Investigation on the Measurement Method for Output Torque of a Spherical Motor

Wen, Yan; Li, Guoli; Wang, Qunjing; Tang, Runyu; Liu, Yongbin; Li, Haolin

doi:10.3390/app10072510

Cited by 9 publications

(6 citation statements)

References 17 publications

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“…In these figures, there are 1.33%-21.88% relative errors between the experimental and the finite element results. The errors are mainly caused by the implementation of experiments and the friction compensations, which is detailed discussed in [32]. Although the experimental and the finite element results are not perfectly matched with each other, it is clear that the they agree with each other, indicating that that the torque calculated by the finite element method is acceptable.…”

Section: B Validation Of Fem Resultsmentioning

confidence: 97%

“…Due to the 3D motion characteristics of the PMSM, traditional single-axis torque measurement methods using torque transducers are not suitable. Instead, a MEMS gyro sensor is adopted to measure the motion dynamics at starting time, then calculate the output torque with the rotor kinematic equations [32]. Conventionally, the magnetic field may affect the accuracy of the MESM gyro sensor, thus, the MPU-6050 is chosen, which is an integrated sensor combining a 3-axis gyroscope and a 3-axis accelerometer together with an onboard digital motion processor.…”

Section: A Experimental Setupmentioning

confidence: 99%

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Modeling and Analysis of Permanent Magnet Spherical Motors by a Multitask Gaussian Process Method and Finite Element Method for Output Torque

Wen

Wang

et al. 2021

IEEE Trans. Ind. Electron.

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Permanent magnet spherical motors (PMSMs) operate on the principle of the DC excitation of stator coils and three freedom of motion in the rotor. Each coil generates the torque in a specific direction, collectively they move the rotor to a direction of motion. Modeling and analysis of the output torque are of critical importance for in precise position control applications. The control of these motors requires precise output torques by all coils at a specific rotor position. It is difficult to achieve in the three-dimension space. This paper is the first to apply the Gaussian process to establish the relationship of the rotor position and the output torque for PMSMs. Traditional methods are difficult to resolve such a complex 3D problem with a reasonable computational accuracy and time. This paper utilizes a data-driven method using only input and output data validated by experiments. The multi-task Gaussian process (MTGP) is developed to calculate the total torque produced by multiple coils at the full operational range. The training data and test data are obtained by the finite element method. The effectiveness of the proposed method is validated and compared with existing data-driven approaches. The results exhibit superior performance of accuracy.

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Section: B Validation Of Fem Resultsmentioning

confidence: 97%

Section: A Experimental Setupmentioning

confidence: 99%

Modeling and Analysis of Permanent Magnet Spherical Motors by a Multitask Gaussian Process Method and Finite Element Method for Output Torque

Wen

Wang

et al. 2021

IEEE Trans. Ind. Electron.

Self Cite

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show abstract

“…Aiming at the situation where a hard sphere rolls on a soft surface, article [26] proposes a method for estimating the dynamic friction factor, which is typically about 0.1 or less. Furthermore, the maximum static friction torque

{bold-italicT}_{b r k}

of the PMSpM was measured with a spring dynamometer, which was about

0.1 N \cdot m

[18]. The estimation formula of the PMSpM parameter

μ_{0}

is deduced as

μ_{0} = \frac{T_{b r k}}{R \cdot m g},

the initial value of the dynamic friction factor of PMSpM

μ_{0} \approx 0.025

.…”

Section: Identification Of the Dynamic Friction Factor And The Fricti...mentioning

confidence: 99%

“…In the above research works, there is a lack of research on friction torque, resulting in errors between the simulated value of the output torque and the experimental value, and the accuracy of the trajectory tracking control is limited [17]. If the friction model is ignored and the maximum static friction torque is directly used for compensation, it will cause obvious over‐compensation [18]. Therefore, the Multi‐DOF motors represented by the PMSpM lacks a theoretical model of friction torque and an accurate compensation method, and they cannot provide data support for the design optimisation of the motor and the improvement of the trajectory tracking control accuracy.…”

Section: Introductionmentioning

confidence: 99%

Friction torque field distribution of a permanent‐magnet spherical motor based on multi‐physical field coupling analysis

Wang

et al. 2021

IET Electric Power Appl

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Non‐linear friction between the rotor and the rotor support mandrels would occur during the movement of the permanent‐magnet spherical motor (PMSpM). The friction which varies with the position causes PMSpM jitter or even stop it when running at low speeds, and the system operation accuracy is reduced. To solve these problems, this work proposes a parameter identification method of the Coulomb friction model. First, a dynamics model with the Coulomb friction of PMSpM is established by using generalised Euler angles and the Lagrangian energy method. Then, a parameter identification method of the Coulomb friction model based on COMSOL Multi physics coupled simulation and MEMS experiment is proposed to obtain the friction torque data of the PMSpM. Finally, the friction torque compensation in a closed‐loop control experiment is completed by using the friction data. The results show that the accuracy of trajectory tracking control is significant, and the error is reduced by 49.32%. Hence, the distribution of the friction torque field is accurate and effective.

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“…The structure optimization design for a motor is to further improve its performance, such as back-electromotive force (EMF) performance, and torque performance, which is largely influenced by the air-gap magnetic field. A permanent magnet spherical motor (PMSM) has a wide application in multi-degree-of-freedom motion systems such as spacecraft, manipulators, and panoramic cameras because of its small size, light weight, and high torque output [1,2]. In [3], the Halbach magnet array is applied to spherical motors, making the air-gap magnetic field closer to the sinusoidal distribution.…”

Section: Introductionmentioning

confidence: 99%

Multi-Objective Optimization of the Halbach Array Permanent Magnet Spherical Motor Based on Support Vector Machine

Cui

et al. 2020

Energies

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The fundamental harmonic amplitude and waveform distortion rate of the air-gap flux density directly affect the performance of a permanent magnet spherical motor (PMSM). Therefore, in the paper, the axial air-gap magnetic field including the end leakage of the Halbach array PMSM is analyzed and optimized. In order to reduce the calculation time of the objective function, the air gap magnetic field model adopts a non-linear regression model based on support vector machine (SVM). At the same time, the improved grid search (GS) algorithm is used to optimize the parameters of SVM model, which improves the efficiency and accuracy of parameter optimization. Considering the influence of moment of inertia on the dynamic response of the motor, the moment of inertia of the PMSM is calculated. This paper takes the air gap magnetic density fundamental wave amplitude, waveform distortion rate and rotor moment of inertia as the optimization objectives. The particle swarm optimization (PSO) algorithm is used to optimize the motor structure with multiple objectives. The optimal structure design of the PMSM is selected from all of non-dominated solutions by the technique for order preference by similarity to an ideal solution (TOPSIS). The performance of the motor before and after the optimization is analyzed by the method of finite element (FEM) and experimental verification. The results verify the effectiveness and efficiency of the optimization method for the optimal structure designing of the complex PMSM.

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Investigation on the Measurement Method for Output Torque of a Spherical Motor

Cited by 9 publications

References 17 publications

Modeling and Analysis of Permanent Magnet Spherical Motors by a Multitask Gaussian Process Method and Finite Element Method for Output Torque

Modeling and Analysis of Permanent Magnet Spherical Motors by a Multitask Gaussian Process Method and Finite Element Method for Output Torque

Friction torque field distribution of a permanent‐magnet spherical motor based on multi‐physical field coupling analysis

Multi-Objective Optimization of the Halbach Array Permanent Magnet Spherical Motor Based on Support Vector Machine

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