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Volume 27, Issue 12
Displaying 1-16 of 16 articles from this issue
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Mitsuhito KAMEI, Toshiro NAKAJIMA, Takahiko INARI1991 Volume 27 Issue 12 Pages 1319-1326
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes an optical simultaneous instrumentation system for the plural quantities to be detected. Simultaneous detection or measurement may be posible by use of plural current instruments for the plural quantities respectively. Such system, however, becomes large in scale. The multifunctional system which can simultaneously detect or measure the plural quantities by itself is required. Application of the various characteristics of light wave is suitable to the need. For application to instrumentation, light wave has various interesting characteistics. By assigning the various characteristics of light wave to the plural measurements or detections, the multifunctional instrumentation system using only one light beam can be realized. This is the fundamental concept of this work. We tried to make a model system using only one laser beam to realize the concept. In this system, leakage of vapor, abnormal vibration, and distance to a target are detected simultaneously by the difference between the polarization of light wave back-scattered from the vapor particles and that scattered from the background of constructions in a plant, the optical doppler effect, and the triangulation distance measurement method using illumination of the light beam, respectively. Wireless communication with light intensity modulation is also possible in this system.
The experimental evaluation proved this model system fulfilled all the specified functions without mutual interference each other. Thus our concept was certificated to be practical and useful.View full abstractDownload PDF (2308K) -
Shunji HIROKAWA1991 Volume 27 Issue 12 Pages 1327-1334
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe anterior-posterior displacement of the tibia elicited by loading of the quadriceps and hamstrings muscles was determined as a function of joint angle and muscle load using a highly accurate computerized radiographic technique. A two-dimensional mathematical model analysis was also performed, simulating the experimental condition precisely.
The simulation results showed good agreement with the experimental data collected from five fresh frozen cadaver knees.
Both the results demonstrate that quadriceps contraction can result in an anterior displacement of the tibia in the range of 0° to 30° of flexion, and a posterior displacement in the range of 80° to 120° of flexion. While hamstring contraction always causes a posterior displacement of the tibia irrespective of knee flexion angle.
The simulation results further showed that the magnitude of the cruciate ligaments stress varied mainly according to knee flexion angle.
It was concluded that quadriceps contraction has direct impact on anterior cruciate ligament stress as well as hamstrings contraction on posterior cruciate ligament stress.
It was further concluded, however, that the absolute magnitude of both the cruciate ligaments were not that much influenced by the quadriceps and hamstrings contraction than knee flexion angle, questioning the assessment of cruciate ligament stress by anteriorposterior displacement of the tibia.View full abstractDownload PDF (2202K) -
Takehiro MORI, Hideki KOKAME1991 Volume 27 Issue 12 Pages 1335-1342
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSGiven a couple of D stability domains in the coefficient space of interval polynomials, what kind of total information can we draw from them altogether? This motivates the present paper and we address ways of merging and extending given two D stable hyper-boxes in the coefficient space. We show that it is in general possible to enlarge a stability interval at the expense of reductions in the other intervals provided the two boxes share a non-empty part. Even when they have no intersections, for some specific D domains in the complex plane, we can merge two separate intervals into a single one, thus yielding anew stability region in the coefficient space. This can, however, be done only when two intervals along a single coefficient axis are disjoint and along the other axes not. This restriction can be eased for some D domains such as open left half complex plane, right and left half of real axis and imaginary axis. For these domains, two intervals in the odd-order term coefficient axes or even-order term coefficient ones are allowed to be separate. In all these results existence of the two D stability boxes areassumed a priori, for simplicity. We next propose easy methods to generate a new D stability box based on a given one. Successive use of these methods yields a series of new boxes in quite a simple manner. Combining this technique with the above merger method, extension of a D stability interval along a desired coefficient axis becomes possible. To illustrate the results presented, some simple numerical examples are worked out.View full abstractDownload PDF (1166K) -
Tsutomu NAGADO, Etsujiro SHIMEMURA, Kenkou UCHIDA, Tsutomu ISHIDA1991 Volume 27 Issue 12 Pages 1343-1348
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, a controller reduction method which considers preserving robust stability is proposed. We regarded the reduction problem as a frequency weighted approximation problem of a controller and derived the weightings for maintaining robustness. The weightings for the coprime fractional representation are also derived. A numerical example is used to demonstrate the effectness of the scheme.View full abstractDownload PDF (730K) -
Masahiro OYA, Toshihiro KOBAYASHI1991 Volume 27 Issue 12 Pages 1349-1357
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper we propose a design method of a robust adaptive control system. And We consider a design method of a control system in which the norm of the output error between the object and the model converges to any small region. The controlled object under consideration here is a linear time invariant system with relative degree less than three and bounded disturbances.
In the case of the relative degree being one, it is presented that the design purpose is established by using of σ-modification approach and a unity feedback of the output error. In the traditional method, a control system is construtted by giving attention to the expanded error in the case where the relative degree is more than two. But it is difficult to guarantee the convergence of the norm of the output error, even if the control system can be constructed so that the convergence of the norm of the expanded error to any small region is guaranteed. Therefore in the case of the relative degree being two, estimated parameters, which are the sum of the output error and the estimated parameters of σ-modification approach, are used in order to construct the control system by giving attention to the output error. Moreover state feedback is used in order to guarantee the convergence of the norm of the output orror. In the case of the relative degree being three the control system is constructed so that the output signal of the first lag system tracks the inputof the case of the relative degree being two, where the input of the object is added to a first lag system, and by means of constructing such the control system, it is shown for plants with relative degree being three that the design purpose is also established.
Finally, computer simulation results are presented to illustrate the effectiveness of the proposed method.View full abstractDownload PDF (1089K) -
Tsuyoshi OKITA, Yasuhide KOBAYASHI, Shogo TANAKA1991 Volume 27 Issue 12 Pages 1358-1365
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we consider the construction of the adaptive control system for linear systems in the self-tuning regulator (STR) type. First, we hypothesize the various change models and then based on them parameters are estimated using the maximum likelihood method. We calculate a posteriori probabilities for all the hypothesized change models using the Bayesian theorem. The model which has the highest probability is considered to be the actual change model. Then according to our regulator design the estimated parameters of the highest probability model are used in optimal control law obtained by dynamic programming and state estimate performed by Kalman filter.
Secondly, we introduce the concept of test signal to improve the system identification.On the other hand, addition of the test signal also results in the disturbance of the system.Thus, in order to have a suitable compromise between the benefit of the system identification and disturbance, we propose to decide the appropriate amount of the test signal.
Finally, we verify in the digital simulation that the test signal input improves the performance index.View full abstractDownload PDF (938K) -
Setsuo SAGARA, Jun IMAI1991 Volume 27 Issue 12 Pages 1366-1373
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSFor a parabolic distributed parameter system with boundary inputs, we consider a finite dimensional approximation scheme of Galerkin type and propose a method yielding approximation models with no static errors.
We illustrate a modal interpretation of the approximation model in the caseeigenfunction is employed for the coordinate function and show that the magnitude of the approximation errors of the higher order modes are proportional to the first-order differential of the system input.
We verify above results numerically both by simulation study in time domain and error evaluation in frequency domain, for an example of a constant parameter system.View full abstractDownload PDF (957K) -
Masahiro TANAKA, Atsushi OSADA, Tetsuzo TANINO1991 Volume 27 Issue 12 Pages 1374-1381
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThere are mainly two approaches to the state estimation or the system identification problems, where the system contains additive unknown values. One is the well-known stochastic approach, and the other is the setmembership approach, where the unknown values are treated as unknown deterministic values in bounded sets. In this paper, we consider the state estimation of linear systems when the initial state vector, input vector and observation noise lie in ellipsoids. Then the state vector is guaranteed to exist in the membership set of the state, where all the points satisfy the system equations with unknown values in given ellipsoids. We first show ellipsoidal approximations that contain the smallest membership set at the prediction step and also at observation-update step, where each step has one free parameter. It is shown that the smallest membership set can be formally obtained by the intersection of infinitely many ellipsoids. But, for practical applications, we derive the optimal ellipsoids whose volumes are the smallest at the prediction step, and at the observation-update step based on the chosen prediction ellipsoid, respectively, for SISO systems. This scheme is called ‘semioptimal’ in this paper, and is free from using nonlinear optimization methods. However, there exist smaller ellipsoids if we do not divide the scheme into two steps. We show a direct method to minimize the volume of the ellipsoid using nonlinear optimization. This method is also applicable to MIMO system. The smoothing problem is also considered.View full abstractDownload PDF (898K) -
Hiroshi NAKAMURA1991 Volume 27 Issue 12 Pages 1382-1388
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA new algorithm for learning control of repetitive motion is described and experimental results are reported. At each sampling time, the control input is modified so as to minimize the cost function of predicted future errors.
This algorithm is very practical because: (1) the algorithm can be easily implemented on a personal computer or a microprocessor since simple calculations are used, (2) existing controllers can be used without modification, (3) the learning converges very quickly, (4) no identification is required other than measuring the step response of the system.
Experimental results on a DC servomotor showed that tracking errors were reduced to within ±1 pulse after only four attempts. In addition, the servomotor accurately followed the reference input of which the frequency was five times as high as the bandwidth of the original position control system.View full abstractDownload PDF (834K) -
Tsuneo YOSHIKAWA, Koh HOSODA1991 Volume 27 Issue 12 Pages 1389-1395
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we propose an approach for modeling flexible manipulators. This approach consists of modeling each flexible link by using virtual rigid links and passive joints which consist of springs and dampers, and modeling the whole arm by connecting the models of individual links. The parameters of the model are determined to make the dynamic and static characteristics of the model coincide with those of the real link. First, the structure of the model is discussed, and a way is shown for determining the parameters of the model from measured characteristics. Then, the dynamic and static characteristics of the model are calculated from its parameters. Using this model, the dynamic equations of motion of the flexible arm are derived in the form of Newton-Euler equations, then reformed to be convenient for solving the direct dynamics problem. An experimental result show that this model can simulate the dynamic and static motion of the real flexible arm fairly well.View full abstractDownload PDF (1434K) -
Satoru GOTO, Masatoshi NAKAMURA, Nobuhiro KYURA1991 Volume 27 Issue 12 Pages 1396-1404
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper describes method for modifying taught data for robot arm, aiming at accurate high speed positioning. For industrial teaching/playback type robots, objective trajectory data has been usually used as taught data which are the input for teaching/playback type robots. In the conventional method, deteriorations of the control performance, such as time delay of robot arm motion and deviation among composed axes occur. Therefore, we propose a method for modifying taught data, which, is designed using the pole placement method through state space description of robot arm control system. By using the proposed method, we can easily calculate the modified taught data. The characteristics of the robot arm performance which is controlled by using the proposed method, are analyzed in the time domain and in the frequency, domain, respectively. The effectiveness of the method for modifying taught data is shown by the experimental results of analogue computer which faithfully simulated actual robot arm equipment. Experiments for positioning were made by the conventional method and the proposed method for objective trajectories of rectangular line and circle, respectively. The experimental results show that the proposed method is far more accurately tracking the objective trajectory compared with the results of the conventional method. The method for modifying taught data can be applied to the robotarm control problem without any changes of hardware of the robot arm system and this method can be used to any objective trajectories of the robot arm. This method can be applied not only for robot arm control but also for other mechanical control and plant control. Therefore the proposed modification of taught data is very useful to engineering and industrial application.View full abstractDownload PDF (1217K) -
Keijiro YAMAMOTO1991 Volume 27 Issue 12 Pages 1405-1411
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSFor realizing an opto-fluidic system without any mechanical moving part, opto-fluitlic controlling element using a photoacoustic cell as the control port of a laminar proportional amplifier was investigated. Carbon black was used as a light absorber of the photoacoustic cell.
Effects of incident light intensity, light modulating frequency, light aqsorber thickness, and cell length on photoacoustic pressure amplitude are clarified. Conversion characteristics of the opto-fluidic converter employing the opto-fluidic controlling element, a laminar proportional amplifier gain block and a rectifier are also reported.View full abstractDownload PDF (818K) -
Toshio TSUJI, Seiya NAKAYAMA, Koji ITO1991 Volume 27 Issue 12 Pages 1412-1419
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe autonomous distributed system (ADS) is one of the attractive approaches for more versatile and autonomous robot systems. The present paper proposes a distributed trajectory generation method for redundant manipulators through cooperative and competitive interactions between subsystems of ADS, which is based on a concept of virtual arm as each subsystem. The virtual arm has the same kinematic structure as the manipulator except that its end-point is located on the joint or link of the manipulator. Therefore the redundant manipulator can be represented by a set of the virtual arms.
In the present paper, each subsystem corresponding to the virtual arm is implemented by a back propagation typed neural network. It is shown that the nonlinear inverse kinematics of the virtual arms can be solved through exchanging position error signals about each virtual end-point computed in each neural network. The method can generate the trajectories of redundant manipulators using only the information in the task space, and each desired end-point position of virtual arms can be planned independently. Moreover, it is robust to some failures of subsystems or actuators, since each subsystem can work fully autonomously. Finally, the effectiveness of the method is verified by computer simulations using a planar manipulator with redundant joint degrees of freedom.View full abstractDownload PDF (1006K) -
Eitaro AIYOSHI, Chieri TANNAI1991 Volume 27 Issue 12 Pages 1420-1426
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA quasi-Newton method with parallel computing capabilities for unconstrained optimization problems, which is called a parallel quasi-Newton method, is converted to linearly constrained cases. A parallel quasi-Newton method is characterized by simultaneous perturbations of a trial point in plural directions, and by approximation to an inverse of the Hessian of the objective function by use of informations at the perturbed points. Then, the parallelism can be induced into the perturbation process as well as the computations of the gradients at the perturbed points. In our converted method, the perturbation process in parallel fashion is performed on the linear manifold of the equality constraints. When the objective function is quadratic, the optimum on the constraints can be obtained by use of the matrix type of the BFGS updating formula after a trial point is renewed only once.
The proposed algorithm is tested on some examples. The experiment in serial fashion on the currently used computer indicates that the algorithm effects better convergence than the gradient projection method and the quasi-Newton projection method. From these results, it is expected that the good convergence becomes pronounced on parallel computers with multi-processor.View full abstractDownload PDF (933K) -
Xiaohua HU1991 Volume 27 Issue 12 Pages 1427-1433
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe reachability tree cannot, in general, be used to solve the reachability problem because of the existence of the ω symbol. The central issue of this paper is to limit the reachability tree to a finite one without using the ω symbol so that it can be used to solve the reachability problem. For this purpose, we consider the marking space in a Petri net as a Euclidean metric space, and limit the reachability tree in a hypersphere in the metric space based on the following ideas: Let II be the set of all executable marking sequences from the initial marking to the final marking. Let aπ be the maximum value of the norms of all the markings included in such a marking sequence π which belongs to II, and let a be the minimum value of all those aπ (if II is empty, let a be 0). Then, the final marking is reachable if and only if it is included in the reachability tree in the hypersphere Ur with its center at the origin and radius r which is an upper bound fo a. This paper also presents the way to get such an upper bound r of a for two classes of Petri nets (one of them includs the well-known trap circuit Petri net). Then, by creating the reachability tree in such a hypersphere Ur, we can determine not only whether the final marking is reachable or not, but also at least one firing sequence of transitions leading to it at the same time.View full abstractDownload PDF (834K) -
Hiroshi SHIBATA, Genmon MARUOKA, Nanayo FURUMOTO, Mikio ONO1991 Volume 27 Issue 12 Pages 1434-1436
Published: December 31, 1991
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes to use a feedback type of digital averaging circuit for removing the noise in motor current and applies the technique to co-axial cylinder type viscometer to contribute accurate and speedy measurement.View full abstractDownload PDF (378K)
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