Higher Order Sliding Mode Research Articles

Adaptive sensorless control for interior permanent magnet synchronious motor based on sliding mode approach

This paper proposes an adaptive sensorless control based on sliding mode approach for Interior Permanent Magnet Synchronous Motor (IPMSM) using the method of the angular position estimation error extraction. The proposed strategy combines a novel Adaptive Super-Twisting Controller (ASTWC) with a novel Adaptive Observer High-Order Sliding Mode (AOHOSM), where: (i) The control and observer gains are parameterized in terms of a single parameter simplifying its implementation and reducing the tuning time. (ii) By using an auxiliary system, which does not depend on machine parameters, an AOHOSM is designed for estimating the angular position, speed and acceleration in a wide speed range of the IPMSM, (iii) and these are used in an ASTWC to track a desired reference of speed and direct-axis current. (iv) Sufficient conditions are given to ensure the stability of the closed-loop system using a Lyapunov approach. Furthermore, the proposed strategy is validated throughout experimental set-up in order to show its effectiveness. Finally, a comparative study between the proposed strategy and other strategies published in the literature is addressed.

Research on High-order Sliding Mode Control Strategy for High Voltage Transmission Line Strip Operation Robot

When performing robotic electrical work, the mechanical arm will come into contact with wires, bolts, and gold tools. In order to prevent the robot from being shocked or vibrating excessively during this process, as well as to accurately control the screwing bolt angle issue, the robot force control issue should be taken into account. Based on the theory of higher order sliding mode control for such non-linear systems, a differential observer-based higher order sliding mode control method is proposed in this study. In order to build a type of controller based on the differential observer, the differential observer is used to observe the information of the derivative of the angular velocity and the information of the derivative order sliding variables of the higher-order sliding mode. The outcomes demonstrate the control method’s applicability to powered robots, as well as its ability to successfully suppress the jitter issue associated with conventional sliding mode control and achieve good control performance.

Super twisting approach of a higher order sliding mode controller for a flyback DC–DC converter in photovoltaic applications

SummarySolar photovoltaic (SPV) modules are frequently utilised to produce electricity. The output voltage and load power in SPV‐based applications are variable and strongly reliant on the operating conditions of solar energy, such as irradiance and ambient temperature. They offer additional challenges for the robust design of power converters, and DC–DC power converters provide the power bus with a constant voltage. Properties of a nonlinear system and load patterns necessitate a more robust control design for the power converter. This paper gives robust control of high‐order sliding mode (HOSM) control in isolated flyback converters for solar photovoltaic applications. The proposed HOSM technique is contrasted with the conventional PI control technique. The proposed HOSM control approach outperforms traditional PI control strategies under uncertainty and disturbance settings. This paper also presents a method for preventing chattering in flyback converters (FCs) using modified super twisting sliding modes.

Coordinate Control for an SMIB Power System with an SVC

To improve power quality in power systems vulnerable to current disturbances and unbalanced loads, a hybrid control scheme is proposed in the present paper. A hybrid adaptive robust control strategy is devised for an SMIB power system equipped with a static VAR compensator to ensure robust transient stability and voltage regulation (SVC). High-order sliding mode control is combined with a dynamic adaptive backstepping algorithm to form the basis of this technique. To create controllers amenable to practical implementation, this method uses a high-order SMIB-SVC model and introduces dynamic constraints, in contrast to prior approaches. Improved transient and steady-state performances of the turbine steam-valve system are the goals of the dynamic backstepping controller. A Lyapunov-based adaptation law is developed to address the ubiquitous occurrence of parametric and nonparametric uncertainty in electrical power transmission systems due to the damping coefficient, unmodeled dynamics, and external disturbance. High-order sliding mode (HOSM) control is used for generator excitation and SVC devices to construct finite-time controllers. The necessary derivatives for HOSM control are calculated using high-order numerical differentiators to prevent simulation instability and convergence issues. Simulations demonstrate that the suggested method outperforms conventionally coordinated and hybrid adaptive control schemes regarding actuation efficiency and stability.

Higher Order Sliding-Mode Observers for State-of-Charge and State-of-Health Estimation of Lithium-Ion Batteries

This paper proposes a new higher-order sliding mode-based approach to deal with the problem of online state of charge (SOC) and state of health (SOH) estimation for Lithium-ion batteries. The proposed approach is based on the conjunction of a Higher-Order Sliding Mode (HOSM) observer with two Generalized Super-Twisting (GST) observer-based identification algorithms. The HOSM observer provides an exact estimation of SOC, while the two identification algorithms guarantee the finite time estimation of the battery capacity and the battery inner resistance. Thanks to the relationship between the battery capacity and the SOH, an accurate estimation of this latter is obtained. The proposed approach has two main advantages: it ensures SOC estimation using only one observer and estimates the battery parameters without requiring any assumption on the system states. Experimental results using the Worldwide Harmonized Light Vehicles Test procedures (WLTP) are used to illustrate the high efficiency of the proposed approach.

Robust Control of UAV with Disturbances and Uncertainty Estimation

In this work, a nonlinear estimator-based robust controller is designed for the position and yaw control of a quadrotor with uncertainty estimation. This controller ensures the tracking of desired references in the presence of parameters variation and external disturbances, making use of high-order sliding mode (HOSM) estimators to estimate these perturbations that can be canceled by the control, thus improving the dynamic behavior of the controlled system. Its performance is evaluated making use of a Simcenter Amesim quadrotor based on physical models generated from experimental data in a co-simulation framework with Matlab–Simulink used to implement the designed controller with FPGA implementation. A challenging and generic maneuver with time-varying wind disturbances and uncertainty model parameters is considered.

High-Order Sliding Mode Magnetometer for Excitation Fault Detection of Elevator Traction Synchronous Motor under the Background of Industrial Engineering

In order to solve the excitation problem of elevator traction permanent magnet synchronous motors (PMSMs), a new high-order sliding mode flux observer based on a hybrid reaching rate is proposed under the background of industrial engineering to detect loss of excitation faults in real time. Firstly, a new high-order sliding mode flux observer is designed to solve the problem of the traditional sliding mode observer not being able to accurately detect the loss of excitation fault when the load resistance changes. Then, based on the sliding mode variable structure equivalent control principle, a PMSM flux estimation formula is established. The sinusoidal input function replaces the traditional symbolic process, and a mixed approach law is designed to replace the constant speed approach rate. The adaptive adjustment of the boundary layer of the sinusoidal input function is realized through a fuzzy control system, which effectively suppresses the chattering problem caused by the sliding mode variable structure and improves the observation accuracy of rotor position. The stability of the system is verified by Lyapunov’s second method. MATLAB/Simulink is used to build the simulation model of the PMSM control system with the new sliding mode observer, and the simulation results are compared with those of a traditional sliding mode observer. The results show that compared with the conventional observer, the new sliding mode observer can track the rotor position quickly, and the system has better anti-interference abilities and stability. Finally, the feasibility and effectiveness of this method are verified via simulations and experiments.

A survey on High-Order Sliding-Mode control design using Lyapunov functions

A survey of (some) recent Lyapunov-based methods to analyze and design High-Order Sliding-Mode (HOSM) controllers and observers is presented. This overview includes also some novel algorithms, taking advantage of a discontinuous integral action, to attain a High-Order Sliding-Mode using a continuous control signal. This account starts presenting the design based on Lyapunov functions of classical sliding-mode controllers using a discontinuous state feedback control law to impose a high-order sliding-mode of arbitrary order. In order to estimate in finite-time the required derivatives of the measured signals for the implementation of the controllers, a Lyapunov-based design of the well-known robust and exact differentiator is shown. As a mechanism to reduce the effect of the undesirable chattering effect a recent method for higher-order sliding-mode controllers has been developed, using a continuous state feedback in conjunction with a discontinuous integral action to enforce a sliding-mode by means of a continuous control signal. The analysis and design tool for this integral controller is also an explicit, strict and particularly tailored Lyapunov function. In order to make this recount accessible to a wide audience the presentation is restricted to the main results, without giving proofs or design details, and leaving aside the rigorous mathematical machinery. For this the main references are provided.

Finite-Time Containment Control for Nonlinear Multi-Agent Systems Based on High Order Sliding Mode

Several finite-time containment control issues under stationary and dynamic leadership are the main emphasis of this thesis, which is concerned with a typical class of second-order nonlinear multi-agent systems susceptible to outside intervention. According to a given network topology, the second-order super-twisting sliding mode control is a technique for distributed control that has been developed. In this paper, we mainly consider the situation that the leader moves at a uniform speed. With the proposed method, the followers update status in real time via communication with each other such that all of them are able to eventually converge to the convex hulls consisting of stationary leaders and dynamic leaders in finite time. It leads to make the followers remain stationary or keep moving within the designed region. Eventually, according to the matrix theory and finite-time stability theorem, the paper proves the stability of the finite-time on the proposed control protocol and validates its effectiveness and correctness through simulation.

Disturbance Observer-based Higher-order Sliding Mode Controller for Frequency Regulation of Hybrid Power Systems

Disturbance Observer-based Higher-order Sliding Mode Controller for Frequency Regulation of Hybrid Power Systems

Improved Position Sensorless Piston Stroke Control Method for Linear Oscillatory Machine via an Hybrid Terminal Sliding-Mode Observer

Since the piston stroke of linear oscillation machine (LOM) is very important for the safe and reliable operation of the system, it is necessary to effectively control the piston stroke. Besides, considering that the use of position sensor will reduce the system reliability, so the accurate position sensorless method is needed to obtain the stroke signals. In this article, a hybrid terminal sliding-mode observer is designed by combing a second-order nonsingular terminal sliding mode (SNTSM) and a high-order sliding-mode (HOSM) to estimate the back-electromotive force signals of the LOM. The SNTSM surface is selected to ensure that the system state variables can converge in a finite time and the HOSM control law is designed by introducing a variable exponential reaching law, which can strengthen the stability of the observer and greatly reduce the sliding chattering. Since the piston stroke is calculated by integrating the estimated piston velocity, the pure integral saturation will occur due to the presence of dc components in the measured current and voltage. In order to cope with this problem, one self-adaptive band-pass filter is introduced to replace the pure integrator, which can obtain smooth stroke signals with almost no amplitude and phase offset. Moreover, the current amplitude controller is designed to improve the control accuracy and response speed. Finally, comprehensive simulation and experimental results are provided to verify the effectiveness and the superiority of the proposed method.

High-Order Sliding Mode Control for Three-Joint Rigid Manipulators Based on an Improved Particle Swarm Optimization Neural Network

This paper presents a control method for the problem of trajectory jitter and poor tracking performance of the end of a three-joint rigid manipulator. The control is based on a high-order particle swarm optimization algorithm with an improved sliding mode control neural network. Although the sliding mode variable structure control has a certain degree of robustness, because of its own switching characteristics, chattering can occur in the later stage of the trajectory tracking of the manipulator end. Hence, on the basis of the high-order sliding mode control, the homogeneous continuous control law and super-twisting adaptive algorithm were added to further improve the robustness of the system. The radial basis function neural network was used to compensate the errors in the modeling process, and an adaptive law was designed to update the weights of the middle layer of the neural network. Furthermore, an improved particle swarm optimization algorithm was established and applied to optimize the parameters of the neural network, which improved the trajectory tracking of the manipulator end. Finally, MATLAB simulation results indicated the validity and superiority of the proposed control method compared with other sliding mode control algorithms.

Research on Automotive Bidirectional CLLC Resonant Converters Based on High-Order Sliding Mode Control

A CLLC resonant converter’s gain is easily influenced by the operating frequency, and when the operating frequency is adjusted over a wide range, the efficiency of the converter is greatly reduced. Traditional closed-loop control strategies also have disadvantages such as slow dynamic response and vulnerability to load. In this paper, a high-order sliding mode control (SMC) design method is proposed based on the current problems and the characteristics of automotive CLLC resonant converters. A sliding mode surface based on the output voltage characteristics of the CLLC converter includes higher-order differential terms for voltage and current and an error integral term for the output voltage, which reduces the operating frequency range of the converter and improves its dynamic responsiveness, thus increasing its efficiency. In order to verify the accuracy of the algorithm, a simulation model is built in MATLAB to verify the stability of the controller by varying the input voltage and the magnitude of the load and to verify the dynamics by abruptly varying parameters such as load and voltage. Comparing high-order SMC with PID control also shows that high-order SMC is more suitable for automotive converters.

Global Finite-Time Controller Design for HOSM Dynamics Subject to Upper-Triangular Structure

In this paper, a novel saturation-based control method is proposed for high-order sliding mode (HOSM) dynamics with upper-triangular nonlinearities. Firstly, a new HOSM dynamics with upper-triangular nonlinearities is constructed based on the traditional HOSM dynamics, so as to reduce the uncertainties in the control input channel. Then, a HOSM controller is established by means of the adding a power integrator method such that the new HOSM dynamics is locally stabilized. Finally, the saturation-based controller is constructed by a combination of the saturation technique and the local HOSM controller to guarantee that the sliding variables can converge into a domain of attraction in a finite time and retain inside it thereafter. The rigorous stability analysis is made by the Lyapunov theory. A simulation example is also given to demonstrate the effectiveness of the proposed method.

Fault-tolerant control with high-order sliding mode for manipulator robot

<p>The safety of manipulators systems is receiving a lot of attention these days. Faults have the ability to carry out harmful activities that harm equipment, the environment, or persons. As a result, it is critical to detect and diagnose problems as soon as possible, as well as to incorporate fault tolerance to avoid performance deterioration and harmful circumstances. Robust sensor fault detection and isolation (FDI) as well as fault-tolerant control (FTC) for a robotic system are discussed in this work. The goal of this research is to create an FDI method that uses a super-twisting third-order sliding mode (STW-TOSM) observer to estimate residual signals. A suggested system based on a higher-order sliding mode (HOSM) observer/controller approaches is used to accomplish this. In comparison to an active FTC technique, the test results demonstrate high level of performance. Finally, simulation results illustrate the efficacy of the presented techniques.</p>

Continuous Higher-Order Sliding Mode Control for a Class of n-th Order Perturbed Systems

In this brief, a general continuous higher-order sliding mode (HOSM) control algorithm is proposed for a class of <inline-formula> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula>-order systems with Lipschitz disturbance, which can be regarded as a generalization of the continuous super-twisting algorithm for arbitrary relative degree with respect to the output. The proposed control algorithm only requires the information of the output and its derivatives up to the order <inline-formula> <tex-math notation="LaTeX">$n-1$ </tex-math></inline-formula>, and can compensate the Lipschitz disturbance exactly by using a discontinuous integral term, generating a continuous homogeneous control signal and achieving finite-time convergence to a sliding mode of order <inline-formula> <tex-math notation="LaTeX">$n+1$ </tex-math></inline-formula>. The convergence of the closed-loop system is proved rigorously by employing an explicit and directly constructed homogeneous Lyapunov function. The simulation results validate the effectiveness of the proposed method by comparing with the existing results.

Angular position estimation error extraction for speed and angular position estimation of IPMSM using a parameter-free adaptive observer

In this paper, an alternative approach for extracting the angular position estimation error for an Interior Permanent Magnet Synchronous Machine (IPMSM) is introduced.The originality of this work consists on obtaining the angular position estimation error by the measurable currents, in the αβ stationary reference frame, without considering the high frequency signal injection. Then, using the obtained angular position estimation error, an Adaptive High Order Sliding Mode Observer (AHOSMO) is proposed for estimating the position, speed and acceleration of the IPMSM. The observer is used for a parameter-free virtual dynamical system to avoid impact of the parameter variations on the estimation. The convergence analysis of the proposed observer is established using a Lyapunov stability theory. Furthermore, simulation and experimental results are presented to illustrate the efficiency of the proposed approach against disturbances and noises. The proposed approach is compared with high frequency (HF) and back electromotive force (BEMF) approaches.

Higher-Order Sliding Mode design with Bounded Integral Control generation

In this paper uncertain continuous-time nonlinear systems affine in the control variable and with saturated actuators are considered. The finite-time regulation problem of the system output to zero is then solved by proposing a generic Higher-Order Sliding Mode (HOSM) controller equipped with a novel mechanism to encounter the saturation limits, thus extending previous results on saturated control inputs valid only in case of specific r-order sliding mode algorithms. The so-called Bounded Integral Control (BIC) method is reformulated into the framework of continuous HOSM, so as to replace the traditional integrator used to generate the continuous signal directly fed into the plant. Stability conditions for tuning the proposed algorithm are provided, and a numerical example finally assesses the effectiveness of the proposed technique.

A Decentralized Higher Order Sliding Mode Control for Islanded Photovoltaic-Storage Systems

Sustainable energy transition, air pollution reduction and climate change mitigation are the most challenging themes in nowadays energy sector. Microgrids (MGs) are one of the most effective ways to integrate Renewable Energy Sources (RES), and among them PhotoVoltaic (PV)-Storage (ST) configuration is relevantly promising. Focusing the attention on the PV and ST converters primary control, the main needs are to properly regulate voltage and frequency and optimally exploit the energy coming from the sun and manage the ST operation without any communication among the converter controllers. The conventional converter control approach presents several drawbacks and thus a strategy based on Higher Order Sliding Mode (HOSM) is presented in this work. The HOSM converter control strategy is fully analysed defining its control laws and the control schemes. A comparison between the HOSM and conventional control is performed with dedicated simulations on a common benchmark MG in order to highlight the advantages of the proposed strategy.

Adaptive high-order sliding mode control for proton exchange membrane fuel cell air-feed system based on high-gain observer

The proficient control algorithms for the air-feed system of proton exchange membrane fuel cell can significantly improve the output net power and prevent the polymeric membranes deterioration. To this end, a novel adaptive high-order sliding mode (HOSM) control method for air feed system is proposed in this paper. There are several meaningful contributions. Firstly, in order to reduce the number of redundant sensors and overall cost, the high-gain observer is implemented to estimate unmeasured tracking error derivatives. Secondly, without the priori knowledge of accurate dynamic model and parameters, the proposed adaptive HOSM controller ensures a real sliding mode established in finite time and a continuous control input signal to the motor. Thirdly, based on the estimated tracking error derivatives, the developed adaptive schemes guarantee the control gain would not be overestimated without the information about the bounds of the uncertainties/perturbations, which significantly suppresses the formidable chattering caused by high frequency switching of the control signal. Finally, the robustness and effectiveness of the adaptive HOSM controller are indicated by numerical simulations and hardware-in-loop experiments.