Sliding Mode Observer

Recently, speed sensorless control of induction motor drives received great attention to avoid the different problems associated with direct speed sensors. However, low speed operation with robustness against parameter variations remains an area of research for sensorless systems. Stator resistance is of greatest importance for good operation of speed sensorless systems in low speed region. In this paper, a sliding mode current observer for an induction motor is presented. An estimation algorithm based on this observer in conjunction with Popov's hyper-stability theory is proposed to calculate the speed and stator resistance independently. The proposed speed observer with parallel stator resistance identification is firstly verified by simulation. Experimental results are included as well to demonstrate the good performance of the proposed observer and estimation algorithms at very low speed.

The disturbance cancellation has always been an important area that has received much attention, especially for the nonlinear drive systems as the dual start induction motor (DSIM). In this paper, a new robust adaptive hybrid strategy based on an improved variable-gain quasi-continuous thirdorder sliding mode (VGQSTOSM) algorithm integrated with RC and a load torque disturbance estimator helps to reduce chattering, cancel the periodic and extended load disturbances, and enhance tracking performance effectively. By using third-order sliding mode with variable gain dependent on the magnitude of the sliding variable, this proposal aims to be adaptive. It provides higher gain when far from the sliding surface (is large), leading to faster convergence and lower gain when close to the sliding surface (is small), potentially reducing chattering further and decreasing control effort near the equilibrium. The robustness of the proposed controller is improved because the adaptive gain mechanism effectively compensates for uncertainties or disturbances. Furthermore, a plug-in RC is integrated into the improved high-order sliding mode structure (DRVGQSTOSM), and an estimated load torque disturbance value is also used to help identify and proactively eliminate disturbances. The system stability is assured using Lyapunov theory the virtual control vectors' outputs are chosen based on Lyapunov theory. Simulation results obtained using the MATLAB software confirm the tracking and harmonic disturbance rejection performance as well as the robustness of the proposed control strategy.

A novel robust feedback linearization scheme is proposed in this paper based on a modified robust exact differentiator. The states and drift terms in the system are estimated simultaneously by the observer using back injection of the control effort. The estimated drift term is used in the feedback loop to compensate the disturbances and observed states are used for feedback linearization. Finite time convergence of the complete closed-loop system is proved and thus a form of separation principle is satisfied, i.e., the controller and observer can be separately designed. The design is verified through simulations and by experiments on a DC motor rig.

This paper uses second-order sliding mode observers to build up an estimation scheme allowing to identify the tyre longitudinal equivalent stiffness and the effective wheel radius using the existing ABS angular sensors. This estimation strategy, based on use of the proposed observer could be used with data acquired experimentally to identify the longitudinal stiffness and effective radius of vehicle tyres. The actual results show effectiveness and robustness of the proposed method.

This paper is concerned with fault estimation in a class of nonlinear fractional order systems using a new super twisting algorithm based second order step by step sliding mode observer. Since the existing sliding mode observers are troubled with the chattering phenomenon, here a new observer structure is proposed and finite time convergence of error dynamics is proved using fractional order super twisting algorithm (FSTA). Two numerical examples of chaotic fractional order systems and a comparison with respect to a similar observer justify the effectiveness of the proposed observer

In this paper we propose a gain matrix selection procedure for a class of full order unknown input observers (UIO). These kinds of observers employ sliding-mode principles to force the observation error into the sliding surface. Then, the error starts a sliding motion along the surface until it asymptotically converges to zero. Although this method exhibits good performance, there is not any explicit and direct method to compute the observer gains. In our approach, we consider the problem of finding the observer gains in the terms of linear matrix inequalities (LMIs). The simulation results for an industrial drum type boiler demonstrate the effectiveness of the proposed approach.

In this paper we propose a gain matrix selection procedure for a class of full order unknown input observers (UIO). These kinds of observers employ slidingmode principles to force the observation error into the sliding surface. Then, the error starts a sliding motion along the surface until it asymptotically converges to zero. Although this method exhibits good performance, there is not any explicit and direct method to compute the observer gains. In our approach, we consider the problem of finding the observer gains in the terms of linear matrix inequalities (LMIs). The simulation results for an industrial drum type boiler demonstrate the effectiveness of the proposed approach.

This paper proposed an estimation approach of temperature rise in stator winding and rotor magnet of a surfaced-mounted permanent magnet (PM) AC motor. By using the 3rd-order extended Kalman filter (EKF) algorithm in rotating reference frame, stator winding resistance and rotor PM flux-linkage can be estimated independently. After comparing the estimation results of resistance and flux-linkage to the rated values measured at 20 respectively, the corresponding temperature rise in stator winding and rotor magnet ℃ can be calculated according to some certain rules. The proposed method was confirmed to be correct and effective by the simulation results from MATLAB/SIMULINK.

A diagnosis strategy based on fuzzy reasoning is presented in this paper. The first stage of the suggested approach consists in generating residuals revealing of the process functioning state. Two methods of residuals generation for linear-dynamic systems, based on the exploitation of analytical redundancy, are proposed. Then, a procedure of fault isolation using these residuals and based on fuzzy concepts is explained and implemented. To illustrate and show the validity of this approach, it's applied to experimental signals collected on a urban water supply network.

This paper deals with the robust fuzzy observer design problem for a class of uncertain nonlinear system represented by Takagi-Sugeno model. Stability conditions of such observers are expressed in terms of linear matrix inequalities (LMI). An example of simulation is given to illustrate the proposed method.

A well known method for residual or redundancy generation is extended to systems with unknown inputs. It is based on the singular form of the system equations which allows the generation of the substate of the system which is insensitive to the unknown inputs. This generation is achieved by a two-steps algorithm including, first, the elimination of the unknown inputs and second, the generation of the redundancy equations. Using these results for fault detection and isolation, we present a simulated example to illustrate our ...

Rollover of trucks is a major problem. In The Netherlands, it occurs about twice a week, and the number is increasing. A factor contributing to this might be the maximised speed of commercial vehicles, not stimulating the driver to reduce this speed in potentially critically conditions. Several causes can be identified, one of them is excessive yaw behaviour of truck or trailer posing major difficulties for the driver, and likely to occur at lateral accelerations far below the static tilting boundary. This paper first treats yaw-stability for a single heavy vehicle in a fundamental way. The analysis is based on the full non-linear vehicle behaviour where critical (stationary) points are discussed within a phase plane representation. Local behaviour of trajectories around these points are analysed yielding the type of (in-)stability, for all possible combinations of effective tyre behaviour (incorporating suspension characteristics). These effects are also presented in terms of the h...

A novel adaptive observer is proposed to perform on-line estimation of both state and parameters of the electrical part of induction motors. The rotor mechanical speed and the stator currents/voltages are assumed to be measured. A particular non-minimal state representation of the machine electrical model is derived and exploited to build the adaptive observer, based on a series-parallel architecture. Lyapunov design is used to develop the adaptation law of the proposed solution. Both simulation results and experimental tests confirm the good performances of the technique.

The adaptive sliding-mode observer has been widely used to estimate the rotor flux and rotor speed in inverter-fed sensorless induction motor drives. However, the technique requires setting a priori the sliding-mode observer constants and also knowledge of the induction motor parameters. This particular aspect can cause significant errors in the estimation of the rotor speed used in sensorless control schemes. Changes in the induction machine parameters due to temperature or different saturation levels will affect the dynamic operation of the observer despite its adaptive nature. In this context, a sensitivity study of the adaptive sliding-mode observer is presented and discussed in this paper. Various experiments are performed on a sensorless indirect vector-controlled induction motor drive under a variety of conditions to verify the observer robustness.

This paper presents an approach to the fault diagnosis and disturbance observation for the hydraulic vertical three-tank system. An observer is designed which contains a corrective term based on a second-order sliding mode control algorithm featuring global convergence properties. Thanks to the proposed global observer, the reconstruction of certain faults and/or disturbances can be performed directly from the continuous observer output injection signal, without requiring any filtration. The effectiveness of the proposed method is shown by means of a simulation example and is then validated by performing real experiments.

This work addresses the state observation problem for a class of switched linear systems with unknown inputs. The proposed high-order sliding-mode observer provides a finitetime converging estimate of the continuous system's state vector in spite of the presence of unknown inputs. The design procedure, which assumes knowledge of the discrete state of the switched system, is based on the principles of disturbance decoupling and hierarchical observer output injection. In order to cope with the switching nature of the plant under observation, jumps in the observer state space are enforced intentionally. The implementation of an additional observer allows for the reconstruction of the unknown inputs, which may be important in the framework of fault detection. Numerical examples illustrate the effectiveness of the suggested technique.

Wind turbine pitch systems are essential for actuating desired blade angles and hence to keep the generator at rated speed in operation region 3. In the presence of parametric pitch actuator faults, pitch systems may have slow dynamics, affecting the pitching performance with the possibility of oscillation on the generator speed and making the turbine system unstable and unsafe. This work proposes a strategy for compensating the pitch actuator faults to recover the nominal pitch dynamics. The proposed fault-tolerant control (FTC) scheme incorporates a traditional Proportional-Integral (PI) controller as baseline system to achieve nominal pitch performance, along with a fault compensator to eliminate the actuator fault effects. The approach is based on estimation of the pitch system states and fault indicator function using an adaptive step-by-step sliding mode observer, effectively handling the nonlinear fault distribution function with a simple design. The effectiveness of the design strategy is verified using a 4.8 MW benchmark wind turbine system.

This paper presents a comparison study of performances and characteristics of three advanced state observers, including the high-gain observers, the sliding-mode observers and the extended state observers. These observers were originally proposed to address the dependence of the classical observers, such as the Kalman Filter and the Luenberger Observer, on the accurate mathematical representation of the plant. The results show that, over all, the extended state observer is much superior in dealing with dynamic uncertainties, disturbances and sensor noise. Several novel nonlinear gain functions are proposed to address the difficulty in dealing with unknown initial conditions. Simulation and experimental results are provided.

This contribution describes several ways of realising application dependent safety measures for the motor angle sensor of the active front steering system. Observer based methods, based on mathematical models of the motor under investigation are derived, realised and tested in a prototype vehicle. A comparison is carried out with respect to accuracy, tracking and computational load.

The aim of this study is to improve road safety by analyzing road influence on vehicle stability. Nowadays, vehicle stability is enhanced by electronic systems. It can be expected that, in a near future, stability systems will rely on complete vehicle dynamics models. This means measuring, on each axle, the forces and deformations of -especially-tires and suspensions. In that perspective, the contact forces can be obtained by using dynamometrical wheels or load bearing sensors (SKF-TNO), which are likely to become available at a sufficiently low cost. For the deformation concern, we can think of lots of possibilities to gauge the suspension parts, but, at the present time, the tire vertical deformation remains difficult to acquire. Although different techniques exist to determine the tire crushing, the most popular consists in measuring the distance between a laser sensor fitted on a wheel and the corresponding local road surface. Nevertheless, this kind of sensor is expensive, difficult to adapt on standard cars and its measurements are highly influenced by the road texture state (water depth, markings ...). The whole new idea is that, assuming the availability of bearing load sensors on a vehicle for force measurement, tire height could be evaluated without any additional equipment by measuring torques and forces applicated to this wheel. So, we propose to evaluate the effectiveness of equivalence between the tensor components and optical crushing measurements. Experiments have been worked out at various speeds and curves. These experiments tend to show that the longitudinal torque and lateral force at the wheel center can be used to determine the wheel radius in the maximum loaded phases. Dynamometrical measurements present the possibility to be used under extreme weather conditions, for particular road texture contrary to optic techniques and at an expected affordable cost in a near future. More deepened studies will be launched to estimate the influence of tire structure, road curvature, evenness and texture on the proposed methodology.

This paper presents a sensorless direct torque control (DTC) combined with sliding mode approach (SM) and space vector modulation (SVM) to achieve mainly a high performance and reduce torque and flux ripples of a parallel-connected two five-phase permanent magnet synchronous machine (PMSM) drive system. In order to increase the proposed drive robustness and decrease its complexity and cost, the rotor speeds, rotor positions, fluxes as well as torques are estimated by using a sliding mode observer (SMO) scheme. The effectiveness of the proposed sliding mode observer in conjunction with the sliding mode control based DTC is confirmed through the application of different load torques for wide speed range operation. Comparison between sliding mode control and proportional integral (PI) control based DTC of the proposed two-motor drive is provided. The obtained speeds, torques and fluxes responses follow their references; even in low and reverse speed operations, load torques changes, and machines parameters variations. Simulation results confirm also that, the ripples of the torques and fluxes are reduced more than 3.33% and 16.66 %, respectively, and the speed overshoots and speed drops are reduced about 99.85% and 92.24%, respectively.

Recent advancements in automated manufacturing and processing industries necessitate fast-responding, efficient, and robust methods for controlling induction motor (IM) drives. Classical proportional-integral (PI) controllers provide optimal performance only at specific operating points and are sensitive to parameter variations. This work proposes an adaptive quasisliding mode controller (AQSMC), which utilizes a tangent (tanh) function as the switching function and demonstrates enhanced robustness and adaptability across a wider range of operating conditions. The AQSMC employs an adaptation law to estimate the dynamic disturbances, offering insensitivity to structured and unstructured uncertainties. Numerical simulations are carried out with the AQSMC that analytically deduces the optimum field flux ensuring efficient performance. A lookup table derived from the efficiency optimization algorithm (EOA) is incorporated to further streamline the computational requirements. To validate simulation results, a prototype was developed using a 1 HP induction motor, a DSP controller board with a TI C2000 Delfino MCU F28379D microcontroller, and an IGBT-based Inverter module. Simulations show a 6.3% efficiency improvement at half load and 300 rpm, while experimental analysis records a 3.9% improvement with the EOA, highlighting the potential for enhancing energy efficiency in various industrial applications.

On this paper, a robust velocity controller applied to a three-phase squirrel-cage induction motor under variable load conditions is designed. The induction motor drives an induction generator representing the load which freely delivers the generated power to the utility grid. The closed-loop scheme is designed at αβ coordinate frame and is based on the linearization block control technique in combination with the super-twisting algorithm. The controlled output variables are the angular mechanical velocity and the square modulus of rotor flux linkages. The motor reference velocity is set up by a pulse train above the synchronous velocity and, consequently, the impelled induction machine operates in generator mode; meanwhile, the reference of rotor flux square modulus varies according to load condition of the induction motor. In order to estimate the non-measurable variables, both a rotor flux linkages observer and a load torque observer are designed. For the first one, a non-linear state observer using first order sliding modes is applied at αβ coordinate frame and, for the second one, a Luenberger reduced asymptotic observer is used. The validation of the robustness for the proposed velocity controller is performed in a real-time experiment using a work-bench. INDEX TERMS Block control, induction motor, sliding mode observer, super-twisting.

International audienceThis paper presents a new and original Mono inverter Multi parallel Permanent Magnet Synchronous Motor (PMSM) system. To obtain the stability of such a system, each of the motor synchronisms should always be respected regardless of their load torque. In this case, only one motor, called "master motor", will be self-piloted. If the chosen master motor is the one with the highest applied load torque, synchronism is respected for each of the motors. To find this machine, a solution which compares the rotor positions is thus developed. Experimental results are given for a system with 2 PMSM plugged in parallel. The proposed solution can however be applied to systems whatever the motor numbers, therefore additional simulations are provided for a 4 PMSM system

Wind turbine pitch systems are essential for actuating desired blade angles and hence to keep the generator at rated speed in operation region 3. In the presence of parametric pitch actuator faults, pitch systems may have slow dynamics, affecting the pitching performance with the possibility of oscillation on the generator speed and making the turbine system unstable and unsafe. This work proposes a strategy for compensating the pitch actuator faults to recover the nominal pitch dynamics. The proposed fault-tolerant control (FTC) scheme incorporates a traditional Proportional-Integral (PI) controller as baseline system to achieve nominal pitch performance, along with a fault compensator to eliminate the actuator fault effects. The approach is based on estimation of the pitch system states and fault indicator function using an adaptive step-by-step sliding mode observer, effectively handling the nonlinear fault distribution function with a simple design. The effectiveness of the design strategy is verified using a 4.8 MW benchmark wind turbine system.

The increasing wide popularity of Electro-Adhension actuation through Dielectric Elastomer is credited to their suitability in several bio-inspired applications such as flexible prosthetics, humanoid grasps, bio-mimicking robots etc. Virtually all DEAs suffer from precise positioning challenges due to their inherent strong nonlinear dynamics, namely: creep and hysteresis. As a consequence, there is a necessity to establish control-enabling DEA models and accompanying control strategies that eliminate these undesirable dynamics and allow for precise reference tracking. In this paper, an experimentally validated DEA model is employed to design a simple yet well-performing control strategy based on the Sliding Mode Control (SMC) philosophy. To further enhance the control performance and improve implementability, a technique to eliminate the inherent control input chattering present in typical SMC designs is also described. Extensive closed-loop simulations are performed, and tracking performances are quantified to justify the designed superiority of the control scheme performance.

This paper presents an analytical and experimental evaluation of the sliding-mode observer (SMO) for eliminating position and speed sensors in switched reluctance motor (SRM) drives. Design guidelines are derived for the SMO to guarantee an upper bound on the observer error for all time. An analysis is presented to demonstrate that the SMO also possesses an automatic adaptation property with respect to the intensity of the measurement noise. The SMO approach is shown, in simulations and in experiments, to provide accurate position and speed estimates under various operating conditions. The resolution and reliability of the scheme are shown to be superior to those obtained using standard state observers. The results demonstrate the applicability of the SMO-based sensorless controllers for SRM drives.

In this paper we present a design method of Sliding Mode Observer (SMO) applied to reconstruct both actuator and sensor faults for a class of output time-delay systems. To guarantee the quadratically stability of the estimation error dynamics, sufficient conditions are developed with the LyapunovKrasovskii approach arising a set of Linear Matrix Inequality (LMI) optimization. Applying the equivalent output error injection, the reconstruction of actuator and sensor faults are obtained. To show the efficacy of the SMO design and faults reconstruction methods, a numerical example is proposed. keywordsSliding mode observer; actuator fault reconstruction; sensor fault reconstruction; time-delay system; LMI technique

This paper addresses fault detection and isolation (FDI) problem using a sliding mode fuzzy observer on the basis of a uncertain Takagi-Sugeno (T-S) fuzzy model. First, a robust fuzzy observer with respect to the uncertainties is designed. The convergence of the fuzzy observer is performed by the search of suitable Lyapunov matrices. It is shown how to synthesis observers using a set of linear matrix inequalities (LMI) conditions. Once the fuzzy observer is designed, FDI problem for nonlinear systems described by T-S fuzzy systems using the fuzzy observer is presented. A bank of fuzzy observer is then designed in order to investigate fault diagnosis problems. The validity of the proposed methodology is illustrated on a dynamic vehicle model.

This paper presents a new adaptive fuzzy backstepping control (AFBC) scheme for doubly-fed induction machine (DFIM). This proposed controller guarantees speed tracking and reactive power regulation at stator side. The DFIM stator windings are directly connected to the line grid, while the rotor ones are controlled by means of an inverter. Using a state-all-flux model, the stator voltage vector oriented reference frame is adopted. The control design principle is particularly based on the decomposition of the motor model in two coupled subsystems, namely: the stator flux subsystem and the speed-rotor flux subsystem. The stator flux subsystem is stabilized independently of the speed behaviour. The DFIM unity power factor control and speed tracking problem is transferred to the rotor flux control problem. The unknown load torque is estimated on-line by a suitable adaptive law, the nonlinear functions appearing in the tracking errors dynamics and uncertainties are reasonably approximated...

The stability of a semi-trailer articulated vehicle is an important research area for automotive engineers. This is in order to enhance good road and passengers' safety. While large weight on this vehicle affects traffic safety, stability and safety of the vehicle [1]. According to the data from the Global Road Safety Partnership, about 1.3 million people are killed while about 40 to 50 million people are injured every year in road accidents [2, 3]. While According to Nigerian Federal Road Safety of Corps (FRSC) road Crash data, 624 and 308 people were involved in trailers and road tanker accident with the total of 3359 causalities in the past three years, and the country has recorded several cases of road traffic crashes involving semi articulated trailers and tankers [4]. Unlike passenger's car crashes, trailer-related crashes always have greater exposure, due to the high fatality and injury rates, as well as excess property damage and traffic congestion [5]. 2. Semi-trailer articulated vehicle A fundamental understanding of the stability concept of this vehicle is highly required so as to ensure safety of goods and passengers. The semi-trailer articulated vehicle has a maximum of 16.5m admissible length, while the vehicle combination has a maximum of 18.75m length [6]. This can lead to dynamic stability problem on a steep road because of its weight; and length, thereby by reducing the visibility of driver which may lead to road crashes [3]. Figure 1 and 2, shows the schematic view of a semi-trailer articulated vehicle. The dynamics of this vehicle are significantly different from those vehicles with single chassis. Some characteristics of the semi articulated vehicle are stated below [7]. i. The vehicle has small stability region in yaw and roll modes at high speed ii. It is prone to Jackknifing and trailer swing conditions iii. It is subjected to lateral trailer oscillation and self-excited iv. It has phase lag between vehicle and trailer motions

Three-phase induction motors admit a complex-valued space state representation. In this paper, this complex description is used to design a torque controller and a rotor flux observer based on sliding modes. The advantage of using the complex representation is an order reduction of the system and a simplification of the analysis. The obtained results are illustrated by means of numerical simulations.

In this paper we introduce novel views of monoids and groups. More specifically, for a given set $S$, let $S^{S\times S}$ be the set of binary operations on $S$. We equip $S^{S\times S}$ with canonical binary operations induced by the elements of $S$. Let $S^{S\times S}_{mn}$ (respectively, $S^{S\times S}_{gr}$) be the set of binary operations that make $S$ monoids (respectively, groups). Then we have the following "duality": for each $z\in S^{S\times S}_{mn}$ a certain subset of $S^{S\times S}$, denoted by $S^*_z$, is a monoid with a canonical binary operation and is isomorphic to $(S,z)$. If $z\in S^{S\times S}_{gr}$, then $S^{S\times S}_{gr}$ can be partitioned into copies of $S^*_z$. We also give a new characterization of group binary operations which distinguishes them from the other binary operations. These results give us new insights into monoids and groups, and will provide new tools and directions in studying these objects.

Automotive engine functions are entirely dependent on installed sensors performance. Any malfunction in the sensors can lead to degraded engine efficiency. This manuscript presents a novel scheme to devise virtual sensors for health monitoring of engine air intake path sensors. The proposed scheme assists in: Sensing of critical immeasurable parameters like Volumetric and Combustion efficiency, development of Virtual Sensor from manifold pressure dynamics for rotational speed and vice versa, Health Monitoring of the manifold pressure and crankshaft sensor. For the suggested scheme, two robust second-order sliding mode observers are employed that require two state mean value engine model based on inlet manifold pressure and rotational speed dynamics. The proposed methodology has the potential of online implementation on any automotive engine after minor tuning. In this paper, the procedure is customized for 1.3 L gasoline engine sensors: Manifold Pressure and Crankshaft sensor. The implementation results demonstrate that all the three mentioned tasks are accomplished efficiently.

The purpose of this paper is to associate a sliding mode control (SMC) with a powerful nonlinear observer robust flux for an induction motor. We implement this design strategy through an extension of a special class of nonlinear multivariable systems satisfying some regularity assumptions. We show by an extensive study that this purpose is completely satisfactory at low and nominal speeds and it is not sensitive to disturbances and parametric errors. It is robust to changes in load torque, rotational speed and rotor resistance. Streszczenie. Celem niniejszego artykułu jest skojarzenie sterowania ślizgowego z nieliniowym obserwatorem strumienia odpowiednim dla silników indukcyjnych. Realizujemy tę strategię projektowania poprzez rozszerzenie specjalnej klasy układów nieliniowych wielu zmiennych spełniających pewne założenia prawidłowości. Przedstawiono analizę wykazująca, że ten cel jest spełniony dla niskich prędkości i nominalnym, a system nie jest wrażliwy na zakłócenia i błędy parametryczne. Jest odporny na zmiany momentu obciążenia, prędkości obrotowej i oporu wirnika. (Sterowanie ślizgowe silnikiem indukcyjnym z odpornym oberwatorem)

This work dealt with comparison of responses of PID and FL controlled Γ-ZSI based wind energy conversion systems. A coupled inductor was employed to produce high voltage gain. Open loop and closed loop control systems with PID and FL controllers were designed and simulated using MATLAB. The principle of operation and simulation case studies was presented in detail. The comparison was made in terms of rise time, steady state error and peak over shoot.

In modern and sustainable concepts for supply chains, cargo bicycles, and cargo trailers can be a target-oriented solution in urban areas. However, drivers should be aware of the dynamics of these systems since, in the case of a loaded trailer, the trailer mass significantly exceeds the mass of the towing vehicle. However, the electrification of cargo trailers opens up the possibility of equipping these systems with an intelligent control system. This type of control system can be based on a model or tested using a model of the system. For this reason, the present research presents a single-track model of a bicycle-trailer system that considers longitudinal dynamics as well. In addition, a detailed tire model of a typical tire for cargo bikes is integrated. With the help of a prototype trailer, which forms the basis for the model's parameters, measurement data is collected and compared with the simulation results. Within the scope of the comparison, speed, acceleration in longitudinal and lateral direction, hitch force, yaw rate, and the angle between the towing vehicle and trailer are compared in a longitudinal and lateral dynamic case. The presented model shows a good agreement with the reality in the longitudinal dynamic investigation regarding the tested scenarios. In terms of lateral dynamics, the model can reproduce a significant part of the measured data but exhibits minor differences related to environmental conditions, limited degrees of freedom, measurement errors, and the implementation of a needed driver model in this setup, which represents the human component. In the future, the model can be used to investigate the driving characteristics of bicycle-trailer systems. Furthermore, adding a model of the trailer powertrain and its control to the simulation can enable simulation-based design and testing of the required vehicle dynamics controller before implementation on a prototype.

This paper presents the backstepping nonlinear control applied to induction motor with on-line adaptation of rotor resistance using a backstepping observer type. This type of control proposed an analysis based primarily on the stability of the system from the Lyapunov theory. This approach takes into account the nonlinearity of the system when designing the control law. The effectiveness of this strategy of control and observation of the rotor resistance was tested using the Matlab-Simulink.

Continuing research has concentrated on the elimination of the problem of sensitivity to parameter variation of induction motor drive. This paper presents a simple method for simultaneous estimation of rotor speed and stator resistance in sensorless indirect vector controlled induction motor drive. This method is based on luenberger observer and the stability of this observer is proved by the lyapunov’s theorem, by using measured and estimated stator currents and estimated rotor flux. Finally the feasibility of the schem is verified by simulation. However, at low speed of rotation we get successful resistance identification.

This paper proposes a diagnosis and mitigation strategy for sensor faults and cyber attacks in a DC microgrid to ensure its fault and cyber attack resilient operation. Sliding mode observer-based fault diagnosis theory has been used in the proposed strategy to estimate the error in the sensor measurements due to any sensor fault or cyber attack in a DC microgrid. The estimated errors are used to initiate the proposed mitigation action, which rectifies the corrupted measurements to ensure fault and cyber attack resilient operation of the microgrid. The performance of the proposed strategy has been evaluated through rigorous simulation studies, carried out on a test DC microgrid under various fault and attack conditions. Simulation results clearly demonstrate that the proposed strategy is able to ensure the reliable and efficient operation of a DC microgrid under sensor faults or cyber attack conditions.

Identification of operating mode is a key step in the fault diagnosis of the hybrid systems. The novelty of this paper is the definition of a hybrid observer where discrete event is identified and then continuous model of a sub-system is selected for the design of observer using sliding mode technique. The observer output is finally used for mode identification and fault diagnosis. The proposed method is applied on Spark Ignition (SI) engine for misfire fault detection. The first order sliding mode observer is used to accomplish the task. The mode identification scheme is validated on data generated through hybrid model simulations as well as for data obtained from a 1.3L production vehicle.

Time varying parameters identification of stochastic systems is addressed via sliding mode parameter observers. Sliding mode observer is governed by control that compensates a so-called Ito's term, which reflects a stochastic nature of a system. The matrix estimation algorithm based on equivalent control is proposed. A numerical example illustrates the effectiveness of the proposed approach.

This paper deals with the observability singularity problem of batch bioreactors on the positive Orthant. This singularity is overcame by the dedicated approach based on the well-known high order sliding mode differentiator proposed by Arie Levant and the resolution of simple second order equation. Nevertheless, it is difficult to distinguish between both solutions, but the second differentiation of the output gives an appropriate test procedure for choice between both solutions. Some simulation results highlight the well-founded of the proposed method.

In this paper, a new controller is proposed, based on a well known homogeneous controller. The suggested controller gives rise to an efficient trade-off between the standard linear state feedback and twisting algorithm. As a consequence, the obtained controller has the advantages of both controllers with their drawbacks reduced. To achieve this objective, a parameter on the exponent terms of the homogeneous controller is adapted. The convergence of the closed loop system to a vicinity of the origin is given. Finally, some simulations validate the effectiveness of the proposed controller.

When chaotic systems is used as support for secure data transmission, singularity of observability and left invertibility is an important problem. In this paper, data secure transmission is analyzed with respect to the observability and left invertibility concept. Moreover, in order to overcome observability and left invertibility singularities, a immersion technique is proposed. The use of high order sliding mode observer on a well known Qi circuit, allows to highlight the well founded of the proposed analysis and method.

In this paper, a hybrid observer for a class of DC-DC power converter is proposed. The considered class of switched system including one or several unobservable subspace. Thus, the state vector of a converter is not observable at any time. The aim is to solve this problem of observability by taking into account the hybrid dynamic behavior appearing in the converter. Such problem can be tacked by a new observability concept (Z(TN)-Observability). An application to a Single-Ended Primary Inductor Converter (SEPIC) is presented. After recalling to hybrid dynamic behavior of the SEPIC, an observability analysis is investigated. Following this analysis, a hybrid observer is designed based on homogeneous observer coupled with an estimator. Finally some illustrative results are given in order to show the efficiency of the designed observer.

This article presents the design of a digital real-time emulator dedicated to the simulation of four-level multicell converter. The design has been made using a new tool: the co-simulation. Co-simulation results are presented in this paper and an experimental setup has been realised on a FPGA 1 in order to validate this new tool. In the final part, we present the test of an observation loop using this emulator.

When chaotic systems is used as support for secure data transmission, singularity of observability and left invertibility is an important problem. In this paper, data secure transmission is analyzed with respect to the observability and left invertibility concept. Moreover, in order to overcome observability and left invertibility singularities, a immersion technique is proposed. The use of high order sliding mode observer on a well known Qi circuit, allows to highlight the well founded of the proposed analysis and method.

A sliding-mode observer is applied toward the operation of a switched reluctance motor (SRM) drive. The sliding-mode observer estimates rotor position and velocity to control the conduction angles of the machine. Conventional on-off control with hysteresis current control is included with the position estimation scheme. The particular case of an automotive brake system motor is considered in detail where the conduction angles are modified with velocity feedback to provide optimum time response to brake system commands. Nonlinear modeling of a SRM is described and a computer simulation is developed based on data from an experimental SRM system. The sliding-mode observer is implemented with fixed-point and floating-point digital signal processors (DSPs) and the discrete-time implementation is first examined under locked-rotor conditions. A comparison is also made between the implementation in two different types of DSPs. After confirming the accuracy of the computer simulation with experimental data, the design considerations in selecting observer coefficients with regard to sampling time, convergence rate, and transient stability are discussed. In conclusion, the effects of flux estimation errors on the system time response during a startup transient are examined.