Optimal Integral Sliding Mode Control Research Articles

Optimal integral sliding mode controller controller design for 2-RLFJ manipulator based on hybrid optimization algorithm

A newly hybrid nature-inspired algorithm called HSSGWOA is presented with the combination of the salp swarm algorithm (SSA) and grey wolf optimizer (GWO). The major idea is to combine the salp swarm algorithm's exploitation ability with the grey wolf optimizer's exploration ability to generate both variants' strength. The proposed algorithm uses to tune the parameters of the integral sliding mode controller (ISMC) that design to improve the dynamic performance of the two-link flexible joint manipulator. The efficiency and the capability of the proposed hybrid algorithm are evaluated based on the selected test functions. It is clear that when compared to other algorithms like SSA, GWO, differential evolution (DE), gravitational search algorithm (GSA), particles swarm optimization (PSO), and whale optimization algorithm (WOA). The ISMC parameters were tuned using the SSA, which was then compared to the HSSGWOA algorithm. The simulation results show the capabilities of the proposed algorithm, which gives an enhancement percentage of 57.46% compared to the standard algorithm for one of the links, and 55.86% for the other.

An improved optimal integral sliding mode control for uncertain robotic manipulators with reduced tracking error, chattering, and energy consumption

This paper proposes an improved optimal integral sliding mode control (IOISMC) for a robust and optimal tracking control of robotic manipulators under the presence of coupling effects, parameter variations, and external disturbances. By representing the system dynamics in the error coordinate and introducing an additional optimal integral term in the nominal control part of IOISMC, the effects of unmeasured forces, reaching phase issue, chattering issue, and position offset associated with conventional optimal integral sliding mode control are significantly addressed. Hence, the proposed approach has several notable merits, namely fast recovery response, low chattering, high tracking performance, high energy efficiency, low computational complexity, and robustness against uncertainties. The idea has been proven in two ways: a strong theoretical framework using Lyapunov stability theory and extensive simulation verification. The superiority of the proposed method has been confirmed through significant reductions of chattering and energy consumption without significant performance loss. Furthermore, the proposed method is capable of sustaining high tracking performance despite the presence of the aforementioned uncertainties and eliminates the reaching phase. It is envisaged that the proposed method can be useful in designing a robust and optimal tracking control for all types of uncertain multivariate systems without compromising on the computational cost.

A Comparative Study of LQR and Integral Sliding Mode Control Strategies for Position Tracking Control of Robotic Manipulators

This paper provides a systematic comparative study of position tracking control of nonlinear robotic manipulators. The main contribution of this study is a comprehensive numerical simulation assessing position tracking performances and energy consumption of integral sliding mode control (ISMC), a linear-quadratic regulator with integral action (LQRT ), and optimal integral sliding mode control (OISMC) under three conditions; namely, Case I) without the coupling effect, Case II) with the coupling effect on Link 1 only, and Case III) with the coupling effect on Link 2 only. The viability of the concept is evaluated based on three performance criteria, i.e., the step-response characteristics, position tracking error, and energy consumption of the aforementioned controllers. Based upon the simulation study, it has been found that OISMC offers performances almost similar to ISMC with more than 90% improvement of tracking performance under several cases compared to LQRT; however, energy consumption is successfully reduced by 3.6% in comparison to ISMC. Energy consumption of OISMC can be further reduced by applying optimization algorithms in tuning the weighting matrices. This paper can be considered significant as a robotic system with high tracking accuracy and low energy consumption is highly demanded to be implemented in smart factories, especially for autonomous systems.

A pseudospectral method based robust-optimal attitude control strategy for spacecraft

This paper proposes an optimal integral sliding mode control (ISMC) scheme for attitude regulation of the rigid spacecraft. This control technique is capable of handling inertial matrix uncertainties as well as external disturbances. To incorporate optimality into the robust control law, the ISMC is integrated with Legendre pseudospectral method (LPSM). The minimization of the cost function and constraint handling of the spacecraft is obtained by LPSM, while the ISMC provides disturbance rejection. LPSM is chosen for its relatively high rate of convergence and its capability of solving a wide range of challenging optimal control problems. Theoretical stability analysis of closed loop system using Lyapunov theorem guarantees the convergence of attitude states. A comparative analysis between the proposed LPSM-ISMC and Chebyshev Pseudospectral Method (CPSM) based ISMC, is also presented in this paper. The effectiveness of the proposed robust-optimal control strategy is established through simulation results.

Optimal Integral Sliding Mode Controller of a UAV With Considering Actuator Fault

Optimal Integral Sliding Mode Controller of a UAV With Considering Actuator Fault

Turning Motion Control Design of a Two-Wheeled Inverted Pendulum Using Curvature Tracking and Optimal Control Theory

This paper presents a control design method for implementing planar turning motion of a two-wheeled inverted pendulum with an input delay. The control task requires that the inverted pendulum is kept stabilized during the whole turning motion process along a pre-settled curve. Firstly, by using the theory of planar curve, key observations about the motion law of the two-wheeled mobile chassis are made and they are used to set up a dynamical trajectory tracking target. Then, by adjusting the parameters in the tracking target and the weights in the quadratic performance criterion, the optimal integral sliding mode controller based on a linear quadratic regulator is designed for keeping the vehicle body stabilized and tracking a circular path for the two-wheeled inverted pendulum. An illustrative example is given to demonstrate the validity of the theory with numerical simulation.

Robust Optimal Integral Sliding Mode Controller for Total Power Control of Large PHWRs

This paper presents the design of an optimal integral sliding mode controller (OISMC) to control the total power of a large pressurized heavy water reactor (PHWR). Considering the dynamics of systems relevant to total power control loop of the large PHWR, the single input and single output model adopted in this paper is characterized by 21 state variables. The nonlinear model is linearized around steady-state full power operating point to obtain a linear model for which an OISMC is designed. Optimal controller which guarantees minimum control effort is combined with an ISMC to ensure the robustness of the system in the presence of uncertainties and external disturbances. Stability of the proposed controller is proven by means of Lyapunov approach. From nonlinear simulation studies, performance of the proposed OISMC is found to be satisfactory.

Erratum to: Robust motion control of a two-wheeled inverted pendulum with an input delay based on optimal integral sliding mode manifold

This paper presents a robust integral sliding mode controller for the back-and-forth motion of a two-wheeled inverted pendulum. The control design of this nonlinear system is based on the linearized system with bounded uncertainty and with an input delay taken into account, where the uncertainty is the integrated effect of the linearization error and bounded system uncertainties. Firstly, a trajectory tacking target is selected according to the control task. Secondly, a quadratic performance criterion with large weight of tilt angle error for optimal control is introduced to “force” the tilt angle of inverted pendulum small enough and in turn to make the linearization error small. Thirdly, a new integral state transformation is used to convert the delayed error system with uncertainty into a delay-free one, and a key relationship between the original state variable and the new state variable is founded. Finally, the robust optimal integral sliding mode controller represented in the form of predictor state is designed by choosing the optimal state of the nominal error system as the integral sliding mode manifold. Numerical simulation shows that the designed controller not only works well in implementing the control task, but also has strong robustness against system uncertainties.

An optimal integral sliding mode control strategy based on a pseudospectral method for a class of affine systems

This paper presents an optimal integral sliding mode control method based on a pseudospectral method for a class of affine systems with state and control constraints. First, a general form of an integral sliding mode is presented. Integral sliding mode control cannot deal with the problem of states and control constraints, nor can it satisfy the minimization of the cost function. The pseudospectral method has a high convergence speed and performs well in solving optimal control problems with general performance index, endpoint conditions and path constraints. In consideration of these advantages, an optimal integral sliding mode controller is determined by the pseudospectral method. Then, the stability analysis of optimal pseudospectral sliding mode method is discussed. Finally, numerical simulations show the effectiveness of the proposed method. An application example, consisting of an overhead crane system, is investigated to demonstrate the effectiveness and robustness of the proposed technique.

Optimal integral sliding mode control scheme based on pseudospectral method for robotic manipulators

For a multi-input multi-output nonlinear system, an optimal integral sliding mode control scheme based on pseudospectral method is proposed in this paper. And the controller is applied on rigid robotic manipulators with constraints. First, a general form of integral sliding mode is designed with the aim of restraining disturbance. Then, pseudospectral method is adopted to deal with constrained optimal control problem. In consideration of the benefits of both methods, an optimal integral sliding mode controller is given, which is based on the combination of integral sliding mode and pseudospectral method. The stability analysis shows that the controller can guarantee stability of robotic manipulator system. Simulations show the effectiveness of proposed method.

Optimal integral sliding mode control for a class of uncertain discrete‐time systems

SUMMARYThis paper considers the problem of sliding mode control for a class of uncertain discrete‐time systems. Firstly, an optimal control law for the nominal system is derived to satisfy linear quadratic performance index. And then, an optimal integral sliding surface is designed to ensure the robustness for sliding dynamics. By combining with the discrete reaching law, the existence condition of the sliding mode is proved, and the bandwidth of the quasi‐sliding mode is given. It is shown that the present method utilizes a lower control gain to attain stronger robustness and eliminate the chattering. Finally, illustrative simulation results are provided. Copyright © 2013 John Wiley & Sons, Ltd.