Review: Recent Advances in Micromotors

Mashimo, Tomoaki; Izuhara, Shunsuke

doi:10.1109/access.2020.3041457

Cited by 25 publications

(8 citation statements)

References 128 publications

(158 reference statements)

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“…To achieve micromotors with sufficient power, many researchers have demonstrated their prototypes in the past 40 years [13], [14]. However, these micromotors have not been able to satisfy the specifications for smaller PAVs.…”

Section: A Selection Of Actuators For Rotary-wing Pavsmentioning

confidence: 99%

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Lift Generation by a Miniature Piezoelectric Ultrasonic Motor-Driven Rotary-Wing for Pico Air Vehicles

2022

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Actuators are key components for further miniaturization of insect-scale microrobots. It is challenging to create a new miniature actuator suited for rotary-wing pico aerial vehicles (PAVs), which have a wing span of a few centimeters and a mass of a few grams. In this paper, we propose a miniature piezoelectric ultrasonic motor that permits high-speed rotation at a sufficient torque to achieve the flight of the simplest device comprising the proposed motor and rotor blades. The prototype motor, which employs a bending vibration mode as a principle, measures 1.6 mm × 1.6 mm × 2 mm and weighs 25 mg. The experimental results show that the miniature motor rotates rotor blades having a length of 20 mm with an angular velocity of over 1800 rad/s. The thrust force generated from this system exceeds its total mass of 110 mg and successfully lifts the system. Although the flight is tethered, the set of the proposed motor and rotor blades demonstrates a takeoff that represents the possibility of rotary-wing PAVs.INDEX TERMS Micro air vehicles, propellers, micromotors, microactuators, microfabrications.

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Section: A Selection Of Actuators For Rotary-wing Pavsmentioning

confidence: 99%

“…Because ultrasonic motors inherently deliver high-torque at low-speed, changes in the design are required to reach the desired speeds (approximately 2000 rad/s) for PAVs. Existing miniature ultrasonic motors have been compared in review papers (e. g., [14], [22]).…”

Section: A Selection Of Actuators For Rotary-wing Pavsmentioning

confidence: 99%

Lift Generation by a Miniature Piezoelectric Ultrasonic Motor-Driven Rotary-Wing for Pico Air Vehicles

2022

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“…Combined with the Finite Element Method (FEM), we designed and fabricated an OSSPSU motor with the dimensions of 5 mm Length × 1.3 mm Height × 1.06 mm Width based on two [001]-poled Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PIMNT) single crystal units, which couples 31- and 36-modes. To the best of our knowledge, it possesses the highest step accuracy (3 nm) among standing wave ultrasonic motors in open-loop control 1 , 21 , 32 , 33 . Due to the ultrahigh strain of the 31–36 coupled vibration mode of the OSSPSU stator, the newly proposed OSSPSU motor exhibits a large output speed in unit volume of 4.66 s −1 mm −2 .…”

Section: Introductionmentioning

confidence: 98%

Miniaturized electromechanical devices with multi-vibration modes achieved by orderly stacked structure with piezoelectric strain units

et al. 2022

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Piezoelectric devices based on a variety of vibration modes are widely utilized in high-tech fields to make a conversion between mechanical and electrical energies. The excitation of single or coupled vibration modes of piezoelectric devices is mainly related to the structure and property of piezoelectric materials. However, for the generally used piezoelectric materials, e.g., lead zirconate titanate ceramics, most of piezoelectric coefficients in the piezoelectric matrix are equal to zero, resulting in many piezoelectric vibration modes cannot be excited, which hinders the design of piezoelectric devices. In this work, an orderly stacked structure with piezoelectric strain units is proposed to achieve all nonzero piezoelectric coefficients, and consequently generate artificially coupled multi-vibration modes with ultrahigh strains. As an example, an orderly stacked structure with two piezoelectric strain units stator, corresponding to 31–36 coupled vibration mode, was designed and fabricated. Based on this orderly stacked structure with two piezoelectric strain units stator, we made a miniature ultrasonic motor (5 mmLength × 1.3 mmHeight × 1.06 mmWidth). Due to the ultrahigh strain of the 31–36 coupled vibration mode, the velocity per volume of the motor reached 4.66 s−1 mm−2. Furthermore, its moving resolution is around 3 nm, which is two orders higher than that of other piezoelectric motors. This work sheds a light on optimizing the performance of state-of-the-art electromechanical devices and may inspire new devices based on multi-vibration modes.

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“…Furthermore, they involve several technical problems to miniaturize the components, such as coils, permanent magnets, and bearings. Instead, piezoelectric ultrasonic motors perform at such a scale as the most prominent microactuators because of their high power density and good machinability [3], [4]. Despite the great scalability, they have obvious nonlinear and time-varying characteristics that complicate their models for control.…”

Section: Introductionmentioning

confidence: 99%

A Closed-Loop Micro-Ultrasonic Motor Control System With Extremum Seeking

et al. 2023

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Microactuators are an essential technology to revolutionize existing micromachines, but making them closed-loop controlled with an internal sensor is a great challenge due to the limited size of the components. In this paper, we build a micro-ultrasonic motor in the 2-3 mm scale, combine it with a tunneling magneto resistance (TMR) sensor with dimensions of 1.4 mm × 1 mm, and construct a closedloop system with a control algorithm. It is currently the smallest rotary actuator-sensor system assembled into a size with a height of 3.2 mm, a width of 3.2 mm, and a length of 5 mm. In the system, we attempt to solve a steady-state error problem for the micro-ultrasonic motor's internal parameter changes, such as a temperature rise and the resonant frequency variation. A model-free, real-time-adaptive extremum seeking controller (ESC) that continuously tracks and localizes the optimum driving frequency is implemented into the system for the desired rotation with minimum steady-state error. Although the controller is simply designed, experiments show a good accordance between the resulting angular velocity and the reference.INDEX TERMS Piezoelectric actuators, ultrasonic motors, micromotors, closed-loop control, extremum seeking controller, and temperature disturbance.

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Review: Recent Advances in Micromotors

Cited by 25 publications

References 128 publications

Lift Generation by a Miniature Piezoelectric Ultrasonic Motor-Driven Rotary-Wing for Pico Air Vehicles

Lift Generation by a Miniature Piezoelectric Ultrasonic Motor-Driven Rotary-Wing for Pico Air Vehicles

Miniaturized electromechanical devices with multi-vibration modes achieved by orderly stacked structure with piezoelectric strain units

A Closed-Loop Micro-Ultrasonic Motor Control System With Extremum Seeking

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