Dynamic Analysis Method of Two-Dimensional Linear Oscillatory Actuator Employing Finite Element Method

I . INTRODUCTIONLinear oscillatory actuators (LOAs) have been used in a wide range of applications because they have a lot of advantages: high efficiency, simple structure, easy control, etc . [1] . Small-sized LOAs have a large potential to be used as handheld haptic devices in the near future . Haptic devices that generate a force vector using asymmetric acceleration can create the illusion of a pulling sensation without needing a grounded structure [2] . However, these devices are not suitable for mobile applications because of their size . Furthermore it can only produce a one-DOF force, and also generates unnecessary torque due to the rotation of the connecting rod . We have proposed a 2-DOF oscillatory actuator, shown in Fig . 1, and succeeded in creating an acceleration waveform that is similar to the one generated by the slider-crank mechanism [3] . However, it was then realized that the slider-crank waveform synthesized by our 2-DOF actuator is unique and specific to the mechanical structure of the slider-crank mechanism . Therefore it is actually not necessary to use it for our 2-DOF actuator, which can synthesize a wide range of acceleration waveforms . In a previous paper, we proposed a new acceleration waveform that consumed less power [4] . However, the asymmetric acceleration waveform shown in [4] is not necessarily the best waveform since it has not been optimized . In this paper, first, how the properties of the asymmetric acceleration properties are relate to haptic perception is investigated by conducting experiments on volunteers . Then, by applying a genetic algorithm to the optimization method, an optimized asymmetric acceleration waveform is created . Finally, We verify the effectiveness of the optimized acceleration waveform is verified through 3-D finite element analysis and also experiments on volunteers . II . REQUIRED ACCELERATION CHARACTERISTICS In this section, the effects of the properties of the asymmetric acceleration on haptic perception were determined through experiments on volunteers . Two effects on haptic perception were studied using the acceleration waveform shown in [3] . Fig . 2 shows the relationship between the size of the negative acceleration peak and the percentage of correct answers, with the ratio of the positive to the negative peaks being constant . As the peak value increases, the percentage of correct answers also increases . The percentage of correct answers seems to saturate when the peak value is about 4 .0 m/s 2 . Therefore we determined that a safe negative peak value to obtain a high percentage of correct answers would be 4 .5m/s 2 . Fig . 3 shows the relationship between the ratio of the positive to the negative peaks and the percentage of correct answers . The percentage of correct answers increased linearly with the ratio . From these results, we determined that the ratio of the negative to the positive peaks needs to be as large as possible and the negative acceleration peak should be more than 4 .5m/s 2 to achieve a high percentage of correct answer...

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“…[1] . Small-sized LOAs have a large potential to be used as handheld haptic devices in the near future .…”

Section: Introductionmentioning

confidence: 99%

Optimization of asymmetric acceleration waveform for haptic device driven by 2-DOF oscillatory actuator

Kato

Nitta

Hirata

et al. 2015

2015 IEEE Magnetics Conference (INTERMAG)

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“…Linear oscillatory actuators (LOAs) have been used in a wide range of applications [1][2][3][4][5] because they can reciprocate in a comparatively short stroke in spite of their compact size and light weight. Especially, linear resonant actuators (LRAs) have been used and studied [6,7] because the resonance causes high efficiency.…”

Section: Introductionmentioning

confidence: 99%

Proposal of Load and Amplitude Estimation Method for Linear Resonant Actuator Using Two Back-EMF Signals

Kato

Hirata

Asai

et al. 2015

Journal of the Japan Society of Applied Electromagnetics and Me

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Linear resonant actuators (LRAs) have been used and studied because of high efficiency. However, the amplitude of LRAs severely decreases when external loads are applied. As a solution to this problem, we have proposed an external load estimation method using two signals of the back-EMF. However, the proposed method was effective only under unipolar drive. This paper proposes load and amplitude estimation method for LRAs using two back-EMF signals under bipolar PWM feedback control. The effectiveness of this method was verified through 2-D FEM analysis of our code.

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“…The interlinkage flux of the coil Ψ is the sum of the flux by permanent magnet Ψ mag and the flux by current excitation Ψ I . The interlinkage flux Ψ is described as (2) and (3) is obtained by substituting (2) into (1):…”

Section: Coupling Of Mechanical and Electrical Resonancementioning

confidence: 99%

Characteristic Evaluation of Linear Resonant Actuator Utilizing Electrical Resonance

Kato

Hirata

2018

IEEJ Journal IA

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Linear resonant actuators (LRAs) have been used in a wide range of applications because they utilize mechanical resonance and operate at high efficiency. However, the amplitude of LRAs severely decreases when external load is applied. To solve this problem, we applied PID (Proportional-Integral-Derivative) control to an LRA, and the mover amplitude remained constant against an external load. When a large external load was applied with the target voltage of PID control high, however, input power reached maximum and the amplitude did not follow the target value. As a solution, it is effective to utilize electrical resonance and generate large current. In this paper, we propose a control method to generate an electrical resonance. The effectiveness of the proposed method was verified through dynamic characteristic analysis employing two-dimensional finite element method and measurements.

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Dynamic Analysis Method of Two-Dimensional Linear Oscillatory Actuator Employing Finite Element Method

Cited by 11 publications

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Optimization of asymmetric acceleration waveform for haptic device driven by 2-DOF oscillatory actuator

Optimization of asymmetric acceleration waveform for haptic device driven by 2-DOF oscillatory actuator

Proposal of Load and Amplitude Estimation Method for Linear Resonant Actuator Using Two Back-EMF Signals

Characteristic Evaluation of Linear Resonant Actuator Utilizing Electrical Resonance

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