Roll eccentricity is a periodic disturbance caused by a structure of back up rolls in rolling mills, and it affects product thickness accuracy. It cannot be measured directly by sensors, so it should be identified by measured thickness or measured roll force. When there is a large difference of diameters between top and bottom back up roll, the performance of roll eccentricity control using feedback signals of roll force or thickness has not been so good. Also it has been difficult for the control to be applied from the most head end because it is necessary to identify the roll eccentricity during rolling. A new roll eccentricity control has been developed to improve these disadvantages and to get better performance. The method identifies top and bottom roll eccentricity respectively from one signal of roll force and it can start the control from head end. In this paper the new control method is introduced and actual application results to a hot strip mill are shown.
This paper presents a frequency domain identification method for linear continuous-time systems. The method exploits the idea of the projection-based identification which has been developed by the authors in the time domain. One distinguished feature is that the convergence condition of the estimated parameters is given explicitly. It is also shown that the proposed method provides us a framework to view the existing methods such as IWLS, IV and Gauss-Newton ones in a unified way. Furthermore, the optimal convergence rate of the method is discussed, which explains the advantage of IV method over IWLS and Gauss-Newton ones. Finally, the validity of the discussion is demonstrated through a numerical example.
This paper proposes an exact direct method to determine all parameters including an envelope peak of the white-light interferogram. A novel mathematical technique, the weighted integral method (WIM), is applied that starts from the characteristic differential equation of the target signal, interferogram in this paper, to obtain the algebraic relation among the finite-interval weighted integrals (observations) of the signal and the waveform parameters (unknowns). We implemented this method using FFT and examined through various numerical simulations. The results show the method is able to localize the envelope peak very accurately even if it is not included in the observed interval. The performance comparisons reveal the superiority of the proposed algorithm over conventional algorithms in all terms of accuracy, efficiency, and estimation range.
In this study, we performed a cardiac motion analysis by using 1000-frames per second (fps) stereo images to capture the three-dimensional motion of small color markers in a rat heart. This method of recording cardiac motion could quantify the rate of change in the myocardial area, which indicated localized myocardial activity of rhythmic expansion and contraction. We analyzed the three-dimensional motion distributions in a rat model for myocardial infarction, in which the heart rate was 4 times/s or more. In the analysis, we spatiotemporally quantified the characteristic cardiac motion in ischemic heart diseases and found that infarction due to ischemia in the rat heart was spread around the left ventricle.
This paper proposes the classification method using Bayesian analytical method to classify the time series data in the international emissions trading market depend on the agent-based simulation and compares the case with Discrete Fourier transform analytical method. The purpose demonstrates the analytical methods mapping time series data such as market price. These analytical methods have revealed the following results: (1) the classification methods indicate the distance of mapping from the time series data, it is easier the understanding and inference than time series data; (2) these methods can analyze the uncertain time series data using the distance via agent-based simulation including stationary process and non-stationary process; and (3) Bayesian analytical method can show the 1% difference description of the emission reduction targets of agent.
Central pattern generators (CPGs) have been increasingly attracting roboticists in the hope that they enable robots to realize truly supple and agile locomotion under real world constraints. Thus far, various CPG models have been proposed, particularly in terms of motion stabilization against external perturbations, i.e., limit cycle behavior. On the other hand, biological CPGs have another crucial aspect that cannot be neglected, i.e., motion exploration. Here, note that motion stabilization and motion exploration should be performed in different time-scales. Now the following questions arise: how can different time-scales be embedded into a single CPG effectively?; and what is a good mathematical tool for describing the coexistence of different time-scales? To overcome these problems, this paper introduces a novel oscillator model in which the two functions of motion stabilization and motion exploration can be seamlessly integrated by exploiting the concept of multi-rhythmicity, without relying on any hierarchical structure, which in turn enables that learning is an integral part of the motor control system. We applied this model to the learning of hopping motion as a practical example. Simulation results indicate that the robot can successfully perform online learning without the need for a separation between learning and performance phases.
Piles for uses in construction are fundamental parts of buildings, and are required to be highly reliable in Japan where seismic activities are quite frequent. Under the Earth Drill Method, a pile construction method, the ground is drilled till its hardness indicator, N-value, reaches 50 before the piles are embedded, in order to secure the safety of the buildings. however, at construction sites where the geological layers are structured intricately, the ground hardness data obtained from standard penetration tests and the actual hardness of the drilling spots occasionally can be quite different; and the drilling process halts while the actual N-value is still less than 50. Enabling the operator of an earth boring machine to confirm a 50-plus N-value during a ground drilling process improves the reliability of the piles, which is advantageous not only for the contractors but for the expected residents in terms of safety and security. In this paper, a system is proposed to determine the 50-plus N-value of the ground during an earth drilling process. The system, operated under a support vector machine, revolves the bucket in the Earth Drill Method. This system, as a result, has made it possible to determine the 50-plus N-value with the judgment ratio of 91.3% for the polynominal kernel, 73.9% for the Gaussian kernel, and 82.6% for the sigmoid kernel.
Electromyogram (EMG) signals can be measured from human muscles and can be used to anticipate movements. In fact, many researchers have tried to use these signals as an interface tool for a prosthetic hand. However, most of these studies focused on the discrimination performance of the EMG signals, and only discussed the control method for the prosthetic hand. Evaluation of the operating performance was seldom reported. This paper proposes a virtual prosthetic control system and presents the analyses of a grasp motion under two different EMG control methods: on/off control and proportional control. The proportional control is able to proportionally control the grasping velocity based on the amplitude of the EMG signal. The on/off control controls the hand at a uniform rate while the amplitude of the EMG signal is greater than a predefined threshold. We conducted experiments with five subjects, and confirmed the usefulness of the developed system.
In this paper, we proposed the evaluation method of the sleepiness by oxygenated hemoglobin. The sleepiness by diver's operation can be considered as the factor of accidents. Therefore, we needed to have evaluated the sleepiness while driving. Then, we gave the driving task to the subjects and researched the relation of oxygenated hemoglobin. As the result of the experiment, compared with facial expression, oxygenated hemoglobin tends to be decreased gradually. Possibility of driver's sleepiness evaluation could be shown.