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Volume 52, Issue 6
Displaying 1-6 of 6 articles from this issue
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Paper
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Hisanori HAYASHI, Toshitsugu UEDA, Hiroshi OOIGAWA2016 Volume 52 Issue 6 Pages 303-309
Published: 2016
Released on J-STAGE: June 25, 2016
JOURNAL FREE ACCESSThis paper proposes a combination of a quartz resonant hydrogen gas sensor and industrial wireless system fulfiled with intrinsic safety requirements in order to apply for hydrogen gas stations and related facilities. Significant key features of this proposed wireless hydrogen gas sensor are suitable for intrinsic safety apparatus. Proposed wireless hydrogen gas sensor system is expected for contribution to increasing safety of hydrogen station and related facilities.View full abstractDownload PDF (2281K) -
Yoshimitsu HASHIZUME, Shoko KAICHIDA, Jun NISHII2016 Volume 52 Issue 6 Pages 310-316
Published: 2016
Released on J-STAGE: June 25, 2016
JOURNAL FREE ACCESSSome previous studies about human walking have suggested that the variance of the toe position relative to the hip position is suppressed by joint synergy which is a compensatory inter-joint coordination, especially during double support phase and at the moment of the minimum toe clearance. However, the ankle position would also be an important variable to be controlled around the end of swing phase just before heel strike against the ground. We hypothesized that the leg joint synergy changes according to the stage in a gait cycle in order to switch the variable to be controlled, i.e., from the toe position in some stages to the ankle position in the others, and investigated the validity of this hypothesis by analyzing gait kinematics. Hip, knee, ankle, and toe trajectories of eight adult subjects were recorded during level walking by a motion capture system by 200fps. The uncontrolled manifold analysis was applied to quantify the joint synergy. The results showed that the leg joint synergy worked so as to adjust the toe position relative to the hip position from the second double support phase to the middle of the swing phase, i.e., from the push-off phase to the moment of the minimum toe clearance, and the ankle joint was strongly involved in the formation of the synergy during these periods. Contrary, the joint synergy worked so as to adjust the ankle position rather than the toe position in the end of the swing phase. These results suggest that the toe or ankle position is selected as a controlled variable according to the distance from the ground during walking and the switching of the joint synergy occurs so as to stabilize the controlled variable.View full abstractDownload PDF (1070K) -
Tadamichi MAWATARI, Kensuke TSUCHIYA2016 Volume 52 Issue 6 Pages 317-329
Published: 2016
Released on J-STAGE: June 25, 2016
JOURNAL FREE ACCESSThere is an increasing need to automate handwork by skilled workers in industry. However, that handwork is usually difficult to express clearly in words. Furthermore, human's motion contains time and spatial perturbations, and this makes the automation even more difficult. In this report, spline functions are applied first to motion-capture data of brush strokes of Japanese calligraphy, and mathematical model of human's technique is established. Then, the isomorphism mapping method is introduced to deal with the time perturbations, and Min-Max norm was applied to deal with the spatial perturbations. Furthermore, a new analytical point of view called controllability is introduced to the mathematical model, and the “target curve” is derived as the goal of the automation. The motion control theory based on controllability is hereby established to automate human's handwork.View full abstractDownload PDF (2556K) -
Closed-loop Identification and Dead Time Estimation Based on Generalized Minimum Variance EvaluationRyota UEMATSU, Shiro MASUDA2016 Volume 52 Issue 6 Pages 330-337
Published: 2016
Released on J-STAGE: June 25, 2016
JOURNAL FREE ACCESSThis paper provides a closed-loop identification method based on generalized minimum variance (GMV) evaluation in case of unknown dead time. A new variance criterion to obtain process parameters and dead time simultaneously is introduced. The optimal dead time is searched for over a prescribed range of dead time. The criterion consists of input and output measurements collected from the closed-loop system with the nominal GMV control law in regulatory control. The paper proves that the optimization of the proposed criterion results in the unique optimal solution which corresponds to the true system parameters and the actual dead time. The efficiency of the proposed method is demonstrated through a numerical example.View full abstractDownload PDF (782K) -
Shun MATSUI, Toshiyuki MURAO, Kenji HIRATA, Kenko UCHIDA2016 Volume 52 Issue 6 Pages 338-347
Published: 2016
Released on J-STAGE: June 25, 2016
JOURNAL FREE ACCESSThis paper presents dynamic output integration mechanisms for LQG power networks based on mechanism design theory in economics. The LQG power network model, which is motivated by an average system frequency model, consists of suppliers and consumers, called agents, and one public commission, called the utility. Each agent, who has a type with his preference, decides his private control to minimize his own cost functional, while the utility decides prices to minimize a public cost functional. In this problem setting, we propose two dynamic output integration mechanisms based on the cost functional and Hamiltonian. Both mechanisms under which the utility estimates agents' state on price calculation, satisfy the public optimality of the optimal private controls, incentive compatibility, and individual rationality. The effectiveness of the proposed mechanisms is assessed through simulation results.View full abstractDownload PDF (1532K) -
Takehiro HOSHINO, Tai TANAKA, Kei SUWA, Teruyuki HARA2016 Volume 52 Issue 6 Pages 348-357
Published: 2016
Released on J-STAGE: June 25, 2016
JOURNAL FREE ACCESSThis document describes a feasibility study for detecting crack of concrete by using Ka-band (from 26GHz to 40GHz) full polarized synthetic aperture radar (SAR). Recently, it becomes important to detect cracks for checking the damage of infrastructure and used houses. If we need transmissive image through the wallpaper, radio-frequency sensor is an effective solution. We conducted an experiment in radio-frequency anechoic chamber to detect the crack by using full polarized SAR system. The system mainly consisted from a vector network analyzer (VNA), a RF-switch, four horn antennas and an actuator. The four antennas obtained full polarized (VV, VH, HV, HH) SAR imagery. In our experiment, VH or HV polarization is effective for the crack along with the radar line of sight (LOS). On the other hand, VV polarization is effective for the crack across LOS. The experiment shows effectiveness of polarized SAR-based monitoring system.View full abstractDownload PDF (4167K)
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