Mode Control For Hypersonic Vehicle Research Articles

Active adaptive continuous nonsingular terminal sliding mode controller for hypersonic vehicle

An active adaptive continuous nonsingular terminal sliding mode algorithm (ACNTSM) is designed for hypersonic boost glide vehicle to achieve higher control accuracy and faster response speed. Firstly, a continuous nonsingular terminal sliding mode controller is presented to make the tracking error and sliding variable converge to zero under the effect of time-varying disturbance in finite time. Compared with traditional terminal sliding mode control using exponential approach law, the ACNTSM algorithm can generate continuous control signal, which effectively reduces chattering. Secondly, a novel active adaptive law is proposed to reduce convergence error, to avoid excessive gain, and to attenuate chattering by adjusting the gain of ACNTSM. The adaptive scheme includes sliding variable and disturbance estimation. The disturbance estimation is obtained by using the integral term of generalized super twisting sliding mode algorithm. The method takes less computational resources and reduces complexity of algorithm. In addition, the gain can automatically increase to shorten convergent time until the sliding mode is reached and then decrease to reduce chattering until the sliding mode is lost. The novel adaptive law ensures the finite-time convergence to a neighborhood of origin for sliding variable without overestimation of gain. Finally, numerical simulations are carried out to demonstrate the effectiveness and superiority of ACNTSM.

Sliding Mode Control for Hypersonic Vehicle Based on Extreme Learning Machine Neural Network Disturbance Observer

The novel extreme learning machine (ELM) neural network disturbance observer (NNDO) - based sliding mode control (SMC) strategy is proposed for the precise tracking control of a hypersonic vehicle (HV) under various disturbance situations. By converting nonlinear dynamics into state-dependent linear model, the control law design process is simplified, and the sliding mode control law based on the power function reaching rate is designed to suppress the chattering effect. Considering the disturbances, the ELM-NNDO is designed based on the single-hidden layer feedforward network (SLFN). Different from conventional ELM using least square optimization approach, the output weight here is updated based on the Lyapunov synthesis approach. In addition, the influences of the disturbances on the velocity and altitude are attenuated by the direct feedback compensation (DFC), and the offset-free tracking control is realized for the output reference signal. Comparison of simulation results verify the superior control performance of the proposed method.

Fractional-order $$PI^{\lambda }D$$ sliding mode control for hypersonic vehicles with neural network disturbance compensator

Fractional-order $$PI^{\lambda }D$$ sliding mode control for hypersonic vehicles with neural network disturbance compensator

Chebyshev Neural Network-Based Adaptive Nonsingular Terminal Sliding Mode Control for Hypersonic Vehicles

This paper presents an adaptive nonsingular terminal sliding mode control approach for the attitude control of a hypersonic vehicle with parameter uncertainties and external disturbances based on Chebyshev neural networks (CNNs). First, a new nonsingular terminal sliding surface is proposed for a general uncertain nonlinear system. Then, a nonsingular sliding mode control is designed to achieve finite-time tracking control. Furthermore, to relax the requirement for the upper bound of the lumped uncertainty including parameter uncertainties and external disturbances, a CNN is used to estimate the lumped uncertainty. The network weights are updated by the adaptive law derived from the Lyapunov theorem. Meanwhile, a low-pass filter-based modification is added into the adaptive law to achieve fast and low-frequency adaptation when using high-gain learning rates. Finally, the proposed approach is applied to the attitude control of the hypersonic vehicle and simulation results illustrate its effectiveness.

A finite-time sliding mode control for hypersonic vehicle

In this paper, a finite-time control strategy based on back-stepping method combining with a terminal sliding mode control (TSMC) and a nonlinear disturbance observer (NDO) is proposed for the longitudinal dynamic model of hypersonic vehicle (HV). Firstly, the model of HV is transformed into two strict feedback subsystem: the mismatched subsystem of altitude and the matched subsystem of velocity. Then, the TSMC and back-stepping method is incorporated to cope with the unmatched issue in the HV altitude subsystem. In addition, a NDO based on a finite-time-convergent differentiator (FD) is proposed to estimate the lumped disturbances. The finite-time stability condition of the system is established via the Lyapunov theory. Finally, the robustness and effectiveness of the method are verified by simulations.

Predictive Sliding Mode Control Using Feedback Linearization for Hypersonic Vehicle

This paper presents a novel predictive sliding mode control for hypersonic vehicle by means of feedback linearization. First, the six degree-of-freedom rotational model of the hypersonic vehicle in three channels is presented and decoupled using feedback linearization control to facilitate the design of control system. Then, the sliding mode surface chosen as a combination of the tracking error and its higher order derivatives is predicted and incorporated into the quadratic performance index of the predictive control. The predictive sliding control law with an explicitly analytical form could be derived by minimizing the performance index which attenuates the undesirable chattering phenomenon due to the switching of sliding mode control law and avoids the large online computational issue of the predictive control. The stability of the designed control system could be demonstrated via Lyapunov stability theorem. Finally, simulation results demonstrate the effectiveness and robustness of the proposed attitude control scheme.

Second-order terminal sliding mode control for hypersonic vehicle in cruising flight with sliding mode disturbance observer

This paper focuses on the design of nonlinear robust controller and disturbance observer for the longitudinal dynamics of a hypersonic vehicle (HSV) in the presence of parameter uncertainties and external disturbances. First, by combining terminal sliding mode control (TSMC) and second-order sliding mode control (SOSMC) approach, the secondorder terminal sliding control (2TSMC) is proposed for the velocity and altitude tracking control of the HSV. The 2TSMC possesses the merits of both TSMC and SOSMC, which can provide fast convergence, continuous control law and high-tracking precision. Then, in order to increase the robustness of the control system and improve the control performance, the sliding mode disturbance observer (SMDO) is presented. The closed-loop stability is analyzed using the Lyapunov technique. Finally, simulation results illustrate the effectiveness of the proposed method, as well as the improved overall performance over the conventional sliding mode control (SMC).

On‐line RNN compensated second order nonsingular terminal sliding mode control for hypersonic vehicle

Purpose – The purpose of this paper is to design a robust control scheme to achieve robust tracking of velocity and altitude commands for a general hypersonic vehicle (HSV) in the presence of parameter variations and external disturbances.Design/methodology/approach – The robust control scheme is composed of nonsingular terminal sliding mode control (NTSMC), super twisting control algorithm (STC) and recurrent neural network (RNN). First, by combing a novel NTSMC and STC algorithm, a second order NTSMC approach for HSV is proposed to provide fast, continuous and high precision tracking control. Second to relax the requirements for the bounds of the lumped uncertainties in control design, a RNN disturbance observer is presented to increase the robustness of the control system. The weights of RNN are updated by adaptive laws based on Lyapunov theorem, thus the closed‐loop stability can be guaranteed.Findings – Simulation results demonstrate that the proposed method is effective, leading to promising perform...