In this paper, a novel method for analyzing a textile fabric structure, particularly a knitted fabric one, is proposed to obtain positional information regarding the yarns of the textile fabric using voxel data made of its X-ray computed tomography (CT) images. It is possible to reconstruct the positional relationships among the yarns from the positional information. The positional information is defined as a sequence of points on the center line of each yarn of the sample in this study, since the sequence can be regarded as the representative position of the yarn and robust against measurement errors. The sequence is estimated by tracing the yarn. The yarn is traced using a three-dimensional yarn model, which is moved along the yarn direction estimated by correlating with the yarn part of the voxel data. The trajectory of the center of the yarn model corresponds to the positional information of the yarn. The effectiveness of the proposed method is discussed by experimentally applying the method to voxel data of a knitted fabric of a net stitch.

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This paper investigates wave-based analysis and impedance matching for the ladder electric networks. The results are a generalized version of our previous work for the cascade connected damped mass-spring systems. We first clarify the class of the ladder networks which satisfies the three conditions for the propagation constants to be analyzed by the wave-based analysis. Secondly, for the class of the networks, we investigate the analyticity of the secondary constants and positive real property of the characteristic impedances. Properties of the impedance matching are also investigated. A numerical example for a mechanical system shows effectiveness of the impedance matching for vibration control.

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The direct closed-loop identification algorithm in frequency domain is considered in this paper. It is shown that the input and output signals obtained through the over-sampling technique have cyclic spectra, which give the frequency transfer function of the over-sampled model. Then a cyclic spectra based identification algorithm is implemented in the frequency domain. It is clarified that the test signal is not necessary, and the identifiability does not depend on the controller structure in the new algorithm. The effectiveness of the proposed algorithm is demonstrated in numerical simulations treating with unstable systems.

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This paper describes a control method that takes into account input saturations based on the structure of the two degree of freedom model matching control system. Concretely, a control method and a procedure are considered so that outputs of a control object track the reference outputs without occurring overshoot. The effectiveness of the method is verified by numerical simulations and experiments.

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We consider the pickup and delivery problem (PDP) as a general model of practical transportation problems in the automated guided vehicle (AGV) transportation systems, elevator systems and so on. In this paper, we focus on the single-vehicle PDP (1-PDP). This 1-PDP is regarded as an extension of traveling salesman problems (TSP), and is more complex due to the presence of the constraints both on precedence and vehicle capacity. We formulate the 1-PDP into a mathematical programming model by introducing decision variables which represent the precedence relations of locations. Based on this model, we propose two approaches based on genetic algorithms (called as GA1 and GA2, respectively). GA1 uses a sequence of customer indices as a genetic representation such that genetic operators designed for TSP can be applied. As for GA2, a sequence of location indices is used as a genetic representation, and a new crossover operator is applied, which can inherit precedence relations in generating new individuals. Several computational experiments show the effectiveness of the proposed approaches. GA2 shows an advantage especially for the 1-PDP with harder capacity constraints.

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In order to enhance dexterity in execution of robot tasks a surplus number of DOFs (Degrees of Freedom) is necessary for design of robotic mechanisms. In case of such redundant robots, it is said that a problem of inverse kinematics becomes ill-posed and therefore an extra performance index is indispensable to determine uniquely the inverse mapping from task space to joint space. This paper treats a problem of reaching tasks under the effect of gravity by a redundant robot arm or hand and shows that such ill-posedness of DOF redundancy can be resolved in a natural way by using a simpler task-space feedback with adequate dampings at joints and gravity compensation and without introducing any extra performance index. An application of the proposed method to control of hand-writing robots is also discussed.

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Developing a monitoring system in a bathroom is important to prevent accidents. The authors previously proposed a bathroom monitoring system which used an acoustic sensor to measure the water level in bathtub to see whether the person is inside the bathtub. This paper shows how the monitoring system recognizes the sound environment in bathroom. Experiments demonstrate the effectiveness of the system.

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The authors previously developed an unconstrained and noninvasive measurement system which measured the continuous trends of the instantaneous heartbeat and respiration periods using an acoustic sensor. The paper improves the method such that it outputs the periods of the heartbeat and respiration discretely in time quite similarly as the electrocardiograph and thermistor-type respiration pick-up used as standard devices. The validity of the proposed system is shown by experiments.

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It is known that a wide class of deterministic systems have so-called quadratic-in-the-state representations. This paper proves that the same kind of property holds for polynomial-type stochastic systems. We also see that a quantum dynamics driven by a measurement back-action is immersed into a low-dimensional quadratic-in-the-state representation.

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This paper newly shows applicability of the “integral-feedback type speed estimation method” to sensorless vector controls of synchronous reluctance motor using disturbance observer, which has identified rotor speed separately from rotor phase by adaptive identification algorithm so far. The employed speed estimation method can exploit the integral-derivative relation between phase and speed of rotor, and consequently can allow simpler realization of sensorless vector controls of synchronous reluctance motor.

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In recent studies, Asai proposed a strategy to analyze disturbance response of control systems across switching. It was shown that the performance deterioration caused by the disturbance can be assessed quantitatively by a sort of L₂ gain of the control system, which can be regarded as a generalization of the well-studied Hankel norm of linear time-invariant systems. In addition, explicit formulas to compute the L₂ gain have also been derived. The derivation explored there is, however, rather involved and does not conform to the elegant results already known in the analysis of Hankel operators. Motivated by these facts, in the present note, we give a concise proof for the results by Asai based on linear operator representations. It turns out that the results can readily be obtained by describing a procedure to compute the norm of the associated compact linear operator.

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A compact humanoid named as “ALPHA” was developed with 22 conventional radio-control servomotors whose servocontrol systems were newly designed to add both torque control and sensing system. By use of these functions, compliance controls were applied to the humanoid legs so as to give soft stiffness to its joints. We examined jumping action and analysis of the humanoid although the jumping action of the humanoid is usually very difficult to be realized due to its body weight. The results show that the soft stiffness obtained by the proposed compliance control is very useful for impact absorption especially at the knee joints.

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In this paper, a simple micro drawing technique for liquid including nano particles is proposed. The width of drawn liquid line was able to control by adjusting two parameters, the drawing speed and the pressure of micro-extrusion. It was confirmed by the fluorescence observation that the nano particles in the drawn line were aligned.

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