Passivity-based Sliding Mode Control Research Articles

Passivity-based sliding mode control for mechanical port-Hamiltonian systems

Passivity-based sliding mode control for mechanical port-Hamiltonian systems

New potential functions for passivity based sliding mode control

Recently, passivity-based sliding mode control has been proposed for mechanical port-Hamiltonian systems. This controller has properties of both sliding mode control and passivity-based control, and Lyapunov stability is ensured by a Hamiltonian function with a non-smooth potential function. In the authors’ previous study, a special form of non-smooth potential function is considered and there are few parameters to adjust the controller for various control objectives. This paper proposes a new passivity-based sliding mode controller based on a wider class of potential functions. This approach enables us to reduce chattering and improve the behavior in reaching mode by adjusting parameters. The effectiveness of the proposed method is demonstrated by a numerical simulation.

RBF Neural Network Sliding Mode Control for Passification of Nonlinear Time-Varying Delay Systems with Application to Offshore Cranes.

This paper is devoted to studying the passivity-based sliding mode control for nonlinear systems and its application to dock cranes through an adaptive neural network approach, where the system suffers from time-varying delay, external disturbance and unknown nonlinearity. First, relying on the generalized Lagrange formula, the mathematical model for the crane system is established. Second, by virtue of an integral-type sliding surface function and the equivalent control theory, a sliding mode dynamic system can be obtained with a satisfactory dynamic property. Third, based on the RBF neural network approach, an adaptive control law is designed to ensure the finite-time existence of sliding motion in the face of unknown nonlinearity. Fourth, feasible easy-checking linear matrix inequality conditions are developed to analyze passification performance of the resulting sliding motion. Finally, a simulation study is provided to confirm the validity of the proposed method.

A Passivity-Based Sliding Mode Controller for a Class of Electro-Mechanical Systems

This letter proposes a novel sliding mode control method for a class of electro-mechanical systems using passivity based approach. For mechanical systems, the authors proposed a passivity based sliding mode controller based on the kinetic potential energy shaping method which allows one to obtain a wider class of Lyapunov function candidates. This letter extends this framework to cope with a class of electro-mechanical systems and gives a new class of energy based Lyapunov function candidates. Based on this technique, a novel sliding mode controller with an explicit energy based Lyapunov function is proposed. It is expected to provide a new basis for a unified control design framework for both passivity based control and sliding mode control. Furthermore, a numerical example demonstrates the effectiveness of the proposed method.

Synchronous Control of 2-D.O.F Master-Slave Manipulators Using Actuators With Asymmetric Nonlinear Dead-Zone Characteristics

Although the various synchronous control techniques of a master-slave manipulator have been explored and developed over the decades, the investigations of the synchronous control for those systems with strong asymmetric dead-zone characteristics have been limited and not been fully considered. Hence, we proposed the robust and easy-to-implement estimation and control strategy to compensate for the actuator’s dead-zone effect and to guarantee synchronous performance. Specifically, we set up a two-step process called prior-estimation control to avoid the performance degradation due to the frequent failures of the desired estimation in a standard adaptive control. The first step is to adaptively estimate the asymmetric nonlinear dead-zone parameters via the Recursive Least Square (RLS) method. At the second stage, those estimated parameters via RLS are delivered to the main synchronous control system designed by a passivity-based sliding mode control technique along with inverse dead-zone control, and then the control is executed whenever a human operator interacts with the system. Finally, the effectiveness of the proposed approach has been validated by the actual 2-D.O.F master-slave manipulators equipped with cost-effective actuators with an inevitable asymmetric dead-zone. This work will be especially a valuable asset for those who wish to accurately control the master-slave systems with dead-zone characteristics such as the industrial construction multiple joints based fork cranes or lifts.

Robust Passivity-based Sliding Mode Control of a Large Class of Nonlinear Systems Subject to Unmatched Uncertainties: A Robot Manipulator Case Study

The existence of unmatched uncertainties is known as a serious challenge for designing a robust sliding mode control (SMC) law for nonlinear systems. To pass over this obstacle, a novel robust passivity-based sliding mode approach is proposed here for a large class of MIMO nonlinear systems. The design procedure is accomplished in two steps in presence of both matched and unmatched uncertainties. First, an efficient adaptive sliding surface is designed based on the passivity concept. The passivity provides a flexible robust structure for the sliding surface and guarantees the global asymptotic stability of the reduced-order equations of the system as well. Furthermore, simple adaptation laws are obtained to eliminate the effects of uncertainties. Then, the robust controller is formulated using the SMC method. As another important advantage, the proposed approach is relaxed from the upper bound’s constraints of the uncertainties. It is also applied to n-link rigid electrically driven robot manipulator as a widely-used practical nonlinear system. The simulation results show the appropriate tracking performance for the industrial selective compliance assembly robot arm (SCARA) in the presence of noisy external disturbances. Also, an extending case is studied with related research to emphasize the potential of the proposed approach.

Robust Passivity-Based Control Scheme for 1.26 KW Proton Exchange Membrane Fuel Cell Under Temperature and Load Variations

Abstract The model-based system engineering (MBSE) is based on simplified mathematical models that reflect the dynamic behavior of the systems. These are most of the time nonlinear and need control schemes taking in consideration of exogenous perturbations. The main contribution of this article is the design of a robust passivity-based sliding mode control scheme for a 1.26 KW proton exchange membrane fuel cell (PEMFC). The uncertainties considered in this article are temperature and load variation. The fuel cell (FC) reference current is adapted in a linear transformation by introducing a temperature sensor. This information is present in most of commercial PEMFC and not used in the closed-loop system. Moreover, the proposed approach cancels the errors caused by the average approach modeling and the observer (the part, which replaces current sensor). Robustness against load variation is assured via a proportional integral compensation of the incremental value of load resistance. The performance of the controller and the effectiveness of our approach is shown through the simulation with matlab-simulink software.

On trajectory tracking control of simple port-Hamiltonian systems based on passivity based sliding mode control

Abstract In this work, the passivity-based sliding mode control technique is applied to trajectory tracking control problems. This method unifies two methods, sliding mode control and passivity-based control, and has the advantages of both control methods. This paper proposes a pair of a pre-coordinate transformation and a state feedback so that we obtain a desired error port-Hamiltonian system that describes the dynamics of the tracking error. This approach enables us to obtain appropriate design parameters satisfying a kind of matching condition to realize sliding mode control with a Lyapunov function. The effectiveness of the proposed method is demonstrated by a numerical simulation.

Passivity based sliding mode control and synchronization of a perturbed uncertain unified chaotic system

The problem of passivity-based sliding mode control is considered, for the unified chaotic system having uncertainties and perturbations. Using a combination between sliding mode method and the passivity method, an appropriate switching surface for the uncertain and perturbed system is designed, and then through passivity theory, the stability of the system is ensured. The proposed design is applied in two control problems, the first one being the stabilization of the uncertain perturbed unified chaotic system and the second one is the synchronization between two unified chaotic systems, where only the slave system contains uncertainties and perturbations. Finally, the effectiveness of the proposed methods are illustrated through numerical simulations, and also through a microcontroller implementation.

Passivity-based robust sliding mode synthesis for uncertain delayed stochastic systems via state observer

In this paper, the problem of passivity-based sliding mode control (SMC) for uncertain delayed stochastic systems (DSS) within state-observer framework is under consideration. A novel linear sliding surface is first presented with the aid of the provided observer and output information, and a new sufficient condition on the passivity and mean square exponential stability of the underlying closed-loop system during the sliding mode is then derived by employing the stochastic stability theory and linear matrix inequality approach. Further, an associated SMC law is designed to guarantee the arrival of the sliding surface almost surely via the adaptive methodology. Finally, two illustrative examples concerning the desirable performance of the system are conducted to confirm the effectiveness and superiority of the proposed method.

Passivity-based sliding-mode control design for optimal power extraction of a PMSG based variable speed wind turbine

Abstract This paper proposes a novel passivity-based sliding-mode control (PB-SMC) scheme of permanent magnetic synchronous generator (PMSG) for maximum power point tracking (MPPT). A storage function is constructed based on the passivity theory at first, in which the beneficial system nonlinearities, e.g., which can make the derivative of storage function to be more negative, are carefully remained so as to improve the system damping while all the other system nonlinearities are fully removed. Then, an additional input is used to lead the closed-loop system to be output strictly passive via energy reshaping, meanwhile a sliding-mode control (SMC) is incorporated to greatly enhance the system robustness against various uncertainties of PMSG. Hence, PB-SMC can simultaneously own the promising merits of improved system damping and significant robustness, together with a globally consistent control performance under various operation conditions. Case studies including step change of wind speed, stochastic wind speed variation, pitch angle variation, and generator parameter uncertainties, are undertaken which verify the effectiveness and superiority of PB-SMC compared to that of other typical controllers. Lastly, a dSpace based hardware-in-loop (HIL) test is carried out to validate the implementation feasibility of PB-SMC.

Passification of Uncertain Singular Semi-Markovian Jump Systems With Actuator Failures Via Sliding Mode Approach

This paper investigates the problem of robust passivity-based sliding mode control (SMC) for uncertain singular systems with semi-Markov switching and actuator failures. The attention is focused on designing a common sliding surface to weaken the jumping effect and developing a sliding mode controller to accommodate to actuator faults for passification of the singular semi-Markovian jump system. Based on linear matrix inequality technique, sufficient conditions are derived to ensure the closed-loop system to be stochastically admissible and robustly passive. Then the finite-time reachability of the sliding surface is guaranteed by the proposed SMC law. Finally, a numerical example is provided to demonstrate the effectiveness of the obtained result.

Flexible Structure Control of Unmatched Uncertain Nonlinear Systems via Passivity-based Sliding Mode Technique

This paper considers the problem of passivity-based sliding mode control of uncertain nonlinear systems. For this purpose, two cases are studied. In the first case, it is assumed that only the matched uncertainties exist in the system dynamics. In this case, the passivity-based control approach is used to design an appropriate sliding manifold with a flexible structure such that the asymptotic stability of the reduced-order model (i.e., the motion equations on the proposed sliding manifold) is guaranteed. In the second case, both matched and unmatched uncertainties are considered in the system dynamics and thus the reduced-order model has uncertain terms. In this case, the modified Lyapunov redesign technique is combined with the passivity-based control method for design of robust sliding manifold. The function that is basically used in the classical Lyapunov redesign method is the signum function, which is not differentiable. Since, for evaluating the derivative of the sliding manifold its equation must be differentiable, a new additional continuous control term is suggested. In addition, the robust practical stabilization of the motion equations is guaranteed without considering any limitation on the upper bound of the unmatched uncertainties. Finally, computer simulations are performed for a practical example (flexible spacecraft) and also a numerical example to demonstrate the ability of the proposed controller in robust stabilization of uncertain nonlinear dynamical systems.

Robust passive control for a class of uncertain neutral systems based on sliding mode observer

The passivity-based sliding mode control (SMC) problem for a class of uncertain neutral systems with unmeasured states is investigated. Firstly, a particular non-fragile state observer is designed to generate the estimations of the system states, based upon which a novel integral-type sliding surface function is established for the control process. Secondly, a new sufficient condition for robust asymptotic stability and passivity of the resultant sliding mode dynamics (SMDs) is obtained in terms of linear matrix inequalities (LMIs). Thirdly, the finite-time reachability of the predesigned sliding surface is ensured by resorting to a novel adaptive SMC law. Finally, the validity and superiority of the scheme are justified via several examples.

Passivity-based Integral Sliding Mode Active Suspension Control

A novel passivity-based sliding mode controller for active suspension system with uncertainties is presented in this paper to decrease vibration and increase robustness. Based on the characteristics of the suspension system, interconnection and damping assignment passivity- based control approach is used to construct integral sliding surface. By elaborately designing desired interconnection matrix, damping matrix and energy function, an original integral sliding surface is completed and a subcontroller is obtained to achieve sliding mode dynamic. A simplified form of subcontroller is provided when some of designable parameters are chosen properly. Combining the subcontroller with a nonlinear component, passivity-based sliding mode controller is created. Robustness analysis is given and it is proofed that the integral sliding surface is robustly stable and can be reached. Simulation under three cases circumstances validates the effect of the proposed method.

Passivity-based sliding mode control for a polytopic stochastic differential inclusion system

Passivity-based sliding mode control for a polytopic stochastic differential inclusion (PSDI) system is considered. A control law is designed such that the reachability of sliding motion is guaranteed. Moreover, sufficient conditions for mean square asymptotic stability and passivity of sliding mode dynamics are obtained by linear matrix inequalities (LMIs). Finally, two examples are given to illustrate the effectiveness of the proposed method.

Passivity-based Sliding Mode Control of Uncertain Nonlinear Singular Time-delay Systems Subjected to Input Nonlinearity

Passivity-based Sliding Mode Control of Uncertain Nonlinear Singular Time-delay Systems Subjected to Input Nonlinearity

Passivity-based sliding mode control of uncertain singular time-delay systems

In this paper the problem of sliding mode control (SMC) with passivity of a class of uncertain nonlinear singular time-delay systems is studied. An integral-type switching surface function is designed by taking the singular matrix into account, thus the resulting sliding mode dynamics is a full-order uncertain singular time-delay system. By introducing some slack matrices, a delay-dependent sufficient condition is proposed in terms of linear matrix inequality (LMI), which guarantees the sliding mode dynamics to be generalized quadratically stable and robustly passive. The passification solvability condition is then established. Moreover, a SMC law and an adaptive SMC law are synthesized to drive the system trajectories onto the predefined switching surface in a finite time. Finally, a numerical example is provided to illustrate the effectiveness of the proposed theory.

Passivity-Based Sliding Mode Position Control for Induction Motor Drives

In this paper, a passivity-based sliding-mode controller is proposed to control the motion of an induction motor. At first, the induction motor is proved to be a state strictly passive system. Then, a sliding-mode position controller with an adaptive load torque estimator is designed to control the position of the induction motor such that the chattering effects associated with a classical sliding-mode position controller can be eliminated. The stability analysis of the overall position control system is carried out by the passivity theory. The proposed approach is robust with regard to variations of motor mechanical parameters and load torque disturbances. Finally, experimental results are included to demonstrate that good position tracking can be obtained without the rotor flux observer.