All issues
Volume 14, Issue 1
Displaying 1-17 of 17 articles from this issue
- |<
- <
- 1
- >
- >|
-
Eiji KONDO1978 Volume 14 Issue 1 Pages 1-7
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper discusses the problem of designing a single linear functional observer (S. L. F. O.) to estimate a single linear function of the state of a linear time-invariant system, for the purpose of implementing a feedback control law.
First, canonical forms of S. L. F. O. are obtained both in the case that S. L. F. O. can have arbitrary poles and in the case that poles of S. L. F. O. must satisfy a constraint condition. Second, an algorithm obtaining the optimal S. L. F. O. is easily derived by using this canonical form. The optimal criterion is the time-integral of the mean-square estimation error. By the presented procedure, the S. L. F. O. is designed under the following conditions:
(1) poles of S. L. F. O. have the most possible freedom of choice,
(2) the order of S. L. F. O. is as small as possible,
(3) the number of paths of S. L. F. O. is as few as possible,
(4) optimality.
Finally, an illustrative example for a power system is given to show the effectiveness of the presented method.View full abstractDownload PDF (800K) -
Shintaro ISHIJIMA1978 Volume 14 Issue 1 Pages 8-13
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn the disturbance decoupling problem (DDP) of the linear system (A, B, C), the A-invariant subspace and the (A, B)-invariant subspace are proved to play a key role. The purpose of this paper is to extend the study of the DDP to nonlinear control systems.
It must be noted that the problems are stated on the tangent bundle over the state space. The state space and the tangent bundle over it can be identified in the analysis of linear systems, but they must be distinguished in the case of nonlinear systems. So it is needed to establish the corresponding concepts in the state space to extend the A-invariance and the (A, B)-invariance to nonlinear systems. From such a point of view, the invariant structure and the structure which can be modified invariant by nonlinear state feedback are introduced as the state space representations of the A-invariant subspace and the (A, B)-invariant subspace.
The main result obtained here, is the algebraic necessary and sufficient condition for the DDP of the nonlinear control systems.View full abstractDownload PDF (854K) -
Shiro HATA, Hiroshi SHIBATA, Hiroshi MAYEDA1978 Volume 14 Issue 1 Pages 14-18
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper deals with the stochastic stability of a class of nonlinear distributed-parameter systems described by Ito's stochastic partial differential equation. Under appropriate assumptions, the state of the system is expanded into a series of eigenfunctions. By using MKY (Meyer-Kalman-Yakubovich) Lemma, a stochastic Liapunov functional in a form of infinite series is proved to exist, if countably many Popov type conditions are satisfied. Consequently, sufficient conditions are obtained for the system to be asymptotically stable with probability one. Finally an example, which is typical of a physical system, is presented to illustrate the applicability of the main result.View full abstractDownload PDF (693K) -
Tsutomu MITA1978 Volume 14 Issue 1 Pages 19-25
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSPreviously the author showed a case where the maximal amplitude of the response of a closed loop regulator becomes extremely large as the ploes approach infinity in the left half complex plane.
This paper, explains this fact by the theory of linear structure of systems.
Namely if the regulator is given by, x=(A+bf)x and y=cx, only for the initial state x(0)∈ν, the maximal amplitude of y increases infinitely as all poles are assigned negative infinity by f. Where ν=span(b, Ab, …, An-m-1b), n. is the dimension of x and m is the number of the zeros of the transfer function c(sI-A)-1b.
The duality of this result provides clear explanation for the similar case given by Bongiorno et al. in the design of an observer.View full abstractDownload PDF (866K) -
Kunihiko ICHIKAWA1978 Volume 14 Issue 1 Pages 26-31
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIt is well known that the necessary and sufficient condition for a pair (A, B) to be completely controllable is that the rank of controllability criterion matrix [B AB…An-1B] equal to n, the dimension of the state vector. Many ways of the proof of the criterion have been contrived by many researchers. Although the point of view that the complete controllability implies the coverage of the whole state space by controllable subspace somehow gives a geometrical interpretation of the controllability criterion, the root of controllability from the geometrical point of view has not yet been disclosed. The author discovered that relative configurations of eigenvectors of A and b (single-input case) play the essential role with regard to controllability. A single-input case is first considered. Realness and multiplicity of eigenvalues are examined in detail. Many examples are provided for a full understanding of the presented theorems. A multi-input case is briefly treated by applying Gopinath's lemma. The problem of dimension of controllable subspace is also examined from the geometrical point of view.View full abstractDownload PDF (620K) -
Teruo ITOH1978 Volume 14 Issue 1 Pages 32-37
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSBy means of a numerical method, the controllability of non-linear discrete systems is discussed. The optimal control problem equivalent to the controllability is reduced to the minimization of the penalty function. A sufficient condition for the optimal control problem to have a local extremal solution within some bounded region around the approximate numerical solution of the penalty function is shown.View full abstractDownload PDF (776K) -
Yasuhiko TAKAHARA, Bumpei NAKANO, Hideomi IKESHOJI1978 Volume 14 Issue 1 Pages 38-43
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents preliminary results of a linear feedback theory in the framework of the mathematical general systems theory. The concept of basic linear systems is introduced as an abstract model of linear dynamical systems. In order to establish a feedback theory in the framework of basic linear systems, the following fundamental questions are to be answered:
(1) Does a feedback system, exist?
(2) If it exists, does it also belong to the class of basic linear systems?
In this paper, in order to discuss the “state feedback”, state systems (which form an important subclass of basic linear systems) are considered and after defining the above questions as a well-posedness problem the following results are given:
(i) A necessary and sufficient condition for the existence of a feedback solution is specified.
(ii) The class of state systems with the above condition is proved closed under the feedback transformation. In other words, the problem of this class is well-posed.View full abstractDownload PDF (959K) -
Kajiro WATANABE, Hatsuo SHIMIZU1978 Volume 14 Issue 1 Pages 44-49
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe result of optimal control is sometimes unsatisfactory on the linear model obtained in the linearized version of a nonlinear system. In this case, the optimal control must be calculated once again on the nonlinear model with a revived nonlinearity. The nonlinear model description becomes complicated, however, to express the nonlinear information in a material form, and the numerical processing of the solutions of optimal control problems becomes difficult.
In this paper, the nonlinearity is considered as a kind of disturbance to the linear model, so it can be reproduced by adding the equivalent input for the disturbance to the linear model. From this thinking, the equivalent mathematical nonlinear model (NBL model) is proposed, which is based on the linear model. The procedure of transient response calculation for the NBL model is given, and the numerical stability of this method based on the Padé approximate method is inquired. In addition, an optimal control problem is formulated under the NBL model, and the optimal control is calculated actually by the optimization algorithm used the steepest descent method. As a result, its numerical solutions were obtained stably.View full abstractDownload PDF (755K) -
Yoshifumi SUNAHARA, Shin-ichi AIHARA, Muneshi KOYAMA1978 Volume 14 Issue 1 Pages 50-56
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is concerned with the optimal control problem of linear distributed parameter systems with stochastic coefficients whose stochastic models are given by the White Gaussian processes.
First, by introducing the concept of a stochastic eigenvalue problem, the mathematical model of its system dynamics with stochastic coefficients is formulated in a form of the equation of random evolution on a function space L2(G).
Secondly, the optimal control problem for the quadratic pay-off functional is solved by using the dynamic programming approach.
For the purpose of supporting the theory developed here, results of simulation studies are also demonstrated.View full abstractDownload PDF (714K) -
Masaya TANUMA1978 Volume 14 Issue 1 Pages 57-64
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSAn optimal preview control utilizing the future values of a desired signal and process inputs is studied for a linear system with transport delay. As a typical transport delay process, the plug flow process is considered in this paper.
The optimal preview control problem is formulated as that of minimizing a quadratic performance index in the preview period, and it is solved by applying conditions for optimality derived by N. N. Krasovskii.
The optimal preview control system has two control functions. One is the feedback control of states of the lumped parameter process and the transport delay process. The other is the feedforward control utilizing the future values of a desired value and process inputs.
The optimal feedback gain and the feedforward control are obtained by solving Ricatti type partial differential equations.
Simulation results show that the proposed control system is superior to the feedback control system.View full abstractDownload PDF (904K) -
Hajime AKASHI, Hiroyuki IMAI, Kamal A. MOUSTAFA1978 Volume 14 Issue 1 Pages 65-70
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe multi-output linear stochastic system identification problem is considered. By regarding the linear combination of the outputs, α'y, as a new output, the multi-output system can be transformed into a single output system. Consequently, the system parameters can be estimated while the difficult problem of structural identification being avoided. However, the value of α has a large effect on the estimation accuracy.
In this paper, the optimum value of α is obtained by minimizing the asymptotic generalized variance of the parameters estimate. It is shown that this optimum value, α*, is the eigen vector corresponding to the maximum eigen value of the covariance matrix of the normalized output. Since the covariance matrix of the innovation is required for calculating α*, the two stage least square method is adopted as the identification technique of this paper. In the first stage, a long AR-model is fitted to the data to calculate the residual sequence which is regarded as an approximation to the innovation sequence. In the second stage, the ordinary least square method is used to estimate the parameters of the transformed single output system. At the end of the paper, a computer simulation is carried out for different, randomly chosen, values of α, and the resulting estimates are compared. The results confirmed our finding that the optimum α yields the best estimates for most of the parameters.View full abstractDownload PDF (721K) -
Toshihiro KOBAYASHI1978 Volume 14 Issue 1 Pages 71-76
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper the identifiability and the problem of determination of unknown functions are investigated for a class of distributed parameter systems. In a distributed parameter system, the identifiability of the system is a sufficient condition for the unknown function to be uniquely determined from the measurement data, but is not a sufficient condition for the function to depend continuously on the measurement data. The problem of the unknown-function determination is not generally well-posed for a distributed parameter system. In this paper a well-posed approximating method is presented for the unknown-function determination. This method gives an approximate function depending continuously on the measurement data. The necessary and sufficient condition for identifiability is also presented for a class of distributed parameter systems.View full abstractDownload PDF (699K) -
Nobuaki KAWATO, Keiken NINOMIYA1978 Volume 14 Issue 1 Pages 77-83
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper deals with an attitude control scheme for an orientation maneuver of spinning spacecrafts with body-fixed gas-jet thrusters.
The spin axis control and the angular momentum vector control are the two controls proposed so far for small-angle maneuvers. The two control methods are extended to the large-angle maneuvers with which nonlinear dynamics must be taken into account. In the spin axis control, the spin axis and the angular momentum vector are simultaneously controlled by gas-jet thrusters to coincide with the desired orientation. The control time interval and the fuel-consumption are adopted as performance criteria. In the angular momentum vector control, only the angular momentum vector is positively controlled. After that, the passive nutation damper aligns the spin axis with the angular momentum vector. The adopted performance criteria is the fuel-consumption. These concepts are formulated as optimal control problems.
The necessary conditions for these problems are obtained via Pontryagin's Maximum Principle. They show that the optimal control is of an on-off or bang-bang type. This result is encouraging to the users of thrusters providing only constant torques, because they may hope to realize optimal controls by applying the thrusters.
Analytical solutions of the above mentioned problems are difficult to obtain because of their high dimensionality and nonlinearity. Minimum fuel problems are numerically solved by the method based upon the linear programming proposed by Wolshe et al. This method is also adopted with modifications to solve minimum time problems. Obtained results reveal that the angular momentum vector control is superior to the spin axis control from the viewpoint of reduction in the minimum fuel-consumption.View full abstractDownload PDF (894K) -
Shigeru ANDO, Yasuhiro DOI1978 Volume 14 Issue 1 Pages 84-89
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe texture gives useful information for dividing a picture into segments, and the analysis by using this information is called a texture analysis. Here two fundamental problems will be encountered; namely,
1) how this texture is characterized or modeled, and 2) how the demands on the class separability and on the segmentation accuracy are compromised.
For the first problem this paper gives a mathematical model of texture to descrive the 1st order density function of pixcell grayness and the autocorrelation function. By synthesizing a texture sample following this model, the model fitness is investigated visually.
For the second problem is given a classification method which uses minimum pixcells for classification through the above mentioned mathematical model under the condition that the class separability must be greater than a given value.
Simulation of this classification method resulted to provide sufficient class separability without much loss of the segmentation accuracy.View full abstractDownload PDF (2784K) -
Gen-ichiro KINOSHITA1978 Volume 14 Issue 1 Pages 90-96
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper deals with a simple tactile sensor model for extracting the feature of an object's surface and the experiment for classifying the shapes of grasped objects.
The proposed model of tactile sensor consists of two layers: the surface layer and the sensor layer. The surface layer is made of an elastic material of which the mechanical properties are determined by the object's surface. These properties of the surface layer are expressed theoretically as the blurring function. It is important that the operation of blurring function is considered as an analogical concept to the receptive field in the visual sense.
The sensor layer derives information from the multi-element sensors which are placed at equal intervals.
The experiment on object classification by one time grasping was performed by using an artificial hand with the tactile sensors. The artificial hand with the five fingers is structurally identical to the skeleton of the human hand. Moreover, the joints of finger are independently actuated by micro-pneumatic cylinders except the first joint of the index finger which is controlled by a positional servo mechanism.
The grasping process from the initial stage to the final stage of grasping the object is computer-controlled to follow the given sequence of a pattern of finger joints. Upon contact of tactile sensors with the object's surface when the object are tightly grasped by the fingers, the computer receives the data of sensor outputs and determines the types of surface at the contact point. Moreover, by the object's surface feature, classification is performed by a learning machine.View full abstractDownload PDF (2089K) -
Ryotaro HIKIDA, Yasutaka HAYASHI, Hideo ARAKAWA, Takahiko MORI, Yuzo Y ...1978 Volume 14 Issue 1 Pages 97-102
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn automotive driving, hard braking may sometimes induce a skid, which significantly impairs the dynamic performance of a vehicle. This study is concerned with a method to control braking pressure of rear wheels for preventing the skid.
Detected signals are the longitudinal acceleration of a vehicle and the mean velocity of the both of rear wheels. The acceleration signal is put into an integrator, which gives the computed vehicle velocity as an output. The difference between the computed vehicle velocity and the measured wheel velocity is amplified. While the amplified signal is small, it is negatively fed back to the integrator through a low-pass filter.
Once a skid occurs, the output from the differential amplifier increases, because the controller is designed not to follow such a rapid change in the wheel velocity. Immediately after the output signal exceeds a predetermined level, the feedback loop is shut off. A capacitance incorporated in the lowpass filter, begins to send to the integrator a constant signal corresponding to the feedback signal just before the shutoff. The signal memorized in the capacitance almost cancels various kinds of noises involved in the acceleration signal, resulting in computation of the accurate vehicle velocity. At the time of the shutoff, an actuator releases the brake pressure in order to recover the wheels from the skid condition. When the signal from the amplifier decreases below the predetermined level, the brake pressure is increased again. The vehicle comes to stop through repetitive control of the brake pressure, keeping the slip ratio close to the optimum level.
The performance of the anti-skid control system has been experimentally investigated under several conditions such as on roads with various frictional coefficients and in engine braking operation. Improvement such as reduction in deflected angle and stopping distance of a vehicle has been confirmed.View full abstractDownload PDF (805K) -
Tetsuo FUJIHARA1978 Volume 14 Issue 1 Pages 103-104
Published: February 28, 1978
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (290K)
- |<
- <
- 1
- >
- >|