When designing a controller for a nonlinear system, the first consideration is how to make it run stably. In other words, the stability of the system is the basis of all expected performance. Many reliable control methods have emerged, including proportional–integral–derivative (PID) control, state feedback, observers, optimal control, fuzzy control, and adaptive control, improving control theory from different perspectives, enabling a variety of engineering problems to be solved. However, in many existing design methods, such as PID control and methods based on the Lyapunov stability theory, only asymptotic stability of the system state can be obtained, that is, only when the time tends to infinity can the state of the system converge to the equilibrium point. In practical engineering, researchers can often be more concerned with the system meeting certain transient performance requirements, showing that the study of finite time control has a strong engineering background.

Early finite time control methods mostly focused on open-loop control methods. However, these methods rely on initial value information, lack robustness and anti-disturbance ability, and are not suitable for use in complex nonlinear systems. To solve these problems, a control method based on state feedback has been proposed, which can not only reduce the dependence on initial values, but also improve the anti-disturbance ability of the system. Terminal sliding mode control (TSMC) is also a commonly used method in finite time control design. However, the disadvantage is that TSMC methods make the system susceptible to chatter. Recently, a state-constrained finite-time control method has been proposed, which aims to design a performance function that can reach an arbitrary small neighborhood in a finite time. Combined with a monotonically increasing and bounded error transformation function, the state or the output or the tracking error of the system can converge to the pre-defined area within the settling time. However, compared with traditional control theory, the research of finite time control is still in the initial stage of development and needs further exploration.

The aim of this Special Issue, therefore, is to collect recent research related to the finite time control of complex nonlinear systems. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Adaptive finite time control of complex nonlinear systems
• Terminal sliding mode control of complex nonlinear systems
• Composite finite time learning control of complex nonlinear systems
• Adaptive fuzzy finite time control of complex nonlinear systems
• Finite time prescribed performance control of complex nonlinear systems
• Finite time control of fractional-order systems
• Finite time learning control