Infinity Control Research Articles

Speed Control of Switched Reluctance Motor using Adaptive Fuzzy Backstepping Sliding Mode Control

The Switched Reluctance Motors (SRMs), with many outstanding advantages, are gradually being widely applied in industries, households, and recommended in many works. However, most studies in the field of SRM control only concentrate on the mathematical model of the motor itself, neglecting the nonlinearity introduced by the inverter, which is responsible for switching between phases to drive the motor. This paper proposes an adaptive backstepping sliding mode control algorithm based on the SRM nonlinear model that combines both the motor and the inverter. Firstly, a backstepping sliding mode controller is used to track the desired value and ensure the stability of the system according to the Lyapunov criterion. Secondly, a fuzzy logic system is added to adjust the controller parameters to account for uncertainty and external disturbance, as well as to minimize the chattering phenomenon. Finally, a few simulation scenarios are performed to assess the effectiveness of the proposed controller. The simulation results clearly demonstrate that the proposed controller surpasses the previously published H infinity controller in terms of speed control quality for the combined nonlinear model of SRM. The proposed controller exhibits zero steady-state error, zero overshoot, and a short settling time of approximately 0.5 seconds. Moreover, the system's output quickly stabilizes when affected by disturbance noise.

Designated‐time stabilizing strategy for a class of time‐varying nonlinear systems and its application to pendulum system

AbstractIn this paper, a new scheme is proposed to stabilize a class of nonlinear systems within a designated time, mainly motivated by two unsolved problems: the singularity caused by infinity control magnitudes at the prescribed time instant and the lack of formulating/manipulating state responses after the prescribed time. Under the proposed scheme, an exquisite controller is constructed by entailing both the state scaling approach and a finite‐time stabilizing procedure. It is shown that the obtained control is well defined with bounded magnitude on the whole‐time horizon and ensures the existence of the solutions of the closed‐loop system. Superior to the existing prescribed time stabilization results, the proposed method is capable of ensuring that the states of the closed‐loop system converge to a small compact set within the designated time, stay inside it thereafter and perform finite‐time convergence eventually. Simulation examples are presented to illustrate the effectiveness of the proposed approach.

Driving safety zone model oriented motion planning framework for autonomous truck platooning

A driving-safety-zone-model-oriented motion planning framework (DSZMF) is proposed for autonomous platoons in heterogeneous driving environments with complex driving behaviors and interactions between human-driven and autonomous vehicles. As an extension of the responsibility-sensitive-safety (RSS) model, the driving safety zone model ensures that autonomous truck platoons adhere to explicit and implicit traffic rules as rational traffic participants.It consists of three zones created by safe distances and artificial potential field (APF), namely the restricted zone, the coordinated zone, and pre-cautionary zone. The Rational Traffic Participant (RTP) module is created by using a Finite State Machine (FSM) to provide an optimized platooning behavioral strategy based on the dynamic states of surrounding vehicles. Furthermore, the distributed model predictive controllers are utilized for motion planning, while the H infinity controller is developed to maintain the string stability of the autonomous platoon. The proposed DSZMF generates behavioral decisions by thoroughly considering the driving safety zone model, string stability, and multiple vehicle dynamics constraints. Finally, three critical scenarios are co-simulated for case studies, and the simulation results demonstrate that the DSZMF improves the safe time integration rate over the existing MCF by 18.9%, 11.1%, and 11.6% in three scenarios, respectively. In addition, DSZMF increases the minimum longitudinal and lateral Time to Collision (TTC) values to reduce collision risks. The case studies validate the efficacy of the proposed method for safety assurance and collaborative control of the autonomous platoon.

An improved H infinity controller using hybrid optimization for PV integrated MMC-HVDC system

An improved H infinity controller using hybrid optimization for PV integrated MMC-HVDC system

Nonlinear robust control of trajectory-following for autonomous ground electric vehicles with active front steering system

<abstract> <p>This paper presents a nonlinear robust <italic>H</italic>-infinity control strategy for improving trajectory following performance of autonomous ground electric vehicles (AGEV) with active front steering system. Since vehicle trajectory dynamics inherently influenced by various driving maneuvers and road conditions, the main objective is to deal with the trajectory following control challenges of parametric uncertainties, system nonlinearities, and external disturbance. The AGEV system dynamics and its uncertain vehicle trajectory following system are first modeled and constructed, in which parameter uncertainties related to the physical limits of tire are considered and handled, then the control-oriented vehicle trajectory following augmented system with dynamic error is developed. The resulting nonlinear robust <italic>H</italic>-infinity state-feedback controller (NHC) of vehicle trajectory-following system is finally designed by <italic>H</italic>-infinity performance index and nonlinear compensation under AGEV system requirements, and solved utilizing a set of linear matrix inequalities derived from quadratic <italic>H</italic>-infinity performance and Lyapunov stability. Simulations for double lane change and serpentine scenes are carried out to verify the effectiveness of the proposed controller with a high-fidelity, CarSim<sup>®</sup>, full-vehicle model. It is found from the results that the proposed NHC provides improved vehicle trajectory following performance compared with the linear quadratic regulator (LQR) controller and robust <italic>H</italic>-infinity state-feedback controller (RHC).</p> </abstract>

Fixed-time bounded H infinity tracking control of a single-joint manipulator system with input saturation

ABSTRACT Based on Lyapunov finite-time stability theory and backstepping strategy, we put forward a novel fixed-time bounded H infinity tracking control scheme for a single-joint manipulator system with input saturation. The main control objective is to maintain that the system output variable tracks the desired signal at fixed time. The advantages of this paper are the settling time of the tracking error converging to the origin is independent of the initial conditions, and its convergence speed is more faster. Meanwhile, bounded H infinity control is adopted to suppress the influence of external disturbances on the controlled system. At the same time, the problem of input saturation control is considered, which effectively reduces the input energy consumption. Theoretical analysis shows that the tracking error of the closed-loop system converges to a small neighbourhood of the origin within a fixed time. In the end, a simulation example is presented to demonstrate the effectiveness of the proposed scheme.

Design of μ – controller for quarter electric vehicle with actuator uncertainties

This research paper deals with the design of a robust controller for a quarter Electric Vehicle based active suspension system. When the vehicle hits the bump on the road, the active suspension system and the hydraulic actuator of the vehicle will inject the forces into the system to tune the performance. But, unfortunately, the injected force is not sufficient for fine-tuning performance. Here two control methods are proposed for controller design. Initially, H – infinity controller is designed for the nominal plant model for guarantee performance, and then an uncertain model is developed based on actuator uncertainty and designed a robust controller using μ-synthesis. The time-domain simulations using MATLAB (version 2021a) are carried out for nominal and uncertain models and results show that the μ-controller shows superior performance for balanced profile compared with passive and H – infinity controller. Finally, a quarter electric vehicle test rig is developed, experimental results are presented and discussed.

Hardy space nonlinear controller design for DC microgrid with constant power loads

The increased use of DC microgrid for critical application lead to the necessity of advanced control design for a stable operation of the system. The loads connected to DC microgrid are controlled with power electronic devices and shows the behaviour of constant power load (CPL), which poses a serious challenge to stability as it adds nonlinearity and minimises the effective damping. This paper presents a robust controller design approach based on Hardy Space (H)-infinity control norms to tackle the nonlinearity added by CPL by expanding the region for stability. The design criteria are based on Lyapunov theory of nonlinear systems within the framework of Linear Matrix Inequality (LMI). The necessary and sufficient conditions are obtained in terms of linear matrix inequalities to ensure the transient performance and stability of the system. The LMI equation is solved to maximize the size of the estimated domain of stability. The performance of the proposed controller is verified using simulation in MATLAB/Simulink. The DC microgrid in this paper consists of a solar photovoltaic (PV) unit and a battery as an energy storage system together with loads. The Proposed controller not only ensures the stability of the system but also guarantees the improved transient performance of the closed loop system by expanding the size of the stability region.

Ride Behaviour of a Four-wheel Vehicle using H Infinity Semi-active Suspension Control under Deterministic and Random Inputs

In this article the ride behaviour of four-wheel vehicle system with H infinity control semi-active suspension is investigated when subjected to sine and random inputs. The random inputs are represented with correlation and cross correlation functions in time domain and represented by PSD using Fast Fourier Transformation. The deterministic inputs are simple functions of specific wavelength and amplitude. The equations of motion are presented using Newtons method. It is investigated from the present analysis that proposed H infinity control semi-active suspension control is effective in isolation of vibrations at high speed.

H∞ Control Design for a Rigid-Flexible Spacecraft under a Fuel Slosh Influence

The spacecraft Attitude Control System (ACS) performance and robustness depend on the interactioneffects between the fuel slosh motion, the panel's flexible motion, and the spacecraft rigid motion, mainly duringtranslational and/or rotational maneuvers. In regards to satellite pointing accuracy flexibility and fuel, slosh is thetwo most important effects that should be considered in the satellite ACS design since their interactions can damage the ACS performance and robustness. Once, the lowest vibration frequencies, normally of the sloshing modeare about six times less than of the ACS bandwidth. Therefore, there is a strong possibility that this mode can destabilize the ACS pointing accuracy. This phenomenon is called spillover because the control effort spills over outside the control bandwidth. As a result, the designer needs to explore the limits between the conflicting requirements of performance, that is, increase of the bandwidth without introduction noise in the ACS keeping the systemrobustness to parameters variation. In this paper, one applies the H infinity control method which can deal withthese two design requirements (performance and robustness) considering the controller error pointing that may belimited by the minimum time necessary to suppress disturbances that affect the satellite attitude acquisition. Theequations of motions are obtained considering the Lagrange method for small flexible deformations and a mechanical model of liquid sloshing which allows modeling and investigating the longitudinal dynamic characteristics of apartially filled liquid tank during a pitch maneuver, satisfying performance and robustness requirements.

Performance Investigation of H∞ Controller for Quarter Car Semi-active Suspension System Using Simulink

This paper affords the design and improvement of a semi-active suspension system for an automobile. The main idea is to increase the semi-active suspension system damping vibration of the automobile body even as crossing the bump and sine pavement on the road. This system is modelled for 1 / 4 car system after which the entire system has been simulated using Mat lab/Simulink. It is used to physically simulate the quarter vehicle system of the automobile and have a look at the time domain response to the road disturbances. H infinity controllers is used to govern the damping properties of the semi-active suspension system mechanically. The system is designed in contrast to the most of the available suspension systems using a third order hydraulic actuator. The proposed system is compared with H2 optimal controller to test the performance of the system for the control targets suspension deflection, body acceleration and body travel for the bump and sine road disturbances. The simulation result of this studies reveal the efficiency of the advanced H∞ controller for the quarter car semi-active suspension system. Keywords : Quarter Car Semi-active Suspension System, H∞ Controller, H2 optimal Controller DOI: 10.7176/CTI/9-02 Publication date: April 30 th 2020

Comparison of Active and Semi-active Suspension Systems Using Robust Controller

Suspension system is used to fulfil the criteria of ride comfort and road handling. In this paper, a quarter car active & semi-active suspension systems are designed using Matlab/Script software. Comparison of active & semi-active suspension systems are done using robust control theory for the control targets suspension deflection, body acceleration and body travel. H infinity controller is selected to compare the two suspensions using time domain analysis. Finally the simulation result prove the effectiveness of the active suspension system by decreasing the body acceleration & sustaining the suspension deflection and body travel outputs. Index Terms--- Active suspension system, semi-active suspension system, H infinity controller DOI: 10.7176/ISDE/11-3-03 Publication date: April 30 th 2020

Performance Investigation of H∞ Controller for Quarter Car Semi-active Suspension System Using Simulink

This paper affords the design and improvement of a semi-active suspension system for an automobile. The main idea is to increase the semi-active suspension system damping vibration of the automobile body even as crossing the bump and sine pavement on the road. This system is modelled for 1 / 4 car system after which the entire system has been simulated using Mat lab/Simulink. It is used to physically simulate the quarter vehicle system of the automobile and have a look at the time domain response to the road disturbances. H infinity controllers is used to govern the damping properties of the semi-active suspension system mechanically. The system is designed in contrast to the most of the available suspension systems using a third order hydraulic actuator. The proposed system is compared with H2 optimal controller to test the performance of the system for the control targets suspension deflection, body acceleration and body travel for the bump and sine road disturbances. The simulation result of this studies reveal the efficiency of the advanced H∞ controller for the quarter car semi-active suspension system. Keywords — Quarter Car Semi-active Suspension System, H∞ Controller, H2 optimal Controller DOI: 10.7176/JIEA/10-2-02 Publication date: March 31 st 2020

Heavy-duty vehicle longitudinal automation with hydraulic retarder via H infinity control and off-policy reinforcement learning

A novel hierarchical heavy-duty vehicle (HDV) longitudinal control strategy with a hydraulic retarder is proposed in this paper to achieve the HDV down-hill longitudinal automation in the deceleration process. The upper level controller generates the optimal desired retarder torque through the H infinity control and the off-policy reinforcement learning (RL), in which the H infinity control is able to attenuate those disturbances and the off-policy RL can solve the H infinity control with completely unknown system dynamics. Then, according to the optimal desired retarder torque, the lower level controller can calculate the desired control pressure for the retarder to control the HDV. The effectiveness of this HDV longitudinal control strategy is verified by simulations based on an experimentally verified retarder model. Compared to the sliding-mode-control (SMC) based controller, the simulation result shows the proposed control strategy has better capability to attenuate the disturbances and guarantee the longitudinal speed tracking performance.

Comparison study of DLOEC and H_Infinity control strategies for transient stability enhancement of power system

This paper studies the control strategies for enhancing the transient stability of a single machine infinite bus (SMIB) power system. First, the dynamical SMIB model is established, and the excitation control is discussed. Next, the damping linear optimal excitation controller (DLOEC) and the output feedback H_infinity control strategy are studied. Then, the DLOEC and the suboptimum H_infinity controller are designed for a specific SMIB power system. The effectiveness of the two presented methods is verified by simulations. The simulation results show that the presented methods improve the transient stability of the SMIB power system and that the H_infinity controller provides better performance than the DLOEC controller.

Heavy-duty vehicle longitudinal automation with hydraulic retarder via H infinity control and off-policy reinforcement learning

Heavy-duty vehicle longitudinal automation with hydraulic retarder via H infinity control and off-policy reinforcement learning

Robust H_infinity control applied on a fixed wing unmanned aerial vehicl

Robust H_infinity control applied on a fixed wing unmanned aerial vehicl

Novelty of Frequency Domain Data in Smart Structures using ?-Analysis

This paper deals with the advantages of robust control in smart structures. First we present the implementations of H infinity control in the frequency domain. A dynamic model for smart structure under wind excitations is considered. Then robust control theory is used a model to synthesize controllers achieving stabilization with guaranteed performance for smart structures. We use ?-analysis to express the control problem as a mathematical optimization problem and then find the controller that solves the optimization problem in the frequency domain.

Novelty of Frequency Domain Data in Smart Structures using μ-Analysis

This paper deals with the advantages of robust control in smart structures. First we present the implementations of H infinity control in the frequency domain. A dynamic model for smart structure under wind excitations is considered. Then robust control theory is used a model to synthesize controllers achieving stabilization with guaranteed performance for smart structures. We use μ-analysis to express the control problem as a mathematical optimization problem and then find the controller that solves the optimization problem in the frequency domain.

PI based indirect-type iterative learning control for batch processes with time-varying uncertainties: A 2D FM model based approach

A robust PI based indirect-type iterative learning control (ILC) is proposed in this paper for industrial batch processes with time-varying uncertainties, based on a two-dimensional (2D) Fornasini-Marchesini (FM) model description of the batch process dynamics. An important merit is that the proposed ILC design is independent of the PI tuning in the closed-loop system, owing to that the ILC updating law is only implemented through tuning the set-point of the closed-loop system. By introducing a specified pole location of the closed-loop system, a robust PI controller design is firstly given with the H infinity performance index to maintain the closed-loop robust stability. Then by developing a 2D FM description of the batch operation with the designed PI controller, the control objective of minimizing the tracking error along both the time and batch directions is formulated based on the 2D robust H infinity control theory, such that a robust ILC updating law is determined by solving the linear matrix inequality (LMI) conditions established for holding the 2D system stability. Moreover, the batch-direction convergence rate can be separately tuned via the performance index in the above LMI conditions. An illustrative application to batch injection molding is given to demonstrate the effectiveness and merit of the proposed method.