Efficient adaptive constrained control with time-varying predefined performance for a hypersonic flight vehicle

Abstract

A novel low-complexity adaptive control method, capable of guaranteeing the transient and steady-state tracking performance in the presence of unknown nonlinearities and actuator saturation, is investigated for the longitudinal dynamics of a generic hypersonic flight vehicle. In order to attenuate the negative effects of classical predefined performance function for unknown initial tracking errors, a modified predefined performance function with time-varying design parameters is presented. Under the newly developed predefined performance function, two novel adaptive controllers with low-complexity computation are proposed for velocity and altitude subsystems of the hypersonic flight vehicle, respectively. Wherein, different from neural network-based approximation, a least square support vector machine with only two design parameters is utilized to approximate the unknown hypersonic dynamics. And the relevant ideal weights are obtained by solving a linear system without resorting to specialized optimization algorithms. Based on the approximation by least square support vector machine, only two adaptive scalars are required to be updated online in the parameter projection method. Besides, a new finite-time-convergent differentiator, with a quite simple structure, is proposed to estimate the unknown generated state variables in the newly established normal output-feedback formulation of altitude subsystem. Moreover, it is also employed to obtain accurate estimations for the derivatives of virtual controllers in a recursive design. This avoids the inherent drawback of backstepping -"explosion of terms" and makes the proposed control method achievable for the hypersonic flight vehicle. Further, the compensation design is employed when the saturations of the actuator occur. Finally, the numerical simulations validate the efficiency of the proposed finitetime-convergent differentiator and control method.

Robust estimation‐free decentralized prescribed performance control of nonaffine nonlinear large‐scale systems

“…Remark Inequality is a common condition adopted in prescribed performance control, which indicates that the initial tracking errors are known well (can be obtained by state observer). The transient performance (overshoot, undershoot, convergence rate, etc) and steady‐state performance (static error) are well‐preplanned by condition .…”

“…Recently, attributed to Bechlioulis and Rovithakis' work, a new control design and synthesis methodology was developed to quantitatively characterize the transient and steady‐state performance of nonlinear systems through user‐specialized prescribed performance function (PPF). This control method was further exploited for servo mechanisms, robot system, and hypersonic vehicle system . However, the foregoing prescribed performance control depends on nonlinear dynamics; in this case, unknown nonlinear dynamics with uncertainty will enhance the difficulty of relevant controller design.…”

Event-driven adaptive fault-tolerant tracking control for uncertain mechanical systems with application to flexible spacecraft

“…Practically, actuator faults are often encountered and would easily degrade the system performance or even make the system lose stability, which has been a very risky and challenging threat for the reliability and safety of industrial systems (Gao et al 2015;Wei et al, 2017aWei et al, , 2017b. To guarantee the system stability and reliability, Tong et al (2013) and Yoo (2015) investigated adaptive decentralized control of nonlinear large-scale systems with consideration of the actuator failures and dead zone.…”

“…However, all the above studies are time driven or time triggered, namely, the corresponding controller is required to update periodically based on the sampling time sequences no matter whether the plant needs or not (Dai and Xiao, 2018;Zhang et al, 2016). This easily brings out signal transmission burdens and leads to the aging of physical institutions because of highly frequent updates and operations like the elevator's changes of flight vehicles according to Wei et al (2017aWei et al ( , 2017b. Thus, how to decrease the signal transmission burdens or controller updating rates has gained extensive attention in recent years, especially for the network systems (Dai and Xiao, 2018).…”

Low‐Complexity Adaptive Saturated Control of a Class of Nonlinear Systems with Its Application

“…Apart from the aforementioned discussions, in practical engineering systems such as air conditioner, flexible crane, robot, and hypersonic vehicle [13,14], state constraints are also often encountered, which makes it pretty difficult to facilitate the corresponding controller. Among the state constraints, output limitation is one typical constraint which potentially degrades the system performance and easily causes serious hazards.…”