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Volume 24, Issue 4
Displaying 1-18 of 18 articles from this issue
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Shinobu HASHIMOTO1988 Volume 24 Issue 4 Pages 323-330
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a new high resolution radiometer used as an airborne or a spaceborne microwave imaging sensor. In these applications, the resolution of radiometer is restricted by large ambient temperature variation and the short observation time available for each pixel which the antenna scans succesively.
The proposed system has two-different-temperature reference noise sources at the input, which is periodically switched amang the antenna and the two references to detect true gain variation3), 4), and a digital signal processor at the backend which calculates signal and gain variation using stored data. Since reference noise measurements are not limited by antenna scan, and hence, large number of reference data taken in different period can be used for smoothing the rms fluctuation, the use of digital processing of stored data is advantageous to decrease the statistical uncertainty in the reference measurements.
This paper presents a complete analysis of the radiometer performance, signal processing algorithm which eliminates cross-talk between signal and AGC data, and total rms fluctuation obtainable. The estimated total rms fluctuation attains as low as that of usual Dicke type as increasing number of reference data used, and asymptotically, close to that of Total Power type. The results of experimental test of the radiometer are also described.View full abstractDownload PDF (1020K) -
Toshiro MAKINO, Takeshi KOSAKA, Jiro ARIMA, Satoshi AOYAMA, Hiroji TSU ...1988 Volume 24 Issue 4 Pages 331-336
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSNew algorithm is presented for the development in radiation pyrometry with high accuracy and precision. A pyrometer is designed on a basis of the algorithm. The algorithm and the pyrometer are examined experimentally to verify the performance.
The pyrometer measures emission and reflection of a target surface at three near-infrared wavelength points simultaneously and remotely. The data are analyzed on a rigorous consideration for the angular characteristics of reflection. We present an idea, which approximates the spectral dependence of the angular characteristics of reflection as wavelength-independent or with a simple series expansion form of wavelength. A least-squares technique is combined with it to reduce the difficulty in the approximation and the experimental errors.
The pyrometer is examined in the temperature measurement of an oxidizing metal surface at high temperatures, whose spectral and angular characteristics are complicated and changing transiently. The inaccuracy is found to be less than 10K/1000K for this most difficult case.View full abstractDownload PDF (1438K) -
Sadao FUJIMURA, Atsuki MATSUMURA1988 Volume 24 Issue 4 Pages 337-343
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn order to get the true temperature of an object in radiation thermometry, we have to correct the deviation of the brightness temperature from the true temperature by estimating the emissivity of the object or to cancel the effect due to the emissivity by some operational procedure. The method proposed in the present paper is basically based on the latter idea. The method uses the radiances measured in two partially overlapped spectral bands, in which the spectral emissivity of the object is approximately equal to each other. The extended Tn relation of radiance for thermal radiation is such that the radiance from the black body at temperature T observed in a spectral band and in a temperature range is given by aTn, where the factors a and n are constant and are different from one spectral band to another. When the object is at much higher temperature than the environment is, the true temperature of the object is easily estimated from the ratio of the radiances at the spectral bands. When the temperatures are similar, we get the true temperature by numerically solving a simple algebraic equation derived from the radiances by using the extended Tn relation.
The validity of the method was confirmed by experiments for objects with various emissivities. The comparison of the results withthose by other conventional methods showed the superiority of this method.View full abstractDownload PDF (803K) -
Hayao MIYAGI, Norio MIYAGI, Takeshi OHSHIRO1988 Volume 24 Issue 4 Pages 344-349
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, the direct method of Lyapunov is used to study the stability of a Liénard-type nonlinear system. The system is given by n second-order differential equations. To establish the procedure for constructing Lyapunov function, the system is rewritten by a transformation. Then, a stability criterion for the system, which introduces a new type Lyapunov function, is presented. While the positive matrix P appeared in the Lyapunov function is obtained by solving matrix equations, the possibility of existence of this P is discussed from the point of view of the condition that the Luré type Lyapunov function for the well-known nonlinear feedback control systems exists. Thus, the construction procedure developed in this paper, for the new type Lyapunov function, is systematic and the result obtained for the Liénard-type nonlinear system corresponds to the Luré type Lyapunov function for the nonlinear feedback control systems.
This new technique is applied to the simple system given by so-called Liénard's equation. In this system, it is shown that the conventional energy function and the Lyapunov function given by generalized Zubov's method are special cases of the Lyapunov function proposed in this paper.View full abstractDownload PDF (694K) -
Toshiharu SUGIE, Koichi OSUKA, Toshiro ONO1988 Volume 24 Issue 4 Pages 350-356
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents a robust control law which achieves model following with prescribed accuracy for a class of nonlinear systems which contain bounded unknown disturbances and uncertain nonlinear terms. Our method consists of nonlinear compensation and linear compensation. The former ensures robustness for the plant, the latter achieves both desired model following response and desired initial error convergence. The distinguish feature of our method is that admissible control error bound, smoothness of input, reference model (or desired command response), and initial error response can be specified independently, and that the controller is designed based on the information of the “bounds” of uncertainty terms.View full abstractDownload PDF (940K) -
Toshiaki TABUCHI, Takashi SOEDA, Terushige KAWATA, Mitsuru SOEDA1988 Volume 24 Issue 4 Pages 357-362
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper deals with the improvement of convergence rate or estimation accuracy of the estimates in ARMA parameter estimation. A recursive parameter estimator is developed by using the method of white-noise estimation for linear discrete-time systems. The main feature of the proposed method is to take into consideration of ∂kx(t)/∂αT·ε(t) which influences considerably to the performance of RPE (Recursive Prediction Error) or EKF (Extended Kalman Filter) estimator. It is shown that significance considering this term has the effect closing the estimation error covariances with Rao-Cramer's lower bound. Resultant algorithm proposed is constructed by linking RPE estimator with Kalman filter.
Numerical experiment indicates that the convergence rate or the estimation accuracy of parameter estimates is considerably improved compared with the standard RPE method.View full abstractDownload PDF (712K) -
Tsutomu NOHARA, Shigeyuki HOSOE, Masami ITO1988 Volume 24 Issue 4 Pages 363-369
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper a method for constructing a reduced order model retaining the internal structure of the original high order interconnected system is derived under a single criterion. Reduced order models are obtained for several interconnected systems which have different interactions between subsystems.
Obtained reduced order model is the optimal approximation in the sense that it minimizes the equation error. The equation errors and input-output characteristics are evaluated according to unit impulse or unit step responses and a sufficient condition for the stability of the reduced order model is derived under the assumption that the original system is stable.
The validity of the proposed method is pointed via the numerical simulation at last.View full abstractDownload PDF (679K) -
Eiji MATSUMOTO, Koichi INOUE1988 Volume 24 Issue 4 Pages 370-376
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA method is proposed for dealing with geometrical concepts of linear algebra by symbolic manipulation. A linear subspace can be represented by the vector expression, i.e., the linear combination of its bases with arbitrary parameters. Algorithms are shown to describe several operations of subspaces by the vector expression. The package of functions LINALG is developed on REDUCE 3.2, which can carry out the operations of linear subspaces: the sum and the intersection of subspaces, the complementary subspace, and the image, the range, the inverse image, the kernel and the invariant subspaces of a linear transformation. The package also includes the functions to compute the rank and the degeneration condition of a symbolic matrix and to solve simultaneous linear equations with symbolic coefficients.
As an application, the function is defined which obtains the Kalman's canonical form of a linear control system with model parameters. Using the functions of LINALG, it is easy to determine the four subspaces distinguished by the controllability and the observability. The function outputs the dimension, the bases and the vector expression of each subspace, the controllability and the observability matrices, and the canonical form.View full abstractDownload PDF (1003K) -
Setsuo SAGARA, Kui YUAN, Kiyoshi WADA1988 Volume 24 Issue 4 Pages 377-384
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper the digital control problem of single-input-single-output (SISO) continuous-time model referrence adaptive control (MRAC) systems is considered. For a given SISO continuous-time system a discrete-time model is developed via block-pulse functions (BPF). Recursive algorithms which can give piece-wise continuous control inputs can be derived from the control rules of the continuous-time MRAC systems using this discrete time model. Since the control algorithms derived by this method still use the parameters of the continuous-time system, the adjustment of the parameters and the choice of the sampling period can be done independently. Therefore one can easily redesign the MRAC systems for different sampling periods according to the requirement of the accuracy once a control algorithm is obtained. Furthermore, the unboundness problem of the multiintegral operation of initial values and input-output varibles of the system is also discussed. The effectiveness of our method is shown by the computer simulation of a numerical example.View full abstractDownload PDF (951K) -
Toshio TSUJI, Koji ITO, Mitsuo NAGAMACHI, Takashi IKEMOTO1988 Volume 24 Issue 4 Pages 385-392
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe CNS has various means of to regaulate the impedances at muscle level, such as variable viscoelastic properties of muscles and stretch reflex. Hawever the motion tasks to be controlled are usually given about end-point coordinates. The mechanical properties of the musculoskeletal system which transfer the muscle impedance into the end-point one is the key of fine regulations of the motor impedance in the human movements.
In this paper, the mechanical properties and the impedance regulations of the musculoskeletal system are discussed. First, the impedance relationships among muscle, joint and end-point levels are formulated and it is shown that these impedances specify the inverse kinematic solutions of redundant arms. Then the manipulation ability of end-point via muscle forces is defined by ellipsoids and an estimation method of muscle forces required for a given end-point movement is presented. It is shown that the manipulation ability of end-point is affected largely by the mechanical properties of the musculoskeletal system, especially the redundancy of joints and muscles.View full abstractDownload PDF (1152K) -
Fan LIU, Masaru UCHIYAMA, Kyojiro HAKOMORI1988 Volume 24 Issue 4 Pages 393-399
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA new approach using finite element method to deriving a fluid line dynamical model for fully-developed laminar flow in a duct with arbitrary shape, is presented. This approach makes it possible to apply the model-based method proposed for measuring instantaneous flow rate in a circular pipe to more general and practical cases of flow measurement.
Initially, we give a general discussion on the deriving of the finite elements fluid line model. The fluid line model is represented by the form of a state variable equation and can be easily implemented on a computer to estimate duct flow velocity profiles.
Next, we show that the model has higher accuracy than an analytical model when they have the same order, by comparing it with truncated analytical fluid line models for circular and rectangular ducts in frequency domain.
The relation between the dynamic accuracy and the system structure of the model, that is, the model order and its eigenvalue distribution, is explained by taking the case of a circular pipe as an example.View full abstractDownload PDF (858K) -
Takeshi MIZUNO1988 Volume 24 Issue 4 Pages 400-405
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSAn output regulation problem of an active dynamic vibration absorber system is considered, where the object is to reject completely the effects of a sinusoidally varying external force on the main mass by manipulating the motion of a auxiliary mass in an absorber attached to the main mass.
The theory of output regulation with internal stability is applied in designing the control system of an active dynamic absorber system which consists of a main mass to be regulated, an auxiliary mass generating inertial reaction, an actuator driving the auxiliary mass and sensors detecting the diplacements of the masses. A new control method is presented which is enable to remove completely the vibration of the main mass at a particular frequency and to attenuate well the vibration in a wide range of frequency as well. Moreover the obtained condition of output regulation includes the tuning condition of a passive vibration absorber without damping as a special case; that is to say, at the natural frequency of the absorber the vibration of the main mass is completely removed automatically. The effectiveness of the control method is confirmed by numerical simulation and analysis of the frequency characteristics of the designed control system.View full abstractDownload PDF (663K) -
Shinichi HIRAI, Haruhiko ASADA, Hidekatsu TOKUMARU1988 Volume 24 Issue 4 Pages 406-413
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA new approach to the kinematic analysis of rigid body motion in assembly operations is presented. An assembly operation is expressed as a successive transition of a state of contact between an assembly object and constraint points. A graph termed Contact State Network is introduced to describe the transition of a contact state. Each node of the graph corresponds to a contact state. An arc between a pair of nodes means that the assembly object can transit directly from one node to another. Using the contact state network, an assembly operation is represented by a path of the network going from an initial node to a goal node.
When the contact state network is complicated, systematic generation of the network is eagerly required. An algorithm for automatically generating the network from geometric data of assembly parts is developed using admissibility conditions for direct transitions.View full abstractDownload PDF (1133K) -
Kyung-Young JHANG, Takuso SATO1988 Volume 24 Issue 4 Pages 414-416
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA new method for noninvasive measurement of the velocity field of curved flow streams is proposed. Five line detectors and 5th order correlation analysis are used in this method. The usefulness of this method is confirmed by computer simulation.View full abstractDownload PDF (384K) -
Junji FURUSHO, Akihito SANO, Yosuke OKAJIMA1988 Volume 24 Issue 4 Pages 417-419
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThere are many kinds of control methods for quadruped walking robots. In this paper, we deal with a walking control method in which the robot system can utilize the gravity effect very skillfully and the energy for walking can be saved. Using computer simulation, we studied the walking controlled by this method from some aspects such as, the mean walking speed, the variation of walking speed, the stability. It is shown that the step width and the bending angle of the knee joints at the touchdown are important factors for the walking control.View full abstractDownload PDF (364K) -
Kazunobu YOSHIDA, Yukio NISHIMURA, Yoh YONEZAWA1988 Volume 24 Issue 4 Pages 420-422
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSFor a linear sampled-data system with bounded control, a nonlinear control law hasbeen derived which is more effective, in the sense of a quadratic cost, than the linear one satisfying the constraint.View full abstractDownload PDF (372K) -
Kanya TANAKA, Takashi SUZUKI1988 Volume 24 Issue 4 Pages 423-425
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe model reference adaptive control system (MRACS) is designed based on a reducedorder model of the plant which accompanies various modelling errors. This paper discusses the robustness of a continuous-time MRACS to the modelling error arising from inexact pole-zero cancellation.View full abstractDownload PDF (351K) -
Kimio KANAI, Yoshimasa OCHI, Takeshi FUJISHIRO, Ken ITO, Taketoshi KAW ...1988 Volume 24 Issue 4 Pages 426-428
Published: April 30, 1988
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (329K)
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