Pub Date : 1995-10-06DOI: 10.1109/ROBOT.1995.525742
V. Bhatt, K. Bijhringer, Ken Goldberg
The existing industrial parts feeders move the parts through a sequence of mechanical filters that reject parts in unwanted orientations. In this paper we develop a new setup that uses a different vibratory mechanism to systematically manipulate parts, by actively orienting and localizing them. The idea is to generate and change dynamic modes for a plate by varying the applied frequency of oscillation. Depending on the node shapes of the plate for these frequencies, the position and orientation of the parts can be controlled. We develop an analysis of the underlying dynamics, and show that it can be used to predict the behavior of objects placed on the vibrating plate. Using this analysis, we propose that the applied frequencies can be automatically sequenced to obtain a "sensorless" strategy for manipulating a given object.
{"title":"Sensorless Manipulation Using Transverse Vibrations of a Plate","authors":"V. Bhatt, K. Bijhringer, Ken Goldberg","doi":"10.1109/ROBOT.1995.525742","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525742","url":null,"abstract":"The existing industrial parts feeders move the parts through a sequence of mechanical filters that reject parts in unwanted orientations. In this paper we develop a new setup that uses a different vibratory mechanism to systematically manipulate parts, by actively orienting and localizing them. The idea is to generate and change dynamic modes for a plate by varying the applied frequency of oscillation. Depending on the node shapes of the plate for these frequencies, the position and orientation of the parts can be controlled. We develop an analysis of the underlying dynamics, and show that it can be used to predict the behavior of objects placed on the vibrating plate. Using this analysis, we propose that the applied frequencies can be automatically sequenced to obtain a \"sensorless\" strategy for manipulating a given object.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125202380","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 : 1995-09-15DOI: 10.1109/ROBOT.1995.525518
O. Matsumoto, S. Kajita, K. Tani, M. Oooto
We have developed a robot called a ' structure type four-wheeled robot' which, with a simple structure, has ability to pass over a step. This robot has only one degree of freedom to change the body's structure and can run on four wheels (4-wheeled mode) or on two wheels like a wheeled inverted pendulum (2-wheeled mode). For the realization of stepping up and down, there are three difficult problems to be solved: stable control in 2-wheeled state, transfer from 4- to 2-wheeled mode (swing-up), and transfer from 2- to 4-wheeled mode (landing). The control method we have developed for a wheeled inverted pendulum is used to control the 2-wheeled state using the signal of a rate gyroscope. In this paper, we mainly discuss control methods for transfers from 4- to 2-wheeled mode and from 2- to 4-wheeled mode. Especially in the transfer from 4- to 2-wheeled state, we make effective use of the driving torque of the motor which change the body's structure. In the transfer from 2- to 4-wheeled state, we have investigated a control method for soft landing to minimize the touch-down impact of the robot which is nonholonomic system. By combining our control methods, we have realized an experiment of passing over a step successfully.
{"title":"A four-wheeled robot to pass over steps by changing running control modes","authors":"O. Matsumoto, S. Kajita, K. Tani, M. Oooto","doi":"10.1109/ROBOT.1995.525518","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525518","url":null,"abstract":"We have developed a robot called a ' structure type four-wheeled robot' which, with a simple structure, has ability to pass over a step. This robot has only one degree of freedom to change the body's structure and can run on four wheels (4-wheeled mode) or on two wheels like a wheeled inverted pendulum (2-wheeled mode). For the realization of stepping up and down, there are three difficult problems to be solved: stable control in 2-wheeled state, transfer from 4- to 2-wheeled mode (swing-up), and transfer from 2- to 4-wheeled mode (landing). The control method we have developed for a wheeled inverted pendulum is used to control the 2-wheeled state using the signal of a rate gyroscope. In this paper, we mainly discuss control methods for transfers from 4- to 2-wheeled mode and from 2- to 4-wheeled mode. Especially in the transfer from 4- to 2-wheeled state, we make effective use of the driving torque of the motor which change the body's structure. In the transfer from 2- to 4-wheeled state, we have investigated a control method for soft landing to minimize the touch-down impact of the robot which is nonholonomic system. By combining our control methods, we have realized an experiment of passing over a step successfully.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126165463","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 : 1995-05-21DOI: 10.1109/ROBOT.1995.525482
J. Zuhars, T. Hsia
This paper deals with problems that arise when robot manipulators are used in milling workpieces with nonhomogeneous material. Damages to the cutting tool and workpiece would occur if the cutting speed is set incorrectly with respect to the characteristics of the tool and the hardness of the workpiece material. This concern is heightened when milling materials which are nonhomogenous where the tool drag can vary unpredictably. It is proposed in this paper that we solve the problem by employing a force controlled velocity (FCV) strategy to automatically adjust the cutting speed in response to the force exerted at the tool tip along the cutting path. The idea of FCV is accomplished by using a nonlinear function of both force and elapsed time in place of elapsed time when evaluating the robot trajectory equation. The effectiveness of this approach is confirmed by simulation and experimentation.
{"title":"Nonhomogeneous material milling using a robot manipulator with force controlled velocity","authors":"J. Zuhars, T. Hsia","doi":"10.1109/ROBOT.1995.525482","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525482","url":null,"abstract":"This paper deals with problems that arise when robot manipulators are used in milling workpieces with nonhomogeneous material. Damages to the cutting tool and workpiece would occur if the cutting speed is set incorrectly with respect to the characteristics of the tool and the hardness of the workpiece material. This concern is heightened when milling materials which are nonhomogenous where the tool drag can vary unpredictably. It is proposed in this paper that we solve the problem by employing a force controlled velocity (FCV) strategy to automatically adjust the cutting speed in response to the force exerted at the tool tip along the cutting path. The idea of FCV is accomplished by using a nonlinear function of both force and elapsed time in place of elapsed time when evaluating the robot trajectory equation. The effectiveness of this approach is confirmed by simulation and experimentation.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116915371","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 : 1995-05-21DOI: 10.1109/ROBOT.1995.525405
H. Wakamatsu, S. Aoyagi, K. Takahara, M. Yasuna
A stereoscopic cutting of virtual object in a real space using a human binocular parallax is discussed. A scissors-type edged-tool with 2-degree of freedom is developed for the realization of reactive force feeling on the cutting into stereoscopically viewed virtual object. An image of sheet is given as a virtual object for cutting. The reactive force is provided for the tool, by which fingers obtain feeling of cutting according to given physical properties to the image. The stereoscopic cutting makes clear a trace of the cutting point of scissors characterized by a different color in a virtual object given as an image. This paper describes first the construction of a scissors-type edged-tool for cutting. Then, force display system is synthesized providing feeling of cutting of materials by the edged-tool according to their given properties.
{"title":"Force display system for realization of cut-in-feeling of virtual sheet object by scissors","authors":"H. Wakamatsu, S. Aoyagi, K. Takahara, M. Yasuna","doi":"10.1109/ROBOT.1995.525405","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525405","url":null,"abstract":"A stereoscopic cutting of virtual object in a real space using a human binocular parallax is discussed. A scissors-type edged-tool with 2-degree of freedom is developed for the realization of reactive force feeling on the cutting into stereoscopically viewed virtual object. An image of sheet is given as a virtual object for cutting. The reactive force is provided for the tool, by which fingers obtain feeling of cutting according to given physical properties to the image. The stereoscopic cutting makes clear a trace of the cutting point of scissors characterized by a different color in a virtual object given as an image. This paper describes first the construction of a scissors-type edged-tool for cutting. Then, force display system is synthesized providing feeling of cutting of materials by the edged-tool according to their given properties.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121013908","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 : 1995-05-21DOI: 10.1109/ROBOT.1995.525726
N. Yamasaki, Y. Anzai
In the near future, robots used by human-like personal computers will appear in office or at home. In this paper, we call these robots personal robots. A personal robot can be thought as a small autonomous mobile robot. First, we discuss a user interface design for personal robots in the face-to-face situation. Second, we consider the features of personal robots and their environments, and propose a new user interface concept for a personal robot an active interface. To show the effectiveness of the active interface, we design and implement a speech dialogue system called Chaser for human-robot interaction based on the active interface.
{"title":"Active interface for human-robot interaction","authors":"N. Yamasaki, Y. Anzai","doi":"10.1109/ROBOT.1995.525726","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525726","url":null,"abstract":"In the near future, robots used by human-like personal computers will appear in office or at home. In this paper, we call these robots personal robots. A personal robot can be thought as a small autonomous mobile robot. First, we discuss a user interface design for personal robots in the face-to-face situation. Second, we consider the features of personal robots and their environments, and propose a new user interface concept for a personal robot an active interface. To show the effectiveness of the active interface, we design and implement a speech dialogue system called Chaser for human-robot interaction based on the active interface.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127243122","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 : 1995-05-21DOI: 10.1109/ROBOT.1995.525300
R. Colbaugh, K. Glass
This paper considers the position regulation problem for uncertain rigid-link electrically-driven manipulators, and presents an adaptive control strategy as a solution to this problem. The proposed controller is computationally simple, requires virtually no a priori information concerning either the manipulator or actuator models, and ensures semiglobal stability and convergence of the manipulator position error to zero. Experimental results are presented for a Zebra Zero manipulator and demonstrate that the proposed scheme provides a simple and effective means of obtaining high performance position regulation. Additionally, the experiments indicate that accurate trajectory tracking can also be realized with this controller.
{"title":"Adaptive regulation of rigid-link electrically-driven manipulators","authors":"R. Colbaugh, K. Glass","doi":"10.1109/ROBOT.1995.525300","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525300","url":null,"abstract":"This paper considers the position regulation problem for uncertain rigid-link electrically-driven manipulators, and presents an adaptive control strategy as a solution to this problem. The proposed controller is computationally simple, requires virtually no a priori information concerning either the manipulator or actuator models, and ensures semiglobal stability and convergence of the manipulator position error to zero. Experimental results are presented for a Zebra Zero manipulator and demonstrate that the proposed scheme provides a simple and effective means of obtaining high performance position regulation. Additionally, the experiments indicate that accurate trajectory tracking can also be realized with this controller.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127463331","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 : 1995-05-21DOI: 10.1109/ROBOT.1995.525308
M. Otsuka, N. Matsumoto, T. Idogaki, K. Kosuge, T. Itoh
This paper proposes a new control system for bilateral telemanipulators to overcome one of the severest problems, the instability in the presence of time delay in data transmission. The control system proposed is based on the impedance control with virtual internal models (VIMs) driven by the sum of two forces detected on a master and a slave. The sufficient condition for the stability with arbitrary time delay is given based on small gain theorem. The sufficient condition can be satisfied by choosing appropriate parameters of the VIMs. Consequently, the control system is stable under any time delay. The proposed control system is applied to an experimental teleoperation system, which consists of two manipulators different in size. Data for teleoperation are transmitted through wireless LAN (256 kbps, max.). With this system, a stable contact task (to teach a desired position of the slave) was accomplished even with the time delay of 0.5 second. And it has been experimentally verified that the system is stable when time delay varies at random or when data transmission ceases and resumes.
{"title":"Bilateral telemanipulator system with communication time delay based on force-sum-driven virtual internal models","authors":"M. Otsuka, N. Matsumoto, T. Idogaki, K. Kosuge, T. Itoh","doi":"10.1109/ROBOT.1995.525308","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525308","url":null,"abstract":"This paper proposes a new control system for bilateral telemanipulators to overcome one of the severest problems, the instability in the presence of time delay in data transmission. The control system proposed is based on the impedance control with virtual internal models (VIMs) driven by the sum of two forces detected on a master and a slave. The sufficient condition for the stability with arbitrary time delay is given based on small gain theorem. The sufficient condition can be satisfied by choosing appropriate parameters of the VIMs. Consequently, the control system is stable under any time delay. The proposed control system is applied to an experimental teleoperation system, which consists of two manipulators different in size. Data for teleoperation are transmitted through wireless LAN (256 kbps, max.). With this system, a stable contact task (to teach a desired position of the slave) was accomplished even with the time delay of 0.5 second. And it has been experimentally verified that the system is stable when time delay varies at random or when data transmission ceases and resumes.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124919214","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 : 1995-05-21DOI: 10.1109/ROBOT.1995.525663
X. Yun
The control of mechanical systems subjected to rolling contacts is studied. Rolling contacts result in both holonomic and nonholonomic constraints. The focus of this paper is on formulating the differential motion equations and algebraic constraint equations into the standard state space representation of dynamic control systems. The position-level holonomic constraints are approximated by a set of velocity-level constraint equations that asymptotically converge to the original holonomic constraints. The approximation removes the numerical instability and ensures the satisfaction of holonomic constraints, particularly in computer simulations. Further, the approximation eliminates the need to solve holonomic constraints either analytically or numerically. The resulting approach makes it possible to treat systems with holonomic constraints, systems with nonholonomic constraints, and systems with both holonomic and nonholonomic constraints in a unified framework. The approach facilitates the computer simulation of mechanical systems with rolling constraints.
{"title":"State space representation of holonomic and nonholonomic constraints resulting from rolling contacts","authors":"X. Yun","doi":"10.1109/ROBOT.1995.525663","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525663","url":null,"abstract":"The control of mechanical systems subjected to rolling contacts is studied. Rolling contacts result in both holonomic and nonholonomic constraints. The focus of this paper is on formulating the differential motion equations and algebraic constraint equations into the standard state space representation of dynamic control systems. The position-level holonomic constraints are approximated by a set of velocity-level constraint equations that asymptotically converge to the original holonomic constraints. The approximation removes the numerical instability and ensures the satisfaction of holonomic constraints, particularly in computer simulations. Further, the approximation eliminates the need to solve holonomic constraints either analytically or numerically. The resulting approach makes it possible to treat systems with holonomic constraints, systems with nonholonomic constraints, and systems with both holonomic and nonholonomic constraints in a unified framework. The approach facilitates the computer simulation of mechanical systems with rolling constraints.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125464362","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 : 1995-05-21DOI: 10.1109/ROBOT.1995.525526
T. Park, B. Lee, Ki Dong Lee, I. Suh, Sang-Rok Oh
The concept of dynamic tracking line is proposed as the feasible tracking region for a robot in a robot-conveyor system, which takes the variable conveyor speed into consideration. This paper presents an effective method to find the dynamic tracking line in a robotic workcell. The maximum permissible line-speed which is a quantitative measure of the robot capability for conveyor tracking, is defined on the basis of the relation between the end-effector speed and the bounds on the joint velocities, accelerations, and torques. This measure is derived in an analytic form, and some of its properties are established mathematically. The problem of finding the dynamic tracking line is then formulated as a root-solving problem for a single-variable equation, and solved by the use of a simple numerical technique.
{"title":"Tracking line analysis of a robot manipulator for conveyor systems","authors":"T. Park, B. Lee, Ki Dong Lee, I. Suh, Sang-Rok Oh","doi":"10.1109/ROBOT.1995.525526","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525526","url":null,"abstract":"The concept of dynamic tracking line is proposed as the feasible tracking region for a robot in a robot-conveyor system, which takes the variable conveyor speed into consideration. This paper presents an effective method to find the dynamic tracking line in a robotic workcell. The maximum permissible line-speed which is a quantitative measure of the robot capability for conveyor tracking, is defined on the basis of the relation between the end-effector speed and the bounds on the joint velocities, accelerations, and torques. This measure is derived in an analytic form, and some of its properties are established mathematically. The problem of finding the dynamic tracking line is then formulated as a root-solving problem for a single-variable equation, and solved by the use of a simple numerical technique.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122538691","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 : 1995-05-21DOI: 10.1109/ROBOT.1995.525396
B. Yao, M. Tomizuka
In this paper, a combined adaptive and smooth sliding mode control (SMC) methodology is suggested to design a constrained motion and force tracking controller so as to achieve asymptotic motion and force tracking without persistent excitation condition in the presence of parametric uncertainties. Filtered error signals are used in both motion and force sliding surfaces to enhance dynamic response of the system. The proposed controller provides guaranteed transient performance with prescribed final tracking accuracy in the presence of both parametric uncertainties and external disturbances or modelling errors. Simulation results are presented to illustrate the proposed controller.
{"title":"Robust adaptive constrained motion and force control of manipulators with guaranteed transient performance","authors":"B. Yao, M. Tomizuka","doi":"10.1109/ROBOT.1995.525396","DOIUrl":"https://doi.org/10.1109/ROBOT.1995.525396","url":null,"abstract":"In this paper, a combined adaptive and smooth sliding mode control (SMC) methodology is suggested to design a constrained motion and force tracking controller so as to achieve asymptotic motion and force tracking without persistent excitation condition in the presence of parametric uncertainties. Filtered error signals are used in both motion and force sliding surfaces to enhance dynamic response of the system. The proposed controller provides guaranteed transient performance with prescribed final tracking accuracy in the presence of both parametric uncertainties and external disturbances or modelling errors. Simulation results are presented to illustrate the proposed controller.","PeriodicalId":432931,"journal":{"name":"Proceedings of 1995 IEEE International Conference on Robotics and Automation","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114508070","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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