Yuri B. Shtessel

Sliding Mode Control and Observation

The sliding mode control methodology has proven effective in dealing with complex dynamical systems affected by disturbances, uncertainties and unmodeled dynamics. Robust control technology based on this methodology has been applied to many real-world problems, especially in the areas of aerospace control, electric power systems, electromechanical systems, and robotics. Sliding Mode Control and Observation represents the first textbook that starts with classical sliding mode control techniques and progresses toward newly developed higher-order sliding mode control and observation algorithms and their applications.The present volume addresses a range of sliding mode control issues, including:*Conventional sliding mode controller and observer design*Second-order sliding mode controllers and differentiators*Frequency domain analysis of conventional and second-order sliding mode controllers*Higher-order sliding mode controllers and differentiators*Higher-order sliding mode observers *Sliding mode disturbance observer based control *Numerous applications, including reusable launch vehicle and satellite formation control, blood glucose regulation, and car steering control are used as case studiesSliding Mode Control and Observation is aimed at graduate students with a basic knowledge of classical control theory and some knowledge of state-space methods and nonlinear systems, while being of interest to a wider audience of graduate students in electrical/mechanical/aerospace engineering and applied mathematics, as well as researchers in electrical, computer, chemical, civil, mechanical, aeronautical, and industrial engineering, applied mathematicians, control engineers, and physicists. Sliding Mode Control and Observation provides the necessary tools for graduate students, researchers and engineers to robustly control complex and uncertain nonlinear dynamical systems. Exercises provided at the end of each chapter make this an ideal text for an advanced coursetaught in control theory.

Brief paper: Smooth second-order sliding modes: Missile guidance application

A new smooth second-order sliding mode control is proposed and proved using homogeneity-based technique for a system driven by sufficiently smooth uncertain disturbances. The main target application of this technique-the missile-interceptor guidance system against targets performing evasive maneuvers is considered. The smooth second-order sliding mode control-based guidance law is designed and compared with augmented proportional navigation guidance law via computer simulations of a guided missile intercepting a maneuvering ballistic target.

New methodologies for adaptive sliding mode control

This article proposes new methodologies for the design of adaptive sliding mode control. The goal is to obtain a robust sliding mode adaptive-gain control law with respect to uncertainties and perturbations without the knowledge of uncertainties/perturbations bound (only the boundness feature is known). The proposed approaches consist in having a dynamical adaptive control gain that establishes a sliding mode in finite time. Gain dynamics also ensures that there is no overestimation of the gain with respect to the real a priori unknown value of uncertainties. The efficacy of both proposed algorithms is confirmed on a tutorial example and while controlling an electropneumatic actuator.

A novel adaptive-gain supertwisting sliding mode controller: Methodology and application

A novel super-twisting adaptive sliding mode control law is proposed for the control of an electropneumatic actuator. The key-point of the paper is to consider that the bounds of uncertainties and perturbations are not known. Then, the proposed control approach consists in using dynamically adapted control gains that ensure the establishment, in a finite time, of a real second order sliding mode. The important feature of the adaptation algorithm is in non-overestimating the values of the control gains. A formal proof of the finite time convergence of the closed-loop system is derived using the Lyapunov function technique. The efficiency of the controller is evaluated on an experimental set-up.

Guidance and Control of Missile Interceptor using Second-Order Sliding Modes

A new smooth second-order sliding mode control (SSOSM) is proposed and proved for a system driven by uncertain sufficiently smooth disturbances. The main target application of this technique, the missile interceptor guidance-control system against targets performing evasive maneuvers, is considered to demonstrate benefits of this design for a two-loop integration of guidance and flight control systems. The designed guidance-control system performance is verified via computer simulations using a miniature hypervelocity kinetic energy endo-atmospheric interceptor planar model.

Quadrotor vehicle control via sliding mode controller driven by sliding mode disturbance observer

Abstract Over the last decade, considerable interest has been shown from industry, government and academia to the design of Vertical Take-Off and Landing (VTOL) autonomous aerial vehicles. This paper uses the recently developed sliding mode control driven by sliding mode disturbance observer (SMC-SMDO) approach to design a robust flight controller for a small quadrotor vehicle. This technique allows for a continuous control robust to external disturbance and model uncertainties to be computed without the use of high control gain or extensive computational power. The robustness of the control to unknown external disturbances also leads to a reduction of the design cost as less pre-flight analyses are required. The multiple-loop, multiple time-scale SMC-SMDO flight controller is designed to provide robust position and attitude control of the vehicle while relying only on knowledge of the limits of the disturbances. Extensive simulations of a 6 DOF computer model demonstrate the robustness of the control when faced with external disturbances (including wind, collision and actuator failure) as well as model uncertainties.

Sliding Mode Disturbance Observer-Based Control for a Reusable Launch Vehicle

The nations goals to replace the aging Space Shuttle fleet and pursue exploration of our solar system and beyond will require more robust, less costly launch vehicles and spacecraft. This paper presents a novel Sliding Mode Control approach, Sliding Mode Control driven by Sliding Mode Disturbance Observers with Gain Adaptation, for the reusable launch vehicle (RLV) flight control system design as a way to improve robustness to many phenomena such as modeling uncertainties and disturbances, while retaining continuity of control without using high control gains. Due to the robustness to external disturbances (including wind gusts), mission guidance trajectories and modeling uncertainties, the proposed flight control system design also can reduce cost by requiring less time in design cycle and preflight analyses. This design is applied to Terminal Area Energy Management and Approach/Landing (TAL), a flight regime that has had little research effort in recent years. The multiple-loop, multiple time-scale design features low order disturbance observers that rely only on knowledge of the bounds of the disturbance. A gain adaptation algorithm is included in the disturbance observer design that provides the least gain needed for existence of the sliding mode. High fidelity 6 DOF computer simulations of the X-33 technology demonstration sub-orbital launch vehicle for nominal and severe wind-gust tests demonstrate improved performance over a more conventional, classical control system design.

Integrated Higher-Order Sliding Mode Guidance and Autopilot for Dual Control Missiles

An integrated autopilot and guidance algorithm, robust to target maneuvers and missile’s model uncertainties, is developed using higher-order sliding mode control for interceptors steered by a combination of aerodynamic lift, sustainer thrust, and center-of-gravity divert thrusters. A smooth higher-order sliding mode guidance that is robust to target maneuvers generates flight-path trajectory angular rates and attitude rate commands. The attitude rate missilemaneuvers are aimed at producing desired aerodynamic lift and/or orienting the sustainer thrust. The lateral acceleration created by themissile attitudemaneuver is treated as a cooperative disturbance andaccounted for by the trajectory control. Robust to themissile’smodel uncertainties, higher-order (second-order) slidingmode autopilot is designed based on a nonlinear dynamic slidingmanifold. The proposed integrated autopilot and guidance algorithm also includes seeker/tracker bore-sight stabilization and estimation of target lateral acceleration. The algorithm is tested using computer simulations against a ballistic maneuvering target.

Brief Tracking in a class of nonminimum-phase systems with nonlinear internal dynamics via sliding mode control using method of system center

A method of asymptotic output tracking in a class of causal nonminimum-phase uncertain nonlinear systems is considered. Local asymptotic stability of output tracking-error dynamics are provided for the specified class of systems with the nonlinear hyperbolic at the origin internal dynamics forced by a reference output profile and external disturbances defined by a known linear exosystem. The nonlinear vector field of the internal dynamics is expanded in a power series, obtained at a selected operational point in the internal dynamics state space. The presented technique employs some linear algebraic methods and sliding mode control approach. The solution is a complete constructive algorithm.

Reusable Launch Vehicle Control in Multiple Time Scale Sliding Modes

A reusable launch vehicle control problem during ascent is addressed via multiple-time scaled continuous sliding mode control. The proposed sliding mode controller utilizes a two-loop structure and provides robust, de-coupled tracking of both orientation angle command profiles and angular rate command profiles in the presence of bounded external disturbances and plant uncertainties. Sliding mode control causes the angular rate and orientation angle tracking error dynamics to be constrained to linear, de-coupled, homogeneous, and vector valued differential equations with desired eigenvalues placement. Overall stability of a two-loop control system is addressed. An optimal control allocation algorithm is designed that allocates torque commands into end-effector deflection commands, which are executed by the actuators. The dual-time scale sliding mode controller was designed for the X-33 technology demonstration sub-orbital launch vehicle in the launch mode. Simulation results show that the designed controller provides robust, accurate, de-coupled tracking of the orientation angle command profiles in presence of external disturbances and vehicle inertia uncertainties. This is a significant advancement in performance over that achieved with linear, gain scheduled control systems currently being used for launch vehicles.