Adaptive Sliding Mode Fixed‐Time Tracking Control Based on Fixed‐Time Sliding Mode Disturbance Observer with Dead‐Zone Input

Abstract

Aiming at the problem of fixed-time trajectory tracking control for high-order dynamic systems with external time-varying disturbance and input dead-zone, an adaptive fixed-time sliding mode control algorithm is proposed by employing a fixed-time sliding mode disturbance observer (FTSMDO) and high-order fixed-time sliding mode algorithm. Firstly, a FTSMDO is presented for the problem that estimating the compound disturbance is composed of input dead-zone and time-varying external disturbance in the higher-order dynamic system, which cannot be measured accurately. Furthermore, for the case that the total disturbance of the system has an unknown upper bound, the corresponding adaptive law is designed to estimate the unknown upper bound, and the fixed-time controller is designed based on FTSMDO algorithm to make all state variables converge in a fixed-time. Based on Lyapunov technique, the fixed-time convergence performance of the proposed algorithm is proved. The effectiveness of the presented fixed-time control algorithm is verified by simulating the depth tracking control of the underactuated underwater vehicle.

Discrete-Time 2-Order Sliding Mode Fault-Tolerant Tracking Control for Non-Gaussian Nonlinear Stochastic Distribution Control Systems with Missing Measurements

“…Theorem 2. e trajectory of the closed-loop system can be driven onto the sliding surface in finite time with control law (23).…”

“…To solve the problem of the nonlinear relationship between DC-link voltage and the control input, a new supertwisting sliding mode control algorithm is implemented in [22]. In [23], the disturbance observer based on fixed-time supertwisting algorithm and the controller based on fixed-time high-order sliding mode are designed for high-order dynamic systems. e main disadvantage of sliding mode control is the chattering problem.…”

“…(2) Formulate 􏽢 f(k) using ( 8). (3) On the basis of fault diagnosis result, a new 2-order discrete-time sliding mode fault-tolerant tracking control method is designed, and the controller u(k) can be obtained by using (23). ( 4) When fault occurs, the practical reconfigured controller in (31) can be obtained based on the estimated information.…”

Construction of Nonsinusoidal Oscillation Waveform Function and Technological Parameters for Continuous Casting Mold

“…e velocity rules of mold oscillation went through rectangular, trapezoid, sinusoidal, and nonsinusoidal oscillation. With the demand growing for the surface quality and casting speed of slab, nonsinusoidal oscillation has been one of the key technologies to realize highly efficient continuous casting [1][2][3][4].…”