Finite-time Command Research Articles

Finite-Time Adaptive Fuzzy Command Filtered Backstepping Control for a Class of Nonlinear Systems

In this article, the problem of adaptive fuzzy finite-time command filtered control is considered for a class of nonstrict-feedback nonlinear systems. The explosion of complexity problem is dealt with by employing the command filter approach. In order to design a finite-time control scheme, a finite-time semi-global practical stability criterion is first presented. Based on this criterion, by applying the command filter technology and backstepping technique, adaptive fuzzy finite-time tracking control scheme is developed with the help of fuzzy logic systems approximation. Under the presented adaptive control scheme, all the closed-loop variables are semi-global practical finite-time stable and the tracking error goes into an adjustable neighborhood around the origin in a finite time. Finally, simulations are utilized to verify the effectiveness of designed control scheme.

Backstepping based adaptive finite-time tracking control of manipulator systems with uncertain parameters and unknown backlash

In this paper, the adaptive finite-time command filtered backstepping control is investigated for uncertain manipulator systems with unknown backlash. The finite-time command filters, virtual control signal, adaptive update law and error compensation mechanism are designed respectively, which can deal with the computation complexity problem of conventional backstepping, and guarantee that the joint position tracking error reaches to a sufficiently small region including the origin in finite time although the uncertain parameters and unknown backlash are existed. The dynamic models of a two-link robot manipulator and the PUMA 560 manipulator are applied in simulation to verify the effectiveness of the given control strategy.

Adaptive fuzzy finite-time command filtered tracking control for permanent magnet synchronous motors

This paper studies the position tracking control problem for permanent magnet synchronous motors (PMSMs) with parameter uncertainties. Firstly, the command filtered method is employed to overcome the “explosion of complexity” in traditional backstepping method. Then, in order to reduce the errors produced by command filters, error compensation mechanism is adopted. In addition, the finite-time control method makes the tracking error converge to the smaller neighborhood in the finite time. The adaptive fuzzy control is used to approximate the nonlinear functions. Finally, the simulation results proved the designed control method can overcome the influence of parameter uncertainties and achieve the satisfactory position tracking control.

Finite-Time Command Filtered Backstepping Algorithm-Based Pitch Angle Tracking Control for Wind Turbine Hydraulic Pitch Systems

In this paper, a novel finite-time command filtered backstepping control algorithm is proposed to address the problems of high order nonlinearity, noise and friction interference when tracking the pitch angles of wind turbine hydraulic pitch systems. Since taking derivative is not required, the system noise cannot be amplified in the algorithm design process. The finite-time command filter is first employed to filter the state variables of the hydraulic pitch systems to eliminate the interference caused by the noise and friction. Moreover, the filter is combined with backstepping design to approximate the derivatives of virtual control variables to avoid “Differential expansion” phenomenon. In addition, in order to ensure the accuracy of the filtered signals to approximate the virtual control variables, a finite-time error compensation mechanism is designed. Simulation results show the effectiveness and high-precision tracking performance of the proposed algorithm in this paper.

Adaptive finite-time fuzzy command filtered controller design for uncertain robotic manipulators

In this article, an adaptive fuzzy control command filtered control approach, which is capable of achieving finite-time trajectory tracking control of uncertain robotic manipulators, is proposed by using the backstepping control technique. To obtain a finite-time estimation of a virtual control input and its first-order derivative, a second-order finite-time command filter is designed. Based on the backstepping control technique, an adaptive fuzzy controller that guarantees not only that the tracking errors tend to an arbitrary small region in finite time but also that all signals in the closed-loop system keep bounded is established. Finally, the effectiveness of the proposed method is demonstrated by simulation on a two-link robotic manipulator.

Finite-Time Trajectory Tracking for Marine Vessel by Nonsingular Backstepping Controller With Unknown External Disturbance

In this paper, a novel nonsingular finite-time backstepping controller is constructed for trajectory tracking of marine vessel subject to unknown external disturbances. Firstly, in the presence of disturbances, a disturbance observer (DO) is proposed to estimate and compensate the disturbances exactly in finite time. Secondly, a finite-time tracking controller is designed in the classical backstepping procedure, however, the inevitable singularity appears in calculating the derivative of virtual control. Furthermore, for overcoming this singularity, a nonsingular finite-time backstepping controller is designed by adopting a finite-time command filter to estimate the derivative, instead of calculating it directly. Theoretical analysis demonstrates the closed-loop system is finite-time stable. Finally, simulation results and comparisons illustrate the effectiveness of the proposed method.

Adaptive Finite-Time Command Filtered Fault-Tolerant Control for Uncertain Spacecraft with Prescribed Performance

In this paper, an adaptive finite-time fault-tolerant control scheme is proposed for the attitude stabilization of rigid spacecrafts. A first-order command filter is presented at the second step of the backstepping design to approximate the derivative of the virtual control, such that the singularity problem caused by the differentiation of the virtual control is avoided. Then, an adaptive fuzzy finite-time backstepping controller is developed to achieve the finite-time attitude stabilization subject to inertia uncertainty, external disturbance, actuator saturation, and faults. Through using an error transformation, the prescribed performance boundary is incorporated into the controller design to guarantee the prescribed performance of the system output. Numerical simulations demonstrate the effectiveness of the proposed scheme.

Adaptive Neural Consensus Tracking for Nonlinear Multiagent Systems Using Finite-Time Command Filtered Backstepping

This paper is concerned with the finite-time consensus tracking control problems of uncertain nonlinear multiagent systems. A neural network-based distributed adaptive finite-time control scheme is developed, which can guarantee the consensus tracking is achieved in finite time with sufficient accuracy in the presence of unknown mismatched nonlinear dynamics. Such a finite-time feature is achieved by the modified command filtered backstepping technique based on the high-order sliding mode differentiator. Moreover, the proposed control scheme is completely distributed, since the control laws only use the local information. In addition, although mismatched uncertainty nonlinear dynamics are considered, only one parameter needs to be updated for each agent in the control scheme, which will simply the computations and make the proposed scheme more effective for applications. An example is included to verify the presented method.

Finite‐time adaptive fuzzy control for induction motors with input saturation based on command filtering

This study develops a fuzzy finite-time command filtered position tracking control approach for induction motors with input saturation. First, the fuzzy logic systems are utilised to approximate the non-linear functions. Then, in order to avoid the `explosion of complexity' in backstepping design, the finite-time command filter is employed. In addition, error compensating signals are introduced to decrease the errors produced by command filters. The fuzzy finite-time adaptive command filtered controllers can guarantee that the tracking error can converge in finite time. The results of simulation show the effectiveness of the proposed method.

Finite-time command filtered backstepping control for a class of nonlinear systems

This paper considers the problem of finite-time tracking control for a class of nonlinear systems. A novel finite-time command filtered backstepping approach is proposed by using the new virtual control signals and the modified error compensation signals. The new design technique not only has the advantages of the conventional command-filtered backstepping control, but also guarantees the finite-time convergent property. Two examples are included to show the effectiveness of the obtained theoretical results.

Fuzzy Finite-Time Command Filtered Control of Nonlinear Systems With Input Saturation

This paper considers the fuzzy finite-time tracking control problem for a class of nonlinear systems with input saturation. A novel fuzzy finite-time command filtered backstepping approach is proposed by introducing the fuzzy finite-time command filter, designing the new virtual control signals and the modified error compensation signals. The proposed approach not only holds the advantages of the conventional command-filtered backstepping control, but also guarantees the finite-time convergence. A practical example is included to show the effectiveness of the proposed method.