Xiwen Guo

Design and analysis of permanent magnetic spherical motor with cylindrical poles

The paper has presented a new structure of three-of-degree (3-DOF) permanent magnetic spherical motor (PMSM) including four layers of cylindrical rotor poles and two layers of coils without ferromagnetic core. The radial magnetic field influenced by magnetization direction and different structure of rotor poles are analyzed based on analytic method by toroidal function. With the torque model the effects on torque characteristic caused by the parameters of cylindrical poles, coil structure, core material and gap length are analyzed. The results provide reference for PMSM optimization.

Research of orientation detection method for spherical motor and effect on PD control system based on machine vision

The rotor orientation detection of spherical motor is crucial to the closed-loop control. The paper presents the method for measuring rotor orientation based on machine vision. The pattern code generation, deriving method and pattern processing algorithm are introduced. With the model built in OpenGL, measurement errors of three degrees of freedom (DOF) are derived. Resolution and accuracy of the measurement method are analyzed. Considering the measurement of time delay, the effect on PD control system with simplified dynamical model of spherical motor is presented.

Effect of stator and rotor notches on cogging torque of permanent magnet synchronous motor

This paper describes the causes of cogging torque in Permanent Magnet synchronous Motor. Establishes a motor model by ANSOFT software, uses Finite Element Method to quantitative analysis and comparative peak cogging torque and torque with notches at different locations, and different number of auxiliary slot. The conclusion is that notch reasonable can reduce the cogging torque of permanent magnet motor effective.

A robust adaptive sliding-mode controller with bound estimation for permanent magnet spherical actuator

This paper presents a novel tracking controller for a three degrees-of-freedom permanent magnet spherical actuator (PMSA). The controller is designed on the basis of the establishment of dynamics model under uncertainties. The major construction of the controller lies in the use of the matrix regressor to isolate unknown parameters from the PMSA. Moreover, sliding-mode control and robust control are adopted to make errors converge to zero and restrain and eliminate distributions and uncertain factors. The stability of the closed-loop system using designed controller is confirmed through Lyapunov theorem. Simulation results are provided to validate the effectiveness of the proposed controller.

Enhanced bearing fault diagnosis using adaptive stochastic resonance

Signal filtering approaches are always used to attenuate noise and enhance useful signal in bearing fault diagnosis. Stochastic resonance (SR) is a nonlinear filter that can utilize noise to enhance weak periodic signal. This study proposes an adaptive SR method which can automatically enhance the bearing fault characteristic frequency (FCF). First, a second-order SR filter is utilized to purify the demodulated vibration signal. Second, a new criterion that measures both the power spectrum kurtosis and the correlation coefficient is proposed to tune the filter parameters in the SR procedure. Finally, the FCF is enhanced, which facilitates bearing fault identification. Experimental verification is conducted to evaluate the effectiveness of the proposed method.

Sliding-mode control of permanent magnetic spherical motor based on co-simulation platform

In order to combine the model-based control algorithm with the physical model, this paper proposed a co-simulation system of permanent magnetic spherical motor (PMSM). Firstly, a new track planning was simulated in ADAMS for the convenience of trajectory tracking. Secondly, a new co-simulation interface was presented, thus the model-based control algorithm can be used to control the physical model generated in ADAMS. Finally, sliding-mode control algorithm was realized based on the co-simulation platform, and the simulation results show that the model-based control algorithm and physical model can combine well based on the above interface.

Parameters estimation of IM with the Extended Kalman filter and least-squares

In the AC drive system, the control performance is highly dependent on the accuracy of the electromagnetic parameters. In order to reduce the influences of the parameter variations, a new scheme for on-line rotor time-constant and magnetizing inductance estimation in induction motors is proposed. The algorithm is obtained by interlacing a Bi-Loop recursive least squares algorithm with forgetting factors (BLFRLS) estimator and an Extended Kalman filter. At every time step, the former provides the rotor time-constant estimate which is used by the latter for the state variable reconstruction. Both computer simulation and experimental results demonstrate that the proposed scheme show a high estimation accuracy of induction motor parameters.

Modeling and simulation of a permanent magnetic spherical motor based on solidworks and ADAMS

As the shortcomings of multi-rigid-body mathematical modeling for permanent magnetic spherical motor (PMSM), such as the complexities vary greatly and even lead to considerable deviations from the actual system. A novel physical modeling method and dynamic simulation based on computer software are proposed in this paper. Firstly, the physical model of PMSM rotor was set up in Solidworks. And then, the dynamic model was imported in ADAMS. Dynamic simulation considering the friction and the gravity or not was analyzed respectively. The results offer a reliable approach for the subsequent closed-loop control about PMSM, as well as in-depth study of its dynamic characteristics.

Adaptive fuzzy tracking control based on backstepping for permanent magnet spherical motor

This paper presents an intelligent tracking control method for a three degrees-of-freedom permanent magnet spherical motor (PMSM). The control method is designed on the basis of the establishment of dynamics model for spherical motor according to Cardan angles. By the use of backstepping design, the nonlinear system of PSMS is divided to several subsystems with less order than that of original system. Moreover, due to an adaptive fuzzy controller, the unknown dynamics of PSMS including external disturbance can be infinitely approximated. The stability of the close-loop system using designed controller is confirmed through Lyapunov theorem. Simulation results are provided to validate the effectiveness of the proposed method.

Adaptive fuzzy decoupling control for permanent magnet spherical motor dynamic system

Due to the nonlinear, strong coupling dynamic system of a direct-drive permanent magnet spherical motor (PMSM), an adaptive fuzzy decoupling controller is developed in this paper. The proposed scheme effectively combines the design techniques of adaptive fuzzy control and robust control in order to achieve dynamic decoupling and compensate for approximation errors. Moreover, a regularized matrix inverse is used to obtain a stable well-defined adaptive controller. Adaptive law can be derived based on the Lyapunov design. Simulation results demonstrate the effectiveness of the proposed scheme. Also, the results in this paper could serve as a basis for the future research and experiment.