Tamio Arai

Shibaura Institute of Technology, Kōtō, Tōkyō, Japan

Are you Tamio Arai?

Claim your profile

Publications (186)56.31 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A teaching-playback robot manipulator system whereby the user controls the manipulator through a teaching pendant has been used widely in industrial applications. Kinematic singularity issue becomes an important problem in the control of robot with a teaching-playback system. In this paper, we propose and investigate three singularity avoidance methods for a teaching-playback robot manipulator system. Nonredundancy singularity avoidance (NRSA) attempts to reduce both the position and orientation errors of the end-effector with the same priority. Redundancy singularity avoidance (RSA) attempts to reduce the position error of the end-effector with the first priority and reduce the orientation error of the end-effector with the second priority; Both NRSA and RSA are based on a modification of a Jacobian matrix. Point-to-point singularity avoidance (PTPSA) makes the end-effector pass through a singular region based on joint-interpolated control without maintaining the position and orientation of the end-effector. Experimental case studies are developed to investigate the manipulator performance when the end-effector approaches the wrist and shoulder singularity. The maximal end-effector trajectory error and users' feelings are statistically evaluated and analyzed in the experiment. The results of the experiment show the effectiveness and practice of the proposed methods.
    No preview · Article · Feb 2015 · IEEE Transactions on Automation Science and Engineering
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper addresses the problem of realizing multi-robot coordination that is robust against pattern variation in a pick-and-place task. To improve productivity and reduce the number of parts remaining on the conveyor, a robust and appropriate part flow and multi-robot coordinate strategy are needed. We therefore propose combining part-dispatching rules to coordinate robots, by integrating a greedy randomized adaptive search procedure (GRASP) and a Monte Carlo strategy (MCS). GRASP is used to search for the appropriate combination of part-dispatching rules, and MCS is used to estimate the minimum-maximal part flow for one combination of part-dispatching rules. The part-dispatching rule of first-in–first-out is used to control the final robot in the multi-robot system to pick up parts left by other robots, and the part-dispatching rule of shortest processing time is used to make the other robots pick up as many parts as possible. By comparing it with non-cooperative game theory, we verify that the appropriate combination of part-dispatching rules is effective in improving the productivity of a multi-robot system. By comparing it with a genetic algorithm, we also verify that MCS is effective in estimating minimum-maximal part flow. The task-completion success rate derived via the proposed method reached 99.4% for 10,000 patterns.
    No preview · Article · Nov 2014 · Robotics and Autonomous Systems
  • [Show abstract] [Hide abstract]
    ABSTRACT: Since service is an artifact as well as physical product, we can observe both function design and activity design of service in a conceptual design phase. Activity design requires designers to deploy all designed functions into activities in service delivery process. However, it is difficult for non-experienced designers to model complicated service delivery processes such as conditional branches and exception handlings while assuring the relationship to functions. To solve this problem, the authors propose a design support of constructing service delivery processes using a collection of structure patterns of processes called Workflow Patterns. In this paper, we make the Workflow Patterns hierarchized by the ISM method so that designers can easily choose a pattern among them according to purpose. The proposed method was implemented on a CAD system for service, and its effectiveness was verified through an evaluation experiment. As a result, it was revealed that the proposed method is especially effective in the case of constructing processes including conditional branches.
    No preview · Article · Jan 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the application of multi-robot system for a pick-and-place task, the appropriate robot arms and their base positions should be rapidly selected to improve the productivity, reduce the purchase cost, and apply the system for a task quickly. However, in current factories, a large amount of computational time is required to select the appropriate robot arms and their base positions because they are selected by the experienced engineers through evaluating the performance index in several trials. In this paper, we call the selection of robot arms and their base positions as integrated design of multi-robot system and propose a method to rapidly realize the integrated design of multi-robot system. We use the multi-objective particle swarm optimization (MOPSO) to select an appropriate multi-robot system, use the particle swarm optimization (PSO) to search for the base positions of the robot arms, and use the M/M/1 queueing model with impatient customer to estimate the performance index. A simulation proves that the proposed method is effective and efficient in comparison to a comparative method that uses simulation-based statistical inference to estimate the performance index. The computational time for the proposed method is 0.48 hour, which is less than 1/20 of the computational time for the comparative method.
    No preview · Conference Paper · Dec 2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: The focus of this study is on the problem of manipulator system selection for a multiple-goal task by evaluating task completion time and cost with computational time constraints. An approach integrating system selection, structural configuration design, layout design, motion planning, and relative cost calculation is proposed to solve this problem within a reasonable computational time. In the proposed approach, multiple-objective particle swarm optimization (MOPSO) is utilized to search for the appropriate manipulator system with appropriate structural configuration from a set of candidate systems. Particle swarm optimization (PSO) and the nearest neighborhood algorithm are employed in layout design and motion planning due to their high convergence speed. Three methods involving a random search algorithm are compared to the proposed approach through a simulation. The simulation is done with a set of tasks and the result shows the effectiveness of the proposed approach.
    No preview · Article · Mar 2013 · Advanced Robotics
  • [Show abstract] [Hide abstract]
    ABSTRACT: A recovery model is proposed to represent the relationship between the muscle fatigue and the rest time. Three experiments were conducted at 50% MVC with the contraction time of 10 s, 30 s and 50 s. Every experiment consists of 5 handgrip tasks with different rest interval. The maximal isometric forces during the pre-fatigue and post-fatigue were recorded to compute the muscle fatigue developed from each handgrip tasks. An exponential function is used to model the relationship between the muscle recovery and rest interval. With this model, the amount of muscle fatigue that is recovered given the rest duration can be estimated. The results suggest that the rate of muscle recovery is correlated to the degree of muscle fatigue at any particular moment, regardless the contraction level or contraction time of the tasks. It is demonstrated that the performance is not significant improved by increasing the number of experiments during calibration process. After that, the recovery model is integrated with the existing fatigue index proposed previously. This is then evaluated on cyclic handgrip tasks. The results show that during the high repetitive motion tasks, the effect of muscle recovery is essential to be taken into consideration for quantifying the degree of muscle fatigue. In average, the estimation error is between 5% MVC, comparing between the estimated value and the force loss measured using dynamometer. This concludes the effectiveness of utilizing force loss as the index to quantify the muscle fatigue and recovery.
    No preview · Article · Jan 2012 · International Journal of Industrial Ergonomics
  • [Show abstract] [Hide abstract]
    ABSTRACT: A cellular manufacturing system is good at producing diversified products flexibly; however, its assembly efficiency depends mainly on its operators' abilities. As the workforce shrinks in Japan, cellular manufacturing systems are difficult to maintain. In this case, a new assembly system has been developed since 2006 that combines both the dexterities of human operators and the advantages of automatic machinery. Its characteristics consist of three aspects: collaboration between an operator and twin manipulators on a mobile base, assembly information guidance, and safe design for collaboration. To meet the rapid changing tastes of customers, operators have to assemble various products without longtime training. This requires an effective assembly skill transfer system to extract assembly skills from skilled operators, and then transfer them to novice ones. Considering the characteristics of a cellular manufacturing system, an assembly skill transfer system was proposed and used to extract and transfer assembly skills in both cognition and execution aspects. Taking a cable harness task as an example, the proposed skill transfer system was applied in a developed assembly system. The results show that working under the developed assembly system with physical support, informational support, and the assembly skill transfer system, novice operators' assembly performance was greatly improved. This verified the effect of the proposed solution to maintain the cellular manufacturing system in the aging Japanese society.
    No preview · Article · Jan 2012 · IEEE Transactions on Automation Science and Engineering
  • Source
    Qi An · Yusuke Ikemoto · Hajime Asama · Tamio Arai
    [Show abstract] [Hide abstract]
    ABSTRACT: In developed countries, an aging society has become a serious issue; many activities of daily living (ADL) are impaired in the elderly. In order to improve this situation, it is necessary to develop an assisting method for the human standing-up motion because it is considered to be an important factor to ADL. It is unclear, however, how humans coordinate their multiple distributed actuators, muscles, due to the ill-posed problem of redundant their body system. In this paper, we analyze the human standing-up motion based on muscle coordinations, called synergies. A simulation method was developed to make mappings between muscle activations, joint torque, and the human body trajectory; thus, it can be predicted how modular muscle coordinations contribute to the motion. As a result, two primary synergies were extracted and how they coordinate to achieve the motion was elucidated; one synergy strongly affected joint movements and speed of the motion while bending the back and lifting the body up, and the other synergy controls their posture after they lift up their body. These findings could be useful for development of an assisting robotic system for rehabilitative training based on extracted distributed synergies from complex redundant human motion.
    Preview · Article · Jan 2012 · Springer Tracts in Advanced Robotics
  • [Show abstract] [Hide abstract]
    ABSTRACT: Task completion time and cost are two significant criteria for the selection of manipulator system. For a given task, several Pareto solutions of manipulator systems should be derived based on the evaluation of these two criteria. However, this process requires a large calculation time. In this paper, we propose a method that can select appropriate systems by evaluating task completion time and cost within the desired calculation time. In the proposed method, multiple objective particle swarm optimization (MOPSO) is employed to search for appropriate manipulator systems from a set of candidate systems. Location optimization and motion coordination are integrated to derive the task completion time and the relative cost is used to evaluate the cost of a manipulator system. We employ particle swarm optimization (PSO) for location optimization and use nearest-neighborhood algorithm (NNA) for motion coordination, since PSO and NNA have a high speed of convergence to a good solution. The proposed method is applied to a set of tasks and is proved to be effective and practical.
    No preview · Conference Paper · Sep 2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: Evaluating customer satisfaction is a key factor in service design. Therefore, some studies of customer satisfaction have been carried out in the field of service engineering. In these studies, customers’ expectations of service have generally been regarded as being shaped before service delivery. However, expectations of some components of service tend to be formed in the process of service receiving. To analyze service from the view of custoemer satisfaction, expectation that changes while customers are receiving service need to be considered. Therefore, we aim to develop the methodology to support designing services in a way that relates to the formation of customer expectations. In this paper, a model of shaping expectations in service receiving is examined and its effect on customer satisfaction is analyzed.
    No preview · Article · Jan 2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study presents a multiple-goal task realization in a system composed of a 6-d.o.f. robot arm and a one-axis rotating table. The problem is complex due to the existence of multiple goals and the kinematic redundancy of the system. We propose a design approach integrating the base placement, task sequencing and motion coordination methods. We show that this approach reduces the task completion time of the robot arm; the motion planning is realized through straight-line paths in the configuration space despite collision occurrences. Furthermore, we introduce a hybrid graph-search method combining the greedy nearest-neighbor method and the Dijkstra method to solve the motion coordination of the robot arm and the table. We show the effectiveness of the design approach and the search method through a time-constrained simulation-based optimization.
    No preview · Article · Jan 2011 · Advanced Robotics
  • [Show abstract] [Hide abstract]
    ABSTRACT: Practices of developing applications based on SOA principles need to be renovated to meet new requirements for large-scale data processing and to adapt advancements in IT infrastructures in cloud computing. Resource planners will have a significant role as they bridge the development and operation phases in application development. To accomplish these tasks, this paper presents architecture design methods, which reinforce designing and assessing architecture with an applied Design Structure Matrix (DSM). This approach can embrace development of both business logics of applications and IT resources to run them in the cloud and the methods are established through consulting practices on a datacenter.
    No preview · Conference Paper · Jan 2011
  • Feng Duan · Jeffrey Too Chuan Tan · Tamio Arai
    [Show abstract] [Hide abstract]
    ABSTRACT: Cellular manufacturing meets the diversified production and quantity requirements flexibly. However, its efficiency mainly depends on the operators' working performance. In order to improve its efficiency, an effective assembly-support system is required to assist operators during the assembly process. In this paper, a multi-modal assembly-support system (MASS) was proposed, which aims to support operators from both informational aspect and physical aspect. To protect operators in MASS system, several safety designs in both hardware and control levels were also discussed. With the informational support and physical support from the MASS system, the assembly complexity and the operators' burden are reduced. To evaluate the effect of MASS, a group of operators were required to execute a cable harness task. From the experimental results, it can be concluded that by using this system, the operators' assembly performance was improved, and the efficiency of the cellular manufacturing was also improved.
    No preview · Article · Jan 2011
  • Yusuke Tamura · Masao Sugi · Tamio Arai · Jun Ota
    [Show abstract] [Hide abstract]
    ABSTRACT: We propose an attentive deskwork support system that quickly delivers required objects to people who work at desks. To meet this goal, we propose methods to understand a user's request for support. To know the existence of the user request, the system uses the characteristics of the user's hand and eye movements and detects hand-reaching movements. The system understands the content of the user's request by integrating sensory and contextual information using a probabilistic model. Finally, the system determines a point of delivery by predicting a user's hand movement and delivers required objects by using self-moving trays. The experiments are conducted to evaluate the usefulness of the system proposed here.
    No preview · Article · Nov 2010 · Journal of Advanced Computational Intelligence and Intelligent Informatics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we proposed a step by step approach to planning robot motions for complex assembly tasks. It can be assumed that a complex assembly motion consists of some basic assembly motions, which can be accomplished with fixed force control parameters. Therefore, we firstly proposed an optimization method for basic assembly motions to obtain appropriate force control parameters that can efficiently achieve operations. Based on the results, we then proposed a policy integration method in order to generate complex assembly motions by utilizing optimized basic assembly motions. These methods were applied to clutch assembly in this paper. Using the parameter optimization method, effective policies for insertion and search motions were obtained; and then, a new control policy for clutch assembly was developed by integrating these basic assembly motions. Based on the new policy obtained by the policy integration method, the effective motion was chosen with perceiving the engagement of the clutch hub and the clutch plates. The result shows that the proposed approach makes it possible to generate complex assembly motions that need some switching of force control parameters according to task states. It is one of the future works to develop a learning method in order to efficiently generate a new policy based on similar policies. Although the approach was applied only to the clutch assembly in this paper, it will be applied to the other complex assembly tasks for more evaluation.
    Full-text · Chapter · Sep 2010
  • Source
    Yusuke Tamura · Masao Sugi · Tamio Arai · Jun Ota
    [Show abstract] [Hide abstract]
    ABSTRACT: We have presented methods to detect an act of reaching among other hand movements and to predict target objects based on measurements of a user's hand and eye movements. In the detection method, we adopted speed, the smoothness and straightness of a user's hand movements, and the relationship between hand and eye movements. The usefulness of the proposed method was experimentally demonstrated. In the future, an error recovery algorithm should be developed for more reliable deskwork support system.
    Full-text · Chapter · Sep 2010
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes a similarity measure for images which can be used in image-based topological localization and topological SLAM problems by autonomous robots with low computational resources. Instead of storing the images in the robot’s memory, we propose a compact signature to be extracted from the images. The signature is based on the calculation of the 2D Haar Wavelet Transform of the gray-level image and its size is only 170 bytes. We called this signature the DWT-signature. We exploit the frequency and space localization property of the wavelet transform to match the images grabbed by the perspective camera mounted on board the robot and the reference panoramic images built using an automatic image stitching procedure. The proposed signature allows, at the same time, memory saving and fast and efficient similarity calculation. For the topological SLAM problem we also present a simple implementation of a loop-closure detection based on the proposed signature.We report experiments showing the effectiveness of the proposed image similarity measure using two kinds of small robots: an AIBO ERS-7 robot of the RoboCup Araibo Team of the University of Tokyo and a Kondo KHR-1HV humanoid robot of the IAS-Lab of the University of Padua.
    Full-text · Article · Jul 2010 · Robotics and Autonomous Systems
  • Genta Kondo · Ryu Kato · Hiroshi Yokoi · Tamio Arai
    [Show abstract] [Hide abstract]
    ABSTRACT: To classify the five individual finger motions from an electromyogram (EMG) signal, a classification system that hybridizes EMG signals in both the transient and converged states of a motion is proposed. The classifications of finger motions are executed individually in each state by a well-established artificial neural network (ANN). Then, the outputs of the two classifiers are combined. The efficacy of the result is evaluated via a piano-tapping task, in which the subjects are instructed to tap a keyboard with each of their five fingers. We use this task to compare the proposed hybrid system and a conventional converged system that uses an EMG signal only in the converged state. For five of the six subjects, the accuracy ratio of finger motions was better in the proposed method: approximately 85% for each finger except the second. Further analysis suggests two remarkable advantages of the hybrid method: (1) the output of the ANN is more credible, and (2) finger motion in the transient state (i.e., the early phase) is more predictable.
    No preview · Conference Paper · May 2010
  • [Show abstract] [Hide abstract]
    ABSTRACT: Our research aims to design and develop a safety strategy for a human–robot collaboration system. Although robotic assistance in a cellular manufacturing system is promising, safety is the uppermost consideration before it can be materialized. Five main safety designs are developed in this work. (i) Safe working areas for humans and robots. (ii) To control the behavior of the robot based on the collaboration requirements, light curtains defined safe collaborative working zones. (iii) Additionally, the robot system was developed using safe mechanical design and Dual Check Safety control strategies in terms of robot speed and travel area to minimize collaboration risks. (iv) A vision system using IP cameras was developed to monitor operator safety conditions by measuring the body posture and position of the operator. (v) The operation control system coordinated the collaborative flow between the operator and robot system. Apart from these developments, risk assessments were conducted to evaluate the safety design of the system, and a mental safety study was performed to investigate robot motion speed and working distance on the operator's physiological effects. Our findings demonstrate the feasibility of the prototype system to safely perform assembly operations.
    No preview · Article · Apr 2010 · Advanced Robotics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The challenge of this work is to develop collaboration planning between human operator and robot system in a collaborative manufacturing system by task analysis approach. The development is worked in parallel with a cable harness assembly operation in a prototype cellular manufacturing system. The core developments of this study are summarized as the following: (a) Task decomposition by hierarchical task analysis ­ by using the capability of HTA, the entire operation is being decomposed into structured hierarchical tasks tree. (b) Collaboration analysis ­ qualitative and quantitative analyses are conducted to identify and justify the possible collaborative solutions from the task model to further define the details of collaboration. Collaboration roles are assigned to all task components with color task role indicators to improve the collaboration relationship representation of the task model. (c) Design enhancements in operation process design ­ improvements in term of (a) group repetitive steps, (b) add interval step, (c) preserve collaboration, and (d) assembly sequence changes are achieved in the task modeling of cable harness assembly. (d) Design extensions in human skill analysis, safety assessment and operation support ­ extensions in facilitate human cognitive and motor skills studies, conduct risk assessment for safety design and assist information support development. (e) Practical implementation in prototype system ­ model validation was conducted successfully with an actual cable harness assembly operation and positive results were obtained in the operation performance evaluation. This work might have completed a preliminary modeling framework for human-robot collaboration planning in manufacturing systems based on task analysis approach. More research studies and developments are needed to further enhance the work: (a) Quantitative studies should be conducted to investigate the effectiveness of the human-robot collaboration planning. (b) Comparison study with other production operations to investigate the modeling capability of the proposed framework. (c) The temporal aspects in collaboration should be taken into consideration to develop a more realistic representation for asynchronous human-robot operations.
    Full-text · Chapter · Apr 2010

Publication Stats

2k Citations
56.31 Total Impact Points


  • 2014
    • Shibaura Institute of Technology
      • Department of Mechanical Engineering
      Kōtō, Tōkyō, Japan
  • 1995-2013
    • The University of Tokyo
      • Department of Precision Engineering
      Tōkyō, Japan
  • 2007
    • NEC Corporation
      Edo, Tōkyō, Japan
  • 2005-2006
    • Yokohama National University
      • • Department of Physics, Electrical and Computer Engineering
      • • Graduate School of Engineering
      Yokohama, Kanagawa, Japan
  • 2002
    • RIKEN
      Вако, Saitama, Japan