Jinyong Yu

Finite-Time Stabilization for Vehicle Active Suspension Systems With Hard Constraints

This paper presents the problem of finite-time stabilization for vehicle suspension systems with hard constraints based on terminal sliding-mode (TSM) control. As we know, one of the strong points of TSM control is its finite-time convergence to a given equilibrium of the system under consideration, which may be useful in specific applications. However, two main problems hindering the application of the TSM control are the singularity and chattering in TSM control systems. This paper proposes a novel second-order sliding-mode algorithm to soften the switching control law. The effect of the equivalent low-pass filter can be properly controlled in the algorithm based on requirements. Meantime, since the derivatives of term with fractional power do not appear in the control law, the control singularity is avoided. Thus, a chattering-free TSM control scheme for suspension systems is proposed, which allows both the chattering and singularity problems to be resolved. Finally, the effectiveness of the proposed approach is illustrated by both theoretical analysis and comparative experiment results.

Decentralized output-feedback formation control of multiple 3-DOF laboratory helicopters

Abstract The decentralized formation control problem of multiple 3-degree of freedom laboratory helicopter models is studied on directed communication topologies in this paper. The laboratory helicopter models are subjected to non-linearity, under-actuated, and equipped only with angular position sensors. We present a decentralized formation controller which includes a non-linear uncertainty and disturbance estimation (UDE) term to compensate the model uncertainties and disturbances in each helicopter and from its neighborhood. The UDE consists of a second-order auxiliary system and a discontinuous term, neither the measurement of angular velocity nor its asymptotic estimation is required. Convergence of the formation tracking error is analyzed using invariance-like theorems. It is also proved that the UDE term will converge to the actual uncertainties and disturbances. Simulation results show that, on a one-way communication topology which only contains one spanning tree, a group of four helicopters reaches the desired formation shape while tracking a given reference trajectory using proposed method.

Robust filter design for a class of uncertain systems with D stability constraints under a unified framework

Abstract Based on a new performance index, the problem of filter design for a class of continuous-time uncertain systems with state-dependent uncertainties is investigated in this paper, taking into account the D stability constraints. Attention is focused on solving the H ∞ , L 2 − L ∞ , passive and dissipative robust filter design problems for such systems with D stability constraints in a unified framework by using the novel performance index. Through employing the Lyapunov stability theory, the feasibility criteria for analysis of robust disturbance attenuation performance are derived first. Furthermore, the linear matrix inequalities (LMIs)-based approach for the design of model-independent filters of the considered systems is developed such that the corresponding filtering error system guarantees the prescribed H ∞ , L 2 − L ∞ , passive and dissipative performance indices with D stability constraints. It is particularly worth mentioning that the model-independent filter proposed in this paper does not require the model information is accessible for the filter design. Finally, a numerical example of tunnel diode circuit system is provided to demonstrate the applicability and effectiveness of the proposed robust filter design method.

Two time-scale observer-based robust motion controller design and realization of a linear actuator:

In this paper, an observer-based sliding mode controller is proposed for a high-accuracy motion plant to suppress the disturbances and improve the tracking performance. In particular, a two time-scale separation technology, which can recover the disturbance state in a faster time scale, is utilized to compensate the disturbances and improve the system robustness. The parameter identification is carried out to obtain the model coefficients with a high fitting rate. Such an identified model can allow the engineers to tune the controller’s gains highly enough when the system suffers from the measurement noises. Instead of the traditional low-pass filter, a differentiator is introduced for the velocity signal prediction and its discrete-time version is provided to attenuate the noises effect. To verify the effectiveness of the proposed approach, an adaptive robust control law is compared with the proposed one in terms of dynamic positioning error, robustness and rapid signal tracking, and the superiority and advantages can be illustrated by the experimental results.

Network-based robust filtering for Markovian jump systems with incomplete transition probabilities

Abstract In this paper, the H∞ filtering problem is investigated for a class of discrete-time Markovian jump nonlinear systems with partly unknown transition probabilities and subject to sensor saturation over unreliable communication. The description of researched plant includes global Lipschitz nonlinearities and state-dependent random noise and external-disturbance. A decomposition approach is used to deal with the characteristic of sensor saturation. Since the communication links between the plant and filter lack enough reliability, the effects of output quantization and data packet losses should both be considered. The proposed quantizer’s parameter is on-line updating and the corresponding practical adjusting rule can ensure the dynamic performance of the controlled system. Among different operation modes, the cross coupling between system matrices and Lyapunov matrices is disposed by introducing proper slack matrix variables. The purpose of this work is to design a full-order filter based on incomplete output measurements in order to guarantee the stochastic stability of the estimation error. Precise expression of the filters and related analysis are depicted in this paper. Finally, a numerical simulation is provided to show the effectiveness of the designing filtering method.

Sliding-mode-based robust controller design for one channel in thrust vector system with electromechanical actuators ☆

Abstract In this paper, a sliding-mode-based robust controller is proposed for the single channel thrust vector system (TVC) to suppress the disturbances and improve the tracking performance. Specifically, the dead-zone input–output relationship is analyzed to depict the mount gap in the mechanical shaft. The system mathematic representation including the mechanical and electrical sections, which suffers from the dead-zone nonlinearity, frictions and unstructured disturbance, is constructed. An adaptive-fuzzy-based observer is developed to estimate and compensate the disturbances because the fuel combustion dynamic and frictions in TVC are inevitable but difficult to obtain the precise dynamic state. Based on the nominal model, a robust controller is designed via the sliding-mode variable structure approach, which is derived in the sense of Lyapunov stability theorem. Instead of the traditional hitting law in the sliding mode controller, the chattering problem due to the discontinuous switch law is addressed by a continuous function. In the end, various illustrative examples are provided to demonstrate the effectiveness of the designed method.

Positioning control for a linear actuator with nonlinear friction and input saturation using output-feedback control

This article deals with the positioning control problem via the output feedback scheme for a linear actuator with nonlinear disturbances. In this study, the proposed controller accounts for not only the nonlinear friction, force ripple, and external disturbance but also the input saturation problem. In detail, the energy consumption for conquering friction and disturbance rejection is estimated and used as compensation based on the hybrid controller including and sliding-mode-based adaptive algorithms, which ensures the tracking performance and robustness of electromechanical servo system. Moreover, to confront the input saturation, a saturation observer and an anti-windup controller are designed. The global robustness of the controller is guaranteed by an output feedback robust law. Theoretically, the designed controller can guarantee a favorable tracking performance in the presence of various disturbance forces and input saturation, which is essential for high accuracy motion plant in industrial application. The simulation results verify the robustness and effectiveness for the motion system with the proposed control strategy under various operation conditions.

Adaptive fault-tolerant control for continuous-time Markovian jump systems with signal quantization

Abstract This paper investigates the adaptive fault-tolerant control problem for a class of continuous-time Markovian jump systems with digital communication constraints, parameter uncertainty, disturbance and actuator faults. In this study, the exact information for actuator fault, disturbance and the unparametrisable time-varying stuck fault are totally unknown. The dynamical uniform quantizer is utilized to perform the design work and the mismatched initializations at the coder and decoder sides are also considered. In this paper, a novel quantized adaptive fault-tolerant control design method is proposed to eliminate the effects of actuator fault, parameter uncertainty and disturbance. Moreover, it can be proved that the solutions of the overall closed-loop system are uniformly bounded, which is asymptotically stable almost surely. Finally, numerical examples are provided to verify the effectiveness of the new methodology.

Simultaneous fault detection and control for uncertain discrete-time stochastic systems with limited communication

Abstract In the paper, the simultaneous fault detection and control (SFDC) problem is concerned for uncertain discrete-time stochastic systems with limited communication. An integrated module with a filter and a dynamic output feedback controller is designed to achieve the desired fault detection (FD) and control objectives, simultaneously. The event-triggered technology is employed to save the network communication resources, while two event detectors are utilized to decrease the amount of data transmitted from the sensor to the SFDC module and from the SFDC module to the plant. A novel method is proposed to ensure that the obtained closed-loop model is robustly stochastically stable and satisfies the desired detection and control performances. Sufficient conditions are derived to obtain the parameters of filter, controller and event detectors. Finally, the validity of the design strategy is verified by a simulation case.

Robust synchronous control of dual linear actuators with load variation, nonlinear friction and disturbances

This paper deals with the problem concerning the design method of synchronous motion controllers in form of output feedback for dual linear actuators with load differences, dynamic nonlinear friction and force ripples. The authors focus on not only nonlinear friction and disturbance but also the dual motors synchronous objective. The energy upper bound for conquering disturbances is estimated and used as compensation. After that, in order to improve the robustness of the dual-motor motion plant in the presence of external disturbances, an interference rejection approach is presented. Furthermore, due to load variation which degrades synchronous tracking performance for dual motors, the controller design method based on the convex optimization scheme is proposed. The illustrative examples show that the controller can significantly improve the tracking performance under nonlinear frictions. In the meanwhile, the disturbances with known model and random one can be restrained well.