Papers - Takahashi, Masaki

Driving Control of a Powered Wheelchair Considering Uncertainty of Gaze Input in Unknown Environment

Airi Ishizuka, Ayanori Yorozu, TAKAHASHI MASAKI

Applied Sciences (Applied Sciences (Switzerland))  8 ( 2 )  2018.02

Research paper (scientific journal), Joint Work, Accepted

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© 2018 by the authors. This paper describes the motion control system for a powered wheelchair using eye gaze in an unknown environment. Recently, new Human-Computer Interfaces (HCIs) that have replaced joysticks have been developed for a person with a disability of the upper body. In this paper, movement of the eyes is used as an HCI. The wheelchair control system proposed in this study aims to achieve an operation such that a passenger gazes towards the direction he or she wants to move in the unknown environment. Implementation of such an operating method facilitates easy and accurate movement of the wheelchair even in complicated environments comprising passages on the same side. This paper presents a system based on gaze detection and environment recognition that are integrated by the fuzzy set theory in real time. In the fuzzy set theory, we achieve the movement to the passage which a passenger gazes towards among some passages by integrating the information of some passages and gaze. Moreover, we design it with consideration of uncertain gaze input by using the value of gaze detection accuracy. Moreover, we achieve obstacle avoidance by integrating the information of obstacles. This motion control system can support safe and smooth movement of the wheelchair by automatically calculating its direction of motion and velocity, to avoid obstacles and move in the gaze direction of the passenger. The effectiveness of the proposed system is demonstrated through experiments in a real environment.

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Accessible ground reaction force estimation using insole force sensors without force plates

Eguchi R., Yorozu A., Takahashi M.

2017 Asian Control Conference, ASCC 2017 (2017 Asian Control Conference, ASCC 2017)  2018-January   2861 - 2865 2018.02

ISSN  9781509015733

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© 2017 IEEE. Ground reaction force (GRF) estimations using instrumented insoles relied on the use of costly force plates in previous works. This paper designed insoles with 15 force sensing resisters and presents an accessible estimation method of vertical GRF (vGRF) using the insole without any cost-prohibitive devices. To determine vGRF from the insole sensor forces, a subject-specific linear regression model was constructed using a least-squares method with a constraint and a bound. The regression matched the sensor forces during single-leg standing (SLS) to a subject's body weight with a linear constraint using data measured while walking. During SLS, standing static and shifting body weight were performed to enhance estimation accuracies. The accuracies of constructed models while walking were evaluated by comparison with the Nintendo Wii Balance Board (WBB) which can measure accurate vGRF compared with force plates. The results for an adult had 8-15 % root mean squared errors (RMSEs) with no significant deviations from previous methods which relied on force plates. From these results, the proposed method was validated as an accessible kinetic gait analysis system.

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Simultaneous dual-arm motion planning considering shared transfer path for minimizing operation time

Kurosu J., Yorozu A., Takahashi M.

2017 Asian Control Conference, ASCC 2017 (2017 Asian Control Conference, ASCC 2017)  2018-January   467 - 472 2018.02

ISSN  9781509015733

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© 2017 IEEE. One of the most basic tasks that a dual-arm robot does is pick-up and place work. Pick-up and place work consists of tasks in which the robot carries objects from a start position (initial position) to a goal position. The following three important points should also be considered when the dual-arm robot does this work efficiently: 1) collision avoidance of the arms, 2) which arm should move an object, and 3) the order in which the objects should be picked up and placed. In addition, dual-arm robot has operation range constraints. Depending on the position relationship between a start position and goal position, unless both arms are used, the object may not be transferred to a goal position. In this paper, we define the transfer path which must use both arms as 'shared transfer path'. Therefore, we propose a motion planning method to achieve efficient pick-up and place work considering shred transfer path. First, we use mixed integer linear programming (MILP) based planning for the pick-up and place work to determine which arm should move an object and in which order these objects should be moved while considering the dual-arm robot's operation range. Second, we plan the path using the rapidly exploring random tree (RRT) so that the arms do not collide, enabling the robot to perform efficient pick-up and place work based on the MILP planning solution. The effectiveness of proposed method is confirmed by simulations and experiments using the HIRO dual-arm robot.

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Motion control of a powered wheelchair using eye gaze in unknown environments

Ishizuka A., Yorozu A., Takahashi M.

2017 Asian Control Conference, ASCC 2017 (2017 Asian Control Conference, ASCC 2017)  2018-January   90 - 95 2018.02

ISSN  9781509015733

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© 2017 IEEE. This paper describes the motion control system for a powered wheelchair using eye gaze in an unknown environment. Recently, new Human-Computer Interfaces (HCIs) that have replaced joysticks have been developed for a person with a disability of the upper body. In this paper, movement of the eyes is used as an HCI. The wheelchair control system proposed in this study aims to achieve an operation such that a passenger gazes towards the direction he or she wants to move in the unknown environment. This paper presents a system based on gaze detection and environment recognition that are integrated by the fuzzy set theory in real time. This motion control system can support safe and smooth movement of the wheelchair by automatically calculating its direction of motion and velocity, to avoid obstacles and move in the gaze direction of the passenger. The effectiveness of the proposed system is demonstrated through experiments in a real environment.

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Attitude Maneuver and Gimbal angle guidance by SDRE controller using SGCMG integrated satellite SDLR model

Ozawa R., Takahashi M.

2017 Asian Control Conference, ASCC 2017 (2017 Asian Control Conference, ASCC 2017)  2018-January   1847 - 1852 2018.02

ISSN  9781509015733

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© 2017 IEEE. In the conventional agile attitude maneuver of a satellite, a control system of the satellite and Single Gimbal Control Moment Gyro (SGCMG) is designed separately and stability is not guaranteed under the singularity of SGCMGs. Therefore, in this research, we integrate the satellite and SGCMGs and design a model with the gimbal angular velocity as input. Since the target gimbal angle can be explicitly designed by a null motion, proposed control system is possible to guide the initial gimbal angle which is advantageous for next mission. In addition, it is shown that proposed method can guarantee stability even under the singularity of SGCMGs by the State-Dependent Riccati Equation (SDRE). Moreover, numerical simulations show that the singularity avoidance performance up to the target gimbal angle and the guidance performance of the gimbal angle are higher than the conventional method due to the optimality of gimbal angular velocity input.

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Agile Attitude Control and Singularity avoidance/escaping by SDRE Method using Biased State-Dependent Weighting Matrix

Ryotaro Ozawa, TAKAHASHI MASAKI

Applied Sciences (Applied Sciences (Switzerland))  8 ( 1 )  2018.01

Research paper (scientific journal), Joint Work, Accepted

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© 2016 by the authors. In recent years there has been an increasing need to improve satellite attitude control performance in terms of agility and attitude accuracy in large-angle attitude maneuvers. To achieve such control performance, single-gimbal control moment gyros (SGCMGs) should be mounted as modern-type actuators. Conventionally, based on the torque command calculated by the attitude control system of the satellite, SGCMGs were controlled by solving inverse kinematics through a pseudo inverse matrix steering law. However, in such a control system structure, it may be difficult to obtain the desired torque required by the attitude control system because of the singularity problem of SGCMGs. Furthermore, with respect to implementation, since the condition number of the Jacobian matrix of SGCMG becomes extremely large in the singularity, the numerical calculation error of the pseudo inverse matrix increases greatly. Therefore, we propose an overall control system that can solve above-described problems and the state-dependent Riccati equation (SDRE) control system that integrates the satellite and SGCMG system. The proposed optimal control system, which does not solve the pseudo inverse matrix, can realize gimbal angle guidance by gimbal angle feedback and singularity avoidance/escape using the biased weighting matrix. In the numerical simulation, the usefulness of proposed system is shown in comparison with the conventional system.

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Optimal Sizing of Energy Storage Systems for the Energy Procurement Problem in Multi-period Markets under Uncertainties

Ryusuke Konishi, Akiko Takeda, TAKAHASHI MASAKI

Energies (Energies)  11 ( 1 ) 1 - 19 2018.01

Research paper (scientific journal), Joint Work, Accepted

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© 2018 by the authors. In deregulated electricity markets, minimizing the procurement costs of electricity is a critical problem for procurement agencies (PAs). However, uncertainty is inevitable for PAs and includes multiple factors such as market prices, photovoltaic system (PV) output and demand. This study focuses on settlements in multi-period markets (a day-ahead market and a real-time market) and the installation of energy storage systems (ESSs). ESSs can be utilized for time arbitrage in the day-ahead market and to reduce the purchasing/selling of electricity in the real-time market. However, the high costs of an ESS mean the size of the system needs to be minimized. In addition, when determining the size of an ESS, it is important to identify the size appropriate for each role. Therefore, we employ the concept of a "slow" and a "fast" ESS to quantify the size of a system's role, based on the values associated with the various uncertainties. Because the problem includes nonlinearity and non-convexity, we solve it within a realistic computational burden by reformulating the problem using reasonable assumptions. Therefore, this study identifies the optimal sizes of ESSs and procurement, taking into account the uncertainties of prices in multi-period markets, PV output and demand.

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Agile attitude maneuver via SDRE controller using SGCMG integrated satellite model

Ozawa R., Takahashi M.

AIAA Guidance, Navigation, and Control Conference, 2018 (AIAA Guidance, Navigation, and Control Conference, 2018)   ( 210039 )  2018.01

ISSN  9781624105265

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© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. In this research, we propose a design method for a nonlinear optimal attitude control system that combines the systems of a single-gimbal control moment gyro (SGCMG) and a satellite that were conventionally designed separately. For this purpose, we designed a state-dependent linear representation model integrating satellite dynamics and SGCMG dynamics using a State-Dependent Riccati Equation (SDRE) controller. In the proposed method, it is possible to design the gimbal angular velocity as input without solving the inverse kinematics in the pyramid-type SGCMG. Therefore, it is possible to avoid the singularity of SGCMG by designing the weighting function matrices considering the relationship between the maneuvering axis and SGCMG steering. A numerical simulation shows that it is possible to achieve a high-speed attitude maneuver of the satellite by optimal attitude control considering singularity avoidance by the proposed method. In addition, usefulness of proposed law is shown in comparison with the GSR Inverse steering logic for the agile attitude maneuver.

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Control system design of a quadrotor moderating the virtual reality sickness

Watanabe K., Takahashi M.

AIAA Modeling and Simulation Technologies Conference, 2018 (AIAA Modeling and Simulation Technologies Conference, 2018)   ( 209959 )  2018

ISSN  9781624105289

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© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Camera-mounted quadrotor is currently being utilized as teleoperation robot for search and rescue purposes. However, controlling a quadrotor with proportional R/Cs in remote is not intuitive. Thus, combination with Head Mount Display (HMD) is proposed to increase the ease of maneuverability and sense of immersion. However, it has been reported that the video that contains vibration may induce virtual reality (VR) sickness. Particularly, a quadrotor can largely be disturbed by the wind causing the video to oscillate. Our experiment implies that the large amplitude of vibration and low frequency may have effect on inducing VR sickness. This study investigates the effect of a certain frequency of vibration to VR sickness, and proposes the attitude control of a quadrotor to avoid such movement which may induce sickness.

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Postpartum radiographic changes in pelvic morphology and its relation with symptoms of pregnancy-related symphysis pain

Ji X., Takahashi M., Morino S., Takakuwa T., Iijima H., Zhang X., Ishihara M., Kawagoe M., Hatanaka Y., Umezaki F., Yamashita M., Tsuboyama T., Aoyama T.

Clinical and Experimental Obstetrics and Gynecology (Clinical and Experimental Obstetrics and Gynecology)  45 ( 5 ) 665 - 670 2018

ISSN  03906663

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© 2018 S.O.G. CANADA Inc. All rights reserved. Introduction: The etiology of pregnancy-related pubic symphysis pain (PSP) is usually considered as the change in pelvic biomechanics during pregnancy. However, the biomechanical changes that occur during puerperium, and the difference of radiographic dimensions in women with different types of PSP remains unknown. Materials and Methods: Fifty women with self-reported PSP were included. Two conventional X-ray radiographic dimensions obtained on the delivery day and one-month postpartum were compared by using paired t-test. Based on the self-reported VAS at one-month postpartum, variables between pain-recovery and non-recovery groups were also compared. Results: The comparison between pre- and post-values indicates a reduced distance between FLAMs (239.1 vs. 237.0 mm), PS separation (7.9 vs. 6.5 mm), and PS translation (4.1 vs. 3.1 mm). No significant differences were observed in the distance between FLAMs, width of PS separation, or pubic symphysial surface (PSS) angle between the recovery and non-recovery groups. However, the non-recovery group exhibited a significantly large change in PS translation at one-month postpartum than the recovery group (-1.8 vs. -1.1 mm). Conclusions: The pelvic radiography demonstrated a 'closure' alteration in the pelvic cavity diameter one-month postpartum with a decrease in the distance between FLAMs and shortened PS separation. The difference in radiographic diameters between groups was not clearly evident.

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Pelvic alignment risk factors associated with sacroiliac joint pain during pregnancy

Morino S., Ishihara M., Umezaki F., Hatanaka H., Yamashita M., Aoyama T., Takahashi M.

Clinical and Experimental Obstetrics and Gynecology (Clinical and Experimental Obstetrics and Gynecology)  45 ( 6 ) 850 - 854 2018

ISSN  03906663

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© 2018 S.O.G. Canada Inc.All rights reserved. Purpose of investigation: To investigate the influence of the change in pelvic alignment during pregnancy on sacroiliac joint pain (SIJP). Materials and Methods: Participants included 168 women without SIJP at recruitment and were evaluated at 12 and 36 weeks of pregnancy. SIJP intensity was assessed using the Numerical Rating Scale (NRS). Pelvic alignment measurements included the anterior and posterior width of the pelvis, anterior pelvic tilt, and pelvic asymmetry. Participants were divided into the SIJP and non-SIJP groups based on the presence of SIJP at 36 weeks of pregnancy. The influence of the change in pelvic alignment during pregnancy between the groups was investigated. Results: The amount of change in pelvic anteversion during pregnancy was smaller and the change in pelvic asymmetry was significantly greater in the SIJP group compared to that in the non-SIJP group. In addition, an increase in pelvic asymmetry was the most strongly associated risk factor for SIJP. Conclusions:A forward-bending pelvis in early pregnancy and an increase in pelvic asymmetry during pregnancy are risk factors for pregnancy-related SIJP.

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Minimum-time attitude maneuver of small satellite mounted with communication antenna

Mori K., Takahashi M.

Space Flight Mechanics Meeting, 2018 (Space Flight Mechanics Meeting, 2018)   ( 210009 )  2018

ISSN  9781624105333

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© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. This paper proposes a simultaneous control method for small satellites mounted with a communication antenna; the objective is to reduce the time involved in satellite maneuver and antenna motion. Recently, small Earth observation satellites have been utilized, even though agile large angle satellite attitude maneuver has been in demand. Small Earth observation satellites acquire high-resolution data, resulting in an increase in the time required for data communication. Therefore, it has become important to ensure that small Earth observation satellites are capable of being maneuvered rapidly so that communication time can be extended by using a data relay system. In conventional operations, the antenna motion is implemented after satellite attitude maneuver. However, this method has a time delay between the completion of the attitude maneuver and the start of data communication. The purpose of this study is to extend the time for Earth observation and data communication. In order to achieve this, we propose a simultaneous control method for satellite maneuver and antenna motion using a nonlinear programming problem.

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Simultaneous Dual-Arm Motion Planning for Minimizing Operation Time

Jun Kurosu, Ayanori Yorozu, TAKAHASHI MASAKI

Applied Sciences 7 ( 12 )  2017.12

Research paper (scientific journal), Joint Work, Accepted

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Markerless Knee Joint Position Measurement Using Depth Data during Stair Walking

Ami Ogawa, Akira Mita, Ayanori Yorozu, TAKAHASHI MASAKI

Sensors 17 ( 11 )  2017.11

Research paper (scientific journal), Joint Work, Accepted

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Estimating co-contraction activation of trunk muscles using a novel musculoskeletal model for pregnant women

Saori Morino, TAKAHASHI MASAKI

Applied Sciences 7 ( 10 )  2017.10

Research paper (scientific journal), Joint Work, Accepted

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Optimal Allocation of Photovoltaic Systems and Energy Storage Systems based on Vulnerability Analysis

Ryusuke Konishi, TAKAHASHI MASAKI

Energies 1 ( 9 ) 305 - 313 2017.10

Research paper (scientific journal), Joint Work, Accepted

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複数レーザレンジセンサを用いた高精度歩行計測システム （高齢者のTimed Up and Go試験への適用）

萬礼 応, 髙橋 正樹

日本機械学会論文集 (日本機械学会)  85 ( 855 ) 01 - 17 2017.09

Research paper (scientific journal), Joint Work, Accepted

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Association between mild cognitive impairment and trajectory-based spatial parameters during timed up and go test using a laser range sensor

Shu Nishiguchi, Ayanori Yorozu, Daiki Adachi, TAKAHASHI MASAKI, Tomoki Aoyama

Journal of NeuroEngineering and Rehabilitation 1 ( 9 ) 305 - 313 2017.08

Research paper (scientific journal), Joint Work, Accepted

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SVM-based Multi-point Prediction System of Solar Irradiance using DTW-based Cluster Analysis

Yukiya Tanaka, TAKAHASHI MASAKI

Transactions of the Institute of Systems, Control and Information Engineers 61 ( 8 ) 305 - 313 2017.08

Research paper (scientific journal), Joint Work, Accepted

Generating linear regression model to predict motor functions by use of laser range finder during TUG

Daiki Adachi, Shu Nishiguchi, Naoto Fukutani, Takayuki Hotta, Yuto Tashiro, Saori Morino, Hidehiko Shirooka, Yuma Nozaki, Hinako Hirata, Moe Yamaguchi, Ayanori Yorozu,, TAKAHASHI MASAKI, Tomoki Aoyama

Journal of Orthopaedic Science 22 ( 3 ) 549 - 553 2017.05

Research paper (scientific journal), Joint Work, Accepted