## 1 Introduction  
Without doubt, the stabilization control of nonlinear systems is important as a first step in performing additional control objectives, such as output tracking, disturbance attenuation, and/or decoupling. In the past decades, global asymptotic stabilization of nonlinear systems has been widely recognized as a challenging problem and received a great deal of attention from the nonlinear control community. With the help of various mathematical tools, tremendous progress has been achieved toward the development of powerful design methodologies for global asymptotic stabilization, including backstepping design [1], feedback linearization [2], sliding mode control [3], fuzzy control [4], nonlinear \(\mathcal{H}_{\infty}\)[5], and so on. Compared to asymptotic stabilization, which means that the convergence rate is, at best, exponential with infinite settling time [6; 7], finite-time stabilization is more attractive as the systems with finite-time convergence usually demonstrate some superior properties, such as faster convergence, high accuracies, and better robustness to uncertainties, and/or external disturbances [7; 8; 9; 10; 11], which are rather important for demanding applications. Being aware of these advantages, the finite-time stabilization problem has been intensively studied for nonlinear systems, and numerous interesting results have been obtained in the past decades (see, e.g., [12; 13; 14; 15; 16; 17; 18; 19; 20; 21]). Among the existing results, owing to its benefits including fast response and easy implementation, the terminal sliding mode control [20], together with its nonsingular modification [21], has been extensively recognized as one of the most popular/effective approaches for finite-time stabilization. By designing a suitable nonlinear sliding surface while constructing a discontinuous controller, the phase of terminal sliding mode can be achieved in finite-time, and thereby guaranteeing finite-time stabilization of the closed-loop system [20; 21; 22]. It should be noted that the associated settling time of the finite-time design is intrinsically related to the initial states [11; 23]. That is, the availability of initial states is somewhat critical for the settling-time estimates; this inevitably prevents us from applying finite-time schemes [24]. Fortunately, with the notion of fixed-time stability, along with the Lyapunov-like criteria recently presented in the seminal work [23], the potential drawback of finite-time schemes was resolved effectively. To be more specific, as stated in [23], the fixed-time stability not only implies global uniform finite-time stability but also provides a settling-time function being uniformly bounded by a tunable constant, which depends on design parameters but is independent of the initial states. In other words, by fixed-time controller design, a predetermined bound of the settling time (function) can be accordingly assigned. Particularly, the fixed-time stabilization is very promising, especially when the organized controller is assigned intentionally to achieve certain control precision in a desired time interval [23; 25; 26]. Realizing this feature, research study has been more recently focused on the fixed-time stabilization of various nonlinear systems, for instance, high-order regulators [27], multi-agent systems [28; 29], power systems [30], etc. To the best of our knowledge, most of the existing studies on fixed-time stabilization are essentially concerned with scalar systems or single input control structures [24; 26; 27; 28; 29; 30]. For multivariable multi-input systems, very few results are available in the literature; see, for example, [31; 32; 33], in which the fixed-time stabilization of time-invariant linear and nonlinear systems are addressed, respectively.