Design Of Sliding Mode Control Law Research Articles

Dissipativity-Based Event-Triggered Sliding Mode Control of Discrete-Time 2-D Systems

This paper focuses on dissipativity analysis and dissipativity-based sliding mode control (SMC) of discrete-time two-dimensional (2-D) systems described by Roesser model. First, dissipativity is introduced for 2-D systems. Aimed at the characteristics of Roesser model, the horizontal and vertical sliding surface functions are constructed for the addressed 2-D systems, respectively. Then sufficient conditions are proposed to guarantee the asymptotic stability and the pre-specified dissipativity for the resultant reduced-order 2-D sliding mode dynamics. Next, the SMC law is developed such that the system trajectories are driven into the quasi-sliding mode band in a finite region and maintained there all the time. In order to achieve a better resource utilisation, the event-triggered strategy is further incorporated in the design of SMC law. The event-triggered rule is also established to implement the event-triggered SMC scheme for 2-D systems. In the meantime, the corresponding quasi-sliding mode band is obtained. Finally, one verification example is given to show the effectiveness of the proposed SMC design method.

Super-Twisting Sliding Mode Control Law Design for Attitude Tracking Task of a Spacecraft via Reaction Wheels

The attitude control has been recognized as one of the most important research topics for spacecraft. If the desired attitude trajectory cannot be tracked precisely, it may cause mission failures. In the real space mission environment, the unknown external perturbations, for example, atmospheric drag and solar radiation, should be taken into consideration. Such external perturbations could deviate the precision of the spacecraft orientation and thereby lead to a mission failure. Therefore, in this paper, a quaternion-based super-twisting sliding mode robust control law for the spacecraft attitude tracking is developed. The finite time stability based on the formulation of the linear matrix inequality (LMI) is also provided. To avoid losing the control degree of freedom due to the certain actuator fault, a redundant reaction wheels configuration is adopted. The actuators distribution associated force distribution matrix (FDM) is analyzed in detail. Finally, the reference tangent-normal-binormal (TNB) command generation strategy is implemented for simulating the scenario of the space mission. Finally, the simulation results reveal that the spacecraft can achieve the desired attitude trajectory tracking demands in the presence of the time-varying external disturbances.

Sliding Mode Control for Lipschitz Nonlinear Systems in Reciprocal State Space: Synthesis and Experimental Validation

This brief proposes a design of new Sliding Mode Control (SMC) for Lipschitz nonlinear systems in a new Reciprocal State Space (RSS) framework. The main objective is to extend the state derivative feedback stabilization methods in SMC designs. The presented SMC law involves the use of RSS feedback approach based on the proper Lyapunov functions. The asymptotic stability of the closed-loop SMC system is guaranteed by two forms of Sliding Mode Surface (SMS). The first method deals with the use of Standard Sliding Function (SSF). The second one is developed with an Integral-type Sliding Function (ISF). The SMC law design resolution problem is ensured through a Linear Matrix Inequalities (LMI) technique under certain conditions. Experimental results show high performances of the proposed approach using Real Time Implementation (RTI) with Digital Signal Processing (DSP) device (DSpace DS 1104).

Model transformation based sliding mode control of discrete-time two-dimensional Fornasini–Marchesini systems

This paper investigates the problem of sliding mode control (SMC) for discrete-time two-dimensional (2-D) systems subject to external disturbances. Given a 2-D Fornasini–Marchesini (FM) local state space model, attention is focused on designing the 2-D sliding surface and sliding mode controller, which guarantees the resultant closed-loop system to be asymptotically stable. Particularly, this problem is solved using the model transformation based method. First of all, sufficient conditions are formulated for the existence of a linear sliding surface guaranteeing the asymptotic stability of the equivalent sliding mode dynamics. Based on this, a sliding mode controller is synthesized to ensure that the associated 2-D FM system satisfies the reaching condition. The efficiency of the proposed 2-D SMC law design is shown by a numerical example. This paper extends the idea of model transformation to the 2-D systems and solves the SMC problem of a more general 2-D model in FM type for the first time.

Drag-based composite super-twisting sliding mode control law design for Mars entry guidance

In this paper, the drag-based trajectory tracking guidance problem is investigated for Mars entry vehicle subject to uncertainties. A composite super twisting sliding mode control method based on finite-time disturbance observer is proposed for guidance law design. The proposed controller not only eliminates the effects of matched and mismatched disturbances due to uncertainties of atmospheric models and vehicle aerodynamics but also guarantees the continuity of control action. Numerical simulations are carried out on the basis of Mars Science Laboratory mission, where the results show that the proposed methods can improve the Mars entry guidance precision as compared with some existing guidance methods including PID and ADRC.

Robust tracking control system design for a nonlinear IPMC using neural network-based sliding mode approach

In this paper, a robust nonlinear tracking control design for an ionic polymer metal composite (IPMC) with uncertainties is proposed by using neural network-based sliding mode approach. The IPMC, also called artificial muscle, is a novel smart polymer material, and many potential applications for low mass high displacement actuators in biomedical and robotic systems have been shown. In general, the IPMC has highly nonlinear property, and there exist uncertainties caused by identifying some physical parameters and approximate calculation in dynamic model. Moreover, the control input is subject to some constraints to ensure safety and longer service life of IPMC. As a result, for a nonlinear dynamic model with uncertainties and input constraints, an IPMC artificial muscles position tracking control system based on sliding mode control approach is presented, where, the improved exponential reaching law is used to design sliding mode controller, a saturation function is used in the sliding mode control law design to suppress chattering. The robust stability can be guaranteed. Moreover, in order to improve tracking performance, a quickly and precisely robust tracking system to the stabilised system is designed and the parameters of tracking controller are optimised by using neural network. Finally, the effectiveness of the proposed method is confirmed by simulation results.

Dynamic Sliding Mode Control Design Based on an Integral Manifold for Nonlinear Uncertain Systems

An output feedback sliding mode control law design relying on an integral manifold is proposed in this work. The considered class of nonlinear systems is assumed to be affected by both matched and unmatched uncertainties. The use of the integral sliding manifold allows one to subdivide the control design procedure into two steps. First a linear control component is designed by pole placement and then a discontinuous control component is added so as to cope with the uncertainty presence. In conventional sliding mode the control variable suffers from high frequency oscillations due to the discontinuous control component. However, in the present proposal, the designed control law is applied to the actual system after passing through a chain of integrators. As a consequence, the control input actually fed into the system is continuous, which is a positive feature in terms of chattering attenuation. By applying the proposed controller, the system output is regulated to zero even in the presence of the uncertainties. In the paper, the proposed control law is theoretically analyzed and its performances are demonstrated in simulation.

Full formation control for autonomous helicopter groups

SUMMARYThis paper reports the design of sliding-mode control laws for controlling multiple small-sized autonomous helicopters in arbitrary formations. Two control schemes, which are required for defining arbitrary three-dimensional formation meshes, are discussed. In the presented leader–follower formation control schemes, each helicopter only needs to receive motion information from at most two neighboring helicopters. A nonlinear six-degree-of-freedom dynamic model has been used for each helicopter. Four control inputs, the main and the tail rotor thrusts, and the roll and pitch moments, are assumed. Parameter uncertainty in the dynamic model and wind disturbance are considered in designing the controllers. The effectiveness and robustness of these control laws in the presence of parameter uncertainty in the dynamic model and wind disturbances are demonstrated by computer simulations.