Toshio Fukuda

Dynamically reconfigurable robotic system

The concept of the DRRS (dynamically reconfigurable robotic system) based on a cell structure is proposed for the next generation of robotic systems. The system can reorganize its configuration and its software to a given task, so that its level of flexibility and adaptability is much higher than that of the conventional robots. It consists of a lot of intelligent cells that have a fundamental mechanical function. Each cell can detach itself and recombine autonomously, depending on a task, e.g. To provide manipulators or mobile robots. The system can also be self-repairing and fault-tolerant. A decision method for cell-structured-manipulator configurations is proposed.<<ETX>>

Approach to the dynamically reconfigurable robotic system

In this paper, a newly proposed robotic system called the dynamically reconfigurable robotic system (DRRS), is reconfigurable for given tasks, so that the level of flexibility and adaptability is much higher for a change of working environments than conventional robots which have un-metamorphic shapes and structures. This robotic system consists of many cells which have fundamental mechanical functions. Each cell is able to detach and combine autonomously, so that the system can self-reorganize depending on a task or on working environments, and can also be self-repairing. DRRS has many applications in many fields, e.g. maintenance robots, more advanced working robots, free-flying service robots in space, more evolved flexible automation, etc. This paper shows the concept of this system, the mechanism of cells, the basic experimental results of the rough approach control between cells, and the decision method of such cell-structured manipulator configurations. This method is based on the reachability of the manipulators for working points, and so is able to apply the design of ordinary manipulators.

A Dynamically Reconfigurable Robotic System (Concept Of A System And Optimal Configurations)

A new concept of robotic systems, Dynamically Reconfigurable Robotic System(DRRS) is shown in this paper. Each cell of the robotic module in DRRS can detach itself and combine them autonomously depending on a task, such as manipulators or mobile robots, so that the system can reorganize the optimal total shape, unlike robots developed so far which cannot reorganize automatically by changing the linkage of arms, replacing some links with others or reforming shapes in order to adapt itself to the change of working environments and demands. The newly proposed robotic system in this paper can be reconfigurable dynamically to a given task, so that the level of the flexibility and adaptability is much higher than that of the conventionals. DRRS has many unique adavantages, such as optimal shaping under circumstances, fault tolerance, self repairing and others. Some demonstrations can be shown experimentally and a decision method for such cell structured manipulator configurations is also proposed.

Structure decision method for self organising robots based on cell structures-CEBOT

A dynamically reconfigurable robotic system (DRRS) is one that can reconfigure itself to an optimal structure, depending on the purpose and environment. To realize this concept, the authors propose CEBOT (cell structured robot), which is a distributed robotic system consisting of separable autonomous units. These functional cells are able to communicate with each other and to approach, connect, and separate automatically. If single cells of CEBOT are damaged, they can be repaired or replaced automatically. Since CEBOT is capable of adapting itself to changing environments, it is a very flexible system applicable in space, factory, and hostile environments. The authors propose an optimal structure decision method that can determine cell type, arrangement, degree of freedom, and link length. It is applicable to fixed-base and mobile-base manipulators. A structure evaluation function, which is the sum of parameters relating to the number of work points, required positioning accuracy, torque, distance between given work points, and cell cost, is presented. Simulation results are given.<<ETX>>

Adaptive force control of manipulators with consideration of object dynamics

In this paper, a force control method for manipulators is presented with consideration of object dynamics based on the adaptive control. This method for the manipulator system is an extension of the previously proposed method for gripper systems by the authors. Since present industrial robotic manipulators commonly employ the input/ output position servo control system, it is of great interest to control both force and position of the manipulator with this control system. However, it is not easy to control the manipulator without the knowledge of object dynamics. Then, it is necessary to adjust control gains, depending on handling objects. For this purpose, a method of the adaptive force control is presented here with consideration of object dynamics. Some simulations are carried out for a manipulator system to adjust pushing forces to various objects, and show the wider applicability and the flexible manipulation of manipulators.

Autonomous pipeline inspection and maintenance robot with inch worm mobile mechanism

A new type of mobile robots with the inch worm mechanism is presented in this paper for inspecting pipelines from the outside of pipe surfaces under hostile environments. This robot, Mark III, is made after the successful investigation of the prototypes, Mark I and II, which can pass over obstacles on pipelines, such as flanges and T-joints and others. Newly developed robot, Mark III, can move vertically along the pipeline and move to the adjacent pipeline for the inspection. The sensors, infra ray proximity sensor and ultra sonic sensors and others, are installed to detect these obstacles and can move autonomously controlled by the microprocessor. The control method of this robot can be carried out by the dual control mode proposed in this paper.

Flexible handling by gripper with consideration of characteristics of objects

Conventional robots in force control, which use the input-output position control system employing high reduction gears for drive control mechanisms, have dynamics of objects in the closed control loop. And so it is necessary to adjust control gains, depending on objects. For this purpose, a method of adaptive force control is presented with consideration of static and dynamic characteristics of objects. Some experiments are carried out for a gripper system to adjust the grasping and/or holding force to various objects whether they are soft and hard, and show the wider applicability and the flexible manipulation of the conventional gripper.

Pipeline inspection and maintenance by applications of computer data processing and robotic technology

Abstract It is very important to detect leakage and flaws on pipelines without hampering pipeline operations by data processing and robotic technology. In this paper, two topics are described, a leak detection method by intensive computer data processing and a flaw detection method by a mobile inspection robot. (i) A new method for remote leak detection and localization in a pipeline system is presented by applying the prewhitening filter method formulated by autoregressive (AR) modelling to ultra acoustic signals, which are obtained from the acoustic emission (AE) sensors installed on the pipeline at certain intervals. (ii) A fully automatic robot for pipeline inspection is built to detect flaws and defects. The robot can move over the outside along pipelines with inspection sensors and has varied mobility and maneuverability, such as passing over flanges and so on. It can also detect small defects and flaws by scanning the surface of pipes.

Expert system driven image processing for recognition and identification of microorganisms

A description is given of an automatic microorganism recognition and identification method, using image processing based on an expert system, for application in a micro-manipulator system. Since microorganisms under a microscope all appear different, are moving, and have time-dependent shapes, the conventional pattern-matching method used for industrial products can be applied. The proposed method is based on segmentation of the microorganisms, taking advantage of characteristic segment features that are independent of individual size and length. Complicated shapes are divided into simple-shaped segments such as lines, circles, ovals, etc. The relation between segments is described in the database of the expert system. Microorganisms can then be expressed simply by a set of segments and so that their individual differences can be avoided. Tracking the movement of a microorganism by its image is also shown.<<ETX>>

Path Planning And Control Of Pipeline Inspection And Maintenance Robot

A new type of mobile robots with the inch worm mechanism is presented in this paper for inspecting pipelines from the outside of pipe surfaces under hostile environments. This robot, Mark 111, is made after the successful investigation of the prototypes, Mark I and 11, which can pass over obstacles on pipelines, such as flanges and T-joints and others. Newly developed robot, Mark TII, can move vertically along the pipeline and move to the adjacent pipeline for the inspection. The sensors, infra ray proximity sensor and ultra sonic sensors and others, are installed to detect these obstacles and can move autonomously controlled by the microprocessor. The control method of this robot can be carried out by the d u a l control mode proposed in this paper. Furthermore, the path planning method for the inspection robot is also shown based on the expert system approach, employing the plant map and the priority information for inspection.