Date: 2015.8.24

Morning (9:00 AM-9:30 AM)

Opening Ceremony

Morning (9:30 AM-12:00 AM)
Introductory Five Generations of Sliding Mode Controllers: Stages of Evolution

Leonid Fridman
Personal Homepage: http://verona.fi-p.unam.mx/~lfridman/

Abstract: The history and evolution of sliding control will be discussed. The reason for the crisis of the first order sliding modes will be explained. The second order sliding mode control algorithms and their specific features will be presented. The control chattering of the continuous second order super-twisting control algorithm will be discussed. The precision of the arbitrary order sliding mode controllers will be shown. The continuous arbitrary order sliding mode controllers will be presented and discussed. Videos with the experimental illustration of the properties of the main sliding mode algorithms will be presented.
References: http://www.springer.com/birkhauser/engineering/book/978-0-8176-4892-3

Afternoon (2:30 PM-5:00 PM)
Homogeneous Sliding Modes and Universal Black-Box Control

Arie Levant
Personal Homepage: http://www.tau.ac.il/~levant/

Abstract: Sliding Modes (SMs) are used to control uncertain dynamic systems by keeping properly chosen outputs at zero. In the Single-Input Single-Output (SISO) case the problem can be reformulated as a black-box control problem. In some cases the very existence of a mathematical model is redundant, and one can design control using only some dynamic input-output relation properties. Thus, the problem of SM Control (SMC) is naturally reformulated as the problem of the finite-time stabilization of a differential inclusion. The main idea is to design a control, producing a closed-loop differential inclusion of a negative homogeneity degree. Coordinate homogeneity and finite-time stability of differential  inclusions are studied. The asymptotic accuracy of disturbed finite-time-stable homogeneous differential inclusions is calculated. In particular, the stabilization accuracy is calculated in the presence of noises and variable delays. Universal SM controllers are designed for SISO systems with known relative degrees. Robust exact differentiators of any order are constructed to be applied in the output-feedback control. Asymptotic SM accuracies are calculated and shown to be optimal under conditions of discrete noisy sampling and zero-hold control. The presented output-feedback SM controllers are proved to be robust to the presence of the singular stable dynamics of unaccounted-for actuators and sensors, and to small system disturbances, changing the system relative degree. In some cases no mathematical model is available, and one can design control using only some dynamic input-output relation properties. A practical relative degree notion is presented and its application is demonstrated. The results are extended to multi-input multi-output (MIMO) systems. The effects of the Euler discretization of the internal dynamics of differentiators and controllers are studied, and the optimal asymptotic accuracy is shown to be preserved in the homogeneous output-feedback MIMO case. A modified discretization scheme is recommended to be used, if the differentiator is used outside of the homogeneous SMC feedback.

References: http://www.springer.com/birkhauser/engineering/book/978-0-8176-4892-3

Date: 2015.8.25
Morning (9:00 AM-11:30 AM)
Sliding Mode Observers and Their Application to Fault Detection Problems

Christopher Edwards
Personal Homepage: http://emps.exeter.ac.uk/engineering/staff/ce255

Abstract: The sliding mode methodology has been proved to be effective in dealing with complex dynamical systems  affected by disturbances, uncertainties and un-modelled dynamics. Robust controllers can be developed  exploiting the well-known insensitivity properties of sliding modes to so-called  matched uncertainties. However these robustness properties have also been exploited in the development of nonlinear observers  for state and unknown input estimation. The talks will explain how sliding mode ideas can be exploited to create robust observer based fault detection schemes (in fact typically fault estimation schemes). Practical real engineering examples and case studies will be considered to demonstrate the features and advantages of using sliding modes in a fault detection and fault tolerant control context. In particular examples of these techniques applied to problems in the aerospace field will be presented.

References: H. Alwi, C. Edwards and C. Tan,Fault Detection and Fault-tolerant Control Using Sliding Modes, AIC Series, Spring-Verlag, 2011

Afternoon (2:30 PM-5:00 PM)
Output Tracking in Nonminimum Phase Systems in Sliding Modes

Yuri B. Shtessel
Personal Homepage: http://www.uah.edu/eng/departments/ece/people/faculty/17-main/engineering/electrical-and-computer/632-ece-shtessel

Abstract: Approaches for output feedback tracking in nonminimum phase, multi-input-multi-output (MIMO) uncertain nonlinear systems withenhanced causality are discussed in this presentation. The control methodology that is based on the conventional and higher order sliding mode techniques and the principles of least-squares estimation are employed. The local asymptotic stability of the output tracking error dynamics along with boundedness of the unstable internal states is discussed are achieved. The full state vector and matched external disturbance are reconstructed for finding a bounded solution of the internal dynamics. Three case studies, the causal output tracking in nonminimum phase boost DC/DC converter, power factor correction of 3-phase boost AC/DC converter, and nonminimum phase flight control of f-16 jet fighter are considered.

Date: 2015.8.26
Morning (9:00 AM-11:30 AM)
Higher Order Sliding Modes based Observation and Identification

Leonid Fridman

Abstract: Higher-order sliding mode based observers can be considered as a successful technique for the state observation of perturbed systems, due to their high precision and robust behavior with respect to parametric uncertainties. The existence of a direct relationship between differentiation and the observability problem makes sliding mode based differentiators a technique that can be applied directly for state reconstruction. Even when the differentiators appear as a natural solution to the observation problem, the use of the system knowledge for the design of an observation strategy results in a reduction in the magnitude of the gains for the sliding mode compensation terms. Moreover, complete or partial knowledge of the system model facilitates the application of the techniques to parametric reconstruction or disturbance reconstruction.

References: http://verona.fi-p.unam.mx/~lfridman/papers-ya.php?

Afternoon (2:30 PM-5:00 PM)
Sliding Mode Control for Steer-by-Wire Systems

Zhihong Man
Personal Homepage: http://www.swinburne.edu.au/science-engineering-technology/staff-profiles/view.php?who=zman

Abstract: It has been predicted by the engineers and scientists in vehicle dynamics & control area that steer-by-wire (SbW) systems will play a key role for the stability control of next generation of road vehicles. The most distinguished features of anSbW system are that the mechanical shaft that links the hand-wheel to the front wheels in conventional steering systems is removed, and two electric motors are used to steer the front wheels and provide a driver with a feeling of the steering effort, respectively. The benefits of using SbW in road vehicles are that both the overall steering performance and cruising comforts can be improved, driving safety can be enhanced, and power consumption and long-term cost can be further reduced. In this talk, the mathematical modelling of anSbW system is first explored based on the bicycle model of road vehicles. The sliding mode control (SMC) technique is then used to design the steering control, returnability control and steering effort feeling control algorithms for the SbW systems with uncertain dynamics in road vehicles. Compared with conventional control techniques, the SMC can ensure that the effects of uncertainties in both self-aligning torque and vehicle parameters can be eliminated and the steered angle can asymptotically follow the reference signal provided by the driver through the hand-wheel. In addition, the lateral dynamics parameters of road vehicles can be accurately estimated on-line in the closed-loop sliding mode steering system, and the estimated lateral vehicle dynamics can then be employed for developing the fault detection and diagnosis of road vehicles, designing lane-keeping algorithm, and improving many other intelligent characteristics of road vehicles. At the end of this talk, the excellent performance of the “sliding mode car” designed by Lishui CA SbW Technical Company will be demonstrated in terms of a short video presentation, and the practical design experiences of SMC in SbW will be communicated with the audiences.

Date: 2015.8.27
Morning (9:00 AM-11:30 AM)
Adaptive Sliding Modes

Yuri B. Shtessel

Abstract: Sliding mode control (SMC) remains, probably, the most popular method for handling bounded perturbations with known bounds. The unknown bounds of the perturbations can be tackled using adaptive SMC techniques. In this presentation, adaptive conventional and second order sliding mode algorithms, derived based on Lyapunov function techniques are presented. A special feature of the discussed adaptive SMC/2-SMC/HOSM algorithms is the possibility to decrease the sliding mode control gains in order not to overestimate them. This feature yields reduced control chattering. Specifically, novel adaptive-gain conventional, twisting and super-twisting controllers that are robust to the bounded disturbances with the unknown boundaries are presented. The adaptive HOSM algorithm based on reconstruction of the equivalent control is also discussed. The presented adaptive SMC/2-SMC/HOSM algorithms are derived using the Lyapunov function techniques. It is shown that an ideal or real second order sliding mode is established, and the adaptation algorithms do not overestimate the control gains. The efficacy of the proposed adaptive sliding mode control algorithms are verified experimentally and via simulations on a variety of case studies.

Afternoon (2;30 PM-5:00 PM)
Sliding Mode Control for Nonlinear Systems with Mismatched Disturbances and Its Applications to Mechatronic Systems

Shihua Li
Personal Homepage: http://automation.seu.edu.cn/Articles.aspx?id=2053

Abstract: Most of existing results on sliding mode control are concentrated on the matched uncertainties attenuation since the sliding phase of traditional SMC is only insensitive to matched disturbances and uncertainties but sensitive to mismatched uncertainties. In the presence of mismatched disturbances/uncertainties, there are mainly two categories of SMCs. The first category mainly focuses on the stability (or robust stability) of various systems under mismatched uncertainties using some classical control design tools, such as Riccati approach and LMI-based approach. The second category is referred to as integral sliding model control (I-SMC). Note that those two categories of SMC methods deal with the mismatched uncertainties in a robust way, which implies that the uncertainty attenuation ability is achieved at the price of sacrificing its nominal control performance. Moreover, the chattering problem in these methods is still a severe problem to be solved. In this talk, we advocate a set of novel sliding mode control methods to counteract the mismatched uncertainties in the system via nonlinear disturbance observers (NDOs). The mismatched uncertainties under consideration are possibly non-vanishing and do not necessarily satisfy the condition of H2 norm-bounded. By designing a new sliding surface based on the disturbance estimation, the system states can be driven to the desired equilibrium asymptotically or in finite time. A reaching control law is then designed to force the initial states to reach the designed sliding surface. There are two remarkable features for this stream of control methods. First, the chattering problem can be alleviated and even totally avoided since the disturbances/uncertainties have been directly handled by NDOs and the discontinuous injection term in the control law is indeed unnecessary. Second, the new SMC methods retain its nominal performance since the NDOs serve like a patch to the baseline controller and do not cause any adverse effects on the system in the absence of disturbances/uncertainties. Applications of the new SMC approaches to Mechatronic Systems are also covered in this talk.

Reference: Li S, Yang J, Chen W-H, Chen X. Disturbance Observer-Based Control: Methods and Applications. Boca Raton: CRC Press, 2014.

Date: 2015.8.28
Morning (9:00 AM-11:30 AM)
Compound Control Methodology for Flight Vehicles

Yuanqing Xia
Personal Homepage: http://csicdgz.bit.edu.cn/xzdw/jq/27387.htm

Abstract: This talk focuses on compound control methodology for flight vehicles. First some new developments of SMC are presented. Second, both SMC and ADRC have their own advantages and limitations, i.e., chattering of SMC and the observability of extended state observer (ESO), respectively, and the concept of compound control is introduced. Compound control combines their advantages and improves the performance of the closed-loop systems. Finally, these methods are adopted to control of multi-flight vehicles.

Afternoon (2:30 PM-5:00 PM)
Sliding Mode Control of Parameter-Switching Hybrid Systems

Ligang Wu
Personal Homepage: http://homepage.hit.edu.cn/pages/wuligang/5

Abstract: Since the 1950's, sliding mode control (SMC) has been recognized as an effective robust control strategy for nonlinear systems and incompletely modeled systems. SMC has been successfully applied to a wide variety of systems such as uncertain systems, time-delay systems, stochastic systems, and some real world applications including robot manipulators, underwater vehicles, aircraft, spacecraft, electrical motors, power systems, and automotive engines. This presentation will cover recent developments in the theory for SMC of parameter-switching hybrid systems. The main aim is to present up-to-date research and novel methodologies on stability/performance analysis and SMC design of parameter-switching hybrid systems in a unified matrix inequality setting. The considered systems include singular Markovian jump systems, switching hybrid systems, and switched stochastic hybrid systems. These new methodologies provide a framework for stability and performance analysis, SMC design, state estimation for these classes of systems. Solutions to the design problems are presented in terms of linear matrix inequalities.

Date: 2015.8.29
Morning (9:00 AM-11:30 AM)

Nonsingular Terminal SMC Methodology and Applications

Yong Feng
Personal Homepage: http://homepage.hit.edu.cn/pages/fengyong

Abstract: Sliding-mode control (SMC) has attracted significant amount of interest due to its fast global convergence, simplicity of implementation, order reduction, high robustness to external disturbances and insensitivity to model errors and system parameter variations. Therefore SMC has been widely used in many applications, including electrical, mechanical, chemical, industrial, civil, military, aeronautical, and aerospace engineering. SMC includes conventional linear sliding-mode (LSM) control and terminal sliding-mode (TSM) control. The former is asymptotically stable, while the latter is finite-time stable. Compared to LSM control, TSM control exhibits various superior properties such as fast and finite-time convergence and smaller steady-state tracking errors. However the singularity problems in TSM control need to be addressed appropriately. Three non-singular TSM control methods are introduced. Firstly a new TSM manifold is proposed for the second-order system to enable the elimination of the singularity problem. The parameters in TSM are inverted to avoid negative exponential term appearing in the controller after differentiation. The time taken to reach the equilibrium point from any initial state is guaranteed to be finite time. It resolves the singularity problem completely via the design of the TSM manifold, and can be extended to a special class of high-order systems. Secondly, a saturation function based TSM control is presented to overcome the singularity problem of TSM control systems. The system behaviors in both the reaching phase and the ideal sliding-mode are analyzed. A global nonsingular TSM control strategy is developed to guarantee the finite-time reachability of the systems to the TSM manifold and the finite-time convergence of the systems towards the origin along the TSM manifold. Thirdly, a full-order TSM manifold is utilized to avoid the singularity. Different from the traditional computable or measurable sliding-mode manifolds, the new sliding-mode manifolds are designed to be neither computable nor measurable. During the ideal sliding-mode motion, the systems using the proposed control strategy behave as desirable full-order dynamics, rather than reduced-order dynamics. Chattering reduction in nonsingular TSM control is studied as well. Many case studies will be presented, including the control of permanent-magnet synchronous motors (PMSMs) and induction motors (IMs), the energy-saving control of AC motors, the grid control for wind energy conversion systems, the rotor position and speed estimation of PMSMs, the flux estimation of IMs, the mechanical parameters estimation of complex mechanical systems, the mechanical resonance supressing of servo systems, the network behavior anomaly detection in TCP/IP networks.

Afternoon (2:30 PM-5:00 PM)
Finite-Time Sliding Mode Control in Continuous and Discrete Time

Xinghuo Yu
Personal Homepage: http://www1.rmit.edu.au/staff/xinghuo-yu

Abstract: Sliding mode control (SMC) has been studied and used extensively due to its robustness and simplicity. Central to SMC is the sliding motion which is induced by a disruptive (discontinuous) control forcing the states of the controlled system into some prescribed switching manifolds which exhibit desired performance characteristics. Finite-time reachability of the switching manifolds is required in order to induce the system states into the sliding motion underpinned by the switching manifolds. In conventional SMC, asymptotical convergence is embedded in these switching manifolds. In recent years, finite-time SMC has been proposed that enables finite-time reachability of the system equilibrium points in the specially designed nonlinear switching manifolds. The advantage of such a control strategy is the enhanced robustness and higher steady states precision. In this talk, we will first introduce the basics of finite-time SMC, and then present an overview of its recent developments in theory and applications. In particular, we will investigate the gap between the very finite-time SMC theory in the continuous-time, and discrete-time domains, respectively, and how to bridge the gap. The discussions will be accompanied by various simulation studies.

Afternoon (5:00 PM-5:30 PM)

Closing Ceremony