Masaki Nagai

Optimal Rear Suspension Preview Control of Nonlinear Vehicles Using Neural Networks

Abstract This paper analyzes the performance of neural networks to be used for identification and control of nonlinear vehicle suspensions. It is shown that neural networks can be efficiently trained to identify the dynamical characteristics of actual vehicle suspensions so that they can predict the vehicle future behavior. After trained, this neuro-vehicle is used to train both front and rear suspension neuro-controllers under a nonlinear rear preview control scheme. To do that, a neuro-observer is trained to identify the inverse dynamics of the front suspension so that front road disturbances can be estimated and used to improve the response of the rear suspension.

REMOTE SENSING BY UNIVERSITY OF TOKYO’S PICO-SATELLITE PROJECT “PRISM”

This paper presents our design concept and some technological topics in our ongoing project, “PRISM” which stands for “Pico-satellite for Remote-sensing and Innovative Space Missions”. Nakasuka laboratory in University of Tokyo has been designing and developing this pico-satellite since 2002. Its main mission is remote sensing. Basically, we aim to obtain Earth images with as high resolution as about 30 meters by its compact spacecraft bus, which is a 17cm*17cm*25cm and will be weigh less than 5kg. PRISM has a refracting optical system using one group of lenses, unlike most of the Earth Observation satellites. A main reason why we adopted this kind of optics is the possibility of downsizing the whole optics with extensible tube framework for telescope. Moreover, we’ve been dedicated to design and development of many components in every subsystem. The fundamentals of its bus technologies are on the basis of the experience in our previous project, “CubeSat XI” [sai] [1], which was launched in 2003 and has been operative for more than 16 months. We are now developing PRISM engineering model with a hope to launch its flight model between 2005 and 2006.

LARGE “FUROSHIKI” NET EXTENSION IN SPACE – SOUNDING ROCKET EXPERIMENT RESULTS

Abstract University of Tokyo and Kobe University conducted a sounding rocket experiment to deploy large “Furoshiki” net in space, which is a promising candidate for the future large antenna or solar power satellites. The experimental system consisting of mother and three daughter satellites as well as a folded net was separated from S-310 sounding rocket of JAXA/ISAS at the altitude of 110km, where the daughter satellites, after separated from mother satellite with 1.2 m/s velocity, deployed a large net of 14m-sized triangle. The deployment was quire successful without any tangling and the dynamics during deployment has been captured by cameras, INS and radar distance measurement system. Retro-directive antenna micro wave transmission experiment using 4 antennae on the bottom of satellites were conducted also successfully.