Ultrasonic stent motor

The purpose of this study is to develop a stent motor for medical blood vessel treatment. The stent motor is a movable stent. It has functions of removing plaque and expanding blood vessels. It consists of two parts; ultrasonic receivers and vibration transmitting coil (stator). In this study, the authors have focused to the vibration analysis of the receiver. In the first design stage, the authors have evaluated resonant phenomenon using finite element method. When driving it in water, the resonant frequency of the air use is shifted due to mass effect of water around the receiver. The frequency analysis of the receiver shows that extremely high precision of dimensions is required because the resonant frequency in water depends not only the size but also the amplitude of the vibration. It is very difficult to design an optimal receiver resonating in water. In order to solve this problem, the authors have tried a new receiver with wide plate receiving ultrasound effectively and requiring no resonant. The authors have succeeded in driving this type of motor in water

Development of spherical ultrasonic motor for pipe inspection robot

We present a pipe inspection robot using a newly developed spherical ultrasonic motor (SUSM) as a camera actuator. The novel SUSM has improved the range of movement compared to previous SUSMs, and the robot can point a camera in any direction. In this study, we determined a method for controlling the rotational direction and strategic control from the kinematics and characteristics of ultrasonic motors. The rotational directions were defined by the phase differences of the applied voltages, and the rotational speeds were changed with the frequencies. Additionally, we developed a very small position sensing system using rotary potentiometers. In the control experiment performed using the sensing system, the SUSM showed the returnability to the default position from several specified points, within an accuracy of 1°

Development of Spherical Ultrasonic Motor for Critical Environment

In recent years, due to advances in science technology, space satellites have made progress. So, the presence of space debris has become problem in the world because they may collide each other. In our study, we have developed Spherical Ultrasonic Motor (SUSM) for space use with 3 DOF to drive the satellite thruster and resolve it. We aim that the satellites enter the atmosphere when the satellites reached the end of life, and SUSM controls thrusters when they inject for the directional control. We have made experiments of measuring torque, durability and lifetime. It shows that the torque and lifetime meets target value. But durability does not meet target value. To resolve it, we have applied stator lining materials and shifted frequency with 0.4kHz from resonant frequency and we have shown that it meets durability required specifications

A study for safety design of electrical machines considering human behavior

Manufacturers have to design machinery considering not only the intended use, but also a reasonably foreseeable misuse, which can lead to product-related accidents. However, manufacturers cannot predict everything the users might do for the machinery. In this study, we have focused on one type of misuse: when the users put their hands inside machinery. Safety mechanisms that deter users from putting their hands inside machinery are required to prevent such accidents. Therefore, in this study we have tried to understand what promotes this action. In this initial stage of our research, we experimented with the visibility and accessibility of an object, and evaluated whether there are related instructions that can affect human behavior

Waterproof ultrasonic motor

The authors have been making a multi degree of freedom piezoelectric actuator that has Translational and Rotational motions in one joint (TR motor). Because the motor has the advantages such as simple structure and excellent controllability, it has high potentials for wide use in non-industrial applications. The authors will apply it to outdoor use, especially, use in water. The authors have applied insulating process to the piezoelectric element for waterproof and designed an optimal shape of it for driving in water to show driving TR motor in water successfully

Wearable agrirobot

We have developed an exoskeleton robot for agriculture. It assists farmers in harvesting vegetables and fruits, and carrying the heavy load such as potato bags and cabbage boxes. We have made the robots for some types of farming and discussed the sensors and control of it. We have also performed experiments in order to demonstrate how the robot operates for agricultural purposes thereby showing the potential of the robo