scholarly journals Event-Triggered Fixed-Time Control for Steer-by-Wire Systems With Prespecified Tracking Performance

2021 ◽  
Author(s):  
Bingxin Ma ◽  
Gang Luo ◽  
Yongfu Wang
Keyword(s):  
Tracking Error ◽  
Output Feedback Control ◽  
Lyapunov Stability Theory ◽  
Fixed Time ◽  
Area Network ◽  
Control Input ◽  
Tracking Accuracy ◽  
Time Control ◽  
Steer By Wire ◽  
Event Triggered

Abstract This paper addresses the event-triggered output feedback control problem for (steer-by-wire) SbW systems with uncertain nonlinearity and time-varying disturbance. First, a new framework of event-triggered control systems is proposed to eliminate the jumping phenomenon of event-based control input, and the trade-off between saving communication resources and attenuating jumping phenomenon can be removed. Then, the adaptive disturbance observer and fuzzy-based state observer are developed to estimate the external disturbanceand unavailable state of augmented SbW systems, respectively. Third, an event-triggered fixed-time control is developed for SbW systems to achieve prespecified tracking accuracy while saving communication resources of the controller area network (CAN). Furthermore, theoretical analysis based on Lyapunov stability theory is provided to verify the tracking error of SbW systems can converge to the prespecified neighborhood of the origin in fixed time regardless of the initial tracking error. Finally, simulations and experiments are given to evaluate the effectiveness and superiority of the proposed methods.

Event-Triggered Adaptive Higher-Order Sliding Mode Tracking Control for Steer-by-Wire Systems

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Bingxin Ma ◽  
Zezheng Wang ◽  
Yongfu Wang
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Sliding Mode ◽  
A Priori ◽  
Higher Order ◽  
Control Input ◽  
Tracking Accuracy ◽  
Event Triggering ◽  
Steer By Wire ◽  
Event Triggered

Abstract The model uncertainty of the steer-by-wire (SbW) system and the limitation of communication bandwidth will have a negative effect on its control performance. For this reason, this paper proposes an event-triggered high-order sliding mode control for uncertain SbW systems. First, to save communication and computing resources, an event-triggering mechanism that depends on the system state is proposed for the SbW system, such that both communication and computing resources can be saved. Second, an event-triggered adaptive higher-order sliding mode (ET-AHOSM) control is proposed for the closed-loop SbW system. The assumptions about the global Lipschitz of nonlinearity and the a priori bounds of the disturbance are no longer required in the control design. Much importantly, the control input continuity can be guaranteed even there is the event-triggering communication in the controller-to-actuator channel. Theoretical analysis shows that the global practical finite-time stability of the closed-loop SbW system can be obtained while avoiding Zeno behavior of the event-triggered control system. Finally, numerical simulation and experiments show that the designed control method can reduce more than 1/2 of the calculation and communication resources while ensuring satisfactory tracking accuracy.

scholarly journals Fixed-Time Sliding-Mode Fault-Tolerant Control of Waste Heat Power Generator Systems

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Zhi Wang ◽  
Yateng Bai ◽  
Jin Xie ◽  
Zhijie Li ◽  
Caoyuan Ma ◽  
...  
Keyword(s):  
Fault Tolerant ◽  
Waste Heat ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
Tracking Error ◽  
Fixed Time ◽  
Fault Estimation ◽  
Actuator Fault ◽  
Heat Power ◽  
Time Control

In order to overcome disturbances such as the instability of internal parameters or the actuator fault, the time-varying proportional-integral sliding-mode surface is defined for coordinated control of the excitation generator and the steam valve of waste heat power generation units, and a controller based on sliding-mode function is designed which makes the system stable for a limited time and gives it good performance. Based on this, a corresponding fault estimation law is designed for specific faults of systems, and a sliding-mode fault-tolerant controller is constructed based on the fixed-time control theory so that the systems can still operate stably when an actuator fault occurs and have acceptable performance. The simulation results show that the tracking error asymptotically tends to be zero, and the fixed-time sliding-mode fault-tolerant controller can obviously improve the dynamic performance of the system.

Event-triggered integral sliding mode fixed time control for trajectory tracking of autonomous underwater vehicle

2021 ◽  
pp. 014233122199438
Author(s):  
Bo Su ◽  
Hongbin Wang ◽  
Ning Li
Keyword(s):  
Trajectory Tracking ◽  
Control Strategy ◽  
Autonomous Underwater Vehicle ◽  
Sliding Mode ◽  
Fixed Time ◽  
Underwater Vehicle ◽  
Reference Trajectory ◽  
Integral Sliding Mode ◽  
Time Control ◽  
Event Triggered

In this paper, an event-triggered integral sliding mode fixed-time control method for trajectory tracking problem of autonomous underwater vehicle (AUV) with disturbance is investigated. Initially, the global fixed time stability is ensured with conventional periodic sampling method for reference trajectory tracking. By introducing fixed time integral sliding mode manifold, fixed time control strategy is expressed for the AUV, which can effectively eliminate the singularity. Correspondingly, in order to reduce the damage caused by chattering phenomenon, an adaptive fixed-time method is proposed based on the designed continuous integral terminal sliding mode (ITSM) to ensure that the trajectory tracking for AUV is achieved in fixed-time with external disturbance. In order to reduce resource consumption in the process of transmission network, the event-triggered sliding mode control strategy is designed which condition is triggered by an event. Also, Zeno behavior is avoided by proof of theoretical. It is shown that the upper bounds of settling time are only dependent on the parameters of controller. Theoretical analysis and simulation experiment results show that the presented methods can realize the control object.

scholarly journals Underactuated AUV Nonlinear Finite-Time Tracking Control Based on Command Filter and Disturbance Observer

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4987 ◽  
Author(s):  
Xu ◽  
Zhang ◽  
Cao ◽  
Pang ◽  
Sun
Keyword(s):  
Finite Time ◽  
Autonomous Underwater Vehicle ◽  
Tracking Error ◽  
Three Dimensional ◽  
Path Following ◽  
Lyapunov Stability Theory ◽  
Ocean Currents ◽  
3D Tracking ◽  
Time Control ◽  
Underactuated Auv

The three-dimensional (3D) path following problem of an underactuated autonomous underwater vehicle with ocean currents disturbances is addressed in this paper. Firstly, the motion equation under the ocean currents disturbance is established, and the dynamic model of 3D tracking error is constructed based on virtual guidance method. Then, a finite-time control scheme based on super-twisting observer and command filtered backstepping technology is proposed. We adopt super-twisting observer based on finite-time theory to observe the ocean currents disturbances for improving the system robust. A command filtered backstepping is proposed to replace the differential process in the conventional backstepping method for avoiding the differential expansion problem. The filter compensation loop is designed to ensure the accuracy of the filtered signal, and the anti-integration saturation link is designed considering the influence of integral saturation. Lyapunov stability theory is used to prove the stability of the underactuated AUV. Simulation studies are conducted to show the effectiveness and robustness of the controller.

scholarly journals Design of fixed-time synchronization algorithm with applications

2019 ◽  
Vol 16 (6) ◽  
pp. 172988141989131
Author(s):  
Peng Zhang ◽  
Yongzheng Cong ◽  
Di Wu ◽  
Guorong Zhang ◽  
Qi Tan
Keyword(s):  
Time Synchronization ◽  
Lyapunov Stability Theory ◽  
Fixed Time ◽  
Homogeneous System ◽  
Synchronization Control ◽  
Multi Agent Systems ◽  
Time Control ◽  
Robot Systems ◽  
Electric Power Networks ◽  
Multi Agent

Fixed-time synchronization problem for a class of leader–follower multi-agent systems with second-order nonlinearity is studied in this article. A new fixed-time synchronization control algorithm is developed by effectively combining homogeneous system theory, Lyapunov stability theory, and fixed-time/finite-time control technology. The leader–follower multi-agent system is considered to achieve fixed-time synchronization control. Finally, numerical simulations including coordination control multiple pendulum robot systems and electric power networks are carried out to verify the control performance of the control strategy.

scholarly journals Backstepping Control Based on Constrained Command Filter for Hypersonic Flight Vehicles with AOA and Actuator Constraints

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Junbao Wei ◽  
Haiyan Li ◽  
Ming Guo ◽  
Jing Li ◽  
Huang Huang
Keyword(s):  
Tracking Error ◽  
Lyapunov Stability Theory ◽  
Backstepping Control ◽  
Control Input ◽  
Tracking Errors ◽  
Hypersonic Flight ◽  
Flight Vehicles ◽  
Control Scheme ◽  
Actuator Constraints ◽  
Command Filter

An antisaturation backstepping control scheme based on constrained command filter for hypersonic flight vehicle (HFV) is proposed with the consideration of angle of attack (AOA) constraint and actuator constraints of amplitude and rate. Firstly, the HFV system model is divided into velocity subsystem and height subsystem. Secondly, to handle AOA constraint, a constrained command filter is constructed to limit the amplitude of the AOA command and retain its differentiability. And the constraint range is set in advance via a prescribed performance method to guarantee that the tracking error of the AOA meets the constraint conditions and transient and steady performance. Thirdly, the proposed constrained command filter is combined with the auxiliary system for actuator constraints, which ensures that the control input meets the limited requirements of amplitude and rate, and the system is stable. In addition, the tracking errors of the system are proved to be ultimately uniformly bounded based on the Lyapunov stability theory. Finally, the effectiveness of the proposed method is verified by simulation.

scholarly journals Distributed fixed-time cooperative control of an islanded microgrid under event-triggered mechanism

2021 ◽  
Author(s):  
Deming Xu ◽  
Ze Li ◽  
Guozeng Cui ◽  
Wanjun Hao ◽  
Fuyuan Hu
Keyword(s):  
Cooperative Control ◽  
Fixed Time ◽  
Active Power ◽  
Settling Time ◽  
Power Sharing ◽  
Control Approach ◽  
Time Control ◽  
Islanded Microgrid ◽  
Control Protocols ◽  
Event Triggered

Abstract The secondary cooperative control problem of an islanded microgrid through event-triggered mechanism is investigated in this paper. A distributed fixedtime secondary cooperative control strategy is proposed to obtain frequency and voltage magnitude secondary restoration, and also a proportional active power sharing under an undirected topology. We consider a centralized event-triggered mechanism to alleviate the communication burden and reduce the frequency of controllers update. Through this mechanism, the distributed fixed-time control protocols using frequency, voltage magnitude and active power sampling measurement values of distributed generations (DGs) only when the predefined event-triggered condition is satisfied. Compared with the conventional distributed asymptotic control protocols under period-triggered communication, the secondary control objectives of an islanded microgrid are achieved within a fixed settling time by applying the presented distributed fixed-time control approach, and the upper bound of settling time is unrelated to any initial states. Meanwhile, the presented centralized event-triggered communication method exhibits excellent performance in alleviating communication burden and promoting control efficiency. The theoretical proof is given by adopting Lyapunov method. The simulation studies are conducted to illustrate the effectiveness of the proposed control scheme.

Optimal Selection of Basis Functions for Minimum-Effort Tracking Control of Nonminimum Phase Systems Using Filtered Basis Functions

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Keval S. Ramani ◽  
Molong Duan ◽  
Chinedum E. Okwudire ◽  
A. Galip Ulsoy
Keyword(s):  
Linear Time ◽  
Tracking Error ◽  
Basis Functions ◽  
Frobenius Norm ◽  
Control Input ◽  
Tracking Accuracy ◽  
Control Effort ◽  
Nonminimum Phase ◽  
B Splines ◽  
Optimal Set

Abstract Accurate tracking of nonminimum phase (NMP) systems is well known to require large amounts of control effort. It is, therefore, of practical value to minimize the effort needed to achieve a desired level of tracking accuracy for NMP systems. There is growing interest in the use of the filtered basis functions (FBF) approach for tracking the control of linear NMP systems because of distinct performance advantages it has over other methods. The FBF approach expresses the control input as a linear combination of user-defined basis functions. The basis functions are forward filtered through the dynamics of the plant, and the coefficients are selected such that the tracking error is minimized. There is a wide variety of basis functions that can be used with the FBF approach, but there has been no work to date on how to select the best set of basis functions. Toward selecting the best basis functions, the Frobenius norm of the lifted system representation (LSR) of dynamics is proposed as an excellent metric for evaluating the performance of linear time varying (LTV) discrete-time tracking controllers, like FBF, independent of the desired trajectory to be tracked. Using the metric, an optimal set of basis functions that minimize the control effort without sacrificing tracking accuracy is proposed. The optimal set of basis functions is shown in simulations and experiments to significantly reduce control effort while maintaining or improving tracking accuracy compared to popular basis functions, like B-splines.

Sign in / Sign up

Export Citation Format

Share Document