Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197143
Y. Fujimoto, Tsubasa Suenaga, Y. Wakayama, Kengo Sawai, A. Shukor
This paper proposes force control of a spiral motor in combination with zero-power magnetic levitation control. The motor has a helical-shape mover, which moves in a helical-shape stator without contact. Due to the manufacturing process, the actual spiral motor contains fluctuation of neutral point of the air-gap displacement depending on the mover rotation angle. The d-axis current remain a finite value and copper loss arises even when the mover is located at the center between the stator cores. Zero-power magnetic levitation control is proposed to solve this problem. The proposed control is experimentally verified. In addition, a model of a musculoskeletal biped robot equipped with spiral motors is introduced.
{"title":"Force control of a spiral motor and its application to musculoskeletal biped robot","authors":"Y. Fujimoto, Tsubasa Suenaga, Y. Wakayama, Kengo Sawai, A. Shukor","doi":"10.1109/AMC.2012.6197143","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197143","url":null,"abstract":"This paper proposes force control of a spiral motor in combination with zero-power magnetic levitation control. The motor has a helical-shape mover, which moves in a helical-shape stator without contact. Due to the manufacturing process, the actual spiral motor contains fluctuation of neutral point of the air-gap displacement depending on the mover rotation angle. The d-axis current remain a finite value and copper loss arises even when the mover is located at the center between the stator cores. Zero-power magnetic levitation control is proposed to solve this problem. The proposed control is experimentally verified. In addition, a model of a musculoskeletal biped robot equipped with spiral motors is introduced.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"116 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87860044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197100
T. Ishii, S. Katsura
Bilateral teleoperation system through network is negatively affected to stability by communication delay. In this paper, bilateral teleoperation system is researched toward a delay free bilateral teleoperation. By using 2ch bilateral control which is transmitting and controlling only positions, the stability of bilateral teleoperation system is enhanced. However, the bilateral teleoperation controlling only position increases force needed to operate master system. So, the operationality comes down, and teleoperation becomes difficult. Therefore, in order to enhance the operationality, local force feedback loop is added, and external force is controlled to 0. So, the proposed method enhances the stability while keeping good operationality. As a result, it turns out that the bilateral control system can enhance the performance of communication delay by reducing connectability of master and slave.
{"title":"Bilateral control with local force feedback for delay-free teleoperation","authors":"T. Ishii, S. Katsura","doi":"10.1109/AMC.2012.6197100","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197100","url":null,"abstract":"Bilateral teleoperation system through network is negatively affected to stability by communication delay. In this paper, bilateral teleoperation system is researched toward a delay free bilateral teleoperation. By using 2ch bilateral control which is transmitting and controlling only positions, the stability of bilateral teleoperation system is enhanced. However, the bilateral teleoperation controlling only position increases force needed to operate master system. So, the operationality comes down, and teleoperation becomes difficult. Therefore, in order to enhance the operationality, local force feedback loop is added, and external force is controlled to 0. So, the proposed method enhances the stability while keeping good operationality. As a result, it turns out that the bilateral control system can enhance the performance of communication delay by reducing connectability of master and slave.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"5 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89693407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197109
Y. Ueyama, E. Miyashita
An understanding of how the brain constrains dimensions of freedom to control the body would be beneficial for the robotic engineering of a humanoid robot. We estimated joint stiffness in a female Japanese monkey (Macaca fuscata) during arm reaching movements and carried out a numerical simulation. The estimated stiffness was high at movement onset and movement end, and decreased at the mid-point of the movement. These characteristic patterns were reproduced by the numerical simulation using a 2-link 6-muscle arm model and an approximately optimal feedback control. Although the arm model was a redundant system with multiple dimensions of freedom, the optimal control was able to solve the redundancy problem by optimizing a task-relevant cost function. We suggest that the brain may control the body according to a similar optimal control law.
{"title":"A numerical simulation using optimal control can estimate stiffness profiles of a monkey arm during reaching movements","authors":"Y. Ueyama, E. Miyashita","doi":"10.1109/AMC.2012.6197109","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197109","url":null,"abstract":"An understanding of how the brain constrains dimensions of freedom to control the body would be beneficial for the robotic engineering of a humanoid robot. We estimated joint stiffness in a female Japanese monkey (Macaca fuscata) during arm reaching movements and carried out a numerical simulation. The estimated stiffness was high at movement onset and movement end, and decreased at the mid-point of the movement. These characteristic patterns were reproduced by the numerical simulation using a 2-link 6-muscle arm model and an approximately optimal feedback control. Although the arm model was a redundant system with multiple dimensions of freedom, the optimal control was able to solve the redundancy problem by optimizing a task-relevant cost function. We suggest that the brain may control the body according to a similar optimal control law.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"2004 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89523929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197026
K. Kaneko, F. Kanehiro, M. Morisawa, E. Yoshida, J. Laumond
This paper presents an external force observer that estimates the external force acting on a biped humanoid robot, such as a collision force with a human or with an object. Since biped humanoid robots balance themselves on a limited area with foot soles, the detection of external force is important to realize for a stable balance controller for humanoid robots working in a real environment. In the proposed observer, the external force is estimated using inertial sensors and foot force sensors based on simple but efficient modeling of the forces applied to the robot. This paper also shows the experiments of the proposed external force observer using a real humanoid robot HRP-2. The experimental results show that the proposed observer has satisfactory performance to estimate the external force with sufficient response and accuracy.
{"title":"Disturbance observer that estimates external force acting on humanoid robots","authors":"K. Kaneko, F. Kanehiro, M. Morisawa, E. Yoshida, J. Laumond","doi":"10.1109/AMC.2012.6197026","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197026","url":null,"abstract":"This paper presents an external force observer that estimates the external force acting on a biped humanoid robot, such as a collision force with a human or with an object. Since biped humanoid robots balance themselves on a limited area with foot soles, the detection of external force is important to realize for a stable balance controller for humanoid robots working in a real environment. In the proposed observer, the external force is estimated using inertial sensors and foot force sensors based on simple but efficient modeling of the forces applied to the robot. This paper also shows the experiments of the proposed external force observer using a real humanoid robot HRP-2. The experimental results show that the proposed observer has satisfactory performance to estimate the external force with sufficient response and accuracy.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"32 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90219731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197140
Dinko Osmankovic, J. Velagić
In this paper we introduce a modification of histogramic in - motion mapping technique for mobile robots. This modification is based on the premise that precise sonar model is not required for accurate map building. We use uniform random distribution approach to replace the probabilistic model of sonar sensor. Problem of localization of the mobile robot is also discussed as it is very important for the precise mapping of the environment. For this purpose we used odometry measurements processed by Extended Kalman Filter for the robot localization. It is shown that this method gives precise maps of an environment in Player/Stage simulator, and also with real world scenarios.
{"title":"Modified histogramic technique for mobile robot indoor environment mapping based on uniform random distribution","authors":"Dinko Osmankovic, J. Velagić","doi":"10.1109/AMC.2012.6197140","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197140","url":null,"abstract":"In this paper we introduce a modification of histogramic in - motion mapping technique for mobile robots. This modification is based on the premise that precise sonar model is not required for accurate map building. We use uniform random distribution approach to replace the probabilistic model of sonar sensor. Problem of localization of the mobile robot is also discussed as it is very important for the precise mapping of the environment. For this purpose we used odometry measurements processed by Extended Kalman Filter for the robot localization. It is shown that this method gives precise maps of an environment in Player/Stage simulator, and also with real world scenarios.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"31 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84357094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197054
Y. Kimura, Sehoon Oh, Y. Hori
This paper proposes kinematics and a control algorithm to control a two-link manipulator to simulate a spring loaded inverted pendulum (SLIP). End-effector kinematics is derived in the reference frame that is defined along the axis that connects the first joint and the end-effector. The derivation of this kinematics reveals that a biarticular actuator is suitable for this kinematics. Based on this kinematics, a disturbance observer is designed in the same reference frame. This disturbance observer removes the unnecessary inertia coupling without calculation of Jacobian matrix.
{"title":"Leg space observer on biarticular actuated two-link manipulator for realizing spring loaded inverted pendulum model","authors":"Y. Kimura, Sehoon Oh, Y. Hori","doi":"10.1109/AMC.2012.6197054","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197054","url":null,"abstract":"This paper proposes kinematics and a control algorithm to control a two-link manipulator to simulate a spring loaded inverted pendulum (SLIP). End-effector kinematics is derived in the reference frame that is defined along the axis that connects the first joint and the end-effector. The derivation of this kinematics reveals that a biarticular actuator is suitable for this kinematics. Based on this kinematics, a disturbance observer is designed in the same reference frame. This disturbance observer removes the unnecessary inertia coupling without calculation of Jacobian matrix.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"16 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86674732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197022
T. Hara, T. Koseki
Suppression of slip and reduction of friction between rail and wheel are important in railway systems. This paper proposes a novel slip re-adhesion control based on the excessive torque and excessive angular momentum for 4 axle and 2 truck model (1C2M, 1 inverter 2 motor drive system). Effectiveness of the proposed method has been confirmed by mathmatical analysis. Furthermore, the proposed method was evaluated by two performance indicators, frictional force reduction and effective utilization of adhesive force. As a result, adhesion characteristic of the proposal method was 7.04 % better than the conventional method. In addition, loss friction force around driving wheel remained unchanged.
{"title":"Study on re-adhesion control by monitoring excessive angular momentum in electric railway tractions","authors":"T. Hara, T. Koseki","doi":"10.1109/AMC.2012.6197022","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197022","url":null,"abstract":"Suppression of slip and reduction of friction between rail and wheel are important in railway systems. This paper proposes a novel slip re-adhesion control based on the excessive torque and excessive angular momentum for 4 axle and 2 truck model (1C2M, 1 inverter 2 motor drive system). Effectiveness of the proposed method has been confirmed by mathmatical analysis. Furthermore, the proposed method was evaluated by two performance indicators, frictional force reduction and effective utilization of adhesive force. As a result, adhesion characteristic of the proposal method was 7.04 % better than the conventional method. In addition, loss friction force around driving wheel remained unchanged.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"46 24 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83560588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197119
K. Natori
This paper studies a design method of time-delay systems with communication disturbance observer (CDOB). A time-delay compensation method based on network disturbance (ND) concept and CDOB has been proposed and applied to various control systems. It compensates time-delay effect without using time-delay model and the effectiveness is equivalent to that of Smith predictor. Furthermore, it works even when time-delay value is unknown, since it does not need time-delay models. In past works, some design methods of time-delay systems with CDOB have been studied basically by using Nyquist diagram. However, detailed design methods of the transient characteristics have not been researched well due to the characteristics of Nyquist diagrams. In other words, we have not addressed design methods based on detailed pole placements studies in order to arbitrarily design the transient characteristics. In this paper, we study a design method of time-delay systems with CDOB based on pole placements by using Pade approximation. The detailed design of the transient characteristics is accomplished by the analytical results. The adequacy of the presented design method is validated by simulation studies.
{"title":"A design method of time-delay systems with communication disturbance observer by using Pade approximation","authors":"K. Natori","doi":"10.1109/AMC.2012.6197119","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197119","url":null,"abstract":"This paper studies a design method of time-delay systems with communication disturbance observer (CDOB). A time-delay compensation method based on network disturbance (ND) concept and CDOB has been proposed and applied to various control systems. It compensates time-delay effect without using time-delay model and the effectiveness is equivalent to that of Smith predictor. Furthermore, it works even when time-delay value is unknown, since it does not need time-delay models. In past works, some design methods of time-delay systems with CDOB have been studied basically by using Nyquist diagram. However, detailed design methods of the transient characteristics have not been researched well due to the characteristics of Nyquist diagrams. In other words, we have not addressed design methods based on detailed pole placements studies in order to arbitrarily design the transient characteristics. In this paper, we study a design method of time-delay systems with CDOB based on pole placements by using Pade approximation. The detailed design of the transient characteristics is accomplished by the analytical results. The adequacy of the presented design method is validated by simulation studies.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"107 22","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91408218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197031
Mireia Perez Plius, Metin Yílmaz, Utku Seven, K. Erbatur
Force control of robotic manipulators is becoming more and more important in applications that involve interaction with the environment. Depending on the nature of the task at hand, different control algorithms can be suitable to be implemented. In this paper the task of reaching an object by the robot tool and applying a constant force on it is considered as a case study. This task is one of the typical manipulation operations. A fuzzy logic scheduling approach, which smoothly changes the control action between two force control schemes, is proposed. The first force control method is admittance control, which is suitable to be used in the phase of approaching the work piece. The second one is an explicit force control strategy, integral force control, suitable for force regulation when the manipulator tool is in contact with the work piece. The fuzzy controller scheduling approach is tested via experimental work on a direct drive SCARA-type manipulator. It is also compared with a crisp controller switching method. Experiments are carried out with fixed and free-to-move work pieces. The results validate that the proposed fuzzy transition has advantages over a crisp switching between controllers.
{"title":"Fuzzy controller scheduling for robotic manipulator force control","authors":"Mireia Perez Plius, Metin Yílmaz, Utku Seven, K. Erbatur","doi":"10.1109/AMC.2012.6197031","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197031","url":null,"abstract":"Force control of robotic manipulators is becoming more and more important in applications that involve interaction with the environment. Depending on the nature of the task at hand, different control algorithms can be suitable to be implemented. In this paper the task of reaching an object by the robot tool and applying a constant force on it is considered as a case study. This task is one of the typical manipulation operations. A fuzzy logic scheduling approach, which smoothly changes the control action between two force control schemes, is proposed. The first force control method is admittance control, which is suitable to be used in the phase of approaching the work piece. The second one is an explicit force control strategy, integral force control, suitable for force regulation when the manipulator tool is in contact with the work piece. The fuzzy controller scheduling approach is tested via experimental work on a direct drive SCARA-type manipulator. It is also compared with a crisp controller switching method. Experiments are carried out with fixed and free-to-move work pieces. The results validate that the proposed fuzzy transition has advantages over a crisp switching between controllers.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"1 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82230153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197135
Kenta Sasahara, N. Motoi, T. Shimono, A. Kawamura
This paper proposes the switching control method to realize stable landing for a biped robot. If the landing of the biped robot is unstable, the robot may fall down. Therefore, it is necessary for the biped robot to realize stable landing. In order to achieve the stable landing, force controller should be implemented at the moment of landing. Since force control enables the sole to softly contact the ground. If the landing state becomes stable, control method needs to change position control for the biped robot moving. In other words, the controller should be switched according to the contact condition between the sole and the ground. Therefore, switching control method which consists of position control and force control is proposed. Zero Moment Point (ZMP) is used as index to switch the controller. Position control is applied when ZMP exists in the area around the center of the foot. Force control is used when ZMP exists around the edge of the foot. The validity of the proposed method is confirmed from the simulation results by using the model of inverted pendulum with a sole.
提出了一种实现双足机器人稳定着陆的切换控制方法。如果双足机器人的着陆不稳定，机器人可能会摔倒。因此，实现双足机器人的稳定着陆是十分必要的。为了实现平稳着陆，需要在着陆时刻实施力控制器。由于力的控制，使鞋底柔软地接触地面。当着陆状态稳定时，控制方法需要改变双足机器人运动的位置控制。换句话说，控制器要根据鞋底与地面的接触情况进行开关。为此，提出了由位置控制和力控制相结合的切换控制方法。零点力矩点(Zero Moment Point, ZMP)作为切换控制器的索引。当ZMP存在于足部中心周围区域时，应用位置控制。当ZMP存在于脚的边缘时，使用力控制。利用带底倒立摆模型进行仿真，验证了所提方法的有效性。
{"title":"Stable landing method for biped robot by using switching control","authors":"Kenta Sasahara, N. Motoi, T. Shimono, A. Kawamura","doi":"10.1109/AMC.2012.6197135","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197135","url":null,"abstract":"This paper proposes the switching control method to realize stable landing for a biped robot. If the landing of the biped robot is unstable, the robot may fall down. Therefore, it is necessary for the biped robot to realize stable landing. In order to achieve the stable landing, force controller should be implemented at the moment of landing. Since force control enables the sole to softly contact the ground. If the landing state becomes stable, control method needs to change position control for the biped robot moving. In other words, the controller should be switched according to the contact condition between the sole and the ground. Therefore, switching control method which consists of position control and force control is proposed. Zero Moment Point (ZMP) is used as index to switch the controller. Position control is applied when ZMP exists in the area around the center of the foot. Force control is used when ZMP exists around the edge of the foot. The validity of the proposed method is confirmed from the simulation results by using the model of inverted pendulum with a sole.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"22 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88792697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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