Takashi Suehiro

Stiffness Analysis and Design of a Compact Modified Delta Parallel Mechanism

In our previous work, we developed a compact 6-DOF haptic interface as a master device which achieved an effective manual teleoperation. The haptic interface contains a modified Delta parallel-link positioning mechanism. Parallel mechanisms are usually characterized by a high stiffness, which, however, is reduced by elastic deformations of both parts and bearings. Therefore, to design such a parallel mechanism, we should analyze its structural stiffness, including elastic deformations of both parts and bearings. Then we propose a simple method to analyze structural stiffness in a parallel mechanism using bearings. Our method is based on standard concepts such as static elastic deformations. However, the important aspect of our method is the manner in which we combine these concepts and how we obtain the value of the elasticity coefficient of a rotation axis in a bearing. Finally, we design a modified Delta mechanism, with a well-balanced stiffness, based on our method of stiffness analysis.

Assembly motion teaching system using position/force simulator-generating control program

We have developed a teaching system based on the assumption that the assembly task is a series of operations for achieving a target contact state among objects through changing their contact states. The features of our system are as follows: 1) teaching data for fine motion is extracted from a demonstration by an operator in a virtual world, 2) the operator can edit intermediate expressions on a display, 3) intermediate expressions can be used by any robot system with a skill library which has the ability to achieve the corresponding contact states. This paper describes the configuration of the system, program generation using intermediate expressions and a skill library to achieve each contact state.

RT(Robot Technology)-Component and its Standardization - Towards Component Based Networked Robot Systems Development

In this paper, we propose RT-component architecture for robot system integration. We have studied modularization of RT (Robot Technology) elements and have developed RT-Middleware, which promotes application of RT in various field. RT-Middleware is a software platform for RT systems and provides RT specific functionality for the component based system development. The component which constructs RT-systems in RT-Middleware is called the RT-Component We are also standardizing the architecture of RT-component in the Object Management Group (OMG). Finally conclusion and future work will be described

Development of Light-Weight RT-Component (LwRTC) on Embedded Processor -Application to Crawler Control Subsystem in the Physical Agent System-

Because the RT middleware is only supported by ORBs implemented on PCs, application to a small-scale system and the small-size robot seems to be difficult. To reduce power consumption and developing distributed RT-components on micro processors, application of the RT middleware to the embedded processing system and arbitrary network system are important. In this paper, we report the LwRTC that is the implementation of the RT-component on embedded micro-processors, and the prototype system for the mobile robot using LwRTC

Development of the master hand for grasping information capturing

Analysis of human hand grasp provides information that can be used to develop a grasping algorithm of robot hands that takes advantage of human knowledge and experience. In analysing the human hand grasp, not only motion of the fingers but also contact force acting on the fingertips should be measured. This paper presents a new master hand which can be attached to a human hand and measures motion of the human fingertips and contact force acting on the fingertips. Our purpose in developing the master hand is to clarify the strategy of a human hand grasp, which is subjected to the same physical constraints as those of a robot hand, and use the obtained information to develop a grasping algorithm of robot hands. Concepts of the development, mechanism and features of the master hand are described.

Fine motion strategy in three-dimensional space using skill-based backprojection

The motion of manipulation in a task can be decomposed into several motion primitives called “skills.” Skill-based motion planning gives the possibility of performing tasks as skillfully as human beings do. On the other hand, the backprojection method performed in configuration space has often been used in fine-motion planning. This paper describes fine-motion planning in three-dimensional space using skill-based backprojection. Now that skill-based planning in three-dimensional space has been developed, it becomes possible to plan manipulation motions like the behavior of the human hand.

A RUNTIME MONITORING SYSTEM FOR HYBRID MANUAL/AUTONOMOUS TELEOPERATION

This paper describes a hierarchical design and implementation of a runtime monitoring system for hybrid manual/autonomous teleoperation and a novel bilateral master control device for teleoperation. Teleoperation tasks are time-consuming and impose heavy loads on human operators in hostile and unstructured environments. In order to realize efficient task execution and to reduce the burden on operators, we propose here a hybrid manual/autonomous approach, with implementation of a teleoperation system based on distributed hierarchical control architecture. A one DOF bilateral master device has been developed as a compact master system with quick response and precise position/force controllability. Using this system, general master-slave operations are performed. Through experimentation, it was confirmed that the hierarchical structure of the runtime monitoring system easily supports hybrid manual/autonomous teleoperation, and that the hybrid approach facilitates the tele-execution of complex tasks by combining with the master device.

Shared autonomy architecture for skill execution manipulator

In this paper, we report a shared autonomy architecture for skill execution manipulator. A skill transfer method has been proposed in our previous research. Many skills for a plant maintenance also have been developed. Our goal is that an autonomous robot implemented the skills executes maintenance tasks in the plant. When the robot fails the task execution, the robot should recognize all conditions and recover by itself. However, in current technology, the robot to recover from all failed conditions could not be developed. Then, an idea of shared autonomy architecture for our research area is introduced. In this idea, when the robot fails to perform the task and can not recover from failed conditions, an operator intervenes to control the manipulator. The operator moves the manipulator to a convenient condition in a bilateral teleoperation. After the operators motion, the robot re-executes the target task. To demonstrate our proposed architecture, we choose a nut attachment task.

A Runtime Monitoring System for Hybrid Manual/Autonomous Teleoperation

Abstract This paper describes a hierarchical design and implementation of a runtime monitoring system for hybrid manual/autonomous teleoperation and a novel bilateral master control device for teleoperation. Teleoperation tasks are time-consuming and impose heavy loads on human operators in hostile and unstructured environments. In order to realize efficient task execution and to reduce the burden on operators, we propose here a hybrid manual/autonomous approach, with implementation of a teleoperation system based on distributed hierarchical control architecture. A one DOF bilateral master device has been developed as a compact master system with quick response and precise position/force controllability. Using this system, general master-slave operations are performed. Through experimentation, it was confirmed that the hierarchical structure of the runtime monitoring system easily supports hybrid manual/autonomous teleoperation, and that the hybrid approach facilitates the tele-execution of complex tasks by combining with the master device.