Hypersonic Vehicle System Research Articles

Low-Complexity Adaptive Tracking Control for Unknown Pure Feedback Nonlinear Systems With Multiple Constraints

A low-complexity adaptive tracking control strategy for a class of pure feedback nonlinear systems is developed in the presence of completely unknown non-affine nonlinearities, prescribed tracking performance constraints, full states constraints, and input saturation constraint. To handle the input saturation nonlinearity and the constrained states without pre-calculating the bound of virtual controllers, a new coordinate transformation approach is presented with an arc-tangent function and an auxiliary first-order dynamics. Subsequently, to deal with the completely unknown non-affine nonlinearities and the problem of prescribed performance, an inverse hyperbolic tangent function and a Nussbaum function are introduced at each step of back-stepping design, which can guarantee the control errors to vary with prescribed performance functions in time and avoid the “explosion of complexity” issue simultaneously. Then, an adaptive controller is derived from the recursive design procedure without the use of any approximators. The semi-globally uniformly ultimate boundedness of all signals in the closed-loop system and the satisfaction of all constraints are rigorously proved through Lyapunov stability analysis. Finally, the simulation studies on a hypersonic flight vehicle system are worked out to demonstrate the effectiveness and the applicability of the investigated approach.

Adaptive attitude tracking control for hypersonic reentry vehicles via sliding mode-based coupling effect-triggered approach

This paper proposed a coupling effect-triggered control approach for hypersonic reentry vehicles attitude tracking system based on the adaptive sliding mode techniques. A coupling effect indicator (CEI), which is established based on the Lyapunov stability theory, is obtained to demonstrate whether a coupling harms or benefits the system. In consequence, the coupling effect-triggered control driven by the CEI is developed to cancel the harmful couplings while keeping the beneficial couplings. Meanwhile, the robustness of the proposed method is enhanced by the adaptive sliding mode approach even when the boundary of the disturbance is unknown. To avoid the non-differentiable terms in the controller design, the command filtered scheme is introduced and the bounded stability of the closed-loop system is guaranteed. This technique outperforms the existing controllers which do not consider the coupling effect in the transient response. Finally, application to the hypersonic vehicle system is presented to demonstrate the validity of the proposed control scheme.

Reliability-based linear parameter varying robust non-fragile control for hypersonic vehicles with disturbance observer

In this paper, the linear parameter varying (LPV) reliable non-fragile control for the hypersonic vehicle (HV) is studied in case of disturbance and controller gain variations. Due to the dramatic and complex change of the HV longitudinal dynamics, a polytopic LPV model is constructed for the HV system stability analysis and controller design in a large flight envelope. Then, a disturbance observer (DOB)-based non-fragile controller for HV system with disturbance and unknown controller uncertainty is designed to guarantee the closed-loop stability and control performance under an adequate level of reliability, which is formed with two parts. One part is a DOB to compensate the uncertain dynamics and disturbance. The other is a robust non-fragile controller, which is designed based on a novel robust reliability method to deal with controller uncertainties, and obtained by carrying out reliability-based linear matrix inequality optimization. The presented controller for HV can provide the robustness as well as an excellent performance under the condition that the prescribed reliability degree is satisfied. Finally, numerical simulation for an HV demonstrates the effectiveness of the proposed method.

Self-Healing Control for Attitude System of Hypersonic Flight Vehicle With Body Flap Faults

This paper provides a mathematical model for a hypersonic flight vehicle system with actuator faults and then, proposes a fault-tolerant algorithm to increase the reliability of the attitude system. A terminal sliding mode controller for attitude angular loop is introduced to obtain the virtual control input. Thus, the required deflection angle of aerodynamic surfaces can be calculated via dynamic surface technique in inner angular rate loop. When the aero-surfaces are saturated and unable to supply the moment vector commanded by the fault tolerant controller, a reaction control system will be driven by quadratic programming allocator to provide the residual control torque. The system stability is analyzed utilizing the Lyapunov function. Several simulation results validate that the system output can track the desired command even under fault situations.

Improved adaptive fault‐tolerant control design for hypersonic vehicle based on interval type‐2 T‐S model

SummaryThis study proposes an improved adaptive fault estimation and accommodation algorithm for a hypersonic flight vehicle that uses an interval type‐2 Takagi‐Sugeno fuzzy model and a quantum switching module. First, an interval type‐2 Takagi‐Sugeno fuzzy model for the hypersonic flight vehicle system with elevator faults is developed to process the nonlinearity and parameter uncertainties. An improved adaptive fault estimation algorithm is then constructed by adding an adjustable parameter. The quantum switching module is also applied to the estimation part to select an appropriate algorithm in different fault cases. The estimation results from the given fuzzy observer are used to design a type‐2 fuzzy fault accommodation controller to stabilize the fuzzy system. The stability of the proposed scheme is analyzed using the Lyapunov stability theory. Finally, the validity and availability of the method are verified by a series of comparisons on numerical simulation results.

Air-Breathing Hypersonic Vehicle Tracking Control Based on Adaptive Dynamic Programming.

In this paper, we propose a data-driven supplementary control approach with adaptive learning capability for air-breathing hypersonic vehicle tracking control based on action-dependent heuristic dynamic programming (ADHDP). The control action is generated by the combination of sliding mode control (SMC) and the ADHDP controller to track the desired velocity and the desired altitude. In particular, the ADHDP controller observes the differences between the actual velocity/altitude and the desired velocity/altitude, and then provides a supplementary control action accordingly. The ADHDP controller does not rely on the accurate mathematical model function and is data driven. Meanwhile, it is capable to adjust its parameters online over time under various working conditions, which is very suitable for hypersonic vehicle system with parameter uncertainties and disturbances. We verify the adaptive supplementary control approach versus the traditional SMC in the cruising flight, and provide three simulation studies to illustrate the improved performance with the proposed approach.

Multiple model predictive control for large envelope flight of hypersonic vehicle systems

Considering the strong nonlinearity, wide flight envelope and hard constraints of hypersonic vehicle (HV), we present a multiple model predictive control (MMPC) strategy for the control of HV's large envelope flight. Firstly, we divide the flight envelope of HV into several sub-regions based on gap metric theory. A novel algorithm is then developed to determine the approximated linear model for each sub-region. On this basis, model predictive control with infinite horizon cost is applied to design the sub-region controllers. To guarantee the stability of closed-loop system, we propose a multi-model switching strategy based on dynamic pressure. At last, the tracking performance of MMPC is verified on the hardware in the loop simulation (HLPS) platform dSPACE.

Slow–fast loop gain-scheduled switching attitude tracking control for a near-space hypersonic vehicle

This article develops a slow–fast loop polytopic linear parameter-varying model and proposes a systematic gain-scheduled switching attitude tracking control scheme for a near-space hypersonic vehicle. First, the dynamics of near-space hypersonic vehicle is modeled as a slow–fast loop polytopic linear parameter-varying model using the Jacobian linearization and tensor-product model transformation approach. Open-loop simulation verification illustrates that the developed polytopic linear parameter-varying model captures the local nonlinearities of the original nonlinear system; therefore, it is suitable for model-based control. Second, for less conservative controller design purpose, the flight envelope is divided into smaller subregions, a family of slow loop and fast loop gain-scheduled controllers are designed, and each of them is suitable for a specific parameter subspace; the slow loop and fast loop gain-scheduled controllers are then switched in order to guarantee the closed-loop near-space hypersonic vehicle system to be asymptotically stable and satisfy a specified performance criteria. The resulting slow loop and fast loop gain-scheduled switching controllers are found by solving a convex constraint problem that can be efficiently solved using available linear matrix inequality techniques. Finally, numerical simulations have demonstrated the effectiveness of the proposed method.

Fuzzy Non-fragile H∞ Tracking Control for Flexible Air-breathing Hypersonic Vehicles

This paper proposed a fuzzy non-fragile tracking control design method for flexible air-breathing hypersonic vehicles (FAHVs). The T-S fuzzy set approach is applied to the modeling of the complex nonlinear dynamics of FAHVs, and a T-S fuzzy model is constructed, which can represent the nonlinear hypersonic vehicle system. Then, by considering the actuator controller coefficients uncertainties and disturbances, the fuzzy non-fragile H∞ tracking problem for FAHVs is proposed. A state-feedback controller design method is proposed to guarantee the tracking performance in the presence of actuator controller coefficients uncertainties. By a Lyapunov approach, the existence conditions for such a controller are established in terms of linear matrix inequalities (LMIs). An illustrative example is given to show the excellent tracking performance of the proposed controller design method.

Reference output tracking control for a flexible air‐breathing hypersonic vehicle via output feedback

SUMMARYThis paper addresses the problem of reference output tracking control for the longitudinal model of a flexible air‐breathing hypersonic vehicle (FAHV) by utilizing the output feedback control approach. The dynamic characteristics of the FAHV along with the aerodynamic effects of hypersonic flight make the flight control of such systems highly challenging. Moreover, there exist some intricate couplings between the engine and flight dynamics as well as complex interaction between rigid and flexible modes in the longitudinal model. These couplings bring difficulty to the flight control design for the intractable hypersonic vehicle systems. This paper deals with the problem of reference output tracking control for the longitudinal model of the FAHV. By utilizing the trim condition information including the state of altitude, velocity, angle of attack, pitch angle, pitch rate and so on, the linearized model is established for the control design objective. Then, the reference output velocity and altitude tracking control design problem is proposed for the linearized model. The flexible models of the FAHV system are hardly measured because of the complex dynamics and the strong couplings of the FAHV. Thus, by using only limited flexible model information, the reference output tracking performance analysis criteria are obtained via Lyapunov stability theory. Then, based on linear matrix inequality optimization algorithm, the static output feedback controller is designed to stabilize the closed‐loop systems, guarantee a certain bound for the closed‐loop value of the cost function, and can make the control output achieve the reference velocity and altitude tracking performance. Subsequently, the condition of dynamic output feedback controller synthesis is given in terms of linear matrix inequalities and a numerical algorithm is developed to search for a desired dynamic output feedback controller which minimizes the cost bound and obtains the excellent reference altitude and velocity tracking performance simultaneously. The effectiveness of the proposed reference output tracking control method is demonstrated in simulation part. Furthermore, the superior reference velocity and altitude performance commands could be achieved via using static and dynamic output feedback controllers under lacking some unmeasured flexible states information in the measurement output vector. Copyright © 2011 John Wiley & Sons, Ltd.