Toshiyuki Taniguchi

A H/sub infinity / optimal theory-based generator control system

A generator control system is designed on the basis of H/sub infinity / control theory, and the control performance of the system is investigated. A Riccati equation approach is first introduced. How to apply this approach to designing the generator control system is then presented. The control performance of the system based on H/sub infinity / control design is studied by numerical examples and is compared with that based on linear-quadratic control design. Some advantages and disadvantages of the generator control system based on the H/sub infinity / design are clarified. >

Open-loop control of a stepping motor using oscillation-suppressive exciting sequence tuned by genetic algorithm

A new method for suppression of rotor oscillation in open-loop drive of a stepping motor is proposed. In this method, the torque equilibrium position of the motor is manipulated so as to guarantee insensitiveness to the variation of rotor inertia; the motion of the equilibrium position is made to be nonoscillatory, and the frequency of the motion is bound within the region limited by the maximum frequency determined by considering the performance on the condition with the largest inertial load. The exciting sequence used for a single-step drive is tuned by using the technique of genetic algorithm. It is shown by the experimental results that rotor oscillation can be well suppressed on the load conditions with different inertial loads.

Three-body attachment in oxygen and an air-like nitrogen and oxygen mixture

Calculations of the three-body attachment coefficient eta 3/N, N being the gas number density, in oxygen and an air-like nitrogen and oxygen mixture, are performed using a Boltzmann equation method. First, an appropriate cross-section Qa3 for this attachment process in oxygen is deduced by modifying that of Spence and Schulz (1972) so that the calculated eta 3/N agrees well with the experimental values of Grunberg (1969). Then, the deduced Qa3 is used for the calculation of eta 3/N in an air-like mixture of 79% nitrogen and 21% oxygen. Good agreement is obtained with the eta 3/N values measured for dry air by Hessenauer (1967) at low E/N, where E is the electric field. The variation of eta 3/N2 with N is studied, and it is found that even though the value of Qa3 is assumed to be proportional to N, eta 3/N2 can decrease with increasing N due to the change in the electron energy distribution, caused by the variation of Qa3.

Speed Control of a DC Motor System through Delay Time Variant Network

Nowadays, information and communication technologies are rapidly developed. Therefore, it is easy to make up a computer network like local area network and its cost is also low. It is guessed that it is standard tool for data communication even in motor control system. In the present work, a specific speed control system for a small DC motor including an Ethernet network is interested. However, the network always has a delay time and it seems to be varied randomly on the surface. This phenomenon gives disadvantage to the control system. Therefore, we discuss the control characteristics and the problems when the DC motor is driven under the system including the Ethernet network. Especially, the relation between the distribution of delay time and control characteristic is examined at the new point of view

Open-Loop Control of a Stepping Motor through IP Network

In this work, IP (internet protocol) network- based control system of a stepping motor is constructed and the control performance is examined. The network has transmission time delays, jitters and packet loss. These give disadvantages to the control system. Therefore, it is important to examine the performance degradations when a motor is driven under the system through IP networks. The position control experiments are done in open-loop using a stepping motor, which is one of the most popular one and an appropriate one for a position control. Then the control ability is examined against various network conditions.

A calculation method for estimating a cross section using a Boltzmann equation analysis

A calculation method is proposed for estimating a momentum transfer cross section or a total cross section (summation of the elastic momentum and inelastic), from electron drift velocity versus E/N data, by a Boltzmann equation method. Here, E is the electric field and N is the gas number density. In this method, the calculation is performed knowing that the electron energy distribution is shifted towards higher energy with increasing electric field. The validity of this method is examined by applying the analysis to a model gas, which consists of elastic momentum transfer and electronic excitation as collisions between an electron and a gas atom. The results show that a good approximation, a correct cross section can be obtained automatically from the electron drift velocity data by this method.

Adaptation of Grouping Structure Analysis in GTTM to Hierarchical Segmentation of Dance Motion

In this paper, the authors propose the adaptation of the rules used in the grouping structure analysis in Lerdahl and Jackendoffs “A Generative Theory of Tonal Music (GTTM)” to dance motion analysis. The success of the adaptation realizes the segmentation of dance motion in a hierarchical fashion. The analysis method obtained by the trial of the above adaptation consists of the following procedures. A motion-capture data stream of a dance is first divided into a sequence of events by piecewise linear regression. The hierarchical structure of groups each of which consists of a sequence of the events is then extracted by applying the grouping rules adapted to dance motion analysis. The above method is applied to motion-data streams acquired by motion capture systems. The obtained results indicate the following advantages: (1) The structure of hierarchical segmentation is precisely extracted in response to the characteristic of an analyzed dance. (2) The extraction of the hierarchical segmentation provides the possibility of the development of a technique distinguishing the oversegmentation from regular boundaries. (3) The possibility of utilizing the information of hierarchical segmentation for the comparison of dance performances is suggested.

Extraction of Motion Characteristics in Dances by Statistical Analysis of Joint Motions

In this paper, the authors attempt to develop a technique for the analysis of the motions of dances having no stylized motion structure, focusing on joint motions. The variance-covariance matrix given by the statistical analysis of the time-series data of joint motions is selected for the evaluation index characterizing dance motions. The application of the derived evaluation index to the representation of dissimilarity between dances is shown to be effective when the whole commonness appearing in both the dances compared should be considered. It is also confirmed that the application of multidimensional scaling (MDS) with the orthogonal rotation of coordinate axes is effective to extract the distribution feature of a database of dances. The evaluation items characterizing all the dances belonging to the database are automatically extracted by the analysis of correlation between the coordinate axes given by MDS and the elements of the variance-covariance matrix.

Multi-level segmentation of dance motion by piecewise regression

It has been recognized that a technique to divide a raw motion-capture data stream of a dance into segments on the time axis is needed [Sonoda 2008]. In particular, the extraction of the higher-level information such as the hierarchical segmentation-structure is a subject of growing interest at the present time. In this study, the authors attempt to develop a method to segment dance motion in a multi-level style, namely in a hierarchical fashion.

Qualitative evaluation of quantitative dance motion data

In the field of dance motion analysis, the development of qualitative evaluation technique for the analysis of body motions described in the form of quantitative data is needed [Nakamura et al. 2008]; it makes dance motion data acquired by motion capture systems intuitively interpretable. In this study, the authors propose a method to automatically summarize the qualitative trend in a group of quantitative dance motion data; the motion features shown in all the dances are first quantitatively extracted by statistical analysis and then qualitatively categorized by cluster analysis.