Faculty Members

Hiroshi Hosaka/Professor/Division of Environmental Studies

Department of Human and Engineered Environment//Mobile sensor network, mechatronics, machine daynamics

Career Summary

1979: Graduated, Faculty of Engineering, The University of Tokyo
1981: Graduated, Master course, Graduate School of Engineering, The University of Tokyo
1981: Research Engineer, Electrical Communications Labs. Nippon Telegraph & Telephone Corp.
1990: Doctor of Engineering from The University of Tokyo
1997: Associate Professor, Graduate School of Engineering, The University of Tokyo
1999: Professor, Graduate School of Frontier Sciences, The University of Tokyo

Educational Activities

Graduate School of Frontier Sciences: Special Lecture on Environmental Information Equipment
Graduate School of Engineering: Mechatronics for Human Environments
Undergraduate School of Engineering: Machine Dynamics 1

Research Activities

Hiroshi Hosaka has investigated the numerical analysis of mechanical vibration as a master's student at the University of Tokyo. He subsequently joined Nippon Telegraph and Telephone Corp. and engaged in research and development of information mechatronics devices; such as magnetic tapes, floppy disks, optical disks, MEMS switch arrays, and tunneling robots for optical fiber burring. He received his PhD for his vibration analysis of floppy disks and magnetic tapes.
After joining the faculty of the University of Tokyo, he has researched sensing systems and machine dynamics. By attaching various motion sensors to a person, the person's behavior can be recognized and his or her next action predicted, then adequate information is obtained through the network. Each person behaves according to a tacit rule affected by time, place, weather, previous action, and so on. Thus, by recording a person's actions for a long time, his or her next regular action can be predicted and irregular actions can be detected.
As another application of the sensor network, he has developed a logistic information system. PHS and other radio transmitters are attached to palettes and containers, and by measuring radio wave intensity, their positions are precisely calculated.
For human and logistic information sensing systems, small and longtime batteries are indispensable. Dr. Hosaka is developing automatic power generators that convert the vibrational energy of moving objects to electricity. He successfully developed resonance type and a shoe built-in type generators. Currently, he is developing a fluid-induced vibration type and a gyroscopic type generators. The latter generates precession of a rotor by the input vibration, and friction force caused by the precession increases spinning speed, generating power over 1 W. By combining these devices and software, and through collaboration with Prof. Sasaki's and Prof. Morita's laboratories, wearable information systems as shown in the figure are being developed.

Wearable sensor system


1) H. Hosaka,"Micro-Optomechatronics", Marcel Dekker, New York, 2005.
2) H. Hosaka,"Technology of Electric Power Generators using Mechanical Vibrations for Wearable Information Equipment", IEEJ Transactions on Electrical and Electric Engineering, 2, 1, pp49-54 (2007)

Other Activities

Institute of Electronics, Information and Communication Engineers of Japan
Japan Society of Precision Engineering
Japan Society of Mechanical Engineers
Holorogical Institute of Japan
The Robotics Society of Japan

Future Plan

Mechatronics is a technology that increases the performance of mechanisms by using electronics, optics and information technologies. The term "mechatronics" was invented by a Japanese company in the 1970's, and mechatronics has lead Japanese industry for 30 years. It was first used for factory production lines to increase production speed and precision. Next, by the drastic miniaturization and cost-down of processors, semiconductor lasers, sensors and other electronic components, mechatronics came to be used for consumer products such as automobiles, information equipment and consumer electronics. In the next stage, mechatronics will be attached to human bodies in clothing, and will be built in the natural environment. Thus far, mass-produced equipment has been designed for the averaged requirement of many individuals. In the future, mechatronics will adapt itself to each user. For example, an air-conditioner will learn favorable temperature of each person for each situation. I consider mechatronics in this stage to be Ubiquitous Mechatronics and will make it the main theme of our laboratory.

Messages to Students

Graduate students must be specialists in their research fields. In our lab, students study dynamics or signal processing intensively. We encourage students with an interest in computers and dynamics to visit our lab.
However, researchers should not limit themselves to a single specialty for their entire careers. We must study other fields all the time. Our graduate school, both as an organization and as an system is intended to encourage the fusion of different fields. We advise students to become both specialists in a field and to experience many related fields.