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

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.

2021 ◽  
Author(s):  
Bingxin Ma ◽  
Gang Luo ◽  
Yongfu Wang

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.


2020 ◽  
Vol 17 (4) ◽  
pp. 172988142094177
Author(s):  
Yanhui Wei ◽  
Zhi Zheng ◽  
Qiangqiang Li ◽  
Zhilong Jiang ◽  
Pengfei Yang

A nonlinear robust control method for the trajectory tracking of the underwater vehicle and manipulator system that operates in the presence of external current disturbances is proposed using double closed-loop integral sliding mode control. The designed controller uses a double closed-loop control structure to track the desired trajectory in the joint space of the underwater vehicle and manipulator system, and its inner and outer loop systems use integral sliding surface to enhance the robustness of the whole system. Then, the continuous switching mode based on hyperbolic tangent function is used instead of the traditional discontinuous switching mode to reduce the chattering of the control input of the underwater vehicle and manipulator system. In addition, the control method proposed in this article does not need to estimate the uncertainties of the underwater vehicle and manipulator system control system through online identification, but also can ensure the robustness of the underwater vehicle and manipulator system motion control in underwater environment. Therefore, it is easier to be implemented on the embedded platform of the underwater vehicle and manipulator system and applied to the actual marine operation tasks. At last, the stability of the control system is proved by the Lyapunov theory, and its effectiveness and feasibility are verified by the simulation experiments in MATLAB software.


Author(s):  
Bingxin Ma ◽  
Yongfu Wang

The steering-by-wire (SbW) system is one of the main subsystems of automatic vehicles, realizing the steering control of autonomous vehicles. This paper proposes an event-triggered adaptive sliding mode control for the SbW system subject to the uncertain nonlinearity, time-varying disturbance, and limited communication resources. Firstly, an event-triggered nested adaptive sliding mode control is proposed for SbW systems. The uncertain nonlinearity is approximated by the interval type-2 fuzzy logic system (IT2 FLS). The time-varying disturbance, modeling error, and event-triggering error can be offset by robust terms of sliding mode control. The key advantage is that the high-frequency switching of sliding mode control only appears on the time derivate of control input without increasing the input-output relative degree of closed-loop SbW systems, such that the chattering phenomenon can be eliminated. Finally, theoretical analysis shows that the practical finite-time stability of the closed-loop SbW system can be achieved, and communication resources in the controller-to-actuator channels can be saved while avoiding the Zeno-behavior. Numerical simulations and experiments are given to evaluate the effectiveness of the proposed method.


2012 ◽  
Vol 190-191 ◽  
pp. 1033-1039
Author(s):  
Hong Hui Wang ◽  
Zhao Hui Yuan ◽  
Juan Wu

For a class of non-matching uncertain nonlinear system such as stratospheric balloon-borne gondola azimuth control system, a new robust adaptive multiple sliding mode controller is proposed. In this control method, the virtual and the practical control variables are obtained by designing the multiple sliding modes step-by-step. For avoiding the chattering problem generated by discontinuous input, the traditional sign function is replaced by hyperbolic tangent function. Meanwhile, the CMAC neural network is used to approximate the system uncertainties and the derivative of virtual control input online, which can reduce the conservation of controller parameters design. The system stability analyses show that the control method can guarantee that the output tracking error and slide modes asymptotically convergent to boundary layer. The simulation results show that the controller has higher tracking accuracy, and stronger robust to nonlinear and uncertainty of system, and it also can be applied to other similar non-matching uncertain nonlinear systems.


Author(s):  
Hongjuan Li ◽  
Tianliang Zhang ◽  
Ming Tie ◽  
Yongfu WANG

Abstract This paper proposes an adaptive higher-order sliding mode (AHOSM) control method based on the adaptive fuzzy logic system for steer-by-wire (SbW) system to achieve the tracking control of the front wheels steering angle. First, an adaptive fuzzy logic system is adopted to estimate the unknown dynamics of the SbW system. Then, the AHOSM control is constructed to overcome the lumped uncertainties including unknown external perturbation and fuzzy logic system approximation error, and has the advantage of attenuating the chattering caused by the discontinuous control signal. Finally, the adaptation scheme is designed for the dynamic gain of the proposed AHOSM controller without a priori knowledge of the bounds of the uncertainties. In contrast to the existing controllers applied in the SbW system, this controller has a better control performance in practical application. By means of Lyapunov stability analysis, it is theoretically proved that the system trajectory converges to an adjustable neighborhood of the origin in finite time. Simulations and vehicle experiments are carried out to verify the effectiveness of the proposed approach.


Author(s):  
M. Roopaei ◽  
M. J. Zolghadri ◽  
B. S. Ranjbar ◽  
S. H. Mousavi ◽  
H. Adloo ◽  
...  

In this chapter, three methods for synchronizing of two chaotic gyros in the presence of uncertainties, external disturbances and dead-zone nonlinearity are studied. In the first method, there is dead-zone nonlinearity in the control input, which limits the performance of accurate control methods. The effects of this nonlinearity will be attenuated using a fuzzy parameter approximator integrated with sliding mode control method. In order to overcome the synchronization problem for a class of unknown nonlinear chaotic gyros a robust adaptive fuzzy sliding mode control scheme is proposed in the second method. In the last method, two different gyro systems have been considered and a fuzzy controller is proposed to eliminate chattering phenomena during the reaching phase of sliding mode control. Simulation results are also provided to illustrate the effectiveness of the proposed methods.


2020 ◽  
pp. 002029402095245 ◽  
Author(s):  
Jing He ◽  
Xingxing Yang ◽  
Changfan Zhang ◽  
Jianhua Liu ◽  
Qian Zhang ◽  
...  

To address the tracking control problem of heavy-haul trains (HHTs) with input saturation during operation, an anti-saturation sliding mode (SMES) control method based on dynamic auxiliary compensator (DAC) is presented. Firstly, an HHT model with nonlinear coupling and uncertain disturbances is built. Secondly, a new type of DAC is introduced to overcome the difficulty of traditional dynamic auxiliary compensator (TDAC) with a large upper bound on the compensation signal. Finally, an anti-saturation SMES control algorithm is designed to reduce the influence of input saturation on the tracking accuracy of each carriage. Simulation results verify the effectiveness of the algorithm in terms of tracking accuracy, anti-interference, and anti-saturation.


2019 ◽  
Vol 42 (2) ◽  
pp. 228-243
Author(s):  
An Zhang ◽  
Pan Yang ◽  
Ding Zhou

This paper focuses on event-triggered finite-time consensus problem of second-order multi-agent system, which is subjected to external bounded disturbance. First, a novel finite-time consensus control algorithm based on the event-triggering control scheme is proposed. The proposed algorithm contains a saturation function that is disturbance rejection and aims at eliminating the chattering problem caused by the discontinuity of the control algorithm in some existing work. Further, the utilization of saturation function reduces damages to the actuators and decreases energy consumptions in practical applications. Second, an event-triggering function is developed to generate the control event sequences, which is fully continuous communication free and avoids continuous update of the controller by contrast with real-time control method and continuous communication event-triggered control scheme. Third, finite-time bounded consensus can be reached with the scale of the convergence region adjusted by appropriate parameter selecting. A rigorous proof based on Lyapunov stability analysis is given to verify that the event-triggered control algorithm, under the derived conditions, solves the second-order finite-time consensus with chattering free and being robust to external disturbances as well as excluding the Zeno behavior. Finally, two simulation examples are performed to validate the effectiveness of the results.


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