Continuous angular position estimation of human ankle during unconstrained locomotion

2020 ◽  
Vol 60 ◽  
pp. 101968 ◽  
Author(s):  
Rohit Gupta ◽  
Inderjeet Singh Dhindsa ◽  
Ravinder Agarwal
Keyword(s):  
Angular Position ◽  
Position Estimation ◽  
Human Ankle

A new reaching law for sliding mode observer of controllable excitation linear synchronous motor

2021 ◽  
pp. 014233122110320
Author(s):  
Xiaolei Shi ◽  
Yipeng Lan ◽  
Yunpeng Sun ◽  
Cheng Lei
Keyword(s):  
Sliding Mode ◽  
Dynamic Performance ◽  
Angular Position ◽  
Lyapunov Stability Theory ◽  
Synchronous Motor ◽  
Position Estimation ◽  
Sliding Mode Observer ◽  
Sigmoid Function ◽  
Reaching Law ◽  
Linear Synchronous Motor

This paper presents a sliding mode observer (SMO) with new reaching law (NRL) for observing the real-time linear speed of a controllable excitation linear synchronous motor (CELSM). For the purpose of balancing the dilemma between the rapidity requirement of dynamic performance and the chattering reduction on sliding mode surface, the proposed SMO with NRL optimizes the reaching way of the conventional constant rate reaching law (CRRL) to the sliding mode surface by connecting the reaching process with system states and the sliding mode surface. The NRL is based on sigmoid function and power function, with proper options of exponential term and power term, the NRL is capable of eliminating the effect of chattering on accuracy of the angular position estimation and speed estimation. Compared with conventional CRRL, the SMO with NRL achieves suppressing the chattering phenomenon and tracking the transient process rapidly and accurately. The stability analysis is given to prove the convergence of the SMO through the Lyapunov stability theory. Simulation and experimental results show the effectiveness of the proposed NRL method.

Adaptive Observer of Rotor Position and Flux for Salient Synchronous Motor

2019 ◽  
Vol 20 (2) ◽  
pp. 114-121
Author(s):  
D. N. Bazylev ◽  
A. A. Pyrkin ◽  
A. A. Bobtsov
Keyword(s):  
Permanent Magnets ◽  
Adaptive Estimation ◽  
Angular Position ◽  
Regression Function ◽  
Estimation Algorithm ◽  
Synchronous Motor ◽  
Position Estimation ◽  
Adaptive Observer ◽  
Estimation Errors ◽  
Persistent Excitation

An algorithm of adaptive estimation of rotor flux and angular position for the salient synchronous motor with permanent magnets is presented. A new nonlinear parameterization of the dynamic motor model is proposed. Due to this parameterization the problem of position estimation is translated to the task of identification of unknown constant parameters. During the synthesis of estimation algorithm the currents and voltages of the stator windings, as well as the rotor speed, are assumed to be known signals. Two variants of the adaptive observer based on the standard gradient estimator and the algorithm of the dynamic extension of the regressor are proposed. It is proved that the both versions of the observer provide global exponential convergence of estimation errors to zero if the corresponding regression function satisfies the persistent excitation condition. Also, the latter version of the observer provides global asymptotic convergence if the regression function is square integrable. The results of numerical simulation demonstrate that the algorithm with the dynamic extension of the regressor provides a better quality of estimation transient processes in comparison with the standard gradient estimator.

A Sensorless Initial Rotor Position Estimation for Permanent Magnet Synchronous Machines

2015 ◽  
Vol 792 ◽  
pp. 83-89
Author(s):  
Ivan Yurievich Krasnov ◽  
Sergey Vladimirovich Langraf ◽  
Stepan Ivanovich Chobanov
Keyword(s):  
Permanent Magnet ◽  
Angular Position ◽  
Initial Position ◽  
Position Estimation ◽  
Permanent Magnet Synchronous Machines ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
In Series ◽  
The Absolute ◽  
Rotor Position Estimation

Permanent magnet synchronous motors for the effective start requires information about an initial position of a rotor. In this regard, most systems use position sensors, which substantially increase a cost of an electrical drive entirely [1-3]. The aim of this article is to develop new method, allowing to determine the absolute angular position of the rotor of the permanent magnet synchronous motors [4,5]. With a certain voltage pulses, in series applied to the motor, stator is magnetized by currents leakage in the windings. This allows, using a special algorithm, to calculate the absolute position of the rotor without using any motor parameters [6]. Simulation results prove the simplicity and efficiency of this method for determining an initial position of the rotor of the permanent magnet synchronous motors. Thus, this method can be widely used in the electrical industry.

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

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2467 ◽  
Author(s):  
Shusheng Li ◽  
Yongling Fu ◽  
Ping Liu
Keyword(s):  
Sliding Mode ◽  
Estimation Error ◽  
Angular Position ◽  
Position Estimation ◽  
Sliding Mode Observer ◽  
Measurement Noise ◽  
Estimation Accuracy ◽  
Second Step ◽  
Optimization Strategy ◽  
Unknown Disturbances

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.

scholarly journals Angle Tracking Observer with Improved Accuracy for Resolver-to-Digital Conversion

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1347 ◽  
Author(s):  
Haoye Qin ◽  
Zhong Wu
Keyword(s):  
Phase Error ◽  
Angular Position ◽  
Position Estimation ◽  
High Order ◽  
Phase Detector ◽  
Type Ii ◽  
Digital Conversion ◽  
Estimation Errors ◽  
Angle Tracking ◽  
Acceleration Signals

A resolver is an absolute shaft sensor which outputs pair signals with ortho-symmetric amplitudes. Ideally, they are sinusoidal and cosinusoidal functions of the shaft angle. In order to demodulate angular position and velocity from resolver signals, resolver-to-digital conversion (RDC) is necessary. In software-based RDC, most algorithms mainly employ a phase-locked loop (PLL)-based angle tracking observer (ATO) to form a type-II system. PLL can track the detected angle by regulating the phase error from the phase detector which depends on the feature of orthogonal symmetry in the resolver outputs. However, a type-II system will result in either steady-state errors or cumulative errors in the estimation of angular position with constant accelerations. Although type-III ATOs can suppress these errors, they are still vulnerable to high-order acceleration signals. In this paper, an improved PLL-based ATO with a compensation model is proposed. By using dynamic compensation, the proposed ATO becomes a type-IV system and can reduce position estimation errors for high-order acceleration signals. In addition, the parameters of ATO can be tuned according to the bandwidth, noise level and capability of error suppression. Simulation and experimental results demonstrate the effectiveness of the proposed method.

scholarly journals Improvement of Position Estimation of PMSMs Using an Iterative Vector Decoupling Algorithm

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 245
Author(s):  
Stefano Fabbri ◽  
Klaus Schuhmacher ◽  
Matthias Nienhaus ◽  
Emanuele Grasso
Keyword(s):  
Iterative Algorithm ◽  
Angular Position ◽  
Experimental Tests ◽  
Position Estimation ◽  
Position Error ◽  
Control Technique ◽  
Synchronous Machines ◽  
Flux Control ◽  
Algorithm Convergence ◽  
Decoupling Algorithm

This paper presents an improvement of sensorless techniques based on anisotropy for the estimation of the electrical angular position of synchronous machines by means of an iterative algorithm. The presented method reduces the effect of the fourth saliency harmonics on the measured signals avoiding the use of an observer or filter, thus, no additional dynamics are introduced on the system. Instead, a static algorithm based on iterative steps is proposed, minimizing the angular position error. The algorithm is presented and applied using the DFC (Direct Flux Control) technique but it is not limited to this choice. The advantages and limitations of this method are presented within this paper. The proof of the algorithm convergence is given. Simulations and experimental tests are performed in order to prove the effectiveness of the proposed algorithm.

scholarly journals Acoustic-Based Position Estimation of an Object and a Person Using Active Localization and Sound Field Analysis

2020 ◽  
Vol 10 (24) ◽  
pp. 9090
Author(s):  
Kihyun Kim ◽  
Semyung Wang ◽  
Homin Ryu ◽  
Sung Q. Lee
Keyword(s):  
Angular Position ◽  
Sound Field ◽  
Position Estimation ◽  
Field Analysis ◽  
Fdtd Simulation ◽  
Field Variation ◽  
Security Systems ◽  
Control Zone ◽  
Home Security ◽  
Active Localization

This paper proposes a new method to estimate the position of an object and a silent person with a home security system using a loudspeaker and an array of microphones. The conventional acoustic-based security systems have been developed to detect intruders and estimate the direction of intruders who generate noise. However, there is a need for a method to estimate the distance and angular position of a silent intruder for interoperation with the conventional security sensors, thus overcoming the disadvantage of acoustic-based home security systems, which operate only when sound is generated. Therefore, an active localization method is proposed to estimate the direction and distance of a silent person by actively detecting the sound field variation measured by the microphone array after playing the sound source in the control zone. To implement the idea of the proposed method, two main aspects were studied. Firstly, a signal processing method that estimates the position of a person by the reflected sound, and secondly, the environment in which the proposed method can be operated through a finite-difference time-domain (FDTD) simulation and the acoustic parameters of early decay time (EDT) and reverberation time (RT20). Consequently, we verified that with the proposed method it is possible to estimate the position of a polyvinyl chloride (PVC) pipe and a person by using their reflection in a classroom.

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