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Volume 43, Issue 12
Displaying 1-13 of 13 articles from this issue
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Michiko NISHIYAMA, Hiroyuki SASAKI, Kazuhiro WATANABE2007 Volume 43 Issue 12 Pages 1075-1081
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, a novel, unconstrained and wearable motion analysis system is described in which entire body posture and motion can be monitored using hetero-core optic fiber sensors with their significant performances in terms of the sensitivity, stability and the reproducibility due to the use of single-mode propagation scheme. The performance characteristics of the wearable sensor system are presented for the analysis of motion in the form of a sensing jacket, a wristband, and a gait system. The jacket has shown attractive performances with two sensors at the shoulder and a single sensor at the elbow. The use of only two hetero-core sensors at the shoulder effectively covered sufficient shoulder motion, such as abduction/adduction and flexion/extension, whereas the elbow sensor detected a loss variation of approximately 3dB for a flexion angle of 0-120°. The wristband is developed and tested to detect waving and beckoning motions of the wrist ranging from-30°to+30°and from -45° to+45°respectively, using only two sensors. The gait system also showed interesting performances with hetero-core sensors in sensing the motion of walking which consisted of knee flexing and the contact of the sole on a real-time basis.View full abstractDownload PDF (21198K) -
Takahiko ONO, Tadashi ISHIHARA2007 Volume 43 Issue 12 Pages 1082-1089
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSFor a linear time-invariant discrete-time system such that the observability index is two, this paper proposes a new observer which estimates unmeasured states and unknown inputs simultaneously. Linear transformation plays an important role in design of the observer. It is performed to obtain an output error equation which is decoupled from the estimation errors of unmeasured state variables. Based on this error equation, the observer is designed by a state feedback control theory. Essentially, the unknown input is estimated without influence of the estimation error of the state. If the unknown input is constant, both the state and the input can be reconstructed exactly in finite time. Under a certain condition, the observer works as a minimal-time deadbeat state observer which is completely insensitive to any unknown input.View full abstractDownload PDF (6768K) -
Ichijo HODAKA, Ichiro JIKUYA2007 Volume 43 Issue 12 Pages 1090-1096
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper presents a new insight into controllability for linear periodic continuous-time systems. A number of necessary and sufficient conditions for linear periodic systems to be controllable have been proposed in mutually different forms. However, it is common for these conditions to be described in terms of input coefficients and fundamental solution matrices or transition matrices of the systems. On the other hand, more convenient controllability criterions such as PBH test are available for linear time-invariant systems: the criterions can be described by system matrices in the state-space representations instead of fundamental solution matrices. The purpose of this paper is to derive a controllability criterion in terms of system matrices for linear periodic systems in parallel with the case of linear time-invariant systems. To be precise, this paper proves the existence of particular state-space representations where controllability can be checked directly through system matrices.View full abstractDownload PDF (4031K) -
Kenji IKEDA, Yoshio MOGAMI, Takao SHIMOMURA2007 Volume 43 Issue 12 Pages 1097-1102
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, a bias-compensated least squares method in the closed loop environment is proposed. It is assumed that the observation noise is a white gaussinan signal while there are no process noises. It is also assumed that the plant is controlled by a linear time invariant controller and that the closed loop system is asymptotically stable. It is shown that the asymptotic bias of the least squares estimate in the closed loop environment is represented as a difference between the parameter of the prefilter and that of an “opetimal prefilter” and that the propsed bias-compensated least squares estimate is consistent.View full abstractDownload PDF (3935K) -
Satoshi SATOH, Kenji FUJIMOTO, Sang-Ho HYON2007 Volume 43 Issue 12 Pages 1103-1110
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper proposes a novel framework to generate an optimal gait trajectory with respect to the energy consumption for a planar one-legged robot via iterative learning control. The proposed method is based on the symmetric property of the variational systems of Hamiltonian systems called variational symmetry. This technique allows one to obtain solutions of a class of optimal control problems without using precise knowledge of the plant system. Furthermore, its application to the robot produces a passive gait trajectory with zero control input. Some numerical examples demonstrate the effectiveness of the proposed method.View full abstractDownload PDF (7917K) -
Yoshihiko MIYASATO2007 Volume 43 Issue 12 Pages 1111-1119
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper provides an alternative approach to solve iterative learning control of robotic manipulators by introducing hybrid adaptation schemes. The hybrid adaptation schemes are adaptive control structures which involve continuous-time control of processes and discrete-time updates of tuning parameters simultaneously. The main advantage of the proposed methodology is that the reference signals to be followed and the time intervals on which each operation is defined, are not necessarily identical to the ones in the other operations. Those peculiar features are owing to parameter estimation schemes included in the proposed methods. Various hybrid adaptation schemes are provided, and convergence properties of those are compared in the simulation studies.View full abstractDownload PDF (2047K) -
Takashi TAKIMOTO, Shigeru YAMAMOTO2007 Volume 43 Issue 12 Pages 1120-1126
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSWe consider a local stabilization problem of an uncertain equilibrium point existed in a nonlinear continuoustime system by a finite-dimensional dynamical state feedback controller. In previous researches, it is investigated that steady-state blocking zeros of the stabilizing controller play an important role. Such a controller is called a washout controller. In this paper, we propose a new washout controller whose order is the same as the control input vector. Moreover, we show that such controllers can be designed by solving a stabilization problem by constant state feedback. Additionally, we also consider a local stabilization problem of an uncertain fixed point of a given discrete-time system.View full abstractDownload PDF (4227K) -
Seitaro TANAHASHI, Keietsu ITAMIYA2007 Volume 43 Issue 12 Pages 1127-1135
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIt is known that model reference adaptive control system (MRACS) based on surrogate model control (SMC) law can decrease the L2-norm of tracking error by increasing the adaptation speed. Generally, the adaptive law combined with parameter projection algorithm is used for avoiding zero singular problem in an adaptive control calculation and maintaining the robust adaptation. However, such an adaptive law may transiently destroy the SMC law. This paper proposes a new design scheme of the MRACS which always guarantees the realization of SMC law. It is accomplished with the high order tuner with a smooth projection. The efficiency of the proposed MRACS is shown by the stability analysis and a numerical simulation.View full abstractDownload PDF (4190K) -
Shun-ichi AZUMA, Toshiharu SUGIE2007 Volume 43 Issue 12 Pages 1136-1143
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper characterizes the stability property of the optimal dynamic quantizers, which has been recently proposed by the authors for the purpose of controlling plants with discrete-valued input. First, a necessary and sufficient condition for the quantizer to be stable is derived, which shows that the quantizer is practicalonly for minimum phase plants. Next, based on the performance analysis of a class of stable dynamic quantizers, optimal design methods of dynamic quantizers are addressed for a general class of plants.View full abstractDownload PDF (2096K) -
Tsuyoshi SAGAMI, Shigeki NAKAURA, Mitsuji SAMPEI2007 Volume 43 Issue 12 Pages 1144-1150
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, a new control method for a class of 1-generator nonholonomic system with drift is introduced. Proposed method is based on a special coordinate transformation which depends on the control input. The original nonholonomic system is transformed into two linear subsystems by the proposed coordinate transformation; one is a linear time invariant system governing the generator dynamics, and the other is a time varying subsystems representing the remaining dynamics. Control problem of the original nonholonomic system can be reduced to linear control problem under a certain constraints.View full abstractDownload PDF (5082K) -
Izumi MASUBUCHI2007 Volume 43 Issue 12 Pages 1151-1155
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper considers LMI-based synthesis of output feedback controllers for descriptor systems based on changeof-variables methodology applied to a new criterion for dissipativity. Without depending on the choice of descriptor realization, a necessary and sufficient condition is obtained in terms of LMIs for existence of a controller with which the closed-loop system is admissible and dissipative.View full abstractDownload PDF (3659K) -
Yuji IGARASHI, Takeshi HATANAKA, Masayuki FUJITA2007 Volume 43 Issue 12 Pages 1156-1164
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper we consider attitude coordination on balanced graphs, where kinematics of each rigid-body is modeled in SE (3). We show that the kinematics in SE (3) satisfies a passivity property with a positive definite storage function and propose an angular velocity, control law for each rigid-body that decreases the sum of the storage functions of the individual rigid-bodies. Attitude coordination results if all rigid-bodies rotation matrices are positive definite and the communication graph is connected. We show that the speed of convergence in the attitude coordination problem is determined by the second smallest eigenvalue of graph Laplacian. Our results are also extended to the case when there are delays in communication among rigid-bodies and communication failures. Using the concept of brief instability we show that attitude coordination is still achieved even if the graph is changed. Finally, the results are demonstrated through numerical simulations.View full abstractDownload PDF (10660K) -
Takayuki WADA, Yasumasa FUJISAKI2007 Volume 43 Issue 12 Pages 1165-1166
Published: December 31, 2007
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSA class of robust feasibility problems is considered, which is to find a design variable satisfying a parameter-dependent constraint for all parameter values. A randomized algorithm for solving the problem with a general nonconvex constraint is proposed, where random samples of design variables and uncertain parameters are used. The algorithm stops in a finite number of iterations. Then, it gives a design variable satisfying the constraint for almost all parameter values with a prescribed confidence or says that the problem is infeasible in a probabilistic sense.View full abstractDownload PDF (321K)
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