Angle Of Attack Constraint Research Articles

Trajectory tracking control of a flexible air-breathing hypersonic vehicle using Lyapunov-based model predictive control

Considering the constraints of inputs and angle of attack (AOA), the trajectory tracking control of a flexible air-breathing hypersonic vehicle (FAHV) is investigated. To solve the problem, the Lyapunov-based model predictive control (LMPC) is presented. Firstly, the virtual controller is designed by nonlinear backstepping control (BSC), and it is integrated into the Lyapunov contraction constraint in LMPC to ensure the stability of the closed-loop system. Secondly, LMPC law is obtained by optimizing the weighted summation performance index of the tracking error and the control. Within the LMPC framework, the input constraints and AOA constraints can be handled simply, and by designing the appropriate parameters of the virtual controller, closed-loop stability is achieved. The effectiveness and superiority of the proposed method are verified by comparing it with the BSC and traditional model predictive control.

Ideal trajectory generation method of missile formation based on Gaussian pseudo-spectrum method

With the increasingly complex combat environment and the diversity of combat tasks, important military targets are surrounded by multi-layer defense. Modern information warfare pays more attention to system confrontation and multi-system cooperative operations,and missile formation to attack targets is the main research content of this paper. For missile wing ideal trajectory generation problems, ensure the attack Angle of time and meet the design requirements, Gaussian pseudo-spectral method is used to generate guarantee missile attacks within the specified time shot on target, at the same time meet the attack Angle constraint at the end of the ideal trajectory, the more missiles cooperative engagement problems into the ideal trajectory tracking problem, avoid the estimate of the remaining time of flight.The main contents of this paper are as follows:(1) Gaussian pseudo-spectral method is used to generate the ideal trajectory model.(2)Use Matlab to simulate the established model.

Adaptive nonsingular fixed‐time control for hypersonic flight vehicle considering angle of attack constraints

AbstractThis article proposes a fixed‐time singularity‐free neural control scheme for hypersonic flight vehicle (HFV) considering asymmetric time‐varying angle of attack (AOA) constraint based on integral barrier Lyapunov function (IBLF). In contrast to the state‐of‐the‐art fixed‐time control methods for HFV with AOA constraint, the most distinguishing feature of our control design lies in designing a direct AOA‐constrained control scheme without needing error transformation and the singularity issue is avoided. The IBLF is adopted to confine the AOA within a predefined asymmetric time‐varying compact set all the time. Moreover, the tracking errors of flight states and the estimate errors of approximations are ensured to converge into the bounded compact sets within fixed time, which can be preset by selecting the design parameters properly. Comparative simulations verify the superiority of the developed methodology.

Research on the Integrated Design of Missile Guidance Control Considering the Angle of Attack Constraint

The integrated guidance and control design of missile considering the attack angle constraint can effectively improve the guidance accuracy and damage effect of the missile, which has become one of the hot spots in current research. In this paper, we review the problem of integrated guidance and control design of missile considering attack angle constraint. First, the steps to construct the ensemble model are described. Second, combining with the fact that modern control theory has been successfully applied to the design of missile weapon systems, the integrated design approach for missile guidance and control in recent years is summarized and summarized in this paper. Finally, the analysis and discussion of the problems and trends that need to be addressed in the integrated design of missile guidance and control can break through the constraints of traditional missile design concepts and methods and serve as a reference for the development of a new generation of missiles.

Analysis of Line-of-Sight Angle Characteristics for Intercepting a Non-Maneuvering Target With Impact Angle Constraints

With the widespread informationization in modern warfare, higher requirements are required for monitoring the high-value target’s movement state and the corresponding attack conditions. Since the impact-angle constraint guidance law can improve the striking effect of a missile, the study of the hitting conditions and corresponding angle range of the attack angle constraint guidance law has become particularly important. This paper proposes a relationship between the missile’s line-of-sight and flight-path angle under terminal conditions and defines the line-of-sight selection region. Then, we analyze the selection method of the line-of-sight restriction at the end of the missile’s terminal phases. Additionally, Cauchy’s inequality is used to derive the mathematical expressions for line-of-sight selection region under extreme and ideal conditions when employing the developed guidance law to intercept non-maneuvering targets. Finally, a thorough analysis and numerous simulations demonstrate that the line-of-sight angle always falls within the extreme selection region during the entire flight and before hitting the target at the expected impact angle. Compared with a head-on interception, the line-of-sight selection region of the tail-chase case is broader, and the selection region range increases with the upward trend of the acceleration limit.

Robust Integrated Guidance and Control Design for Angle Penetration Attack of Multimissiles

Angle penetration attack ability plays a more and more important role for missiles in modern warfare, and the traditional separate guidance and control system design problem is the key to restrict the improvement of time-sensitive attack and cooperative attack ability of multimissiles. Firstly, the deviation control strategy of line-of-sight angle and attack angle is put forward in this paper, and the integrated guidance and control system model with impact angle constraint is established, according to the characteristics of angle penetration attack. Then, an integrated guidance and control controller for angle penetration attack is designed by using adaptive dynamic surface control, with the dynamic constraints, nonlinear input saturation, and terminal line-of-sight and attack angle constraints concerned. In order to ensure the robustness of the system, nonlinear disturbance observers are introduced to estimate the uncertainty of the system model. Finally, the stability of the integrated design method is proven based on the Lyapunov theory. Simulation results verify the effectiveness of the integrated guidance and control design method proposed in this paper in multimissile angle penetration attack.

Asymmetric integral BLF based state‐constrained flight control using NN and DOB

AbstractThis article proposes an adaptive back‐stepping flight controller under angle of attack (AOA) constraints. Taking the hypersonic flight vehicle (HFV) for example, considering the AOA constraints caused by the scramjet intake requirements, the asymmetric integral barrier Lyapunov function is used to design the controller, while the AOA is directly limited to a predefined interval without setting the tracking error and virtual control constraints separately. Furthermore, the neural networks and disturbance observer are applied in the controller to deal with the model uncertainty and external disturbance. The system stability and the AOA constraints are proved via Lyapunov analysis. Simulation tests on HFV longitudinal dynamics present that the proposed controller can prevent the AOA from exceeding the given bounds while altitude and velocity tracking.

Backstepping Control Based on Constrained Command Filter for Hypersonic Flight Vehicles with AOA and Actuator Constraints

An antisaturation backstepping control scheme based on constrained command filter for hypersonic flight vehicle (HFV) is proposed with the consideration of angle of attack (AOA) constraint and actuator constraints of amplitude and rate. Firstly, the HFV system model is divided into velocity subsystem and height subsystem. Secondly, to handle AOA constraint, a constrained command filter is constructed to limit the amplitude of the AOA command and retain its differentiability. And the constraint range is set in advance via a prescribed performance method to guarantee that the tracking error of the AOA meets the constraint conditions and transient and steady performance. Thirdly, the proposed constrained command filter is combined with the auxiliary system for actuator constraints, which ensures that the control input meets the limited requirements of amplitude and rate, and the system is stable. In addition, the tracking errors of the system are proved to be ultimately uniformly bounded based on the Lyapunov stability theory. Finally, the effectiveness of the proposed method is verified by simulation.

Phase plane design based fast altitude tracking control for hypersonic flight vehicle with angle of attack constraint

In this paper, fast setpoint altitude tracking control for Hypersonic Flight Vehicle (HFV) satisfying Angle of Attack (AOA) constraint is studied with a two-loop structure controller, in the presence of parameter uncertainties and disturbances. For the outer loop, phase plane design is adopted for the simplified model under Bang-Bang controller to generate AOA command guaranteeing fast tracking performance. Modifications based on Feedback-Linearization (FL) technique are adopted to transform the phase trajectory into a sliding curve. Moreover, to resist mismatch between design model and actual model, Fast Exponential Reaching Law (FERL) is augmented with the baseline controller to maintain state on the sliding curve. The inner-loop controller is based on backstepping technique to track the AOA command generated by outer-loop controller. Barrier Lyapunov Function (BLF) design is employed to satisfy AOA requirement. Moreover, a novel auxiliary state is introduced to remove the restriction of BLF design on initial tracking errors. Dynamic Surface Control (DSC) is utilized to ease the computation burden. Rigorous stability proof is then given, and AOA is guaranteed to stay in predefined region theoretically. Simulations are conducted to verify the efficiency and superior performance of the proposed method.

A novel adaptive second-order nonsingular terminal sliding mode guidance law design

Aiming at the problem of missile attacking ground target in pitch plane, combined with a composite fast nonsingular terminal sliding mode, a new adaptive finite-time stable guidance law with attack angle constraint is designed based on the second-order sliding mode control. The improved extended state observer is used to estimate the uncertainties and compensate the control quantity, and the dynamic control gains are designed to avoid the problem about “excessive estimation” of the parameter upper limit. According to the Lyapunov stability theory, it is proved that the system states can converge into a small neighborhood near the equilibrium point in a finite time. Monte Carlo simulation is carried out by randomly generating initial conditions, which proves that the guidance law has strong adaptability to different initial conditions and has good guidance precision.

Cooperative guidance strategy for multiple hypersonic gliding vehicles system

Cooperative guidance strategy for multiple hypersonic gliding vehicles system with flight constraints and cooperative constraints is investigated. This paper mainly cares about the coordination of the entry glide flight phase and driving-down phase. Different from the existing results, both the attack time and the attack angle constraints are considered simultaneously. Firstly, for the entry glide flight phase, a two-stage method is proposed to achieve the rapid cooperative trajectories planning, where the control signal corridors are designed based on the quasi-equilibrium gliding conditions. In the first stage, the bank angle curve is optimized to achieve the attack angle coordination. In the second stage, the angle of attack curve is optimized to achieve the attack time coordination. The optimized parameters can be obtained by the secant method. Secondly, for the driving-down phase, the cooperative terminal guidance law is designed where the terminal attack time and attack angle are considered. The guidance law is then transformed into the bank angle and angle of attack commands. The cooperative guidance strategy is summarized as an algorithm. Finally, a numerical simulation example with three hypersonic gliding vehicles is provided for revealing the effectiveness of the acquired strategy and algorithm.

A Convex Programming Method for Rocket Powered Landing With Angle of Attack Constraint

Real time trajectory planning is vital in rocket precision powered landing guidance. Due to the nonconvex angle of attack (AOA) constraint and other constraints, including nonlinear dynamics and thrust constraint, the powered landing trajectory planning problem is highly nonconvex, which makes it difficult to be solved in real time via existing nonconvex optimization algorithms. As the main contribution of this paper, the AOA constraint is taken into account in the problem. A convex feasible set method is presented to handle it, in which a quadratic concave function is introduced to find a convex feasible subset in the original AOA constraint and the second order term of this function is estimated by Gersgorin disc theorem. For the remaining nonconvexities, the lossless convexification is employed to address the thrust constraint, and the successive linearization is performed to handle the nonlinear dynamics. Thus, a convex optimization problem with AOA constraint for landing trajectory planning is built. The optimal solution to the original problem is obtained by iteratively solving convex problems. Numerical simulations show that the proposed method can find a feasible landing trajectory where the AOA constraint is satisfied and has a better convergence performance compared with the traditional linearization method.

Adaptive back-stepping sliding mode guidance laws with autopilot dynamics and acceleration saturation consideration

This paper studies the guidance scheme for the terminal guidance problem subject to input constraints, attack angle constraints, and second-order dynamics of missile autopilot. Firstly, the guidance system model with the above multi-constraint model is given. Secondly, an anti-saturation back-stepping guidance law which makes use of the low-pass filter to avoid the differential of the virtual control signals is designed based on the terminal sliding mode method, auxiliary system, and adaptive technique. Finally, Lyapunov theory and numerical simulations are utilized to prove that the states of the system under the proposed guidance law are uniformly ultimately bounded.

Rapid Altitude Tracking for Air-Breathing Hypersonic Vehicle With Limited Angle of Attack

This paper focuses on the altitude tracking issue for air-breathing hypersonic vehicles. It proposes a rapid altitude tracking method with synthetical consideration on the angle of attack constraint, which is crucial to keep the scramjet away from the inlet unstart. For the inner-loop, the novel compensator is considered in the conjunction of the backstepping approach to design a flight path angle tracking controller. The compensator helps the controller to limit the angle of attack with the uncertainties. For the out-loop of the control system, the altitude controller involves the combination of Bang-Bang control and the sliding mode technique to generate the command which accommodates the constraint on the angle of attack. The atmosphere density model is taken into account, which makes the proposed method more adaptable to the altitude variation. The effectiveness of the proposed control method is evaluated in the simulations.

Two controller designs of hypersonic flight vehicle under actuator dynamics and AOA constraint

This paper studies the controller design for hypersonic flight vehicle (HFV) considering the actuator hysteresis and the angle of attack (AOA) constraint respectively. Firstly, the effect of input hysteresis dynamics are regarded as the combination of the partial loss of effectiveness (PLOE) and a bounded disturbance-like item, while the controller is modified by constructing adaptive compensation laws. Secondly, to ensure the constraint on AOA, a prescribed performance control (PPC) method is designed while the AOA tracking error is restricted by the pre-defined performance function. The two controllers are designed based on dynamic surface control, where a nonlinear adaptive filter is utilized to eliminate the bound layer error. The effectiveness of the designed controllers are demonstrated via the simulation results.

Barrier Lyapunov Function Based Learning Control of Hypersonic Flight Vehicle With AOA Constraint and Actuator Faults.

This paper investigates a fault-tolerant control of the hypersonic flight vehicle using back-stepping and composite learning. With consideration of angle of attack (AOA) constraint caused by scramjet, the control laws are designed based on barrier Lyapunov function. To deal with the unknown actuator faults, a robust adaptive allocation law is proposed to provide the compensation. Meanwhile, to obtain good system uncertainty approximation, the composite learning is proposed for the update of neural weights by constructing the serial-parallel estimation model to obtain the prediction error which can dynamically indicate how the intelligent approximation is working. Simulation results show that the controller obtains good system tracking performance in the presence of AOA constraint and actuator faults.

Robust state-constrained control design for nonlinear systems with uncertainties using a new barrier Lyapunov function

In this paper, a robust state-constrained control algorithm is proposed by introducing time-varying barrier Lyapunov functions (BLF) for nonlinear systems with uncertainties. Novel time-varying symmetric/asymmetric forms of error barrier functions are investigated in order to relax the requirements of the initial state compared with existing BLF-based literatures. By integrating the proposed time-varying BLF method with the backstepping technique, constraint satisfaction is achieved and signals in closed-loop are uniform asymptotically stable. In addition, the extended state observer technique is utilized to prevent the constraint violation during the transient phase and strengthen the robustness of the control system in the presence of uncertainties. Numerical simulations are implemented to illustrate the attitude tracking performance obtained from the proposed method for a homing missile with angle of attack constraint, parametric uncertainties and external disturbances.

Quasi-equilibrium glide adaptive guidance for hypersonic vehicles

The entry-glide guidance strategy for hypersonic vehicles that can satisfy both terminal and path constraints is investigated in this paper. We propose a quasi-equilibrium glide adaptive guidance methodology based on the quasi-equilibrium glide condition (QEGC), which innovatively utilizes the quasi-equilibrium glide phenomenon in lifting entry. With the aid of QEGC, both range and terminal velocity can be predicted analytically with high precision. The path constraints are converted into angle of attack constraints, which has been difficult to realize by using traditional predictive guidance methods. The algorithm is independent of the standard trajectory. All the guidance commands, including the bank angle and the angle of attack, are calculated analytically in real time, which endows the algorithm with sufficient adapbility. The results of a CAV-H vehicle guidance test show that the algorithm leads the vehicle along a quasi-equilibrium glide trajectory satisfying both the terminal and path constraints and has sufficient flexibility for occasional mission changes. Furthermore, the robustness of the guidance algorithm under disturbances is validated through a Monte Carlo simulation.