Discrete Adaptive Sliding Mode Control Research Articles

Decentralized discrete adaptive sliding mode control for interconnected nonlinear systems

This article presents a study on controlling a class of large-scale systems composed of interconnected subsystems. The systems are represented by discrete block-oriented models with unknown parameters. This article proposes a novel adaptive sliding mode control strategy to address the tracking control problem and minimize the impact of interconnection. This approach leverages the robustness of sliding mode control against unmodeled dynamics and disturbances with the advantages of adaptive control. To adapt the system’s parameters, a recursive parametric estimation algorithm using least-squares techniques is employed. The proposed method offers benefits such as robustness against parameter uncertainties, handling of nonlinearities, improved tracking accuracy, and reduced chattering phenomena. The effectiveness of the method is demonstrated through the evaluation of two simulation examples.

An Energy Efficient Control Strategy for Electric Vehicle Driven by In-Wheel-Motors Based on Discrete Adaptive Sliding Mode Control

This paper presents an energy-efficient control strategy for electric vehicles (EVs) driven by in-wheel-motors (IWMs) based on discrete adaptive sliding mode control (DASMC). The nonlinear vehicle model, tire model and IWM model are established at first to represent the operation mechanism of the whole system. Based on the modeling, two virtual control variables are used to represent the longitudinal and yaw control efforts to coordinate the vehicle motion control. Then DASMC method is applied to calculate the required total driving torque and yaw moment, which can improve the tracking performance as well as the system robustness. According to the vehicle nonlinear model, the additional yaw moment can be expressed as a function of longitudinal and lateral tire forces. For further control scheme development, a tire force estimator using an unscented Kalman filter is designed to estimate real-time tire forces. On these bases, energy efficient torque allocation method is developed to distribute the total driving torque and differential torque to each IWM, considering the motor energy consumption, the tire slip energy consumption, and the brake energy recovery. Simulation results of the proposed control strategy using the co-platform of Matlab/Simulink and CarSim® demonstrate that it can accomplish vehicle motion control in a coordinated and economic way.

Discrete Sliding Mode Adaptive Vibration Control for Space Frame Based on Characteristic Model

A novel characteristic model-based discrete adaptive sliding mode control (SMC) scheme is proposed for vibration attenuation of the space frame. First, this paper establishes a characteristic model as real time model for the space structure. The characteristic model is simple and accurate. Furthermore, a novel discrete sliding mode control strategy is proposed with low chattering and strong robustness. In addition, the stability of the closed-loop control system is proved. Finally, simulation results show the effectiveness and strong robustness of the proposed scheme.

Characteristic Model-Based Discrete Adaptive Sliding Mode Control for System with Time Delay

A novel characteristic model-based discrete sliding mode control (CMDSMC) for time delay system is presented in this paper. Firstly, to solve the challenge of establishing a accurate and simple model for time delay system, characteristic theory is applied to establish characteristic mode with time delay. Secondly, due to the uncertainties of time delay system, discrete sliding mode control based on characteristic model is proposed and stability analysis is done. At last, two illustrative examples taken from literatures are included to indicate the simplicity and superiority of the proposed method.

Discrete Adaptive Sliding Mode Control via Wavelet Network for a Class of Nonlinear Systems

Unmodelled dynamics and perturbations are always immeasurable. In this paper, an adaptive sliding mode control (ASMC) based on wavelet network (WN) for a class of non-affine multi-variable nonlinear discrete systems is presented in order to compensate them. Wavelet network which parameters are tuned on-line is adopted to realize the equivalent control, and hitting controls are added in order to satisfy reaching conditions. By combining the adaptive WN with SMC strategy, the constructed control law has many advantages such as robustness, adaptive characters, and the precise mathematic models of controlled plants are not required. Finally, experiment on an inverted pendulum control system based on the proposed control design method is given to verify its effectiveness and performance.

New model and sliding mode control of hydraulic elevator velocity tracking system

A new model of hydraulic elevator dynamics has been developed. It includes an improved dynamic friction model. This hydraulic elevator dynamics model is used in a new input–output based discrete adaptive sliding mode control algorithm comprised of an integral action, a nonlinear output feedback, and an adjustable sliding mode. The characteristic feature of the algorithm is an on-line update of the hyperplane coefficients and the integral gain to enable improved control loop behavior. Compared with the optimally tuned PID controller applied to a hydraulic elevator system, the new controller exhibits an increased robustness with regard to model uncertainties, unknown external disturbances and changes in the operation conditions, as well as much better velocity tracking characteristics.

Neural Network Based, Discrete Adaptive Sliding Mode Control for Idle Speed Regulation in IC Engines

An adaptive sliding mode control design method is proposed for discrete nonlinear systems where explicit knowledge of the system dynamics is not available. Three-layer feedforward neural networks are used as function approximators for the unknown dynamics. The control law is designed based on the outputs of the approximators, and the sliding surface is defined in terms of a stable polynomial of the system outputs. Convergence of the state trajectories into a small sliding sector is proved. The method is applied to the internal combustion (IC) engine idle speed control problem. Simulation and experimental results are provided. [S0022-0434(00)01702-0]

Discrete adaptive quasi-sliding mode control

This article presents the discrete adaptive quasi-sliding mode control of linear systems represented by the state space. The control scheme is a natural extension of the discrete adaptive sliding mode control scheme in that an additional design parameter is incorporated into the existing scheme to allow systematic modification of the amplitude of the control signal during the transient stage. A lemma, useful for establishing the stability of discrete adaptive quasi-sliding mode controllers, is given. The adaptive controller is shown to lead to a stable closed-loop system. Also, simulation results are presented to illustrate the features of the control scheme.

Discrete Adaptive Sliding Mode Control of a State-Space System with a Bounded Disturbance

This paper presents the discrete adaptive sliding mode control of a state-space system in the presence of a bounded disturbance. The delta form of the discrete state-space model is used as it closely resembles that of the continuous model. The control law takes into account of the effect of the disturbance by using its approximate value. The system behavior in the vicinity of the sliding surface is studied. It is shown that the adaptive controller leads to a stable closed-loop system. Also, simulation results are presented to illustrate the features of the proposed adaptive control strategy.