Chaos-based communication scheme using proportional and proportional-integral observers

In this paper, we propose a new chaos-based communication scheme using the observers. The novelty lies in the masking procedure that is employed to hide the confidential information using the chaotic oscillator. We use a combination of the addition and inclusion methods to mask the information. The performance of two observers, the proportional observer (P-observer) and the proportional integral observer (PI-observer) is compared that are employed as receivers for the proposed communication scheme. We show that the P-observer is not suitable scheme since it imposes unpractical constraints on the messages to be transmitted. On the other hand, we show that the PI-observer is the better solution because it allows greater flexibility in choosing the gains of the observer and does not impose any unpractical restrictions on the message

Driver torque estimation in Electric Power Steering system using an H ∞ /H 2 Proportional Integral Observer

International audienceThis paper deals with the design of a Proportional Integral (PI) observer to estimate the driver torque in an Electric Power Steering (EPS) system. The PI observer is obtained by solving a multi-objective optimization problem: it should both be barely sensitive to road disturbances and sensor noise, and converge swiftly. The performance of the proposed observer is illustrated by simulation results using experimental data

Robust Nonlinear Control Design with Proportional-Integral-Observer Technique

In this thesis, the motivation is explained in the introduction part based on a review of the development of observer technique especially the Proportional-Integral-Observer (PI-Observer) technique and an analysis of robust control for nonlinear systems. After that, the goals of the work are set as: improvement of the high gain PI-Observer design in the way that the high observer gains of PI-Observer can be automatically chosen and fit the current situation; and the application of PI-Observer in robust nonlinear control for nonlinear systems with unknown effects. To the first point, the high-gain PI-Observer design is systematically discussed and the online adjustment of the PI-Observer gains proposed as an advanced PI-Observer (API-Observer) is detailed. At the same time, the implementation of the addressed adjustment algorithm is included showing the adaption of the PI-Observer gains to the current situation of system dynamics and disturbances on a practical system with simulation results and real measurements respectively. To the other aspect, a high gain PI-Observer-based nonlinear control method is proposed as a combination of the PI-Observer and the classical exact feedback linearization method (EFL-PIO) and directly after it the applicability on mechanical systems is surveyed. Numerical examples of mechanical systems are given to illustrate the application of the EFL-PIO approach. At last, the implementation of the proposed PI-Observer-based nonlinear control method is illustrated in detail on a hydraulic cylinder system for its position control. Besides that, the position control for the cylinder system without direct position measurement is realized with the PI-Observer applied as virtual sensor. Here a discrete-time control algorithm is also designed and programmed to satisfy the normal industrial requirement. At last, a broader application of the robust EFL-PIO approach, a more efficient and compact numerical realization of the adaption algorithm for the API-Observer, and an API-Observer-based robust control or fault detection are suggested as future work

Actuator and sensor fault estimation based on a proportional-integral quasi-LPV observer with inexact scheduling parameters

© 2019. ElsevierThis paper presents a method for actuator and sensor fault estimation based on a proportional-integral observer (PIO) for a class of nonlinear system described by a polytopic quasi-linear parameter varying (qLPV) mathematical model. Contrarily to the traditional approach, which considers measurable or unmeasurable scheduling parameters, this work proposes a methodology that considers inexact scheduling parameters. This condition is present in many physical systems where the scheduling parameters can be affected by noise, offsets, calibration errors, and other factors that have a negative impact on the measurements. A H8 performance criterion is considered in the design in order to guarantee robustness against sensor noise, disturbance, and inexact scheduling parameters. Then, a set of linear matrix inequalities (LMIs) is derived by the use of a quadratic Lyapunov function. The solution of the LMI guarantees asymptotic stability of the PIO. Finally, the performance and applicability of the proposed method are illustrated through a numerical experiment in a nonlinear system.Peer ReviewedPostprint (author's final draft

Continuous-Time Switched H∞ Proportional-Integral observer: Application for sideslip and road bank angles estimation

International audience— In this work, a Continuous-Time Switched H ∞ Proportional-Integral (CTSH ∞ PI) observer is presented. The estimation method is based on a proportional-integral observer introduced by [13], [11], [12]. The estimation method is used to estimate simultaneously the state variables and unknown inputs of switched systems. A design method is established using a common Lyapunov function and H ∞ norm. Its stability and global convergence conditions are proved and expressed in term of LMIs. All conditions are established under given switching signals. The estimation method is applied in vehicle dynamics to estimate simultaneously the vehicle sideslip angle and road bank angle. Moreover, the switching signal is deduced from measured premise variables. Simulation tests with experimental data are included to demonstrate the advantage of this method

An adaptive disturbance rejection control scheme for voltage regulation in DC micro-grids

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Uncertain generation by renewable sources and load variations have resulted in adding energy storage systems in the grid to maintain grid parameters (voltage, frequency) within prescribed limits. The disturbances being non-deterministic in nature, the voltage regulation control by the storage systems relies mostly on dual loop architecture with an outer voltage and inner current loop. Improvement in controller dynamics can be achieved through feed forward of disturbance profile but at expense of additional sensors and communication in the grid. This work explores the application of an adaptive disturbance rejection control scheme for disturbance estimation (without using additional sensors) employing an extended state and proportional integral observer (PI+ESO). The proposed observer aim to achieve robust disturbance estimation under grid parameter uncertainty. The effectiveness of the proposed scheme over the conventional one will be put forward through H8 and H2 norm analysis of the system. The design and simulation results of the proposed scheme will be presented in this work.Peer ReviewedPostprint (author's final draft

Fault detection on bearings coupled to permanent magnet DC motors by using a generalized Takagi-Sugeno PI observer

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThis paper presents a fault detection system for rotative machinery. A permanent-magnet DC motor is used as case of study. The main idea is to estimate on-line the non-load torque (To) in order to monitor the bearing health condition. The fault detection system is based on the design of a generalized Takagi-Sugeno PI (proportional-integral) observer. The main advantage of this approach is that it can be easily implemented because the observer gains are obtained by solving a set of LMIs (linear matrix inequalities). Moreover, the method can be extended to more complicated nonlinear systems by using the Takagi-Sugeno approach. A simulation is performed to show that this fault detection scheme can be applied to detect abrupt faults on rotative machinery which can lead the system to undesirable performance caused by vibrations or breakdown.Accepted versio

State and disturbance estimation of a linear systems using proportional integral observer

This paper offers a short survey of linear systems Proportional-Integral-Observer design. This observer has the capacity to estimate simultaneously the states and unknown inputs which include disturbances or model uncertainties appearing on the system. The design of state and output estimation using PO and state, output and disturbance estimation using PIO is done using Matlab/Simulink successfully. The simulation is done for estimating using PO and PIO and the results proved that estimates the state variables and output correctly when there is no disturbance in the plant and there is a constant steady-state error in estimation after leading a constant disturbance into the plant for both state variables and plant output for the Proportional Observer and there is ability to estimate state variables, disturbance and system output correctly with or without the disturbance in plant for the Proportional Integral Observer