Shuailin Lv

Global finite-time heading control of surface vehicles

In this paper, a global finite-time heading control (GFHC) scheme for surface vehicles is proposed. The salient features of the GFHC scheme are triple-fold: (1) A discontinuous control law is proposed to guarantee the finite-time stability of the entire closed-loop heading control system. (2) The finite-time convergence leads to accurate heading control and remarkable disturbance rejection. (3) Furthermore, it reveals that the proposed GFHC scheme treats asymptotic heading controllers as special cases. Simulation studies and comprehensive comparisons on various scenarios demonstrate the effectiveness and superiority of the proposed GFHC scheme.

Fast and Accurate Trajectory Tracking Control of an Autonomous Surface Vehicle With Unmodeled Dynamics and Disturbances

In this paper, fast and accurate trajectory tracking control of an autonomous surface vehicle (ASV) with complex unknowns, including unmodeled dynamics, uncertainties, and/or unknown disturbances, is addressed within a proposed homogeneity-based finite-time control (HFC) framework. Major contributions are as follows: first, in the absence of external disturbances, a nominal HFC framework is established to achieve exact trajectory tracking control of an ASV, whereby global finite-time stability is ensured by combining homogeneous analysis and Lyapunov approach; second, within the HFC scheme, a finite-time disturbance observer (FDO) is further nested to rapidly and accurately reject complex disturbances, and thereby contributing to an FDO-based HFC (FDO-HFC) scheme, which can realize exactness of trajectory tracking and disturbance observation; and third, aiming to exactly deal with complicated unknowns including unmodeled dynamics and/or disturbances, a finite-time unknown observer (FUO) is deployed as a patch for the nominal HFC framework, and eventually results in an FUO-based HFC (FUO-HFC) scheme, which guarantees that accurate trajectory tracking can be achieved for an ASV under harsh environments. Simulation studies and comprehensive comparisons conducted on a benchmark ship demonstrate the effectiveness and superiority of the proposed HFC schemes.

Fuzzy Uncertainty Observer Based Filtered Sliding Mode Trajectory Tracking Control of the Quadrotor

In this paper, a filtered sliding mode control (FSMC) scheme based on fuzzy uncertainty observer (FUO) for trajectory tracking control of a quadrotor unmanned aerial vehicle (QUAV) is proposed. To be specific, the dynamics model of QUAV is decomposed into three subsystems. By virtue of the cascaded structure, sliding-mode-based virtual control laws can be recursively designed. In order to remove the smoothness requirements on intermediate signals, a series of first-order filters are employed to reconstruct sliding mode control signals together with their first derivatives. Moreover, fuzzy uncertainty observers are employed to indirectly estimate lumped unknown nonlinearities including system uncertainties and external disturbances and make compensation for the QUAV system. Stability analysis and uniformly ultimately bounded tracking errors and states can be guaranteed by the Lyapunov approach. Simulation studies demonstrate the effectiveness and superiority of the proposed tracking control scheme.

Global finite-time trajectory tracking control of autonomous surface vehicles

In this paper, a global finite-time tracking control (GFTC) scheme is proposed for trajectory tracking control of an autonomous surface vehicle (ASV). The salient features of the GFTC scheme are triple fold: 1) A discontinuous controller is developed to realize the finite-time stability of the closed-loop ASV trajectory tracking system. 2) The GFTC scheme can render tracking errors converge to zero with faster convergence rate than traditional asymptotic and exponential controllers. 3) Moreover, it can treat conventional asymptotic approaches as special cases. Simulation studies and comprehensive comparisons demonstrate the effectiveness and remarkable performance of the proposed GFTC scheme for an ASV.

Nonsingular Terminal Sliding Mode Based Trajectory Tracking Control of an Autonomous Surface Vehicle with Finite-Time Convergence

In this paper, a nonsingular terminal sliding mode (NTSM) based tracking control (NTSMTC) scheme for an autonomous surface vehicle (ASV) subject to unmodelled dynamics and unknown disturbances is proposed. The salient features of the NTSMTC scheme are as follows: (1) The NTSMTC scheme is designed by combining the NTSM technique with an established finite-time unknown observer (FUO) which enhances the system robustness significantly and achieves accurate tracking performance; (2) By virtue of the NTSMTC scheme, not only that unknown estimation errors are controlled to zero but also tracking errors can be stabilized to zero in a finite time; (3) The finite-time convergence of the entire closed-loop control system can be ensured by the Lyapunov approach. Simulation studies are further provided to demonstrate the effectiveness and remarkable performance of the proposed NTSMTC scheme for trajectory tracking control of an ASV.

Command filtered adaptive control for integrated missile guidance and autopilot with terminal angular constraint

For homing missiles considering terminal angular constraint, integrated design of guidance and control utilizing adaptive command filtered backstepping is studied in this paper. The proposed control scheme guarantees not only the stability of the missile dynamics with state constraints but also the interception performance with a desired terminal attitude angle. An adaptive law is introduced to compensate unknown uncertainties in the varying-time system. Simulation results are further presented to show the effectiveness and performance of the proposed approach.

Finite-time disturbance observer based non-singular integral terminal sliding mode trajectory tracking control of unmanned surface vehicles

In this paper, a finite-time disturbance observer based non-singular integral terminal sliding mode tracking control scheme for trajectory tracking of an unmanned surface vehicle (USV) is proposed. The salient features of the proposed scheme are as follows: 1) The proposed control scheme contributes to precise trajectory tracking control of an USV. 2) Under the proposed control law, tracking errors can be stabilized to zero with a faster convergence rate than conventional backstepping-based approaches. 3) It ensures that external disturbances can be identified exactly in a finite time, thereby leading to better robustness to complex disturbances. Simulation studies and comprehensive comparisons demonstrate the feasibility and superiority of the proposed control scheme for tracking an USV.

Disturbance observer based finite-time trajectory tracking control of unmanned surface vehicles

This paper addresses the finite-time trajectory tracking control problem of an unmanned surface vehicle with external disturbances. The salient features of the proposed control scheme are as follows: 1) A disturbance observer is designed firstly such that the external disturbances can be exactly observed in a finite time; 2) A disturbance observer based nonsingular terminal sliding mode control law is then developed to realize the finite-time stability of the closed-loop trajectory tracking system; 3) Tracking errors can be stabilized to zero in a finite time, whereby fast and accurate trajectory tracking can be obtained pertaining to the proposed control law. Simulation studies and comprehensive comparisons demonstrate the feasibility and remarkable performance of the proposed control scheme.

Finite-time trajectory tracking control of unmanned surface vehicle with input saturation

In this paper, a finite-time trajectory tracking control approach is proposed for an unmanned surface vehicle (USV) with unknown external disturbances and input saturation. Significant contributions of this paper are as follows: 1) an auxiliary design system is employed to address input constraint effectively, and make sure control performance ideally; 2) an disturbance observer is designed via a robust homogeneous differentiator so that the unknown external disturbances can be exactly identified in finite-time; 3) the proposed finite-time controller can achieve an excellent tracking performance and enhance the robustness of the overall control system; 4) by the proposed control scheme, tracking errors can be rendered to zero faster than conventional backstepping approach as well as all the signals of the closed-loop are bounded. The simulation studies illustrate the effectiveness of the proposed approach.