Traditional Sliding Mode Observer Research Articles

Reduced-Order Sliding-Mode-Observer-Based Fault Estimation for Markov Jump Systems

This paper is concerned with the fault and state estimation problem for Markovian jump systems (MJSs) with simultaneous actuator and sensor faults. To deal with the design issues, we propose a novel descriptor reduced-order sliding mode observer (SMO), based on which the estimation of the actuator faults, sensor faults, and the states can be obtained simultaneously. Compared with the traditional SMO design issues in MJSs, we reconstruct the actuator faults directly without employing the equivalent output error injection method. Thus, the reachability analysis of the sliding surface is not necessary. The superiority of this kind of the SMO method is that the sliding surface switching problem is avoided. Finally, the effectiveness (as suggested by the theoretical results) of the approach described is tested on a mobile manipulator by simulation studies.

Sensorless control of permanent magnet synchronous motor based on adaptive sliding mode observer and sliding mode gain design

Aiming at the chattering problem in the traditional sliding mode observer of permanent magnet synchronous motor, an improved sliding mode observer is designed. The Kalman observer is designed, the phase-locked loop (PLL) control algorithm is introduced, and the problem of phase delay and precision reduction caused by ordinary filter is solved. The simulation results show that the improved sliding mode observer can accurately estimate the rotation speed and reduce the chattering phenomenon in the process of rotor position estimation.

Descriptor Observers Design for Markov Jump Systems With Simultaneous Sensor and Actuator Faults

In this study, based upon designing a novel observer for Markovian jump systems (MJS), the state and fault estimation problem in the presence of simultaneous sensor and actuator faults in MJS is investigated. The novel observer is a linear descriptor reduced-order one. By employing the proposed linear descriptor reduced-order observer with decoupling technology, the estimation of state and sensor fault can be obtained directly without any supplementary design. Compared with the traditional sliding mode observers in MJS, the advantage is that the sliding surface switching problem is avoided. Finally, a practical example of mobile manipulators is given to illustrate the effectiveness of the theoretical results.

Robust Estimation for State-of-Charge and State-of-Health of Lithium-Ion Batteries Using Integral-Type Terminal Sliding-Mode Observers

This paper investigates the real-time estimation on the state-of-charge (SoC) and state-of-health (SoH) of lithium-ion (Li-ion) batteries for the purpose of achieving reliable, safe, and efficient use of batteries. Three terminal sliding-mode observers (TSMOs) are designed; each observer is used to estimate one variable of a Li-ion cell for developing a real-time SoC estimation algorithm. To estimate the SoH, two additional TSMOs are subsequently presented. Finally, a set of complete estimation algorithms for SoC and SoH are formulated. The output injection signals of the proposed TSMOs are designed to be continuous. This can attenuate chattering that exists in the traditional sliding-mode observers and simplify the estimation algorithms. The main advantage of the proposed algorithms is eliminating the low-pass filter in the estimation algorithms. Therefore, higher estimation accuracy and faster response speed are obtained. The proposed methods are tested and evaluated using the acquired dynamic stress test and federal urban driving schedule test data, which demonstrate the effectiveness and feasibility.

Actuator and Sensor Fault Estimation for Time-Delay Markov Jump Systems With Application to Wheeled Mobile Manipulators

In this paper, fault and state estimation issue for wheeled mobile manipulators with time delay, using a novel sliding mode observer (SMO) approach has been discussed. It is well-known that the traditional SMO method, i.e., the equivalent output error injection technique cannot be simply employed to Markov jump systems (MJSs) to estimate actuator faults. In this paper, we propose a novel SMO to reconstruct the actuator and sensor faults for MJSs with time delay. First, we decouple the actuator faults from the first subsystem by utilizing coordinate transformation technique. Then, construct an augmented plant for the new system and propose a novel reduced-order SMO. By the proposed novel SMO, the state and fault can be reconstructed simultaneously. Finally, an illustrative wheeled mobile manipulator example is given to show the effectiveness of the proposed approach.

Anti-disturbance speed control of low-speed high-torque PMSM based on second-order non-singular terminal sliding mode load observer

This paper presents an anti-disturbance speed control of low-speed high-torque permanent magnet synchronous motor (PMSM) based on the second-order non-singular terminal sliding mode load observer. According to the coordinate transformation theory, the mathematical model of PMSM is established. Subsequently, the second-order non-singular terminal sliding mode observer (SNTSMO) is designed to observe the changes of load disturbance in the PMSM system. The SNTSMO combines the advantages of both high-order sliding mode and non-singular terminal sliding mode to achieve the fast convergence and no chattering. Next, the sliding mode controller (SMC) is designed to achieve speed loop control of PMSM. Then, the anti-disturbance compound speed controller is established on the basis of SMC and SNTSMO, wherein the feed-forward compensation is used to reduce the disturbance from the load. Finally, the numerical simulations and experiments are presented according to the schematic diagram of the designed compound speed controller of PMSM. The results demonstrate that the designed SNTSMO can precisely estimate the load disturbance and suppress the effects of buffeting in the traditional sliding mode observer (SMO). Additionally, the designed compound speed controller of PMSM can achieve smooth speed control in the presence of load disturbance, achieve the purpose of anti-disturbance speed control and further improve the robustness of the control system.

Sensorless Control of Permanent Magnet Synchronous Motor Based on the Improved Sliding Mode Observer

Sliding mode observer (SMO) which has a strong robustness is used in the sensorless control system of permanent magnet synchronous motor (PMSM). The method is usually used to estimate the rotor position although it has the chattering problem. According to the causes of the chattering in traditional SMO, the method of improved sliding mode observer (ISMO) is proposed in this paper. Sign function is replaced by the saturation function to suppress the chattering problem, and the speed of PMSM is estimate when combined with field oriented control (FOC) method. A hardware platform of 2.7 kW, 10 000 r/min PMSM is built to verify the control effectiveness of ISMO. Simulation analysis and experimental result show that ISMO can estimate the rotor speed accuracy and reduce the chatting at the same time.

Non-linear tyre model–based non-singular terminal sliding mode observer for vehicle velocity and side-slip angle estimation

Vehicle velocity and side-slip angle are important vehicle states for the electronic stability programme and traction control system in vehicle safety control system and for the control allocation method of electric vehicles with in-wheel motors. This paper proposes an innovative side-slip angle estimator based on the non-linear Dugoff tyre model and non-singular terminal sliding mode observer. The proposed estimation method based on the non-linear tyre model can accurately present the tyre’s non-linear characteristics and can show advantages over estimation methods based on the linear tyre model. The utilised Dugoff tyre model has a relatively simple structure with few parameters, and the proposed non-linear observer can be applied in various vehicle tyres and various road conditions. Precise determination of the Dugoff tyre model parameters is not required and the proposed observer can still perform good estimation results even though tyre parameters and the tyre–road friction coefficient are not accurate. The proposed non-singular terminal sliding mode observer can achieve fast convergence rate and better estimation performance than the traditional sliding mode observer. At the end of this paper, simulations in various conditions are presented to validate the proposed non-linear estimator.

Position Estimation and Compensation Based on a Two-Step Extended Sliding-Mode Observer for a MSFESS.

This paper aims to deal with the problem of rotor position estimation and compensation for a magnetically suspended flywheel energy storage system under the consideration of measurement noise and unknown disturbances. First, the flywheel system working principle and description are analyzed and, based on this, the mathematical model as well as the coordinates transformation are introduced. For the purpose of the state estimation, a two-step extended sliding-mode observer is considered to obtain the estimates of the rotor angular position. In this control strategy, a traditional sliding-mode observer is adopted as a first-step original state estimator. After that, the relationship between the angular position and the estimation error is established and a second-step observer is designed to obtain the estimation of the error. The estimated error is then used to compensate the real values of the rotor angular position generated by the first-step observer. To reject the influences of the measurement noise and unknown disturbances, the H∞ optimization strategy is considered to determine the second-step observer structure. Finally, experimental results are presented to demonstrate the effectiveness of the proposed method. It is demonstrated that the proposed two-step observer method has a better estimation accuracy and control performance.

Rotor position estimation scheme with harmonic ripple attenuation for sensorless controlled permanent magnet synchronous motors

To achieve high-performance sensorless control of permanent magnet motors with non-sinusoidal back electromotive force (EMF), an improved sliding mode observer (SMO) adopting synchronous rotating low-pass filter (SRLPF) is proposed. The SRLPF is utilised to reduce the back-EMF harmonics and extract the fundamental component. Different from the traditional rotor position observer, the proposed observer can calculate the rotor position with the back-EMF fundamental component. Owing to the decrease in the influence of non-sinusoidal back-EMF, the estimated rotor position harmonic ripple error can be greatly reduced. Then, the high estimated accuracy and excellent sensorless control performance can be obtained. In addition, the proposed strategy is easy for implementation. With the comparison between the traditional SMO and the proposed observer, the experiments of the system steady-state error, the speed tracking performance, and the disturbance rejection ability in the speed range from 60 r/min to the rated speed 750 r/min are presented. The validity of the proposed method is conformed.

An Adaptive-Gain Sliding Mode Observer for Sensorless Control of Permanent Magnet Linear Synchronous Motors

In this paper, a novel adaptive-gain sliding mode observer (SMO) is designed for sensorless control of permanent magnet linear synchronous motors (PMLSMs). By the proposed adaptive-gain algorithm, the gain can dynamically adapt to a changing operation condition of the PMLSMs and reach an appropriate value in finite time. Stability of the SMO is proved by using Lyapunov stability theory. Compared with the traditional SMO, the adaptive-gain SMO can improve the control precision, especially when the operation condition is not invariant. Simulation results are given to show the advantages of the proposed method.

A new result on observer-based sliding mode control design for a class of uncertain It[formula omitted] stochastic delay systems

This paper develops a new observer-based sliding mode control (SMC) scheme for a general class of Ito^ stochastic delay systems (SDS). The key merit of the presented scheme lies in its simplicity and integrity in design process of the traditional sliding mode observer (SMO) strategy, i.e., the state observer and sliding surface design as well as the associated sliding mode controller synthesis. For guaranteeing to use the scheme, a new LMIs-based criterion is established to ensure the exponential stability of the underlying sliding mode dynamics (SMDs) in mean-square sense with H∞ performance. A bench test example is provided to numerically demonstrate the efficacy of the scheme and illustrate the application procedure for potential readers/users with interest in their ad hoc applications and methodology expansion.

Sensorless Control of a Shearer Short-Range Cutting Interior Permanent Magnet Synchronous Motor Based on a New Sliding Mode Observer

Considering the low reliability and poor adaptability of existing drum shear cutting parts, this paper presents a permanent magnet short-range cutting transmission system with a low-speed and high-torque interior permanent magnet synchronous motor (IPMSM) as the driving source and a sensorless control strategy based on a new sliding mode observer (SMO). To increase the robustness of the observer and reduce the error caused by chattering in the traditional SMO, the phase-locked loop technique is used instead of the traditional arc-tangent function estimation, and the sigmoid function is introduced to replace the traditional sign function; then, the sliding mode gain is adjusted through the fuzzy control algorithm in the new SMO. The scheme effectively improves the problems of the high failure rate caused by the long transmission chain of the shearer cutting section and the environmental impact for the mechanical sensor measurement results. Finally, the mathematical model of IPMSM based on the two-phase rotating coordinate system and end cutting load is established to verify the effectiveness and feasibility of the program. The results show that the new observer can accurately realize the speed and position estimation of the shearer cutting motor, and it has good dynamic response performance, observation accuracy, and robustness.

Chattering-free sliding mode observer for speed sensorless control of PMSM

This article presents a new speed observer based on fuzzy logic for speed sensorless control applications of permanent magnet synchronous motor “PMSM”. The switch function in traditional Sliding Mode Observer “SMO” is replaced by a rule based fuzzy logic system. The proposed observer not only improves the system dynamic performance during disturbances or parameter variations, but also has a high accuracy tracking performance with sufficient chattering reduction. The validity of the new observer corroborated through experimental results using TMS320F28069M Digital Signal Processor “DSP”.

Descriptor reduced-order sliding mode observers design for switched systems with sensor and actuator faults

This paper investigates the state and fault estimation problem for linear continuous-time switched systems with simultaneous disturbances, sensor and actuator faults, and two types of observer approaches are presented to solve this design issue. The first one is a linear descriptor reduced-order observer, which generates the exact estimation of state and sensor faults together with disturbances by decoupling them from the state vector without any supplementary design. The second one refers to a descriptor sliding mode observer approach, where the state, disturbances, sensor and actuator faults can be reconstructed simultaneously. In the second method, the reachability of sliding surface is not necessary to be investigated, since the actuator faults can be estimated directly without using the equivalent output error injection scheme as in traditional sliding mode observers. Therefore, both developed observer approaches avoid the sliding surface switching problem of traditional sliding mode observers in application to switched systems. Finally, an example is given to demonstrate the effectiveness of the two designed observer methods.

Fault Estimation for Nonlinear Dynamic System Based on the Second-Order Sliding Mode Observer

This paper is concerned with the problem of fault estimation for a class of Lipschitz nonlinear systems. In order to settle the chattering problem caused by traditional sliding mode observer for fault estimation, a second-order sliding mode observer is proposed on the basis of the super-twisting algorithm. Firstly, linear coordinate transformations are introduced to decouple the fault signal from the system. Secondly, the Lyapunov function approach is applied to derive the criteria guaranteeing the stability of the observer error dynamic system. The obtained results eliminate the cumbersome proving process for the stability of the super-twisting algorithm by the geometric method. Thirdly, an estimation of the fault is generated by the proposed second-order sliding mode observer. Furthermore, only the output information of the system and observer is necessary for fault estimation. Finally, a robotic arm system is employed to show the effectiveness of the proposed fault estimation method.

Research on Sensorless Control of PMSM Based on Sliding Mode Observer

In the foundation of the realization of sensorless control of permanent magnet synchronous motor(PMSM) based on the traditional sliding mode observer, the paper focuses on the research on the chattering impacts on the estimation of rotor position and speed, which are caused by the sliding mode variable structure control. To weaken the chattering, the paper proposes two kinds of methods. First, the paper designs the saturation function with boundary layer thickness variable instead of sign function in the traditional sliding mode observer. Meanwhile, let the phase-locked loop (PLL) combine to the sliding mode observer, and construct the rotor position signal detection unit. Finally, the paper verifies the correctness and effectiveness of the proposed methods through the theoretical analysis and simulation.

Fault reconstruction of thruster for autonomous underwater vehicle based on terminal sliding mode observer

The motion modeling and thruster fault reconstruction for autonomous underwater vehicle (AUV) system are addressed in this paper. Considering the modeling uncertainty of the AUV motion model given by dynamics analysis method, we present an AUV motion modeling method based on RBF neural networks. Since there is asymptotic convergence problem in the process of using traditional sliding mode observer to estimate the state signal, which cannot be measured directly by sensor, the fault signal cannot be reconstructed timely. Therefore, a Terminal sliding mode observer is presented to ensure each estimated state signal converge in a finite time. According to the output of Terminal sliding mode observer, the equivalent output injection method is used to reconstruct thruster fault. Finally, the feasibility and effectiveness of the proposed approach is demonstrated with pool experiments of the experimental prototype.

Sensorless Control of High Speed Permanent Magnet Synchronous Motor Based on Modified Sliding-Mode Observer

In sensorless vector control of permanent magnet synchronous motor, it is necessary to achieve an accurate estimate of the motor speed and position of the rotor. Traditional sliding mode observer algorithm has the inherent chattering problem which reduces accuracy. The Sigmoid function was used to replace the sign function in the traditional sliding mode observer as the switching control function to cancel the filter and phase compensation links. A new sliding mode observer was designed and its stability was proved. High-speed permanent magnet synchronous motor simulation and experimental results show: the new modified sliding mode observer based on Sigmoid function can eliminate the severe buffeting of the traditional sliding mode observer, achieve the accurate estimation of the rotor speed and position for high-speed permanent magnet synchronous motor to complete a wide range of speed control; the correctness and feasibility of the sensorless control strategy based on this method is verified.

Position Sensorless Control of Brushless DC Motor

According to the chattering problem in the traditional sliding mode observer of the position sensorless control of brushless DC motor, a novel quasi sliding mode observer for rotor position estimation was proposed, which took the error between the actual and estimated currents as sliding surface and tracked the actual rotor position according to the mathematical relationship of back EMF and speed of the motor. Then the sensorless control system of the brushless DC motor based on the novel sliding mode observer was designed. Simulation results showed that the novel sliding mode control method could improve the rotor position estimation accuracy and effectively suppress the chattering problem to enhance the robustness of system.