A rocket-boosted unmanned aerial vehicle launch attitude control method based on active disturbance rejection control
By combining a multi-channel collaborative strategy of linear active disturbance rejection control and dynamic inverse control, the problems of model uncertainty and external disturbance in the launch attitude control of rocket-assisted UAVs were solved, achieving high-precision and low-cost attitude control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIHANG UNIV
- Filing Date
- 2025-07-01
- Publication Date
- 2026-07-21
AI Technical Summary
Traditional rocket-assisted UAV launch attitude control methods struggle to achieve high-precision control when faced with model uncertainties and external disturbances. In particular, they are prone to response lag or coupled oscillations when controlling pitch, roll, and yaw channels in a coordinated manner, and the hardware costs are also high.
By adopting an active disturbance rejection control (ADRC)-based approach and combining linear ADRC and dynamic inverse control, a multi-channel cooperative control strategy is designed, including cascade attitude control of pitch, roll, and yaw channels. This enhances the system's robustness and anti-interference capability, and reduces the accuracy requirements of sensors and actuators.
It has achieved precise and stable control of the launch attitude of rocket-assisted UAVs, improved the launch success rate and flight safety, reduced hardware costs, and optimized the handling capability of multi-channel coupling problems.
Smart Images
Figure CN120704376B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of unmanned aerial vehicles (UAVs), specifically a method for controlling the launch attitude of a rocket-assisted UAV based on active disturbance rejection control. Background Technology
[0002] Rocket-assisted unmanned aerial vehicles (UAVs) possess characteristics such as rapid response and flexible deployment, playing a vital role in fields such as military reconnaissance, meteorological monitoring, and geographic mapping. However, rocket-assisted UAVs face numerous challenges during launch: on the one hand, the UAV model itself has uncertainties, including inaccurate aerodynamic parameters and variations in mass distribution; on the other hand, there are bounded unsteady external disturbances, including airflow interference, rocket thrust deviation, and sensor noise. These factors can significantly affect the UAV's launch attitude, leading to attitude instability, trajectory deviation, reduced launch success rate, and compromised flight safety.
[0003] Currently, traditional rocket-assisted UAV launch attitude control methods have significant limitations: simple PID control is poorly adaptable 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 insufficient in handling multi-channel coupling and rapidly changing disturbances, especially when controlling pitch, roll, and yaw channels in a coordinated manner, easily leading to response lag or coupled oscillations. Some traditional solutions only control a single channel (such as angle or angular rate), lacking comprehensive optimization for multiple channels, making it difficult to meet the control requirements of rocket-assisted UAVs in high-dynamic launch scenarios. Furthermore, the highly volatile and rapidly changing booster launch scenarios place high demands on the accuracy of 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 unmanned aerial vehicles. Summary of the Invention
[0005] The purpose of this invention is to provide a launch attitude control method for rocket-assisted unmanned aerial vehicles (UAVs) based on active disturbance rejection control (ADRC). By integrating linear ADRC and dynamic inverse control, it achieves precise and stable control of the launch attitude of the rocket-assisted UAV, enhancing system robustness and anti-interference capability, and improving launch success rate and flight safety. Furthermore, LADRC, by estimating and compensating for the total system disturbance in real time, reduces the accuracy requirements of sensors and actuators, effectively lowering the hardware cost of the UAV while ensuring robust control performance.
[0006] The specific steps of the rocket-assisted UAV launch attitude control method based on active disturbance rejection control are as follows:
[0007] Step 1: The rocket-assisted drone enters the ready-to-fly phase. Ground staff send an engine ignition command, and the engine ignites and starts, entering idle mode.
[0008] Step 2: Ground staff send the takeoff command, the engine speed increases to the designated speed, and the booster rocket begins to ignite.
[0009] The rocket is considered to have ignited successfully when the axial acceleration of the drone is greater than 30 m / s² or the ground speed is greater than 5 m / s.
[0010] Step 3: After the rocket ignition is successful, the speed and acceleration of the UAV increase, and it enters the takeoff phase, where it begins linear active disturbance rejection attitude control.
[0011] The attitude control channel includes three main control channels: pitch, roll, and yaw.
[0012] The pitch control channel includes cascaded attitude control consisting of pitch angle and pitch rate; the roll control channel includes cascaded attitude control consisting of roll angle and roll rate; and the yaw control channel includes cascaded attitude control consisting of lateral acceleration and yaw rate.
[0013] In the outer loop of attitude control, the pitch and roll control loops adopt a dynamic inverse control structure, while the yaw channel adopts a lateral acceleration control structure. In the inner loop of attitude control, the pitch rate, roll rate, and yaw rate control loops all use linear active disturbance rejection control (LADRC).
[0014] The control law for the pitch angle control loop of the outer ring of the pitch channel is:
[0015]
[0016] in, The pitch rate command generated for the pitch control loop. For the pitch angle control loop bandwidth, The pitch angle command generated for the position navigation loop. The current pitch angle, The current roll angle, This represents the current yaw rate.
[0017] The control law for the outer ring roll angle control loop of the roll channel is:
[0018]
[0019] in, The roll rate command generated for the roll angle control loop For the roll angle control loop bandwidth, The roll angle command generated for the position navigation loop. This represents the current pitch rate.
[0020] The control law for the outer ring lateral acceleration control loop of the yaw channel is:
[0021]
[0022] in, The yaw rate command generated for the lateral acceleration control loop. For the lateral acceleration control loop bandwidth, The lateral acceleration command generated for the position navigation loop, The current lateral acceleration, For the Laplace operator, The current vacuum speed of the aircraft, These are intermediate parameters (without explicit physical meaning).
[0023] The control law for the pitch rate control loop within the pitch channel is:
[0024]
[0025] in, Elevator deflection commands generated for the pitch rate control loop. For the pitch rate control loop bandwidth, The total system disturbance observation output by the extended state observer. This refers to the rudder effect of the elevator.
[0026] The control law for the inner loop roll rate control loop of the roll channel is:
[0027]
[0028] in, Aileron deflection commands generated for the roll rate control loop For the roll rate control loop bandwidth, The current roll rate, For the rudder effect of the aileron.
[0029] The control law for the inner loop yaw rate control loop of the yaw channel is:
[0030]
[0031] in, The rudder deflection command generated for the yaw rate control loop. The bandwidth of the yaw rate control loop. This refers to the rudder's rudder effect.
[0032] Upon entering the takeoff phase, the maximum pitch rate is set to 2° / s. At 0.7s, the control law is activated, implementing closed-loop control of roll, pitch, and yaw rates. The target roll command is zero, the target pitch command is the preset launch pitch angle, and the target yaw rate command is zero. After 5.7s, the rocket has separated. If there are more than 6 satellites, the UAV's flight path switches to the climb phase, using satellite positioning for heading control.
[0033] Step 4: After entering the climb phase, implement lateral deviation control mode based on the lateral offset between the UAV and the flight path, and use lateral acceleration control mode for heading control.
[0034] Step 5: Once the indicated airspeed is greater than the safe airspeed, the drone's flight process switches to the cruise phase and begins to fly along the preset route.
[0035] The advantages of this invention are:
[0036] (1) The present invention provides a launch attitude control method for rocket-assisted UAVs 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 capability; the pitch and roll control loops in the attitude outer loop control adopt dynamic inverse control structure, and the yaw channel adopts lateral acceleration control structure to achieve rapid command tracking, effectively solving the shortcomings of traditional control methods in handling model uncertainty and external disturbances.
[0037] (2) The present invention provides a launch attitude control method for rocket-assisted unmanned aerial vehicles based on active disturbance rejection control, which implements independent and coordinated control of pitch, roll and yaw channels. The pitch channel adopts cascade attitude control composed of pitch angle and pitch rate, the roll channel adopts cascade attitude control composed of roll angle and roll rate, and the yaw channel adopts cascade attitude control composed of lateral acceleration and yaw rate; it significantly improves the processing capability of multi-channel coupling problems and optimizes the overall attitude control effect.
[0038] (3) The present invention provides a rocket-assisted unmanned aerial vehicle (UAV) launch attitude control method based on active disturbance rejection control, which involves a phased and refined control strategy design. During the launch phase, the speed and altitude of the UAV are rapidly increased and asymmetric thrust disturbances are compensated by using open-loop engine control and fixed-angle preset elevator deflection. During the takeoff phase, closed-loop control is activated in a timely manner to ensure the stability of the UAV attitude. During the climb phase, lateral and heading control are implemented based on the flight path deviation to ensure the safety and reliability of the launch process. Attached Figure Description
[0039] Figure 1This is a flowchart illustrating the flight phases in this invention.
[0040] Figure 2 This is a flowchart of a rocket-assisted unmanned aerial vehicle launch attitude control method based on active disturbance rejection control in this invention.
[0041] Figure 3 This is a block diagram of the dynamic inverse structure of the pitch angle control loop in this invention.
[0042] Figure 4 This is a block diagram of the dynamic inverse structure of the roll angle control loop in this invention.
[0043] Figure 5 This is a block diagram of the linear self-disturbance rejection structure of the pitch angular rate control loop in the pitch channel of the present invention.
[0044] Figure 6 This is a block diagram of the linear self-disturbance rejection structure of the inner loop roll rate control loop in the roll channel of the present invention.
[0045] Figure 7 This is a block diagram of the linear self-disturbance rejection structure of the inner loop yaw rate control loop in the yaw channel of the present invention. Detailed Implementation
[0046] The specific implementation method of the present invention will be further described in detail below with reference to the accompanying drawings.
[0047] This invention employs an active disturbance rejection (ADR)-based control method for the launch control of a rocket-assisted unmanned aerial vehicle (UAV). The difference from traditional attitude control methods for rocket-assisted UAVs lies in the combination of Linear Active Disturbance Rejection Control (LADRC) and Dynamic Inverse Control. The core attitude control method is LADRC. The pitch and roll control loops in the outer attitude control loop both utilize a dynamic inverse control structure. The pitch, roll, and yaw rate components in the inner attitude control loop all employ LADRC. This composite control structure fully leverages the advantages of both methods, utilizing dynamic inverse control for rapid command tracking while enhancing system robustness and anti-interference capabilities through LADRC. This effectively addresses the shortcomings of traditional control methods in handling model uncertainties and external disturbances.
[0048] Rocket-assisted unmanned aerial vehicles (UAVs) typically take off using a zero-length launch method with a rocket booster. For rocket-assisted launch vehicles, the entire usage process from takeoff to landing, depending on the specific operational scenario, is as follows: Figure 1 As shown, the phases include: the pre-flight phase, the launch phase, the takeoff phase, the climb phase, the cruise phase, the recovery phase, the parachute deployment phase, and the landing phase. Each phase can only be executed sequentially.
[0049] Among them, the flight control computer, which is responsible for the flight control of the rocket-assisted UAV throughout the entire flight process, has a pre-set logic take-off mode that is responsible for the flight control and management of the waiting-to-fly phase, launch phase, take-off phase, and climb phase.
[0050] Flight phase switching logic and speed, position, and attitude channel control modes in each flight phase, such as Figure 2 As shown:
[0051] The specific steps are as follows:
[0052] Step 1: The rocket-assisted drone enters the ready-to-fly phase. Ground staff send an engine ignition command, and the engine ignites and starts, entering idle mode.
[0053] After the flight control computer is powered on, it enters the standby phase by default. Personnel perform pre-flight ground preparations and tests, including rocket booster installation. During the standby phase, the UAV's speed channel is in open-loop control; specifically, the speed channel is in closed mode. The UAV's position channel is also in open-loop control; specifically, the longitudinal position channel and the lateral position channel are both in closed mode. The UAV's three-axis attitude channels are in open-loop control; specifically, the outer and inner loops of the roll, pitch, and yaw channels are both in closed 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: Ground staff send the takeoff command, the engine speed increases to the designated speed, and the booster rocket begins to ignite.
[0056] Once the launch phase begins, the engine has ignited and entered idle mode. The rocket booster ignition test is complete. Ground control station operators send the takeoff command. The engine channel is controlled in open-loop mode, with the target control speed being the engine's maximum speed. The engine speed increases to the designated speed. If the UAV is currently within the safe control zone, the engine throttle command uses the maximum throttle. The aim is to quickly achieve a safe altitude and speed under the combined thrust of the rocket and the engine's maximum thrust. The elevator uses a fixed-angle preset deflection to ensure an initial pitch-up moment is provided during speed establishment under the booster rocket thrust, preventing the UAV from pitching down and avoiding the risk of crashing due to insufficient altitude during takeoff, thus simplifying the control system complexity.
[0057] The flight control computer records the current latitude, longitude, and altitude as the return-to-home point location for emergency measures such as drone loss of contact and return-to-home. If the drone is currently within the safe control zone, the engine throttle command will be set to maximum throttle, and the drone's axial acceleration under the discrimination system will be greater than 30 m / s². 2 If the ground speed is greater than 5 m / s, the rocket ignites successfully and switches to the takeoff phase.
[0058] Set axial acceleration greater than 30 m / s² 2 The reason why the ground speed is greater than 5 m / s is that this threshold can effectively determine that the rocket ignition was successful and the boost flight began. The drone's axis generates a large acceleration and the speed begins to rise, reaching the judgment threshold.
[0059] During the launch phase, the UAV'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. The UAV's position channel also operates in open-loop control. Specifically, the longitudinal position channel and the lateral position channel are both in closed mode. The UAV's three-axis attitude channels operate in open-loop control. Specifically, the outer and inner loops of the roll channel are both in closed mode; the outer loop of the pitch channel operates in control surface command mode, with the elevator directly set to a fixed preset deflection angle; the inner loop of the pitch channel is in closed mode; and the outer and inner loops of the yaw channel are both in closed mode.
[0060] Step 3: After the rocket ignition is successful, the speed and acceleration of the UAV increase, and it enters the takeoff phase, where it begins linear active disturbance rejection attitude control.
[0061] The attitude control channel includes three main control channels: pitch, roll, and yaw.
[0062] This invention provides independent and coordinated control of three channels: pitch, roll, and yaw. Each channel employs a suitable control strategy based on its characteristics. The pitch control channel includes cascaded attitude control composed of pitch angle and pitch rate; the roll control channel includes cascaded attitude control composed of roll angle and roll rate; and the yaw control channel includes cascaded attitude control composed of lateral acceleration and yaw rate.
[0063] This multi-channel collaborative control method can better handle the coupling problem between channels and improve the overall attitude control effect. In addition, the lateral coupling of rocket-assisted UAVs is usually quite serious. In this invention, the yaw rate controller based on active disturbance rejection control theory is used in the launch phase. The goal is to control the lateral rate to zero. At the low speed during takeoff, this means controlling the target lateral acceleration to zero, reducing the sideslip angle, and avoiding mutual coupling in the lateral direction from the source.
[0064] The pitch channel controller design includes:
[0065] (1) An inner-loop pitch rate controller for pitch rate error control is designed using a control architecture based on active disturbance rejection control theory.
[0066] (2) Based on the inner loop pitch rate controller, design a pitch angle controller based on dynamic inverse for pitch angle error control;
[0067] (3) Based on the dynamic inverse pitch angle controller, design a longitudinal rise and fall rate controller for longitudinal rise and fall rate error control;
[0068] (4) Based on the longitudinal lifting rate controller, design a longitudinal height controller for longitudinal height error control;
[0069] The design of the roll channel controller includes:
[0070] (1) An inner loop roll rate controller for roll rate error control is designed using a control architecture based on active disturbance rejection control theory.
[0071] (2) Based on the inner loop roll rate controller, design a roll angle controller based on dynamic inverse for roll angle error control;
[0072] (3) Based on the dynamic inverse roll angle controller, design a lateral position controller for lateral deviation control;
[0073] The yaw channel controller design includes:
[0074] (1) An inner-loop yaw rate controller for yaw rate error control is designed using a control architecture based on active disturbance rejection control theory.
[0075] (2) Based on the inner loop yaw rate controller, design a lateral acceleration controller for lateral acceleration error control;
[0076] In the outer loop of attitude control, both pitch and roll control loops adopt dynamic inverse control structures; in the inner loop of attitude control, the pitch rate, roll rate, and yaw rate control loops all use linear active disturbance rejection control (LADRC).
[0077] like Figure 3 As shown, the pitch angle control loop adopts a dynamic inverse control structure. The derivation process of the control law for the outer loop pitch angle control loop of the pitch channel is as follows:
[0078] The kinematic equations for the pitch channel are:
[0079]
[0080] Based on dynamic inverse control, the pitch controller can quickly track commands even in the presence of model uncertainties and external bounded unsteady disturbances. The pitch control employs a proportional control structure, and the pitch rate of change is expressed as:
[0081]
[0082] in, Let be the bandwidth of the pitch angle control loop. Substituting this into the above equation, we get:
[0083]
[0084] By limiting the roll angle accordingly, the control law of the pitch angle control loop of the pitch channel outer ring can be obtained using the above formula:
[0085]
[0086] in, The pitch rate command generated for the pitch control loop. The pitch angle command generated for the position navigation loop. The current pitch angle, The current roll angle, This represents the current yaw rate.
[0087] like Figure 4 As shown, the roll angle control loop adopts a dynamic inverse control structure. The control law of the outer loop roll angle control loop of the roll channel is:
[0088]
[0089] in, The roll rate command generated for the roll angle control loop For the roll angle control loop bandwidth, The roll angle command generated for the position navigation loop. This represents the current pitch rate.
[0090] The control law for the outer ring lateral acceleration control loop of the yaw channel is:
[0091]
[0092] in, The yaw rate command generated for the lateral acceleration control loop. For the lateral acceleration control loop bandwidth, The lateral acceleration command generated for the position navigation loop, The current lateral acceleration, For the Laplace operator, The current vacuum speed of the aircraft, No clear physical meaning ( At the current atmospheric density, The current vacuum speed of the aircraft, For wing reference area, This is the derivative of the lateral force coefficient with respect to the sideslip angle. (Current aircraft mass).
[0093] The pitch rate loop uses the LADRC architecture control law. The derivation process of the pitch rate controller in the inner loop of the pitch channel 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 motion about the y-axis:
[0099]
[0100] have:
[0101]
[0102] Pitch moment The general expression is:
[0103]
[0104] Substituting the above equation, we get:
[0105]
[0106] In the formula:
[0107]
[0108] Let c be the reference chord length. Substituting this into the previous equation, we get:
[0109]
[0110] make and Then the above formula can be written as:
[0111]
[0112] definition:
[0113]
[0114] The above equation can then be described in the form of a state equation:
[0115]
[0116] Design a state observer to observe the system. The observer should be of the following form:
[0117]
[0118] in They are respectively for The observation, It 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, the control law for the pitch rate control loop within the pitch channel is:
[0121]
[0122] in, Elevator deflection commands generated for the pitch rate control loop. The pitch rate command generated for the pitch control loop. The current pitch rate, The total system disturbance observation value output by the extended state observer (the additional pitch acceleration caused by the combined effects of internal and external disturbances of the system, excluding the aerodynamic control surfaces of the aircraft). This refers to the rudder effect of the elevator.
[0123] The derivation process of the roll rate controller in the inner loop of the roll channel is similar to that in the pitch channel, and the derivation process of the yaw rate controller in the inner loop of the yaw channel is similar to that in the pitch channel.
[0124] like Figure 6 As shown, the roll rate loop uses a LADRC architecture control law. The control law for the inner loop roll rate control loop of the roll channel is:
[0125]
[0126] in, Aileron deflection commands generated for the roll rate control loop For the roll rate control loop bandwidth, The roll rate command generated for the roll angle control loop The current roll rate, The total system disturbance observation value output by the extended state observer (the additional roll acceleration caused by the combined effect of internal and external disturbances of the system, excluding the aerodynamic control surfaces of the aircraft). For the rudder effect of the aileron.
[0127] like Figure 7 As shown, the yaw rate loop uses a LADRC architecture control law. The control law for the yaw rate control loop within the yaw channel is:
[0128]
[0129] in, Aileron deflection commands generated for the yaw rate control loop The bandwidth of the yaw rate control loop. The yaw rate command generated for the lateral acceleration control loop. The current yaw rate, The total system disturbance observation value output by the extended state observer (the additional yaw angle acceleration caused by the combined effect of internal and external disturbances of the system, excluding the aerodynamic control surfaces of the aircraft). This refers to the rudder's rudder effect.
[0130] After entering the takeoff phase, the maximum pitch rate is set to 2° / s (based on historical flight experience) to prevent large fluctuations in pitch rate during takeoff, which could affect flight safety.
[0131] The axial acceleration of the UAV under the discrimination system is greater than 30 m / s². 2 When the ground speed is greater than 5 m / s, the UAV flight process switches to the takeoff phase, and the internal timer of the flight control computer starts counting.
[0132] During takeoff, before the timer reaches the preset time (0.7 seconds prior), the UAV's speed channel operates in open-loop control; specifically, it operates in throttle command mode. The UAV's position channel also operates in open-loop control; specifically, the longitudinal position channel and the lateral position channel are both off. The UAV's three-axis attitude channels operate in open-loop control; specifically, the outer and inner loops of the roll channel are both off; the outer loop of the pitch channel operates in control surface command mode, with the elevator directly set to a fixed preset deflection angle; the inner loop of the pitch channel is off; and the outer and inner loops of the yaw channel are both off.
[0133] When the timing reaches 0.7s, the control law is activated, and closed-loop control is implemented for the roll angle, pitch angle and yaw rate. 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.
[0134] At 0.7s, the aircraft has established an initial velocity, and the aerodynamic control surfaces begin to produce control effects, thus meeting the conditions for attitude control (this moment is determined based on historical flight data). 0.7s was chosen as the control initiation moment because at this time the UAV has gained sufficient speed with the rocket boost, and the aerodynamic torque of the servo control surfaces can effectively respond to control commands and perform attitude control.
[0135] After the timer 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 needs to perform heading control based on satellite positioning).
[0136] The 5.7s timeframe is set because within 5 seconds of the control law starting, the rocket boost has ended, the drone's speed has basically reached a safe airspeed, and the control law can perform position control. The number of satellites is set to be greater than 6 because this number of satellites indicates that the drone's positioning status is good, and the control law can perform position control.
[0137] During takeoff, after the timer reaches the preset time (accumulated after 0.7 seconds), the UAV's speed channel operates in open-loop control, specifically, in throttle command mode. The UAV's position channel also operates in open-loop control, specifically, the longitudinal and lateral position channels are both closed. The UAV's three-axis attitude channels operate in closed-loop control. Specifically, the outer loop of the roll channel controls the roll angle, and the inner loop controls the roll rate. The target roll angle command is zero, and the target roll rate command is automatically calculated by the outer loop target roll angle closed-loop control law. The outer loop of the pitch channel controls the pitch angle, and the inner loop controls the pitch rate. The target pitch angle command is the preset launch pitch angle, and the target pitch rate command is automatically calculated by the outer loop target pitch angle closed-loop control law, with a maximum pitch rate set to 2° / s. The outer loop of the yaw channel is closed, and the inner loop controls the yaw rate, with the target yaw rate command being zero.
[0138] If the number of satellites exceeds 6 after 5.7 seconds, the drone's flight process switches to the climb phase.
[0139] During the climb phase, after the timer reaches the preset time (accumulated after 5.7 seconds), the drone's speed channel is in open-loop control, specifically, the speed channel is in throttle command mode. The drone's longitudinal position channel is in closed mode; the drone's lateral position control is in side offset control, and it begins tracking the target's flight path in the lateral position, with the target's side offset being zero. The UAV's three-axis attitude channels are controlled in a closed-loop manner. Specifically, the outer loop of the roll channel controls the roll angle, and the inner loop controls the roll rate. The target roll angle command is zero, and the target roll rate command is automatically calculated by the outer loop target roll angle closed-loop control law. The outer loop of the pitch channel controls the pitch angle, and the inner loop controls the pitch rate. The target pitch angle command is the preset launch pitch angle, and the target pitch rate command is automatically calculated by the outer loop target pitch angle closed-loop control law. The outer loop of the yaw channel controls lateral acceleration, and the inner loop controls the yaw rate. The target lateral acceleration command is zero, and the target yaw rate command is automatically calculated by the outer loop target lateral acceleration closed-loop control law.
[0140] Step 4: After entering the climb phase, implement lateral deviation control mode based on the lateral offset between the UAV and the flight path, and use lateral acceleration control mode for heading control.
[0141] The lateral offset is calculated based on the relationship between the UAV and the flight path, and a lateral deviation control mode is implemented; the heading mode uses a lateral acceleration control mode.
[0142] Step 5: Once the indicated airspeed is greater than the safe airspeed, the drone's flight process switches to the cruise phase and begins to fly along the preset route.
[0143] During the cruise phase, the UAV's speed channel operates under closed-loop control. Specifically, the speed channel is for airspeed control, with the target airspeed command determined by the speed commands of each waypoint along the target flight path. The UAV's position channel also operates under closed-loop control. Specifically, the UAV's longitudinal position channel is for altitude deviation control, where it begins tracking the target flight path at an altitude of zero; the UAV's lateral position channel is for side offset control, where it begins tracking the target flight path at a side offset of zero. The UAV's three-axis attitude channels are controlled in a closed-loop manner. Specifically, the outer loop of the roll channel controls the roll angle, and the inner loop controls the roll rate. The target roll angle command is zero, and the target roll rate command is automatically calculated by the outer loop target roll angle closed-loop control law. The outer loop of the pitch channel controls the pitch angle, and the inner loop controls the pitch rate. The target pitch angle command is the preset launch pitch angle, and the target pitch rate command is automatically calculated by the outer loop target pitch angle closed-loop control law. The outer loop of the yaw channel controls lateral acceleration, and the inner loop controls the yaw rate. The target lateral acceleration command is zero, and the target yaw rate command 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 this invention selects the pitch rate as the inner loop control signal and uses active disturbance rejection control theory to design the pitch rate controller, which in principle ensures the robustness, anti-interference ability, and speed of the pitch channel; it selects the pitch angle as the outer loop control signal and uses dynamic inverse theory to design the pitch angle controller. Based on dynamic inverse control, it can ensure that the pitch angle controller can complete accurate nonlinear compensation and realize multivariable decoupled control under the presence of model uncertainty and external bounded unsteady disturbances, and ultimately can quickly track commands.
[0145] This invention focuses on pitch rate controllers based on active disturbance rejection (ADRR) theory, pitch rate controllers based on dynamic inverse, roll rate controllers based on ADRR theory, roll rate controllers based on dynamic inverse, and yaw rate controllers based on ADRR theory. The emphasis of this invention is on launch attitude control methods; longitudinal climb rate controllers and longitudinal altitude controllers are not within the scope of this invention and will not be described in detail here.
Claims
1. A launch attitude control method for a rocket-assisted unmanned aerial vehicle based on active disturbance rejection control, characterized in that, The specific steps are as follows: Step 1: The rocket-assisted drone enters the ready-to-fly phase. Ground staff send an engine ignition command, and the engine ignites and starts, entering idle mode. Step 2: Ground staff send the takeoff command, the engine speed increases to the designated speed, and the booster rocket begins to ignite; Step 3: When the axial acceleration of the UAV is greater than 30m / s² or the ground speed is greater than 5m / s, the rocket is determined to have ignited successfully. The speed and acceleration of the UAV increase, and it enters the takeoff phase, and begins linear active disturbance rejection attitude control. The attitude control channel includes three main control channels: pitch, roll, and yaw. In the outer loop of attitude control, the pitch and roll control loops adopt a dynamic inverse control structure, while the yaw channel adopts a lateral acceleration control structure; in the inner loop of attitude control, the pitch rate, roll rate, and yaw rate control loops all use linear active disturbance rejection control (LADRC). The control law for the pitch angle control loop of the outer ring of the pitch channel is: in, The pitch rate command generated for the pitch control loop. For the pitch angle control loop bandwidth, The pitch angle command generated for the position navigation loop. The current pitch angle, The current roll angle, This is the current yaw rate; The control law for the outer ring roll angle control loop of the roll channel is: in, The roll rate command generated for the roll angle control loop For the roll angle control loop bandwidth, The roll angle command generated for the position navigation loop. This is the current pitch rate; The control law for the outer ring lateral acceleration control loop of the yaw channel is: in, The yaw rate command generated for the lateral acceleration control loop. For the lateral acceleration control loop bandwidth, The lateral acceleration command generated for the position navigation loop, The current lateral acceleration, For the Laplace operator, The current vacuum speed of the aircraft, These are intermediate parameters without a clear physical meaning; The control law for the pitch rate control loop within the pitch channel is: in, Elevator deflection commands generated for the pitch rate control loop. For the pitch rate control loop bandwidth, The total system disturbance observation output by the extended state observer. For the rudder effect of the elevator; The control law for the inner loop roll rate control loop of the roll channel is: in, Aileron deflection commands generated for the roll rate control loop For the roll rate control loop bandwidth, The current roll rate, For the rudder effect of the aileron; The control law for the inner loop yaw rate control loop of the yaw channel is: in, The rudder deflection command generated for the yaw rate control loop. The bandwidth of the yaw rate control loop. The rudder effect; Step 4: After entering the climb phase, implement lateral deviation control mode based on the lateral offset between the UAV and the flight path, and use lateral acceleration control mode for heading control. Step 5: Once the indicated airspeed is greater than the safe airspeed, the drone's flight process switches to the cruise phase and begins to fly along the preset route.
2. The method as described in claim 1, characterized in that, In step three, the pitch control channel includes cascaded attitude control consisting of pitch angle and pitch rate, the roll control channel includes cascaded attitude control consisting of roll angle and roll rate, and the yaw control channel includes cascaded attitude control consisting of lateral acceleration and yaw rate.
3. The method as described in claim 1, characterized in that, In step three, after entering the takeoff phase, the maximum pitch rate is set to 2° / s.
4. The method as described in claim 1, characterized in that, In step three, when the timing reaches 0.7s, the control law is activated to implement closed-loop control of the roll angle, pitch angle, and yaw rate. 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.
5. The method as described in claim 1, characterized in that, In step three, after the timer 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 the heading control is based on satellite positioning.