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Research
We have been researching and developing various technologies for distributed real-time systems, which include processor architecture, VLSI design, communications, operating systems, robotics, etc. "Real-Time" means that the processing or communications should be completed untill their specified deadlines in brief. The real-time systems have been becoming more popular and important in recent years.
The demands for real-time systems have been becoming more complex, so that the systems should be built as prallel/distributed systems.
To build the parallel/distributed real-time systems, the key technologies are the real-time communications among nodes, the real-time processing architecture in processors, and real-time operating systems.
Hardware Group
The members of the hardware group have been researching and
developing generic technologies to realize a dependable and
practical VLSI system for distributed real-time systems such as
humanoid robots by co-designing SoC (System-on-Chip) and
SiP (System-in-Package).We have been designing and implementing Dependable Responsive Multi-Threaded Processor (D-RMTP). D-RMTP is a SoC that integrates a real-time processing core (RMT Processing Unit), Responsive Link (ISO/IEC 24740:2008) for a real-time inter-node communication, and various I/O peripherals including SpaceWire, IEEE1394, PCI-X, Ethernet, PWM generators, SPI for ADCs/DACs, etc.
RMT Processing Unit executes eight prioritized threads simultaneously by using a prioritized SMT architecture. An IPC (Instruction Per Clock) control scheme and a tracing mechanism are also designed and implemented on D-RMTP to improve the dependability.
Responsive Link provides a dependable real-time inter-node communication, so that Responsive Link has the priority-based packet-overtaking function at each node and a robust error correction function.
Members
- Nobuyuki Yamasaki
- Hiroki Matsutani
- Kazutoshi Suito
- Yujiro Sasagawa
- Masakazu Taniguchi, Yuji Toshinaga, Kohei Matsumoto
- Kensuke Kaneda, Yuki Kawaguchi, Daiki Kawase, Daiki Yamazaki
Interests
Our research focuses on the following subjects:
| Bus Architecture |
Software Group
The software group works in several sub-groups to give solutions to many of the problems newly emerged
in modern real-time systems.
Modern real-time systems differs from classical ones in various aspects.
First, they tend to use complex hardware whose details are not
fully available.
Second, they often use off-the-shelf components whose behaviors are
not well known in oder to reduce costs.
Third, more than one applications are multiplexed on a
system.
Fourth, they are required to operate in a highly dynamic
environment.
Each one of the above makes the system unpredictable and unreliable.We aim to provide new bases of software technologies for guaranteeing timing requirements of real-time applications under significant amount of uncertainty.
Members
Nobuyuki Yamasaki,Hiroyuki Chishiro,
Kei Fujii,
Yuki Tomizawa, Osamu Yoshizumi,
Yasuhito Ito, Rikuhei Ueda
Interests
Our research focuses on the following subjects:
Development of flexible computation models and
scheduling algorithms for handling unpredictable
loads.
The research aims to provide a practical solution that can be easily applied to real-world applications.
This area works on design and implementation issues related to
real-time operating systems.
The goal is to provide real-time guarantee without relying on excessive reservations of resouces.
Development of protocols for synchronization between imprecise
computations.
The focus of the research is in how the properties of imprecise
computations can be utilized to increase overall performance in
terms of cost for blocking/unblocking and blocking delays.
| Task Migration |
Design and implementation of task migration scheme for high
performance and high avilability on multithreaded/multicore
processors.
Design and evaluation of flexible network management and real-time channel construction algorithm
for real-time communications over Responsive Link.
Robot Group
The robot group is investigating essential architecture for modern robot systems. We are applying Responsive Processor to robotics. Responsive Processor has many peripherals for controls such as A/D converters, D/A converters, PWM generators, PIOs, and so on. Various sensors and actuators can be connected directly to Responsive Processor and controlled. These specifications and properties are suitable for robot systems which consist of many sensors and actuators.
Members
Nobuyuki Yamasaki,Yuta Kojima,
Hajime Imamura
Interests
Our research focuses on the following subjects:
Design and implementation of a fuctionally
distributed control architecture for autonomous mobile robots. The
robot system is composed of several functional modules. Each module
has a PU (Processing Unit) and controls I/O peripherals
independently. Asynchronous interrupts are used among modules to
inform of occurrences of events for controls. A prototype robot is
shown in the picture.
The application of a position estimation
scheme for autonomous mobile robots using Kalman Filter to a position
and task management system for office robots.
| Reconfigurable Modular Robot System |
Design and implementation of a software
framework for reconfigurable modular robot systems. The research aims
to build a block-type robot like LEGO where the form and functions can
be changed freely by the user. Function call mechanism which is
independent on the location of each module and common interfaces have
been investigated, in order to use functions of each module in the
whole system.
| Plug-and-Play |
Development of software (middleware)
architecture to enable Plug-and-Play in modular robot systems. This
includes design protocols from a detection of structural changes to
the reconfiguration of the whole system, proposals for management
scheme of the system information and application programs, and implementation
of function based multi-threaded architecture.