Integrator Backstepping Research Articles

Power Factor Improvement and MPPT of the Grid-Connected Solar Photovoltaic System Using Nonlinear Integral Backstepping Controller

Power Factor Improvement and MPPT of the Grid-Connected Solar Photovoltaic System Using Nonlinear Integral Backstepping Controller

Backstepping Sliding Mode Control of a Permanent Magnet Synchronous Motor Based on a Nonlinear Disturbance Observer

In this paper, a backstepping sliding mode controller based on a nonlinear disturbance observer (NDO-SMC) is proposed to realize the high-performance speed control of a permanent magnet synchronous motor (PMSM). This paper compares the advantages and disadvantages of the traditional backstepping sliding mode control algorithm (SMC) and integral backstepping sliding mode control algorithm (I-SMC) in the face of mismatched disturbances. In view of the shortcomings of these two algorithms, the idea of using a disturbance observer to observe disturbance and carry out dynamic compensation is proposed, and the composite controller is designed. The overshoot and settling time is improved by 30% and 8 s, respectively, for the proposed NDO-SMC controller compared with the SMC controller. The simulation and experimental results illustrate that the designed controller not only effectively solves the torque jitter problem of SMC, but also improves the overshoot problem caused by the integral module of I-SMC. There is also a better matching degree between the theoretical derivation, the simulation results, and experimental data. It also proves that the composite control algorithm proposed in this paper provides a meaningful solution to the operation disturbance suppression problem of the permanent magnet synchronous motor.

Command filter-based adaptive fuzzy integral backstepping control for quadrotor UAV with input saturation

This paper presents an adaptive fuzzy integral backstepping control strategy combined with command filter to solve trajectory tracking problem of quadrotor unmanned aerial vehicle (UAV). By using Fuzzy logic system to approximate uncertain disturbance. The tracking error integral term is introduced to reduce the steady-state tracking error. The backstepping approach is combined with the command filter to solve the “computational explosion” problem, and the error compensation mechanism is introduced to reduce the influence of filtering error. The hyperbolic tangent function is used to solve the problem of input saturation. By choosing the appropriate Lyapunov function to calculate the adaptive law for tuning the adjustable parameters of the fuzzy logic system. Morever, the stability of the controller is analyzed by using Lyapunov stability theory. Numerical simulation results are provided to illustrate the effectiveness and superiority of the proposed control method.

Control of a Flapping Wing Aerial Vehicle in the Presence of Matched and Mismatched Disturbances

The work presented in this paper addresses trajectory tracking and position control of a six-degrees-of-freedom flapping wing micro aerial vehicle (FWMAV) in the presence of matched and mismatched disturbances. FWMAV is an unstable system which is affected by various disturbances. These disturbances can be classified into matched and mismatched disturbances according to their entrance via the same or different channels from control inputs. In order to handle these disturbances, an integral command-filtered block backstepping controller is applied to a nonlinear high-fidelity time-variant dynamic model. The stability of the proposed controller and the ultimate boundedness of the tracking error is derived based on Lyapunov stability arguments. Finally, the control law is validated by various simulation studies on the high-fidelity model. The proposed controller performance proves its ability to successfully track the arbitrary desired reference trajectories with feasible control effort in the presence of both constant and time-varying matched and mismatched disturbances.

Dynamic characteristics and motion control of pipeline robot under deformation excitation in subsea pipeline

The in-pipe maintenance and repair technology based on the pipeline isolation plugging robot (PIPR) is the primary means for ensuring the safety of subsea pipelines. Under the excitation of pipeline deformation, the shock vibration will occur, resulting in inaccurate detection results or damage to PIPR. In this paper, the dynamic characteristics and motion control of PIPR were studied. The dynamic model of PIPR was established. And the dynamic analysis of the wheels and sealing cups passing through the convex deformation was carried out. Through dynamic simulation and experimental research, the axial vibration caused by different velocities and attitude angles passing through the convex deformation was analyzed. The results showed that the axial vibration intensified as the motion velocity increased, and the PIPR experienced the speed excursions. With the increase of the deformation height, the axial vibration was more intense, and when the attitude angle was 60°, the amplitude of axial vibration was the largest. Aiming at the change of motion state caused by convex deformation, an extended state observer (ESO) and an integral backstepping controller based on the beetle antennae search algorithm (BAS-Integral backstepping) were designed to control the motion of PIPR. It can reduce the influence of convex deformation on the motion. Through parameters optimization, the position error can be reduced by 97.7%. In order to solve the speed excursions caused by the large-scale complex deformation of the pipeline under long-term service, an Actor-Critic controller was proposed to control the velocity. It can adjust the driving torque of the PIPR through self-learning to adapt to the pipeline deformation. The effectiveness of the controller was verified by two cases. The results showed that the average velocity errors were controlled at about 3% and 5.2%, respectively. The proposed method can realize the motion control of PIPR under pipeline deformation excitation and improve the accuracy of detection results.

A predictive sliding mode control for quadrotor’s trackingtrajectory subject to wind gusts and uncertainties

<p>In this paper, a predictive sliding mode control (PSMC) strategy for the quadrotors tracking trajectory problem is proposed. This strategy aims to combine the advantages of sliding mode control (SMC) and non-linear model predictive control (NMPC) to improve the tracking control performance for quadrotors in terms of optimality, inputs/states constraints satisfaction, and strong robustness against disturbances. A comparative study of three popular controllers: the SMC, NMPC, and the integral backstepping control (IBC) is performed with different criteria. Accordingly, IBC and SMC show less computational time and strong robustness, while NMPC has minimum control effort. The discrete Dryden turbulence model is used as a benchmark model to represent the wind effect on the trajectory tracking accuracy. The effectiveness of the proposed method PSMC has been proven and compared with discrete-time slidingmode control (DSMC) and NMPC in several scenarios. Simulation results show that under both wind turbulence and time-variant uncertainties, the PSMC outperforms the other controllers by providing simultaneously disturbance rejection and guarantee that the control inputs are within bounded constraints.</p>

An integral backstepping controller design for compensated distribution networks with rapid earth fault current limiters in bushfire prone areas

AbstractThis paper presents a nonlinear integral backstepping controller (I‐BSC) design scheme for a T‐type residual current compensation (RCC) inverter used in compensated distribution networks with rapid earth fault current limiters (REFCLs). The major control task for the proposed scheme is to reduce the fault current to a value suitable for the mitigation of powerline bushfires due to single phase‐to‐ground faults in compensated distribution networks. The key distinct feature of the proposed I‐BSC over the traditional backstepping controller (T‐BSC) is that it introduces an integral action for analyzing the dynamic of the tracking error which minimizes its steady‐state value and ensures better dynamic performance. In order to prove the global asymptotic stability of the RCC inverter with the proposed integral backstepping controller (I‐BSC), the Lyapunov function‐based theory is used. Finally, the performance of the I‐BSC is analyzed on the MATLAB/Simulink environment and compared with a T‐BSC. The performance of both I‐ and T‐BSCs is assessed in terms of transient behaviors of the injected current to the neutral, fault current, and line‐to‐ground voltage of the faulty phase to ensure the standard operational criteria for self‐extinguishing powerline bushfires. Simulation results clearly demonstrate that both controllers fulfill operational standards for REFCL‐compensated networks though the I‐BSC archives better transient behaviors while comparing with the T‐BSC. Results from the processor‐in‐loop (PIL) validations are also included to further justify the applicability of the newly proposed scheme in the real‐time environment.

Design of Arbitrary Time Convergence Controller for n -th Order System

A class of arbitrary time convergence controllers based on a special time-varying scaling function provide designers with a good choice to realize prescribed time stable systems. However, these controllers have the problem of conservative control parameter range and lack a uniform formula for systems of different order. Herein, the arbitrary time convergence controller is improved, the unified formula for n -th order system is given, and a more accurate control parameter range is obtained. By constructing an ingenious auxiliary function and a novel Lyapunov function, the arbitrary time convergence of the n -th order controller is proved, and the reasonable parameter selection range is obtained using the integrator backstepping and the mathematical induction method. The effectiveness and advantages of the proposed arbitrary time convergence controllers under saturated input constraints are illustrated through numerical simulations by comparative studies in unmanned aerial vehicle (UAV) formation control.

Grid Synchronization of Equivalent Wind Farm Equipped with DFIG Model for Transient Stability by Using Nonlinear Integral Backstepping Control

Grid Synchronization of Equivalent Wind Farm Equipped with DFIG Model for Transient Stability by Using Nonlinear Integral Backstepping Control

A generalized proportional integral observer–based robust tracking design approach for quadrotor unmanned aerial vehicle

This article mainly studies the trajectory tracking control for quadrotor unmanned aerial vehicle with unknown time-varying disturbances including parametric uncertainties, model errors, and external disturbances such as wind effects. Conventional backstepping control schemes usually cannot guarantee the performance when it faces the time-varying disturbances. Improved schemes, such as integral backstepping, can only compensate the disturbances in a relatively slow way. By introducing disturbance observer technology into the design of controller, a composite generalized proportional integral observer–based robust control design method is developed. First, by utilizing the generalized proportional integral observer, the lumped time-varying disturbances of unmanned aerial vehicle are estimated. Secondly, combining the value of disturbance estimation and feedforward controller by using backstepping control technology together, a composite controller has been developed, which can be called as backstepping control + generalized proportional integral observer. The proposed control method has a better capability of disturbance rejection and is easy to implement. Simulation and experimental results illustrate the good robustness and tracking performance of the proposed scheme.

Smart Emergency EV-to-EV Portable Battery Charger

With the increase in the number of electric vehicles (EVs) and developments in their related charging infrastructures, consumers have still some concerns about some limiting factors in the EV industry such as battery life, charging station availability, electric grid capacity, limited driving range, and slow charging of batteries. Although some solutions are proposed for these limitations, they are not sufficiently efficient and cost-effective. Moreover, charging of EVs on-the-road is still a challenging issue which requires more innovation. This paper proposes a novel battery charger, known as an Emergency EV-to-EV Portable Battery Charger (EPBC), which provides a cost-effective solution for charging EVs on-the-road in emergency mode. The suggested smart charger can charge another EV based on the state of charge (SOC), capacity, and other important technical specifications of batteries in a safe and reliable manner. The smart charger can regulate the output voltage and the injected current to the EV simultaneously. To realize these features, a model free nonlinear integral backstepping control (MF-NIBC) is adopted to regulate the output voltage of the battery charger. By utilizing the actor and critic networks, a deep deterministic policy gradient (DDPG) is adopted to adjust the MF-NIBC controller. Finally, real-time tests based on the OPAL-RT setup are conducted to confirm the applicability and feasibility of the proposed EV-to-EV portable battery charger.

Modeling of Cerebral Blood Flow Autoregulation Using Mathematical Control Theory

A mathematical model of cerebral blood flow in the form of a dynamical system is studied. The cerebral blood flow autoregulation modeling problem is treated as a nonlinear control problem and the potential and applicability of the nonlinear control theory techniques are analyzed in this respect. It is shown that the cerebral hemodynamics model in question is differentially flat. Then, the integrator backstepping approach combined with barrier Lyapunov functions is applied to construct the control laws that recover the cerebral autoregulation performance of a healthy human. Simulation results confirm the good performance and flexibility of the suggested cerebral blood flow autoregulation design. The conducted research should enrich our understanding of the mathematics behind the cerebral blood flow autoregulation mechanisms and medical treatments to compensate for impaired cerebral autoregulation, e.g., in preterm infants.

An Advanced Nonlinear Controller for the LCL-Type Three-Phase Grid-Connected Solar Photovoltaic System With a DC–DC Converter

In this article, an advanced nonlinear control scheme is proposed for a three-phase grid-connected inverter and a solar photovoltaic (PV) system connected dc–dc converter. The proposed control scheme is based on a nonlinear adaptive integral backstepping approach. The robustness of the proposed control scheme is achieved through maintaining stability of the overall system, extacting maximum power from the solar PV, and controlling active power. Moreover, the injection of less harmonic components into the grid, the superior performance against different atmospheric conditions, and external disturbances enduring capability are also key features of the controller. The stability of the overall system is achieved through the negative-definite control Lyapunov functions of the proposed control scheme. An adaptive law of the proposed control scheme on external disturbances provides the undergoing capability against the external disturbances. Maximum dc power from the solar PV system is obtained using the proposed control scheme on the dc–dc converter along with the incremental conductance algorithm. The proposed control scheme embedded in the three-phase grid-connected inverter with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> -type filter provides maximum active power in the presence of external disturbances, controls reactive power, and injects less harmonic current into the grid. The simulation results under different atmospheric conditions further demonstrate the robustness of the proposed control scheme. The laboratory scale experiments validate the superiority of the proposed control scheme.

Robust nonlinear control of battery electric vehicle charger in grid to vehicle and vehicle to grid applications

The battery electric vehicle (BEV) charger provides an effective two-way interconnection between the grid and the vehicle in both grid to vehicle (G2V) and vehicle to grid (V2G) configurations. However, the control of power flow in either of the configurations is a challenging task. In this study, a supertwisting sliding mode-based controller (ST-SMC) is designed for the control of the bi-directional power converter in a BEV charger for tracking the desired current and output voltage of the charger in both G2V and V2G operations. The proposed controller reduces the chattering effect, which is a major drawback in power converters. The robust integral backstepping controller (IBS-SMC) is also designed in this paper for comparison purposes. The stability of the system is analyzed using the Lyapunov stability criterion. The proposed controllers are simulated in Matlab/Simulink environment. The proposed controller shows better dynamic performance as compared to the IBS-SMC controller. Hardware in loop (HIL)-based experimental verification has been done by using the Delfino F28369D dual core microcontroller in order to prove the effectiveness of the proposed controller.

Finite-Time Orbit Control for Spacecraft Formation with External Disturbances and Limited Data Communication

This work addresses the finite-time orbit control problem for spacecraft formation flying with external disturbances and limited data communication. A hysteretic quantizer is employed for data quantization in the controller-actuator channel to decrease the communication rate and prevent the chattering phenomenon caused by the logarithmic quantizer. Combined with the adding one power integrator method and backstepping technique, a new finite-time tracking control strategy with adaptation law is designed to ensure that the closed-loop system is practical finite-time stable, and that the tracking errors of relative position and velocity are bounded within finite-time despite with limited data communication and external disturbances. Finally, an example is shown to validate the effectiveness of the proposed finite-time tracking controller.

Steady-State and transient assessments of integral back-stepping current controllers in high-voltage direct current transmission systems

In the last five decades, proportional-integral (PI) controller remains dominant in control of high-power converters in industrial and utility power systems despite its bandwidth, hence, the performance is coupled to power circuit parameters and degrades in parts of operating range. Consequently, further mitigation measures such as fine-tuning or loop reshaping might be needed. In contrast, integral back-stepping (IBS) decouples controller bandwidth and performance from the system parameters; hence, leads to consistent performance throughout the operating range and simplifies tuning of controllers with complex structures with multiple loops. Therefore, this paper investigates the suitability of IBS for implementation of inner current controllers of the voltage source converter (VSC)-based high-voltage direct current (HVDC) transmission systems. The paper presents step-by-step synthesis of back-stepping current controller and supporting theoretical bases, and assesses its performance against the conventional PI current controller. Theoretical analysis and discussions and comparative simulations reveal that the characteristics of IBS technique enjoys unique characteristics: decouples the controller gains from the converter parameters; restricts closed loop poles to real axis; and exhibits larger closed loop bandwidth than the PI counterpart. It has been shown that the gains of IBS current controllers are explicitly specified in terms of the desired natural frequency and damping ratio, which are advantageous compared to that of the PI equivalent, in which the closed loop bandwidth are limited by converter parameters. For ease of illustration of similarities and differences, only inner current controllers of the converter stations were designed using integral back-stepping technique and compared against PI equivalents. The outer control loops such as dc link voltage, active and reactive power controllers are designed based on proportional-integral controllers. MATLAB-SIMULINK models of the point-to-point VSC-HVDC system, in which the current controllers implemented using integral back-stepping and proportional-integral controllers (active/reactive power and DC link voltage controllers) have been developed and subsequently used for performance comparison. Results of the one-to-one comparison show that the integral back-stepping current controller can match and even outperform its proportional-integral equivalent during normal and abnormal conditions, including current limitation during ac faults. Selected experiments conducted on grid connected voltage source converter that employs IBS current controller have confirm its viability.

Congestion tracking control for wireless TCP/AQM network via immersion and invariance

AbstractThis paper deals with an immersion and invariance (I&amp;I) control design for wireless Transmission Control Protocol (TCP) network to solve Active Queue Management (AQM) problems. With the help of this strategy, the developed control law can be used to cope with congestion tracking problems for a nonlinear wireless network model. Besides, the nonlinear congestion control law is proposed to assure that the queue length is able to track the desired queue length despite having sudden changes. The developed control design is validated in the MATLAB environment. The effectiveness of the developed control is verified through a simulation and compared with integral backstepping design, backstepping design, sliding mode design, and synergetic control design. The simulation results demonstrated that the presented strategy is not only able to solve the desired congestion tracking control problem but also provide improved transient performances.

Adaptive integral backstepping control of a reconfigurable quadrotor with variable parameters’ estimation

This work presents the control of a quadrotor capable of changing its configuration while flying. The designed controller should handle several arising issues since the drone geometric parameters are varying over time. This variation has a great influence on the quadrotor control, which prompts us to propose an efficient nonlinear adaptive integral backstepping controller. The control architecture includes an estimator of the inertia and other specific blocks to calculate the center of gravity and the mixing matrix. The performance of the proposed control approach has been compared with the conventional integral backstepping controller in two cases, with and without disturbances. The obtained results of the inertias and the center of gravity are also compared and confirmed with those calculated using Computer-Assisted Design–based model.

Modified backstepping control of IPMSM: Experimental tests

The purpose of this paper is to propose a new control technique for an interior permanent magnet synchronous motor that has been designed using a modified integral backstepping controller. This architecture consists of a nonlinear backstepping control scheme to achieve the purpose of speed tracking. Then the nonlinear controller based on the backstepping control scheme with the introduction of integral actions is designed for the IPMSM drive system. The suggested controller is not only designed to stabilize the interior permanent magnet synchronous motor system, but also to ensure that the speed tracking error converges asymptotically to zero in the existence of system uncertainties and external disturbances. The advantage of the suggested approach is that the proposed controller guarantees good tracking performance, reduces steady-state errors, robustness against all parameter uncertainties, and load torque disturbances in the interior permanent magnet synchronous motor system. A new speed control scheme for the design of the interior permanent magnet synchronous motor is being developed in this work. To show the feasibility of the suggested approach, the experiment is carried out with a real-time interface based on dSPACE. A comparison with the proportional-integral controller has been made. The results prove that the proposed backstepping controller has a rapid transient response and strong robustness for all disturbances under different conditions.

Distributed secondary control of islanded microgrids using modified integral backstepping technique

Distributed secondary control of islanded microgrids using modified integral backstepping technique