Tomoyuki Kaga

Haptic information in Internet-based teleoperation

Many tasks can be done easily by humans turn out to be very difficult to accomplish with a teleoperated robot. The main reason for this is the lack of tactile sensing, which cannot be replaced by visual feedback alone. Once haptic devices are developed, their potential in many fields is obvious. Especially, in teleoperation systems, where haptic feedback can increase the efficiency and even render some tasks feasible. This paper studies Internet-based teleoperation systems that include haptic feedback, concentrating on the control of such systems and their performance. The potential of this technology and its advantages are explored. In addition, key issues, such as stability, synchronization, and transparency are analyzed and studied. Specifically, an event-based planning and control of Internet-based teleoperation systems is presented with experimental results of several implemented system scenarios in micro- and macro-scales.

Supermedia in Internet-Based Telerobotic Operations

In the past decade robotics and the Internet, fed by the great advances in computing and networking, matured into giant interdisciplinary scientific fields. Therefore, it is not surprising that many are trying to merge these two technologies and develop Internet-based robotic teleoperation. More interestingly, Internet-based bilateral teleoperation, where supermedia is fed back to the operator in order to increase efficiency and achieve telepresence. Supermedia is the collection of multimedia (video, audio, ...), haptic and other sensory information. This paper studies supermedia enhanced teleoperation via the Internet, concentrating on the real-time control of such systems and their performance. The potential of this technology and its advantages will be explored. In addition, key issues, such as stability, synchronization and transparency, will be analyzed and studied. Specifically, event-based planning and control of Internet-based teleoperation systems is presented with experimental results of several implemented system scenarios.

Multi-site Internet-based cooperative control of robotic operations

The e-world, also known as the Internet, has added a new dimension to many of the traditional concepts in industrial applications and everyday life. The use of robots has dramatically expanded the potential of e-services. Individuals with particular expertise can perform highly accurate and fairly complicated tasks remotely via the Internet. This increase in the human reachability is faced by several obstacles. Reliable and efficient robot facilitated services via the Internet face several challenges. These range from human-computer interfacing and overcoming random time delay to task synchronization and human-robot interaction. These limitations intensify when many operators in many sites are involved. This paper provides new theoretical and experimental results on these challenges. Specifically, multisite cooperative control of an Internet based mobile manipulator is presented. The two main characteristics of this system are Internet based real-time closed loop control and coordinated operation. In addition, it is shown that despite random time delay the stability and synchronization of the system were achieved using event-based control.

Experimental Study on Self-organized and Error Resistant Control of Distributed Autonomous Robotic Systems

The assignment of distributed mobile autonomous robots to targets, which occurs for instance as an important task in flexible manufacturing environments, is solved by using a self-organization approach motivated by pattern formation principles in biological, chemical, and physical systems. Similar to observations in many natural systems, such as ant tribes, the pattern formation of colored shells or convection patterns in the Rayleigh-Bénard problem of fluid dynamics, the self-organization principles lead to a robust and fault tolerant behavior where the patterns or structures recover from disturbances. The considered problem is the dynamic assignment of a number of robots to given targets where the mobile robots have to move to the targets in order to perform some tasks there. Hereby, each robot uses only local information (i.e., no world coordinate system is necessary). The underlying mathematical problem of the robot-target assignment is the so-called two-index assignment problem from combinatorial optimization. The approach used guarantees always feasible solutions in the assignment of robotic units to targets. As a consequence, for scenarios with only convex obstacles with large enough distances to each other, no spurious states cause the assignment process to fail. The error resistant control method for distributed autonomous robotic systems is demonstrated by several experiments with mobile robots. These results are compared and supplemented with computer simulations.

Dynamic Robot-Target Assignment — Dependence of Recovering from Breakdowns on the Speed of the Selection Process

The self-organized and fault tolerant behavior of a novel control method for the dynamic assignment of robots to targets using an approach proposed by Starke and Molnar is investigated in detail. Concerning the robot-target assignments the method shows an excellent error resistivity and robustness by using only the local information of each robot. Experimental results verify the dynamic assignment of the mobile robots to the targets and the capability to cope with sudden changes like a breakdown of one of the robots. The dependence of the assignment on the speed of the target-selection dynamics is shown by both experiments and numerical simulations. The results suggest the existence of an optimal value for the speed of the target-selection dynamics.

An Analysis of Collective Property caused by Structure Reconfiguration

Cellular Robotic System (CEBOT) is one of the Distributed Autonomous Robotic System(DARS) which consists of heterogeneous robotic units called “cell”s. A robot of CEBOT can change their function through structure reconfiguration achieved by mechanical connection or disconnection of cell. Pointedly, an important peculiarity of this system is availability of variable function of a robot by structure reconfiguration. Structure reconfiguration increases adaptability against the change of environment. However, it has a specific problem concerned with the cost for changing functions. So we analyzed this property and indicate the trade-off between adaptability and efficiency through computer simulations by using a model of load transportation.

An oscillation analysis on distributed autonomous robotic system

We assume that analyses of collective property is necessary for the establishment of swarm control theory. This paper deals an oscillation as one of the intrinsic collective properties of distributed autonomous robotic systems. The oscillation is a very important property, which influences the entire system performance. Factors which cause the oscillation include an information delay, fluctuation of the system, etc. We analyze the influence of such factors on the oscillation property. In addition, we examine the influence of oscillation on the system performance in terms of task sufficiency and efficiency. The cellular robotic system (CEBOT) is used as a model for the analysis.

Generation of observation behavior in distributed robotic system

Addresses generation of observation behaviors considering various combinations of robotic units. Toward the recognition of group robots, integration of sensing information among robots and autonomous positioning for acquiring better sensing information are required. In the paper, an architecture of recognition and integration based on mappings which are obtained through learning is proposed and a method of autonomous positioning for acquiring better sensing information is also proposed. The results of numerical simulation suggest that robots are capable of generating observation behaviors in order to decrease sensing errors.

Augmentation of space perception by integration of multiple observation systems

We have studied a dynamically reconfigurable robot system which is a model of a multiple robot system. The purpose of our study is the realization and practical use of dynamic reconfiguration, especially in cooperation relations among robots according to task, environment and function. We consider space perception by multiple robots as the basic and important ability for robots to behave in environments. The space perception means the mapping from sensing information of each robot to a common task oriented observation coordinate system given by the designer. In the paper the mapping is acquired through learning using time series sensing information. Self-evaluation of reliability of observation for integration is also reported. We examined the proposed the method by using a task model in a two robots environment and the advantage of dynamic reconfiguration of the observation system is reported.