Discrete-time Sliding Mode Control Research Articles

Observer-based discrete-time sliding mode throttle control for drive-by-wire operation of a racing motorcycle engine

In this brief, the problem of designing a drive-by-wire throttle control system for a high-performance motorcycle engine is considered. Given the characteristics of the electromechanical system to be controlled, an observer-based, discrete-time sliding mode (DTSM) servo controller with integral action is adopted. The controller is designed on the basis of an identified model of the system, whose states are estimated by means of a state observer. Different state observer structures are analyzed, and it is shown that the main characteristics of standard state-feedback-based sliding mode control systems are preserved. A theoretical analysis is also presented showing that a separation principle holds, so that the state observer and the DTSM controller can be designed independently. The performances of the designed controller are illustrated by reporting the results of tests performed on track with a racing motorcycle.

Output feedback discrete-time sliding mode control for time delay systems

Several algorithms for discrete-time quasi-sliding mode control of time-delay systems with different delay and disturbance structures are proposed. Four different delay structures are considered. All the algorithms are based on multirate output feedback. Hence, they are more practical than state feedback and are less complex compared with observer-based control strategies.

A new discrete-time sliding-mode control with time-varying gain and neural identification

In this paper, we present a new sliding mode controller for a class of unknown non-linear discrete-time systems. We make the following two modifications. (1) The neural identifier which is used to estimate the unknown non-linear system uses the projection and the dead-zone approaches to assure non-singularity in the controller and stability of identification error. (2) We propose a new sliding mode controller with time-varying gain to reduce chattering. A necessary condition is given to make the switching function decrease exponentially. We prove that the closed-loop system with the sliding mode controller and the neural identifier is stable.

Discrete-Time Sliding Mode Controller Design with State Estimator and Disturbance Observer

In this paper, a discrete-time output feedback sliding mode controller for a class of MIMO linear systems with matched disturbances is proposed. Both a state estimation and a disturbance observer are included in the control scheme so that the system states and the upper bound of disturbance are not required. It is shown that the tracking error will be constrained in a small bounded region, and the system stability is guaranteed. Finally, a numerical example is presented to demonstrate the applicability of the proposed control scheme.

Chattering alleviation in vibration control of smart beam structures using piezofilm actuators: Experimental verification

This paper presents a new discrete-time sliding mode controller to alleviate undesirable chattering in vibration control of a flexible beam structure. A smart beam featuring a piezoelectric film is devised and its governing equation of motion is derived. A discrete-time sliding mode controller which consists of discontinuous part and equivalent part is then designed by considering the separation principle. By doing this, undesirable chattering of the beam structure can be attenuated in the settled phase. The proposed controller is experimentally realized, and both transient and forced vibration control responses are evaluated in time domain.

Boundary Layer Eigenvalues in SISO Discrete-Time Sliding Mode Control with Observer

A result that allows us to specify the sliding manifold in observer-based discrete-time sliding mode control is presented. Selection of coefficients is done by analyzing the tracking error dynamics inside the boundary layer, where the closed-loop system has a linear state feedback configuration, rather than assuming that ideal sliding occurs. The result facilitates assignment of eigenvalues for the system matrix which defines such linear dynamics.

706 適応スライディング面を用いた離散時間系スライディングモード制御に関する研究(制御・非線形振動)

706 適応スライディング面を用いた離散時間系スライディングモード制御に関する研究(制御・非線形振動)

Discrete-time sliding-mode controller for dual-stage systems—A hierarchical approach

A discrete-time hierarchical sliding-mode control scheme for a dual-stage tracking control system with bounded parameter variation and external disturbance is proposed in this study. This scheme is capable of performing a positioning servo control task that requires driving both coarse tracking and fine tracking stages simultaneously. The desired tracking performances, both the coarse tracking and fine tracking, are ensured. The settling time of the controlled system could be pre-specified by selecting a sliding hyperplane. Furthermore, explicit conditions, involving inequality constraints on the controller parameters, to ensure a one-sided behavior, quasi-sliding mode and chattering-alleviated performance with uncertainty and/or external perturbation of known bounds of the plant are derived. Experimental studies on the design of a track-seeking controller for an optical pick-up head is conducted to further illustrate its feasibility and effectiveness. The experimental results also demonstrate that the proposed scheme provides better performance than a discrete-time sliding mode control method with controller switching method.

Discrete-Time Sliding Mode Control on a Flexible Truss Structure

Implementation of discrete-time sliding mode control on a sampled-data system leads to sliding motion in an OT2 boundary layer of the discontinuity surface, where T is the sampling period. A truss panel structure vibration control experiment is conducted to demonstrate the effectiveness of the proposed method. This paper utilizes a truncated model to characterize the models of interest and treats all the high frequency modes as disturbances. The experiment includes system identification, state observer design, and discrete-time sliding mode control.

Continuous-time and discrete-time sliding mode control accomplished using a computer

A computer-based sliding mode control (SMC) is analysed. The control law is accomplished using a computer and A/D and D/A converters. Two SMC designs are presented. The first one is a continuous-time conventional SMC design, with a variable structure law, which does not take into consideration the sampling period. The second one is a discrete-time SMC design, with a smooth sliding law, which does not have a structure variable and takes into consideration the sampling period. Both techniques are applied to control an inverted pendulum system. The performance of both the continuous-time and discrete-time controllers are compared. Simulations and experimental results are shown and the effectiveness of the proposed techniques is analysed.

ROBUST POSITION CONTROL OF LINEAER PIEZOELECTRIC MOTOR DRIVE SYSTEMS

The friction and load variation are the main uncertainties in the linear piezoelectric motor system. Only the viscous friction is considered in previous work, but it is quite different with the practical condition. Highly nonlinear friction in the system is measured and compensated by a radial basis function (RBF) network. A discrete-time sliding mode controller, which is insensitive to the perturbed state matrix and input matrix and disturbances, is proposed for LPM drive system. Furthermore, three free design parameters are optimized to achieve better transient performance by genetic algorithm and one online mass estimator is adopted to extend the robustness. The simulation and experiment results show that the proposed controller has a stronger robustness than PID controller.

Intelligent on-line fault tolerant control for unanticipated catastrophic failures

As dynamic systems become increasingly complex, experience rapidly changing environments, and encounter a greater variety of unexpected component failures, solving the control problems of such systems is a grand challenge for control engineers. Traditional control design techniques are not adequate to cope with these systems, which may suffer from unanticipated dynamic failures. In this research work, we investigate the on-line fault tolerant control problem and propose an intelligent on-line control strategy to handle the desired trajectories tracking problem for systems suffering from various unanticipated catastrophic faults. Through theoretical analysis, the sufficient condition of system stability has been derived and two different on-line control laws have been developed. The approach of the proposed intelligent control strategy is to continuously monitor the system performance and identify what the system's current state is by using a fault detection method based upon our best knowledge of the nominal system and nominal controller. Once a fault is detected, the proposed intelligent controller will adjust its control signal to compensate for the unknown system failure dynamics by using an artificial neural network as an on-line estimator to approximate the unexpected and unknown failure dynamics. The first control law is derived directly from the Lyapunov stability theory, while the second control law is derived based upon the discrete-time sliding mode control technique. Both control laws have been implemented in a variety of failure scenarios to validate the proposed intelligent control scheme. The simulation results, including a three-tank benchmark problem, comply with theoretical analysis and demonstrate a significant improvement in trajectory following performance based upon the proposed intelligent control strategy.

Multirate output feedback discrete-time sliding mode control for a prescribed sliding sector

This paper presents an output feedback based discrete-time sliding mode control strategy using the concept of a PdRd sliding sector. The resulting control is based on the system output and immediate past control input and is independent of the system states. It ensures that the norm of the system states decreases monotonically and continue to do so even with a zero input inside the designed sliding sector.

Model reference discrete-time sliding mode control of linear motor precision servo systems

This paper studies high-precision motion control of linear motor servo systems. A model reference discrete-time sliding mode control is constructed, which converts servo problems to simple regulator problems. Moreover, based on one-step delayed disturbance approximation, unknown disturbances, including friction, can be well compensated without using any complicated friction modelling and corresponding on-line identification techniques, hence the design of the controller is simple and satisfactory performance is easy to achieve. For tracking control, the overall tracking errors can be further reduced by introducing an extra integral action, although it is not possible to completely eliminate the friction effect in the case that reference trajectories cross zero velocity. Since friction is a complicated non-smooth disturbance, detailed investigation on the influence of choice of sampling period on friction compensation performance is performed through simulation analysis. Experimental results are presented to illustrate the effectiveness and achievable control performance of the proposed scheme.

레이저 마킹 시스템의 이산시간 슬라이딩 모드 제어기 설계

레이저 마킹 시스템의 이산시간 슬라이딩 모드 제어기 설계

Co-Simulation of Algebraically Coupled Dynamic Subsystems Without Disclosure of Proprietary Subsystem Models

A method for simultaneously running a collection of dynamic simulators coupled by algebraic boundary conditions is presented. Dynamic interactions between subsystems are simulated without disclosing proprietary information about the subsystem models, as all the computations are performed based on input-output numerical data of encapsulated subsystem simulators coded by independent groups. First, this paper describes a system of interacting subsystems with a causal conflict as a high-index, Differential-Algebraic Equation (DAE), and develops a systematic solution method using Discrete-Time Sliding Mode control. Stability and convergence conditions as well as error bounds are analyzed by using nonlinear control theory. Second, the algorithm is modified such that the subsystem simulator does not have to disclose its internal model and state variables for solving the overall DAE. The new algorithm is developed based on the generalized Kirchhoff Laws that allow us to represent algebraic boundary constraints as linear equations of the subsystems’ outputs interacting to each other. Third, a multi-rate algorithm is developed for improving efficiency, accuracy, and convergence characteristics. Numerical examples verify the major theoretical results and illustrate features of the proposed method.

A Minor Correction to “A New Algorithm for Discrete-Time Sliding Mode Control Using Fast Output Sampling Feedback”

The purpose of this letter is to show that the recently proposed fast output sampling sliding-mode control method in an earlier paper by the authors needs a small correction in the expression for the control law. The results or the corrected algorithm is illustrated by the same example considered in the earlier paper.

適応スライディング面による離散時間系スライディングモード制御(機械力学・計測制御I)

適応スライディング面による離散時間系スライディングモード制御(機械力学・計測制御I)

Sliding mode-based minimum variance and generalized minimum variance controls with O(T 2) and O(T 3) accuracy

The paper deals with the discrete-time sliding mode control with O(T2) and O(T3) accuracy, based only on input/output measurements. The linear parts of the control algorithms, recognized as the traditional minimum variance and the generalized minimum variance controls, enable the implementation of the sliding mode control on minimum and non-minimum phase plants. The chattering phenomenon is suppressed by filtering the high-frequency control signal of the sliding mode component through the discrete-time integrator.

Positioning and Tracking Control of an X-Y Table with Sliding Mode Control

In this paper, de-coupled discrete-time sliding-mode tracking controllers are designed for an x-y sliding table driven directly by linear motors. The controllers are designed using an integrated reaching law method, based on a simplified model of the current control loop of these motors. To achieve high bandwidth tracking performance, a feedforward controller is added. Although the sliding table is operating in the presence of friction, no friction compensation is applied. Experimental results are presented.