We developed a high response pneumatic servo valve for a pneumatic precise positioning system. This valve is not affected by friction force by an air bearing and has a high-resolution position sensor to accurately control position. We analyzed characteristics of this valve and the designed controller. The characteristic experiment was done to confirm the effectiveness of the designed controller.

View full abstract

In this paper, we present an alternative ubiquitous computing environment based on an integrated design of real and virtual worlds. We implement three different research prototype systems: the Virtual Kyoto Garden, Touchy Internet, and the Human Pacman. The functional capabilities implemented in these systems include spatially-aware 3D navigation, tangible interaction, and ubiquitous human media spaces.

View full abstract

To support caring interaction based on Sandplay Therapy and Narrative Therapy, Mixed Reality for Sandplay Therapy is introduced. Mixed Reality enables us to express ourselves more effectively by Sandplay, which reflects various discrepancies of a client's socially-induced self-image, which is sometimes referred to as the Dominant Story” in Narrative Therapy. Mixed Reality for Sandplay enables us to detect various ways of changing a client's inadequate perceptual consistenceies in the dominant story into an adequate and consistent one.

View full abstract

In nonverbal communication such visual tools as signs and pictograms are widely used to help others understand, they should be designed based on shared concepts. For this purpose, we propose a framework for exploring such concepts by putting them in a topology space based on Mathematical Morphology and Modal Logic to clarify how common sense or misconceptions occur.

View full abstract

It is still difficult for casual users to author 3D models from scratch. Our goal is to design easy-to-use 3D graphics authoring tools so that people can use 3D graphics as an everyday communication tool such as word processors and emails. This paper introduces some of our projects toward the goal.

View full abstract

The main purpose of this study is to develop the ventricular assist device “VAD” which promotes the recovery of failing hearts. We developed a new VAD which is driven by linear oscillatory actuator. The durability of the VAD as well as the adaptive control method was evaluated in an animal experiment. The study confirmed the feasibility of the new VAD.

View full abstract

The totally implantable electrohydraulic total artificial heart system has been developed. The maximum cardiac output and the efficiency of the pumping unit were improved to 12 L/min and 15.4 %, respectively. The system was successfully implanted in 16 calves of more than 60 kg range. The longest surviving calf lived for 70 days and remained in good general condition.

View full abstract

We produced experimentally a bio-signal monitoring system that could measure bio-signals simply and non-restrictively using an air-mat sensor. We performed signal processing of the output obtained by this air-mat sensor using the wavelet transform that is expected as a processing and analysis technology for bio-signals to explore the possibility of detecting respiration and heartbeat as well as SAS.

View full abstract

We suggest requirements for the human-friendly control and a control design which satisfies some of those. For a demonstration of this human-friendly control, we adopt a power-assisted wheelchair and apply proposed control to it. We pick up two problems which happen in power-assisted wheelchair control by gravity, then propose solutions to each problem and try to establish the human-friendly control.

View full abstract

To move independently is very important for people with walking disability, thus, so is the development of walking assistance robotic-suit. To make this happen, a compact and simple control theory which predicts walking motion was proposed based on strategies derived from present biped walking technologies. We introduce about our trial product being developed to verify this walking assistance theory.

View full abstract

A novel scheme to expand the spatial measurement range of multiplexed fiber Bragg grating (FBG) strain sensor by syntheses of optical coherence function (SOCF) is proposed, which allows de-multiplexing of FBGs of similar Bragg wavelengths. By actively making use of the multiple coherence peaks synthesized in SOCF to de-multiplex the FBGs, the measurement range is expanded per vernier effect.

View full abstract

In the White-Light Interferometry, two peaks appear in the interferogram if a transparent film exists on the surface to be measured. An algorithm has been developed that can detect the peak positions, and a Film Profiler” has been put into practical use

View full abstract

We devised an automatic height measurement technique for plural pulverized particles utilizing an optical microscopic camera and two semi-conductor lasers. Each height of pulverized coal particles was automatically and consecutively measured. As a result, it was verified that the automatic height measurement technique was of almost equivalent precision and six times faster measurement as compared with our developed 3-dimensional particle size measuring method.

View full abstract

We propose real-time heterodyne imaging interferometry using the three-phase correlation image sensor (3PCIS). The 3PCIS simultaneously demodulates amplitude and phase images of heterodyne interference within a single frame. We developed a real-time imaging system of heterodyne interferometry based on a Michelson polarization interferometer using a two-frequency He-Ne laser with a beat frequency of 25 kHz.

View full abstract

This paper presents the invariant discrete-time model for a continuous-time system governed by the logistic differential equation. The state of this model matches that of the continuous-time original at the discrete-time instants for any sampling interval. Simulations are carried out to show the superior performance of the proposed method over other known methods.

View full abstract

New method of generating algebraic algorithms for estimating unknown frequencies of multi-tone signals is derived by mathematical induction. By using the method, the triple-tone algorithm is generated. Next, a handy generation method is introduced to generate the quadruplet-tone, and the higher-tone algorithms. The generated algorithms are verified, and shown to be identical with the ordinary algorithms.

View full abstract

Microphone array technique are representative method for Direction OF Arrival(DOA) estimation. A large hard ware amount of the system is required to obtain sharp directivity characteristics using these techniques. The fundamental principle of multiple sound sources based on the parameter estimation method is proposed. The fundamental principle of the DOA estimation and the frequency and phase estimation technique are discussed.

View full abstract

In Kagoshima, typhoons repeatedly hit power systems very badly and sometimes cut off electricity. To ensure the rapid restoration of electricity supply, one needs to predict the accurate amount of damage. This paper considers the damage prediction in each district in Kagoshima Prefecture by using a two-stages predictor, which consists of Linear regression model and Neural networks.

View full abstract

In this paper, a new method to predict time-varying system parameters is proposed. This method uses the concept of the angle between subspaces spanned by the extended observability matrix used in 4SID methods and predict the future subspace by rotating past subspace in the geometrical sense. Then, estimates of each system matrices are derived by the 4SID framework.

View full abstract

We have designed a slip control system for a lock-up clutch by using two-degree-of-freedom control with a feedback controller for ensuring stability and a feedforward controller for obtained the desired response. Test results have confirmed that it contributes to an appreciable improvement of fuel economy.

View full abstract

The Quasi-Zenith Satellite System (QZSS) is based on satellites at inclined geo-synchronous orbits, which are visible from users with high elevation angles. Therefore, the combined use of QZSS with GPS and/or Galileo (GNSS), especially in canyon and urban environments, has special interest. This paper describes simulation results conducted to evaluate the effectiveness of QZSS in supplementing GNSS.

View full abstract

This paper describe the results of an investigation of the expected navigation ( Orbit determination ) accuracy during the approach phase of a planet orbiter mission. The target planet is Venus. This expected accuracy was determined for Earth-based Doppler observation data with and without the addition of ranging or on-board optical observation data.

View full abstract

This paper deals with design of a failure tolerant control system where failures are identified using the normalized coprime factorization method. The identification method employed is a closed-loop one, which is also based on coprime factorization. The impact of failure on the closed-loop stability is evaluated by v-gap metric obtained from the estimated plant.

View full abstract

This paper proposes a dual-rate global digital redesign method for flight control. Given a continuous-time autopilot, dual-rate digital redesign based on the concept of plant-input-mapping is applied at each operating point, constraining the orders of the discrete-time controllers. The technique provides satisfactory performances over an extended range of sampling rates, as compared with other widely used methods.

View full abstract

Repetitive control method is well known for its high performances in feedback systems that are subject to periodic exogenous inputs. This paper reviews the theory and applications of repetitive control based on both the internal model and external model, together with some repetitive control methods for nonlinear plants.

View full abstract

The experiments of modeling the classical T2 multivariate statistical process chart with an ART2 neural network proposed in this paper were verified very well. Some intrinsic variable cross-correlations existing in the simulated process that could not be detected with the T2 chart could be found by the proposed system.

View full abstract

This paper addresses a new decentralized robust LFC design in a deregulated environment under bilateral-based policy scheme. The LFC problem is formulated to a PI based multi-objective control problem via a mixed H2/Hinf control technique. The robust PI control problem is reduced to a static output feedback control synthesis, and is solved using a developed iterative linear matrix inequalities algorithm.

View full abstract

A control based on human knowledge is flexible and effective for the nonlinear system. Double inverted pendulum is an unstable nonlinear system, it is difficult to control it. On the other hand, human can get knowledge of operation of such a complicated system by moving it several times. In this paper, we propose an intelligent control method based on human knowledge of operation.

View full abstract

This paper proposes a new design scheme for a reduced-order state observer. The method is derived by using duality between a reduced-order observer and a sliding mode controller. In the method, a reduce-order observer is designed by calculating eigenvectors corresponding to the assigned poles.

View full abstract

A Piezo-electric inchworm type actuator for an ultra precision linear stage is proposed. The linear stage is integrated with the developed inchworm actuator, so it has a compact size, and it provides long stroke fast motion with a precise positional accuracy. We use an I/Q heterodyne interferometer system and develop a counting method to measure its position.

View full abstract

This paper presents a multirate H₂ control synthesis for the horizontal navigation system of a micro-tunneling robot, in which the sampling intervals for sensing and control are different. The trajectory is combined with a dynamic model of the robot. Then, for the corresponding lifted system we design a multirate H₂ controller. The validity of the system is verified in simulations.

View full abstract

In this paper, the model following control problem for mechanical systems with discontinuous uncertainty is considered. The approach to design the controller is based on Filippov's framework and generalized Lyapunov stability theory. A model following controller which makes the error system asymptotically stable is derived in Filippov's framework.

View full abstract

For stabilizing an inverted pendulum system, a switching control law is proposed. It is based on a modified energy such that the potential energy is minimum in upright position. Paying attention to the transition of the modified energy, the stability of the switching controlled system can be ensured. Simultaneously, the control parameters and the switching conditions are shown.

View full abstract

In this paper, a risk-sensitive control of a single-link flexible arm subject to random disturbance is considered. Assuming that effect of nonlinear terms in the dynamics, a set of liberalized model is obtained for applying the LEQG control theory which is one of the risk-sensitive controls. Simulation studies are presented to demonstrate the effect of variations of the risk-sensitive parameter.

View full abstract

In this paper, a file selector is constructed based on causal network. In order to help users easily estimating use possibility of each file in the file directory. It offers users with the information about selected probability or popularity degree for each file. Moreover, the order of files is sorted in terms of this selected probability value.

View full abstract

A representational scheme for describing the mental model of an operator for performing operations is discussed. Situation theory is introduced into a representational model of operator behavior based on Petri nets and modal logic. In this framework, restrictions tuned by operators are considered, leading to an intuitive representation of the transition of the operator's mental model through interaction with the system.

View full abstract

Our purpose was to determine if there was an effective way to quantitatively assess the physiological effects of various forms of stress and to correlate these assessments with different psychological mood states. As a result, we found that the Middle Frequency region of the heart was affected suggesting that it could be a useful tool in assessing mental stress.

View full abstract

The purpose of this research is to construct walking support system as a musical communication process. Our strategy is to extend Walk-Mate system, which realizes mutual adaptation process between human and virtual walker by exchanging step sound. We replaced this step sound to the music performance and showed the effectiveness in the experiment of walking support.

View full abstract

The use of time series of human heart rate in basic and clinical biomedical sciences, especially recent finding on the origin(s) of complex long-term heart rate variability, is introduced.

View full abstract

We report results of experimental and simulation studies on the fluctuation dynamics of interbeat intervals (IBIs) in aggregated systems of spontaneously beating cultured neonatal rat cardiac myocytes. The correlation properties of the IBI fluctuations vary depending on incubation time, which can be reproduced using Bonhoeffer-van der Pol coupled oscillator model with appropriate values of coupling strength among the oscillators.

View full abstract

Coupled oscillator systems with oscillating cells of plasmodium of the true slime mold were constructed with a cell pattering method using microfabrication technique. Parameters in this system such as coupling strength can be systematically controlled like in computer simulations. We constructed three-oscillator systems in rings and observed spontaneous switching among typical spatio-temporal patterns even when coupling strength was fixed.

View full abstract

Alternating occlusion of the bilateral femoral arteries, which simulates rhythmic intramuscular pressure changes during locomotion, caused human heartbeats to become phase-locked with the occlusion rhythm. The synchronized phase did not include overlap between peak arterial flow velocity in the leg and elevated cuff pressure. Functional significance of phase synchronization between cardiac and locomotor rhythms is discussed.

View full abstract

This paper studies the constraints in filterbank design and seeks to quantify the fundamental limitations and limits inherent in this design process. The paper outlines an approach built on lifting and optimal model matching, which attempts to quantify analytically the minimal signal recovery error in channel equalization via multirate filterbanks.

View full abstract

The limitations imposed by non-square plants, non-minimum phase zeros, and unstable poles in optimal tracking problem for LTI SIMO continuous-time systems responding to a step reference signal are now known. This paper examines and derives equivalent results for discrete-time feedback control systems. An extension is made by considering a problem of minimizing the tracking error simultaneously with the control effort.

View full abstract

The Hankel norm model reduction problem for discrete-time systems with time-varying state delay is investigated. This paper focuses on the construction of reduced-order models under the Hankel norm error criterion. Two different linear matrix inequality approaches are proposed. A numerical example is provided to illustrate the effectiveness of the methods.

View full abstract

Compressed Hankel matrix is given by using orthonormal rational functions constructed from the Jury table. The solutions to the optimal and suboptimal Nehari problems via the compressed Hankel matrix are also given. Robust stabilization problem is reduced to the Nehari problem, so it can also be solved via Jury table.

View full abstract

This paper proposes a new digital audio coding method. This method combines subband-coding with an interpolator that recovers the high frequency spectrum according to analog audio signal model. The interpolator is designed via sampled-data control theory. Efficient compression can be achieved by the Huffman coding at low bit-rate transmission. The proposed algorithm is better and simpler than MPEG-1 Audio.

View full abstract

This paper presents a learning controller for repetitive gait control of biped walking robot. The learning control scheme consists of a feedforward learning rule and linear feedback control input for stabilization of learning system. The feasibility of learning control to biped robotic motion is shown via dynamic simulation with 12 DOF biped walking robot.

View full abstract

Most of a humanoid robot need smooth and stable walking gait. A humanoid robot is unstable basically, and it spends more energy than other mobile robot, when it moves. To solve these problems, genetic algorithm is employed to guarantee the optimal gait trajectory. The fitness functions are introduced to find out optimal trajectory that can have a optimal movement.

View full abstract

We propose method for reaching movement at high-speed and precise by humanoid robot using LVS control and open-loop control. Moreover, Open-loop control was not able to need the camera angle, either and was able to control it by using a maker like LVS.

View full abstract