of lateral acceleration and yaw angle rate.

[0013] In the attitude outer loop control, the pitch angle and roll angle control loops adopt a dynamic inverse control structure, and the yaw channel adopts a lateral acceleration control structure; in the attitude inner loop control, the pitch angle rate, roll angle rate, and yaw angle rate control loops all use linear active disturbance rejection control (LADRC).

[0014] The control law of the pitch angle control loop of the pitch channel outer loop is:

[0015]

[0016] in, The pitch rate command generated for the pitch control loop, is the pitch angle control loop bandwidth, The pitch angle command generated for the position guidance loop, is the current pitch angle, is the current roll angle, is the current yaw rate.

[0017] The control law of the roll angle control loop of the roll channel outer ring is:

[0018]

[0019] in, The roll angle rate command generated for the roll angle control loop, is the roll angle control loop bandwidth, The roll angle command generated for the position navigation loop, is the current pitch angle rate.

[0020] The control law of the lateral acceleration control loop of the yaw channel outer ring is:

[0021]

[0022] in, The yaw rate command generated for the lateral acceleration control loop, is the lateral acceleration control loop bandwidth, The lateral acceleration command generated for the position guidance loop, is the current lateral acceleration, is the Laplace operator, is the current true airspeed of the aircraft, It is an intermediate parameter (without clear physical meaning).

[0023] The control law of the pitch angle rate control loop in the pitch channel is:

[0024]

[0025] in, The elevator rudder command generated for the pitch rate control loop, is the pitch rate control loop bandwidth, is the total disturbance observation value of the system output by the extended state observer, The rudder effect of the elevator.

[0026] The control law of the roll angular rate control loop of the inner ring of the roll channel is:

[0027]

[0028] in, The aileron rudder deflection command generated for the roll rate control loop, is the roll rate control loop bandwidth, is the current roll angular rate, is the rudder effect of the aileron.

[0029] The control law of the yaw rate control loop in the yaw channel is:

[0030]

[0031] in, The rudder deflection command generated for the yaw rate control loop, is the yaw rate control loop bandwidth, The steering effect of the rudder.

[0032] After entering the liftoff phase, the maximum pitch rate is set to 2° / s. When the timer reaches 0.7s, the control law initiates closed-loop control of the roll, pitch, and yaw rates. The target roll angle command is zero, the target pitch angle command is the preset launch pitch angle, and the target yaw rate command is zero. After the timer reaches 5.7s, the rocket has separated. If there are more than six satellites, the UAV flight process switches to the climb phase, with heading control based on satellite positioning.

[0033] Step 4: After entering the climb phase, the lateral deviation control mode is implemented according to the lateral deviation distance between the UAV and the route, and the heading control adopts the lateral acceleration control mode.

[0034] Step 5. When the indicated airspeed is greater than the safe airspeed, the drone's flight process switches to the cruise phase and begins flying along the preset route.

[0035] The advantages of the present invention are:

[0036] (1) The present invention provides a launch attitude control method for a rocket-assisted UAV based on active disturbance rejection control, which organically combines linear active disturbance rejection control (LADRC) and dynamic inverse control: the pitch rate, roll rate, and yaw rate links in the attitude inner loop control all adopt linear active disturbance rejection control (LADRC) to enhance robustness and anti-interference ability; the pitch angle and roll angle control loops in the attitude outer loop control adopt a dynamic inverse control structure; the yaw channel adopts a lateral acceleration control structure to achieve rapid instruction tracking, which effectively solves the shortcomings of traditional control methods in dealing with model uncertainty and external disturbances.

[0037] (2) The present invention provides a launch attitude control method for a rocket-assisted UAV based on ADRC, which implements independent and coordinated control of the pitch, roll, and yaw channels. The pitch channel adopts a cascade attitude control consisting of pitch angle and pitch rate, the roll channel adopts a cascade attitude control consisting of roll angle and roll rate, and the yaw channel adopts a cascade attitude control consisting of lateral acceleration and yaw rate. This significantly improves the ability to handle multi-channel coupling problems and optimizes the overall attitude control effect.

[0038] (3) This invention proposes a launch attitude control method for a rocket-assisted UAV based on ADRC, which implements a phased and refined control strategy design. During the launch phase, the engine open-loop control and elevator fixed-angle preset rudder deflection are used to rapidly increase the UAV's speed and altitude and compensate for asymmetric thrust disturbances. During the takeoff phase, closed-loop control is initiated at the appropriate time to ensure the UAV's attitude stability. During the climb phase, lateral and heading control is implemented based on course deviation, ensuring the safety and reliability of the launch process. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1This is a diagram of the flight phase process division in the present invention.

[0040] Figure 2 This is a flow chart of a launch attitude control method for a rocket-assisted UAV based on active disturbance rejection control in the present invention.

[0041] Figure 3 This is a block diagram of the dynamic inverse structure of the pitch angle control loop in the present invention.

[0042] Figure 4 This is a block diagram of the dynamic inverse structure of the roll angle control loop in the present invention.

[0043] Figure 5 This is a block diagram of the linear auto-disturbance rejection structure of the pitch angle rate control loop in the pitch channel inner loop of the present invention.

[0044] Figure 6 This is a block diagram of the linear auto-disturbance rejection structure of the inner-ring roll angular rate control loop of the roll channel in the present invention.

[0045] Figure 7 This is a block diagram of the linear active disturbance rejection structure of the yaw angular rate control loop in the inner loop of the yaw channel in the present invention. DETAILED DESCRIPTION

[0046] The specific implementation method of the present invention is further described in detail below with reference to the accompanying drawings.

[0047] This invention uses an active disturbance rejection control (ADRC)-based control method for launch control of rocket-assisted UAVs. This method differs from traditional rocket-assisted UAV launch attitude control methods in that it combines linear active disturbance rejection control (LADRC) with dynamic inversion control. The core attitude control method is linear active disturbance rejection control (LADRC). The pitch angle control loop and the roll angle control loop in the attitude outer control loop employ dynamic inversion control structures. The pitch, roll, and yaw rate components in the attitude inner control loop all utilize linear ADRC. This composite control structure leverages the advantages of both control methods, leveraging dynamic inversion control to achieve rapid command tracking while enhancing the system's robustness and interference rejection capabilities through linear ADRC. This effectively addresses the shortcomings of traditional control methods in handling model uncertainty and external disturbances.

[0048] Rocket-assisted drones usually take off by launching a rocket with zero length. For rocket-assisted launch aircraft, the entire process from takeoff to landing is as follows: Figure 1 As shown, it includes: waiting stage, launching stage, taking off stage, climbing stage, cruising stage, recovery stage, parachute opening stage and landing stage. Each stage is only allowed to be executed in sequence.

[0049] Among them, the takeoff mode with preset logic in the flight control computer responsible for the full-process flight control of the rocket-assisted UAV is responsible for completing the flight control and management of the waiting phase, launch phase, take-off phase and climbing phase.

[0050] Flight phase switching logic and speed, position, attitude channel control modes in each flight phase are as follows: Figure 2 As shown:

[0051] The specific steps are as follows:

[0052] Step 1: The rocket propels the drone into the flight-ready phase. Ground personnel send an engine ignition command, and the engine ignites and starts, entering idle mode.

[0053] After powering on the flight control computer, it defaults to the flight-ready phase. Pre-takeoff ground preparations and ground inspections are performed by personnel, including rocket booster installation. During the flight-ready phase, the drone's velocity channel operates in open-loop control; specifically, the velocity channel is in off mode. The drone's position channel operates in open-loop control; specifically, the longitudinal position channel is in off mode, and the lateral position channel is in off mode. The drone's three-axis attitude channels operate in open-loop control; specifically, the roll channel's outer loop is in off mode, and the roll channel's inner loop is in off mode; the pitch channel's outer loop is in off mode, and the pitch channel's inner loop is in off mode; and the yaw channel's outer loop is in off mode, and the yaw channel's inner loop is in off mode.

[0054] After the preparations are completed, the ground control station operator sends the engine ignition command, and the UAV flight process enters the launch phase;

[0055] Step 2: The ground staff sends the takeoff command, the engine speed increases to the specified speed, and the booster rocket begins to ignite.

[0056] After entering the launch phase, the engine has been ignited and started to idle. The rocket booster ignition test is completed. The ground control station operator sends the takeoff command, and the engine channel is open-loop controlled. The target control speed is the maximum engine speed. The engine speed increases to the specified speed. If the current UAV is within the safety control zone, the engine throttle command uses maximum throttle. The purpose is to quickly get the UAV to a safe altitude and safe speed under the combined action of the rocket thrust and the maximum engine thrust. The elevator uses a fixed-angle preset rudder deflection to ensure the initial pitch torque is provided during the process of building speed under the booster rocket thrust to prevent the UAV from lowering its head, avoiding the risk of the UAV falling to the ground due to insufficient altitude during takeoff, and simplifying the complexity of the control system.

[0057] The flight control computer will record the current latitude, longitude and altitude as the return point position, which will be used for emergency measures such as the drone losing contact and returning to the home position. If the current drone is in the safety control area, the engine throttle command will use the maximum throttle, and the axial acceleration of the drone under the judgment system is greater than 30m / s 2 Or when the ground speed is greater than 5m / s, the rocket ignites successfully and switches to the liftoff stage.

[0058] Set the axial acceleration to be greater than 30m / s 2 Or the ground speed is greater than 5m / s because this threshold can effectively determine that the rocket ignition is successful and the boosted flight begins. The UAV generates a large axial acceleration and the speed begins to increase, reaching the judgment threshold.

[0059] During the launch phase, the drone's speed channel operates in open-loop control. Specifically, the speed channel is in throttle command mode. After the takeoff command is sent, the target throttle is generally at maximum throttle. The drone's position channel operates in open-loop control. Specifically, the longitudinal position channel is in closed mode, and the lateral position channel is in closed mode. The drone's three-axis attitude channels operate in open-loop control. Specifically, the outer loop of the roll channel is in closed mode, and the inner loop of the roll channel is in closed mode. The outer loop of the pitch channel operates in rudder command mode, with the elevator directly set to a fixed-angle preset rudder deflection, and the inner loop of the pitch channel is in closed mode. The outer loop of the yaw channel is in closed mode, and the inner loop of the yaw channel is in closed mode.

[0060] Step 3: After the rocket is successfully ignited, the speed and acceleration of the UAV increase, and it enters the takeoff phase and begins to perform linear active disturbance rejection attitude control;

[0061] The attitude control channel includes three major control channels: pitch, roll and yaw.

[0062] The present invention independently and collaboratively controls pitch, roll, and yaw, each channel employing a control strategy tailored to its specific characteristics. The pitch control channel utilizes a cascaded attitude control system consisting of pitch angle and pitch rate; the roll control channel utilizes a cascaded attitude control system consisting of roll angle and roll rate; and the yaw control channel utilizes a cascaded attitude control system consisting of lateral acceleration and yaw rate.

[0063] This multi-channel collaborative control approach can better address coupling issues between channels and improve overall attitude control. Furthermore, rocket-assisted drones typically experience significant lateral and yaw coupling. In this invention, a yaw rate controller based on active disturbance rejection control theory is used during the launch phase to control the yaw rate to zero. During the low takeoff phase, the target lateral acceleration is controlled to zero, reducing the sideslip angle and ultimately avoiding lateral and yaw coupling.

[0064] The pitch channel controller design includes:

[0065] (1) Using a control architecture based on active disturbance rejection control theory, an inner-loop pitch rate controller for pitch rate error control is designed.

[0066] (2) Based on the inner loop pitch rate controller, a dynamic inversion-based pitch controller is designed for pitch error control.

[0067] (3) Based on the dynamic inversion pitch angle controller, a longitudinal rate controller with longitudinal rate error control is designed;

[0068] (4) Based on the longitudinal lift rate controller, design a longitudinal height controller for longitudinal height error control;

[0069] The roll channel controller design includes:

[0070] (1) Using a control architecture based on active disturbance rejection control theory, an inner loop roll rate controller for roll rate error control is designed.

[0071] (2) Based on the inner loop roll angle rate controller, a roll angle controller based on dynamic inversion is designed for roll angle error control.

[0072] (3) Design a lateral position controller for lateral deviation control based on the roll angle controller of dynamic inversion;

[0073] The yaw channel controller design includes:

[0074] (1) Using a control architecture based on active disturbance rejection control theory, an inner-loop yaw rate controller for yaw rate error control is designed.

[0075] (2) Based on the inner loop yaw rate controller, design a lateral acceleration controller for lateral acceleration error control;

[0076] In the attitude outer loop control, the pitch angle and roll angle control loops all adopt dynamic inverse control structure; in the attitude inner loop control, the pitch angle rate, roll angle rate and yaw angle rate control loops all use linear active disturbance rejection control (LADRC).

[0077] like Figure 3 As shown in Figure 1, the pitch angle control loop adopts a dynamic inverse control structure. The control law derivation process of the pitch angle control loop of the pitch channel outer loop is as follows:

[0078] The kinematic equation of the pitch channel is:

[0079]

[0080] Based on dynamic inverse control, it can ensure that the pitch angle controller can quickly track the command in the presence of model uncertainty and external bounded unsteady disturbances. The pitch angle control adopts a proportional control structure, and the pitch angle change rate expression is:

[0081]

[0082] in, is the bandwidth of the pitch angle control loop. Substituting into the above formula, we can get:

[0083]

[0084] The roll angle is limited accordingly, and the control law of the pitch angle control loop of the pitch channel outer loop is obtained by the above formula:

[0085]

[0086] in, The pitch rate command generated for the pitch control loop, The pitch angle command generated for the position guidance loop, is the current pitch angle, is the current roll angle, is the current yaw rate.

[0087] like Figure 4 As shown in Figure 1, the roll angle control loop adopts a dynamic inverse control structure. The control law of the roll angle control loop of the roll channel outer ring is:

[0088]

[0089] in, The roll angle rate command generated for the roll angle control loop, is the roll angle control loop bandwidth, The roll angle command generated for the position navigation loop, is the current pitch angle rate.

[0090] The control law of the lateral acceleration control loop of the yaw channel outer ring is:

[0091]

[0092] in, The yaw rate command generated for the lateral acceleration control loop, is the lateral acceleration control loop bandwidth, The lateral acceleration command generated for the position guidance loop, is the current lateral acceleration, is the Laplace operator, is the current true airspeed of the aircraft, No clear physical meaning ( is the atmospheric density at current altitude, is the current true airspeed of the aircraft, is the wing reference area, is the derivative of the side force coefficient with sideslip angle, is the current aircraft mass).

[0093] The pitch rate loop uses the LADRC architecture control law. The derivation process of the pitch rate controller in the pitch channel inner loop is as follows:

[0094] The kinematic equation for the pitch angle is:

[0095]

[0096] Differentiate both sides of the above equation:

[0097]

[0098] Using the equations of angular motion about the y-axis:

[0099]

[0100] have:

[0101]

[0102] Pitching moment The general expression is:

[0103]

[0104] Substituting the above formula, we get:

[0105]

[0106] Where:

[0107]

[0108] c is the reference chord length, and substituting this formula into the above formula, we can get:

[0109]

[0110] make and , then the above formula can be written as:

[0111]

[0112] definition:

[0113]

[0114] The above formula can be described in the form of state equation:

[0115]

[0116] Design a state observer to observe the system. The observer form is:

[0117]

[0118] in They are respectively Observation, is the gain of the observer.

[0119] Through proportional control, the closed-loop control bandwidth of the pitch rate controller is set to .

[0120] like Figure 5 As shown in Figure 2, the control law of the pitch angle rate control loop in the pitch channel is:

[0121]

[0122] in, The elevator rudder command generated for the pitch rate control loop, The pitch rate command generated for the pitch control loop, is the current pitch angle rate, is the total disturbance observation value of the system output by the extended state observer (the additional pitch acceleration caused by the combined effects of the system internal disturbance and external disturbance except the aircraft aerodynamic control surface), The rudder effect of the elevator.

[0123] The derivation process of the inner-loop roll angular rate controller of the roll channel is similar to that of the pitch channel, and the derivation process of the inner-loop yaw angular rate controller of the yaw channel is similar to that of the pitch channel.

[0124] like Figure 6 As shown in Figure 1, the roll rate loop uses the LADRC architecture control law. The control law of the roll rate control loop in the roll channel is:

[0125]

[0126] in, The aileron rudder deflection command generated for the roll rate control loop, is the roll rate control loop bandwidth, The roll angle rate command generated for the roll angle control loop, is the current roll angular rate, is the total disturbance observation value of the system output by the extended state observer (the additional roll angular acceleration caused by the combined action of the system internal disturbance and external disturbance except the aircraft aerodynamic control surface), is the rudder effect of the aileron.

[0127] like Figure 7 As shown in Figure 1, the yaw rate loop uses the LADRC architecture control law. The control law of the yaw rate control loop in the yaw channel is:

[0128]

[0129] in, The aileron rudder deflection command generated by the yaw rate control loop, is the yaw rate control loop bandwidth, The yaw rate command generated for the lateral acceleration control loop, is the current yaw rate, is the total disturbance observation value of the system output by the extended state observer (the additional yaw acceleration caused by the combined action of the system internal disturbance and external disturbance except the aircraft aerodynamic control surface), The steering effect of the rudder.

[0130] After taking off, the maximum pitch rate is set to 2° / s (based on historical flight experience) to prevent large fluctuations in pitch rate during takeoff that could affect flight safety.

[0131] The axial acceleration of the drone under the discriminator system is greater than 30m / s 2 Or when the ground speed is greater than 5m / s, the drone flight process switches to the take-off stage, and the internal timer of the flight control computer starts timing.

[0132] During liftoff, before the timer reaches the preset time (0.7 seconds cumulatively), the drone's speed channel is in open-loop control. Specifically, the speed channel is in throttle command mode. The drone's position channel is in open-loop control. Specifically, the longitudinal position channel is in closed mode, and the lateral position channel is in closed mode. The drone's three-axis attitude channels are in open-loop control. Specifically, the outer loop of the roll channel is in closed mode, and the inner loop of the roll channel is in closed mode. The outer loop of the pitch channel is in rudder command mode, with the elevator directly set to a fixed angle preset rudder deflection, and the inner loop of the pitch channel is in closed mode. The outer loop of the yaw channel is in closed mode, and the inner loop of the yaw channel is in closed mode.

[0133] When the timing reaches 0.7s, the control law starts to implement closed-loop control of the roll angle, pitch angle and yaw angle rate. The target roll angle command is zero, the target pitch angle command is the preset launch pitch angle, and the target yaw angle rate command is zero.

[0134] At 0.7 seconds, the aircraft has established its initial velocity, and the aerodynamic control surfaces begin to produce steering effects, enabling attitude control. (This timing is determined based on historical flight data.) 0.7 seconds is chosen as the control start time because, at this point, the drone, boosted by rocket propulsion, has achieved sufficient speed for the aerodynamic torque of the servo control surfaces to effectively respond to control commands and maintain attitude control.

[0135] After the timing reaches 5.7 seconds, if the number of satellites is greater than 6, the drone's flight process switches to the climb phase (at 5.7 seconds, the rocket has separated, the drone has established a safe speed and safe altitude, and heading control is required based on satellite positioning).

[0136] The reason for setting the time to 5.7s is that within 5 seconds after the control law starts to take control, the rocket boost has ended and the drone's speed has basically reached the safe flight airspeed, so the control law can perform position control. The reason for setting the number of satellites to be greater than 6 is that the number of satellite positioning indicates that the drone is in good positioning status and the control law can perform position control.

[0137] During liftoff, after the timer reaches the preset time (after 0.7 seconds), the drone's velocity channel enters open-loop control. Specifically, the velocity channel is in throttle command mode. The drone's position channel enters open-loop control. Specifically, the longitudinal position channel enters closed mode, and the lateral position channel enters closed mode. The drone's three-axis attitude channels enter closed-loop control. Specifically, the outer loop of the roll channel controls roll angle, while the inner loop controls roll rate. The target roll angle command is zero, and the target roll rate command is automatically calculated using the outer loop's target roll angle closed-loop control law. The outer loop of the pitch channel controls pitch angle, while the inner loop controls pitch rate. The target pitch angle command is the preset launch pitch angle, and the target pitch rate command is automatically calculated using the outer loop's target pitch angle closed-loop control law. The maximum pitch rate is set to 2° / s. The outer loop of the yaw channel enters closed mode, while the inner loop controls yaw rate, with the target yaw rate command set to zero.

[0138] After the timing reaches 5.7s, if the number of satellites is greater than 6, the drone's flight process switches to the climb phase.

[0139] During the climb phase, after the timer reaches the preset time (5.7 seconds cumulatively), the drone's speed channel switches to open-loop control. Specifically, the speed channel switches to throttle command mode. The drone's longitudinal position channel switches to closed mode. The drone's lateral position control switches to side offset control, and the drone begins tracking the target route in the lateral position, with the target side offset set to zero. The three-axis attitude channel of the drone is closed-loop control. Specifically, the outer loop of the roll channel is roll angle control, the inner loop of the roll channel is roll angular rate control, the target roll angle instruction is zero, and the target roll angular rate instruction is automatically calculated by the outer loop target roll angle closed-loop control law; the outer loop of the pitch channel is pitch angle control, the inner loop of the pitch channel is pitch angular rate control, the target pitch angle instruction is the preset launch pitch angle, and the target pitch angular rate instruction is automatically calculated by the outer loop target pitch angle closed-loop control law; the outer loop of the yaw channel is lateral acceleration control, the inner loop of the yaw channel is yaw angular rate control, the target lateral acceleration instruction is zero, and the target yaw angular rate instruction is automatically calculated by the outer loop target lateral acceleration closed-loop control law.

[0140] Step 4: After entering the climb phase, the lateral deviation control mode is implemented according to the lateral deviation distance between the UAV and the route, and the heading control adopts the lateral acceleration control mode.

[0141] The lateral deviation distance is calculated based on the relationship between the UAV and the route, and the lateral deviation control mode is performed; the heading adopts the lateral acceleration control mode.

[0142] Step 5. When the indicated airspeed is greater than the safe airspeed, the drone's flight process switches to the cruise phase and begins flying along the preset route.

[0143] During the cruise phase, the drone's speed channel operates in closed-loop control. Specifically, the speed channel controls airspeed, with the target airspeed command determined by the speed commands for each waypoint along the target route. The drone's position channel operates in closed-loop control. Specifically, the drone's longitudinal position channel controls altitude deviation, with the target altitude deviation set to zero. The drone's lateral position channel controls lateral offset, with the target route tracked at the lateral position, with the target lateral offset set to zero. The three-axis attitude channel of the drone is closed-loop control. Specifically, the outer loop of the roll channel is roll angle control, the inner loop of the roll channel is roll angular rate control, the target roll angle instruction is zero, and the target roll angular rate instruction is automatically calculated by the outer loop target roll angle closed-loop control law; the outer loop of the pitch channel is pitch angle control, the inner loop of the pitch channel is pitch angular rate control, the target pitch angle instruction is the preset launch pitch angle, and the target pitch angular rate instruction is automatically calculated by the outer loop target pitch angle closed-loop control law; the outer loop of the yaw channel is lateral acceleration control, the inner loop of the yaw channel is yaw angular rate control, the target lateral acceleration instruction is zero, and the target yaw angular rate instruction is automatically calculated by the outer loop target lateral acceleration closed-loop control law.

[0144] Taking the pitch channel as an example, the pitch channel attitude controller in the present invention selects the pitch angular rate as the inner-loop control signal, and uses the self-disturbance rejection control theory to design the pitch angular rate controller, which in principle ensures the robustness, anti-interference ability and rapidity of the pitch channel; selects the pitch angle as the outer-loop control signal, and uses the dynamic inverse theory to design the pitch angle controller. Based on dynamic inverse control, it can be ensured that in the presence of model uncertainty and external bounded unsteady disturbances, the pitch angle controller can complete precise nonlinear compensation, realize multivariable decoupling control, and ultimately be able to quickly track instructions.

[0145] This invention focuses on a pitch rate controller based on active disturbance rejection control theory, a pitch angle controller based on dynamic inversion, a roll rate controller based on active disturbance rejection control theory, a roll angle controller based on dynamic inversion, and a yaw rate controller based on active disturbance rejection control theory. This invention focuses on the launch attitude control method; the longitudinal lift rate controller and longitudinal altitude controller are not part of this invention and will not be described in detail here.

Claims

1. A launch attitude control method for a rocket-assisted UAV based on active disturbance rejection control, characterized in that: The specific steps are as follows: Step 1: The rocket propels the drone into the flight-ready phase. Ground personnel send an engine ignition command, and the engine ignites and starts, entering idle mode. Step 2: The ground crew sends the takeoff command, the engine speed increases to the specified speed, and the booster rocket begins to ignite; Step 3: When the UAV's axial acceleration is greater than 30m / s² or the ground speed is greater than 5m / s, the rocket is considered to have successfully ignited. The UAV's speed and acceleration increase, entering the liftoff phase and starting linear active disturbance rejection attitude control. The attitude control channel includes three major control channels: pitch, roll and yaw; In the attitude outer loop control, the pitch and roll angle control loops use a dynamic inverse control structure, and the yaw channel uses a lateral acceleration control structure. In the attitude inner loop control, the pitch rate, roll rate, and yaw rate control loops all use linear active disturbance rejection control (LADRC). The control law of the pitch angle control loop of the pitch channel outer loop is: in, The pitch rate command generated for the pitch control loop, is the pitch angle control loop bandwidth, The pitch angle command generated for the position guidance loop, is the current pitch angle, is the current roll angle, is the current yaw rate; The control law of the roll angle control loop of the roll channel outer ring is: in, The roll angle rate command generated for the roll angle control loop, is the roll angle control loop bandwidth, The roll angle command generated for the position navigation loop, is the current pitch angle rate; The control law of the lateral acceleration control loop of the yaw channel outer ring is: in, The yaw rate command generated for the lateral acceleration control loop, is the lateral acceleration control loop bandwidth, The lateral acceleration command generated for the position guidance loop, is the current lateral acceleration, is the Laplace operator, is the current true airspeed of the aircraft, It is an intermediate parameter with no clear physical meaning; The control law of the pitch angle rate control loop in the pitch channel is: in, The elevator rudder command generated for the pitch rate control loop, is the pitch rate control loop bandwidth, is the total disturbance observation value of the system output by the extended state observer, is the rudder effect of the elevator; The control law of the roll angular rate control loop of the inner ring of the roll channel is: in, The aileron rudder deflection command generated for the roll rate control loop, is the roll rate control loop bandwidth, is the current roll angular rate, is the rudder effect of the aileron; The control law of the yaw rate control loop in the yaw channel is: in, The rudder deflection command generated for the yaw rate control loop, is the yaw rate control loop bandwidth, is the steering effect of the rudder; Step 4: After entering the climb phase, the lateral deviation control mode is implemented according to the lateral deviation distance between the UAV and the route, and the heading control adopts the lateral acceleration control mode; Step 5. When the indicated airspeed is greater than the safe airspeed, the drone's flight process switches to the cruise phase and begins flying along the preset route.

2. The method according to claim 1, wherein In step three, the pitch control channel includes a cascade attitude control consisting of a pitch angle and a pitch angle rate, the roll control channel includes a cascade attitude control consisting of a roll angle and a roll angle rate, and the yaw control channel includes a cascade attitude control consisting of a lateral acceleration and a yaw angle rate.

3. The method according to claim 1, wherein In step 3, after entering the lift-off phase, the maximum pitch rate is set to 2° / s.

4. The method according to claim 1, wherein In step three, when the timing reaches 0.7s, the control law is started, and closed-loop control is implemented on the roll angle, pitch angle and yaw angle rate. The target roll angle command is zero, the target pitch angle command is the preset launch pitch angle, and the target yaw angle rate command is zero.

5. The method according to claim 1, wherein In step three, after the timing reaches 5.7 seconds, the rocket has separated. If the number of satellites is greater than 6, the UAV flight process switches to the climb phase and performs heading control based on satellite positioning.

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