Researcher List

Laboratories in Department of Electrical and Electronic Systems Engineering

System Control Laboratory (at Department of Electrical and Electronic Systems Engineering)
Prof. Wataru KASE

Analog Computer
Analog Computer

For example, when you first try to ride a bicycle, it is not easy to do so, but with practice, you will gradually get better at it. What if you let a computer do the same for you? After all, even if you are not good at it at first, it would be great if you could get better and better. However, in order to do so, we need to create a system that can make use of past experiences in the next driving. We will be working on such a system in this laboratory.

Main Research Topics

  • Research on adaptive and iterative learning control
  • Analysis and synthesis of linear control systems using polynomial matrices

Mechatronics Laboratory
Prof. Toshimitsu MORIZANE

Electric Vehicle and Linear Motor for Research
Electric Vehicle and Linear Motor for Research

In order to achieve a sustainable and prosperous society, we need to use electric energy efficiently. On the other hand, in the field of ICT, electricity is also treated as information, and electricity has become one of the indispensable things. Thus, by making good use of the two aspects of electricity, energy and information, we can make efficient and effective use of electrical devices. This technology is called mechatronics. In the Mechatronics Laboratory, we conduct research on the control of electrical equipment and power conversion devices. These researches will be used in various fields such as motors for electric vehicles, motors for industrial equipment, linear motors, magnetic levitation, matrix converters and non-contact power supply.

Main Research Topics

  • Research on linear induction motor transport systems that simultaneously control magnetic levitation and propulsion
  • Research on matrix converters for electric motor drive
  • Research on electric motor control for electric vehicles
  • Research on non-contact power supply over medium distances
  • Research on high-frequency transformers used in wind power generation system

High Frequency Circuit Design Laboratory
Prof. Tsutomu YOSHIMURA

Photo of IC chip designed and fabricated in the lab
Photo of IC chip designed and fabricated in the lab

Technological innovations in semiconductor integrated circuits have brought dramatic changes in our lives from the latter half of the 20th century to the present day. Nowadays, the ultra-high speed and the high-performance LSIs (large-scale integration) are mandatory for cell phones, game consoles, and other devices that are now commonly found in our daily lives. In this laboratory, students learn circuit design techniques by understanding the operating principles of transistor-based circuits, which are the basis of integrated circuit design, and by designing and fabricating various high-frequency analog circuits. In addition, we would like to contribute to the advancement of circuit technology in the future by analyzing the causes and proposing new circuits to solve the problem of degradation of noise tolerance in analog circuits, which has become a problem in circuit design using ultra-fine transistors in recent years.

Main Research Topics

  • Design of injection-locked PLL circuits with low phase noise
  • Study on the effect of mutual interference in phase-locked circuits
  • Development of power supply circuits for energy harvesting

Systems Optimization Laboratory
Prof. Yuji SHIGEHIRO

Figuring out how to arrange a large number of boards of different shapes.
Figuring out how to arrange a large number of boards of different shapes.

What would you do if you have to arrange a large number of boards of different shapes in such a way that there are as few wasted gaps as possible? Optimization is the search for a more optimal (less wasteful) solution. We mainly research methods to find less wasteful solutions for such puzzle-like problems. The range of applications of such techniques is very wide, and we have been working on a variety of problems such as filter circuit design, control of road traffic systems, and learning of autonomous agents.

Main Research Topics

  • Development of an autonomous distributed multi-point optimization method
  • Autonomous agent configuration and learning methods
  • Application of meta-heuristics to traffic jam mitigation problems

System Dynamics Laboratory
Prof. Katsuyoshi TSUJITA

Development of motion estimation and autonomous docking system for small spacecraft
Development of motion estimation and autonomous docking system for small spacecraft

This laboratory aims to develop mechanical systems that enable humans and machines to cooperate and collaborate with affinity. For example, living organisms and humans behave in a superior and skillful manner depending on their situation. They can detect and integrate much different quality information from the environment and execute appropriate behaviors in context. This laboratory will elucidate such systems' behaviors to develop robotic systems that connect with humans, mechanical systems that coexist with humans, and robotic systems that can skillfully do things that humans cannot easily do.

Main Research Topics

  • Elucidation of autonomous control mechanisms based on analysis of biological and human motions and their application to mechanical systems
  • Development of motion estimation and autonomous docking system for small spacecraft
  • Development of a motor-assist robot system for people with motor dysfunction
  • Development of exploration-type autonomous robots in unknown environments
  • Process analysis of cognitive activities in human creative process

Pulsed Power Engineering Laboratory
Prof. Tomoaki MIICHI

Various plasmas and pulse power supplies built in the lab
Various plasmas and pulse power supplies built in the lab

Pulsed power is a technology that converts energy stored for a long time at low power into high voltage and high current (i.e., high power) in a short time. In this laboratory, we conduct research on water purification using the plasma generated by this technology. Substances called reactive oxygen species generate by electrons in the plasma. By making good use of these reactive oxygen species, we are able to decompose harmful substances that are difficult to decompose with conventional water treatment technology. In addition, by using pulsed power, treatment can be carried out with less energy than conventional technologies.

Main Research Topics

  • Highly efficient decomposition of persistent substances in water using plasma
  • Development of nanosecond pulsed power supply

Robotics Laboratory
Prof. Takashi TAKUMA

Robotics Laboratory

One of the challenging issues in the robotics research area is to achieve dexterous and energy efficient motion like living animals as well as humans. The living animals have viscoelastic joint supported or driven by muscles and ligaments, and they drive their body by different mechanism from robot that has 'rigid' joint. We adopt viscoelasticity to the robot that is avoided to embed in the engineering field, and achieved novel motion that is difficult for the current robot such as jumping with higher impact, trunk twisting by the arm swinging, and invasion of the narrow path by changing its body according to the shape of the path. Currently, by progressing such achievement, we've aimed to develop the robot that moves around rough terrain and wreckage easily, enhance the human understand the dynamics of the human exercise capacity, and understand the dynamics of the human motion.

Main Research Topics

  • Achieving stable jumping in human-like robots driven by artificial muscles
  • Achieving diverse motion in quadrupedal robots with flexible trunks
  • Achieving energy-efficient walking in bipedal robots with flexible trunks
  • Achieving deft holding and handling using flexible materials in robust hands
  • Development of intuitive robot model construction systems in virtual reality

Nanodevices Laboratory
Prof. Shigehiko SASA

Flexible transparent transistors
Flexible transparent transistors

In the Nanodevice Laboratory, we are conducting research to develop devices that have unprecedented features related to "invisible" technologies. "Terahertz" is an electromagnetic wave region that is remaining unexplored. It resides between "lights" and "radio waves", and has unique characteristics. With this "invisible" light becomes available, it enables nondistructive inspections through opaque materials, which is useful for sustainable society. Novel semiconductor technologies are indispensable for both emitting and receiving device developments. Using the equipments at the Nanomaterials and Microdevices Research Center, we are exploring semiconductor heterostructures for the light-emitting devices that operate in the terahertz region, and have succeeded in realizing devices that exceed conventional characteristics. We are also working on the development of "transparent" oxide semiconductors and their fabrication processes.

Main Research Topics

  • Development of terahertz light emitting and receiving devices
  • Development of high-performance zinc oxide transparent transistors

Plasma and Environmental Engineering Laboratory
Associate Prof. Keiichiro YOSHIDA

Plasma and Environmental Engineering Laboratory

This laboratory aims to contribute to solving environmental and energy problems through research on plasma and electrostatics. Non-thermal plasma can induce chemical reactions that never occur at room temperature and can give various objects electrical charges. Electrostatic forces have advantages in moving small objects. Combining these natures, firstly we explore how to remove harmful tiny particles from the atmosphere and to detoxify them, and secondly, we develop the technique to manipulate small objects such as micro plastics and to sort them using electrostatic forces. Moreover, we challenge to control heat flow using the gas stream produced in small spaces by plasma and electrostatic forces that is known as "ionic wind."

Main Research Topics

  • Research on the principle of collection and decomposition of harmful particles using electrostatic and non-thermal plasma
  • Manipulation technology of micro objects using electrostatic force
  • Research on airflow generation in micro spaces using non-thermal plasma and its applications

Plasma Science and Engineering Laboratory
Associate Prof. Masako SHINDO

Roots length of lettuce at two weeks after seeding.
Roots length of lettuce at two weeks after seeding.
Antioxidant ability of lettuce leaves at one month after seeding.
Antioxidant ability of lettuce leaves at one month after seeding.

Main Research Topic

Growth enhancement of plant by plasma irradiation to seeds

Non-thermal atmospheric pressure plasmas produce wide variety of reactive oxygen species (ROS) as well as charged species. Plants which are oxidatively stressed from these ROS show growth enhancement and antioxidant action. We develop dielectric barrier discharge (DBD) plasma sources and irradiate the plasma to plant seeds such as lettuce, herbs and broccoli sprouts to study the correlation between the amount of oxidative stress and the growth speed. It is found that about 30-minutes plasma irradiation to lettuce seeds enhances both the antioxidant ability and the growth acceleration.

Advanced Devices and Process Engineering Lab
Associate Prof. Masatoshi KOYAMA

Next Generation Device and Process Laboratory

Semiconductor devices such as integrated circuits and power semiconductors have been developed using silicon as a base material for many years. In recent years, new materials have been introduced to achieve higher performance and functionality. In this laboratory, we are working on semiconductor engineering from the viewpoint of new materials and processes and developing next-generation devices to realize an affluent and colorful society. Specifically, we are developing high-performance semiconductor devices using oxide materials, novel devices using hybrid structures of nitride and oxide materials and related technologies.

Main Research Topics

  • Development of room temperature operating terahertz wave detectors using InAs-based heterostructures
  • Research on plasma treatment of oxide semiconductor surfaces
  • Development of novel devices based on oxide/nitride semiconductor composite structures

Power Control Lab
Assistant Prof. Hidehito MATAYOSHI

Development of novel control systems for renewable energy sources.
Development of novel control systems for renewable energy sources.

There are various technical challenges in order to introduce a large number of renewable energy sources into power systems. In this laboratory, we are investigating control schemes of renewable energy sources in order to solve energy problems. As one example, we are verifying a novel coordinated operation for multiple photovoltaic generators. In addition, we are developing a new control system for wind power generators to improve the reduction of generated power due to wind speed fluctuations. We will also investigate management schemes for smart grids for efficient use of renewable energy sources.

Main Research Topics

  • Management schemes for distributed generators in smart grids
  • Control strategies for wind power generators
  • Coordinated control systems for multiple photovoltaic generators