Sliding Mode Observer Method Research Articles

Fault Estimation Sliding-Mode Observer With Digital Communication Constraints

This paper addresses the actuator fault estimation sliding-mode observer (SMO) design problem of linear continuous-time systems over digital communication channels. This problem frequently occurred in a network environment where data has to be quantized before being transmitted via digital communication channels. Traditional observers (linear Luenberger observer, Walcott–ZaK SMO) are not effective to solve this design issue since the effects of signal quantization will degrade estimation performances evidently. In this paper, a new descriptor SMO method is presented to overcome this difficult problem. It is shown that, if the quantizer density is larger than $\sqrt{2}-1$ , the designed observer can compensate quantization errors completely, and the fault vector can be reconstructed despite of signal quantization. Finally, a simulation example with the F-404 aircraft engine model is proposed to demonstrate the effectiveness of the proposed robust digital observer design approach.

Review of Sliding Mode Observers for Sensorless Control of Permanent Magnet Synchronous Motor Drives

Permanent magnet synchronous motors (PMSMs) are increasingly used in high performance variable speed drives of many industrial applications. PMSM has many features, like high efficiency, compactness, high torque to inertia ratio, rapid dynamic response, simple modeling and control, and maintenance free operation. Presence of position sensors presents several disadvantages, such as reduced reliability, susceptibility to noise, additional cost and weight and increased complexity of the drive system. For these reasons, the development of alternative indirect methods for speed and position control becomes an important research topic. Advantages of sensorless control are reduced hardware complexity, low cost, reduced size, cable elimination, increased noise immunity, increased reliability and decreased maintenance. The key problem in sensorless vector control of ac drives is the accurate dynamic estimation of the stator flux vector over a wide speed range using only terminal variables (currents and voltages). The difficulty comprises state estimation at very low speeds where the fundamental excitation is low and the observer performance tends to be poor. Moreover, the noises of system and measurements are considered other main problems. This paper presents a comprehensive study of the different sliding mode observer methods of speed and position estimations for sensorless control of PMSM drives.

Adaptive Sliding Mode Control for High-Frequency Sampled-Data Systems with Actuator Faults

This paper investigates the sliding mode control for high-frequency sampled-data systems with actuator faults. Besides matched nonlinearity, this paper also considers unmeasurable states and unknown actuator degradation ratio as important factors of the overall system. The estimates of system state vector are obtained by an adaptive sliding mode observer method firstly. Then, a novel integral-type sliding surface, corresponding to the unified closed-loop delta operator system, is provided based on aforementioned estimation values, and the fault closed-loop system is proven to be stable by the proposed sliding mode control law. Finally, the fault-tolerant control theory is verified to be valid via a practical simulation example.

A sliding-mode observer for high-performance sensorless control of PMSM with initial rotor position detection

ABSTRACTThis paper proposes a new method to detect the initial rotor position at standstill of permanent magnet synchronous motor (PMSM). To estimate rotor position and rotor speed from the back electromotive force (EMF) voltage, we apply sensorless speed control based on sliding-mode observer (SMO). The initial rotor position is detected by using a suitable high-frequency sequence of voltage pulses intermittently applied to the stator windings at standstill. With this approach, we managed to minimise the error on the estimated position to 3.75° electrical degrees without additional materials and uncomplicated calculations. The stability of the proposed SMO was verified using the Lyapunov method. Numerical simulations and experiments demonstrate that the novel SMO method can effectively estimate rotor position and speed with achievement of good static and dynamic performance. The experimental implementation is carried out on powerful dSpace DS1103 controller board based on the digital signal processor (DSP) TMS320F240.

State estimation based on fractional order sliding mode observer method for a class of uncertain fractional-order nonlinear systems

State estimation of dynamic systems is quite significant in many research areas, such as state-based control and stabilization, state-based monitoring and fault detection. This paper is concerned with the problem of observer-based state estimation for a class of fractional-order (FO) nonlinear dynamic systems. The objective is to consider the state estimation of FO nonlinear system with the sliding mode control (SMC) technique, and conduct the asymptotic stability analysis for the estimate error dynamic system. Firstly, the considered FO nonlinear system models with constant and uncertain parameters are both presented. Fractional order sliding mode observer (FOSMO) structures are established for the FO nonlinear system models. Then, the asymptotic stability of the estimate error dynamic systems are analyzed via employing the Lyapunov stability analysis method for FO systems, and the sufficient conditions of asymptotic stability are derived. FOSMOs design for FO nonlinear systems of Caputo׳s and Riemann–Liouville׳s differential operators are both investigated, and the corresponding asymptotic stability sufficient conditions of the error dynamic systems are presented to insure the estimation accuracy of FOSMOs. Finally, multiple simulation examples are provided to demonstrate the effectiveness of the presented FOSMOs.

IMU Sensor Fault Diagnosis and Estimation for Quadrotor UAVs

This paper presents a fault detection, isolation and estimation scheme for sensor bias fault in inertial measurement units (IMUs) of quadrotor unmanned air vehicles (UAVs). By using estimated roll and pitch angles obtained using a sliding-mode observer method, a diagnostic algorithm is developed for detecting, isolating and estimating sensor bias fault in the gyroscope and accelerometer measurements. The stability and estimation performance properties of the fault estimation algorithm are rigorously established. Flight data collected from a real-time quadrotor test environment is used to illustrate the effectiveness of the proposed method.

Sensorless control of ship propulsion interior permanent magnet synchronous motor based on a new sliding mode observer

This paper proposes a sensorless speed control strategy for ship propulsion interior permanent magnet synchronous motor (IPMSM) based on a new sliding-mode observer (SMO). In the SMO the low-pass filter and the method of arc-tangent calculation of extended electromotive force (EMF) or phase-locked loop (PLL) technique are not used. The calculation of the rotor speed is deduced from the Lyapunov function stability analysis. In order to reduce system chattering, sigmoid functions with switching gains being adaptively updated by fuzzy logic systems are innovatively incorporated into the SMO. Finally, simulation results for a 4.088MW ship propulsion IPMSM and experimental results from a 7.5kW IPMSM drive are provided to verify the effectiveness of the proposed SMO method.

Sensorless Vector Control of Five-phase Induction Motor under Open-phases Fault

—This article deals with proposed solutions for five-phase induction motor drives, specifically aimed to sensorless vector control under an open-phases fault. Exploiting the modified transformation matrices for dual planes, the motor model in the synchronous frame is established under open phases. Torque ripple is reduced by particular magnitude ratio currents. Furthermore, the third harmonic current is used to improve iron utilization and torque density. The proposed sliding-mode observer method for wide-range speed estimation combined with online resistance identification is investigated, especially for low-speed operation. Experimental tests are performed to validate the effectiveness of the proposed method.

Sliding-Mode Observer for Speed and Position Sensorless Control of Linear-PMSM

Abstract The paper presents a sliding-mode observer that utilizes sigmoid function for speed and position sensorless control of permanent-magnet linear synchronous motor (PMLSM). In conventional sliding mode observer method there are the chattering phenomenon and the phase lag. Thus, in order to avoid the usage of the low pass filter and the phase compensator based on back EMF, in this paper a sliding mode observer with sigmoid function for detecting the back EMF in a PMLSM is designed to estimate the speed and the position of the rotor. Most of conventional sliding mode observers use sign or saturation functions which need low pass filter in order to detect back electromotive force (back EMF). In this paper a sigmoid function is used instead of discontinuous sign function to decrease undesirable chattering phenomenon. By reducing the chattering, detecting of the back EMF can be made directly from switching signal without any low pass filter. Thus the delay time in the proposed observer is eliminated because of the low pass filter. Furthermore, there is no need to compensate phase fault in position and speed estimating of linear-PMSM. Advantages of the proposed observer have been shown by simulation with MATLAB software.

Sensorless Control of PMSM Based on Improved Sliding Mode Observer Method

This paper introduces an improved sliding mode observer for sensorless control of PMSM. In order to reduce the chattering phenomenon of traditional sliding mode observer, replace the ideal switching function with sigmoid function and use two-stage low frequency filter. At last, the simulation was done to verify the measures.

State of Charge Estimation of Power Lithium-Ion Battery Based on Sliding Mode Observer

The study of the application of the sliding mode observer method that estimates the state of charge. Based on the state space model of battery established on the model of improved EMF equivalent circuit, a sliding mode state observer is designed to help improve the jitter problem. Considering the nonlinear terms in the model for the analysis of the stability of the observer and the characteristics of the industry under its derivative, and using Lagrange mean value theory to guarantee the convergence conditions of the observer, the design parameters of the observer can thus be determined .Then, this thesis compares the simulation of this method under Matlab environment with the extended Kalman filter method. The results show that the method has higher estimation accuracy in the case of the same battery modeling errors. Therefore, the SOC estimation of the sliding mode observer can effectively reduce the state of charge estimation error introduced by the model error.

Output Feedback Terminal Sliding Mode Control for a Class of Second Order Nonlinear Systems

AbstractIn this study, a novel output feedback terminal sliding mode control (TSMC) approach is proposed for a class of second order nonlinear systems in light of the equivalent output injection sliding mode observer (SMO) method and TSMC principle. The SMO method is applied to reconstruct full states in finite time and the non‐singular TSMC algorithm is designed to stabilize system states to equilibrium points in finite time. The corresponding stability analysis is presented. An indispensable illustrative example is bench tested to validate the effectiveness of the proposed approach.

Fault‐Reconstruction‐Based Cascaded Sliding Mode Observers for Descriptor Linear Systems

This paper develops a cascaded sliding mode observer method to reconstruct actuator faults for a class of descriptor linear systems. Based on a new canonical form, a novel design method is presented to discuss the existence conditions of the sliding mode observer. Furthermore, the proposed method is extended to general descriptor linear systems with actuator faults. Finally, the effectiveness of the proposed technique is illustrated by a simulation example.

Real time implementation of adaptive sliding mode observer based speed sensor less vector control of induction motor

Sensor less induction motor drives are widely used in industry for their reliability and flexibility. However, rotor flux and speed sensors are required for vector control of induction motor. These sensors are sources of trouble, mainly in hostile environments, and their application reduces the drive robustness. The cost of the sensors is not also negligible. All the reasons lead to development of different sensor less methods for rotor flux and mechanical speed estimation in electrical drives. The paper deals with the speed estimators for applications in sensor less induction motor drive with vector control, which are based on application of model adaptive, based sliding mode observer methods. This paper presents the development and DSP implementation of the speed estimators for applications in sensor less drives with induction motor.

Sliding mode observers: a survey

Sliding mode observers have unique properties, in that the ability to generate a sliding motion on the error between the measured plant output and the output of the observer ensures that a sliding mode observer produces a set of state estimates that are precisely commensurate with the actual output of the plant. It is also the case that analysis of the average value of the applied observer injection signal, the so-called equivalent injection signal, contains useful information about the mismatch between the model used to define the observer and the actual plant. These unique properties, coupled with the fact that the discontinuous injection signals which were perceived as problematic for many control applications have no disadvantages for software-based observer frameworks, have generated a ground swell of interest in sliding mode observer methods in recent years. This article presents an overview of both linear and non-linear sliding mode observer paradigms. The use of the equivalent injection signal in problems relating to fault detection and condition monitoring is demonstrated. A number of application specific results are also described. The literature in the area is presented and qualified in the context of continuing developments in the broad areas of the theory and application of sliding mode observers.

High frequency sound signal detector: United States Atomic Energy Commission, French patent 1, 569, 459, (30 May 1969) (applied for 24 June 1968. in US 26 June 1967) (1917)

This paper presents a fault detection, isolation and estimation scheme for sensor bias fault in inertial measurement units (IMUs) of quadrotor unmanned air vehicles (UAVs). By using estimated roll and pitch angles obtained using a sliding-mode observer method, a diagnostic algorithm is developed for detecting, isolating and estimating sensor bias fault in the gyroscope and accelerometer measurements. The stability and estimation performance properties of the fault estimation algorithm are rigorously established. Flight data collected from a real-time quadrotor test environment is used to illustrate the effectiveness of the proposed method.