Abstract of Special Research Report (SRR-No.33)
National Institute of Occupational Safety and Health, Japan
Research on Fundamental Safety Technologies for Man-Machine Cooperative Working Systems (Midterm Report)
Introduction
SRR-No.33-1 |
Hiroyasu IKEDA and Shigeo UMEZAKI |
: Recently, along with the technical innovation in robotics, human-collaborative robots, mobile robots and other similar robots have begun to be introduced in industrial sites. The introduction of these robots is expected to increase rapidly as the time passes. Since these robots require mutual approach and direct contact between humans and machines, the conventional safe measures, such as the isolation of humans and machines from each other with fences or enclosures, are no longer applicable and some new safety technology should be developed instead.
This midterm report describes experimental results and accident prevention strategies performed from 2002 to 2004 mainly. Chapter 2 and 3 are related to the research subject (1). Chapter 2 suggests a human pain tolerance as a safe design index for human-collaborative robots. An inherently safe design method based on its index is also suggested. Chapter 3 shows experimental results of the human pain tolerance. The worst limitation of pain tolerance is clarified to be 57.7N. Chapter 4 and 5 are related to research subject (2). Chapter 4 suggests an object zone detection algorism considering the occlusion problem. Chapter5 shows a gesture recognition method as a new type of human-robot communication. |
Propasal of Inherently Safe Design and Safe Design Indexes for Human-Collaborative Robots
SRR-No.33-2 |
Hiroyasu IKEDA and Tsuyoshi SAITO |
: Recently, there has been a tendency for robots having no guard but a moving mechanism to approach humans and for humans to positively utilize the abilities of robots. Such coexistent and collaborative relation between humans and robots is expected to have demand not only in industrial fields but also in service fields. However, while they are implementing their work, it is assumed that such new-mode human-collaborative robots contact and dynamically work on human bodies. Due to this assumption, the rules of isolation and the rules of stop, which have been regarded as the preconditions of the safety securement for workers when they are working with conventional-mode industrial robots, are no longer applicable. As a result, the safety securement for humans is one of the most important problems with their practical application. Particularly, there is no definite index of the relation between humans and robots, such as how much force output should be permitted to a robot according to the degree of contact required in the course of implementing the target work. |
Measurement of Human Pain Tolerance to Mechanical Stimulus of human-Collaborative Robots
SRR-No.33-3 |
Tsuyoshi SAITO and Hiroyasu IKEDA |
: Concerning the inherently safe design measures of a new type of robot which aims to contact with persons like a mobile robot not enclosed with a guard, this report focuses on the tolerant limits of the sense of pain that the persons feel while being contacted by such the human-collaborative robot. The pain tolerance is predictable information linked directly to the external injuries of human bodies and a significant parameter to determine the acceptable limits of mechanical stimuli that the human-collaborative robot can give to the persons in the process of a designated task. However, from the previous studies related to the level of human sense of pain, the great difficulty of numerically analysis of the pain tolerance has been pointed out because the distributions of the human subcutaneous tissues and pain sensing organs are greatly depending on the human body portions. Therefore, there still has not been enough data available to manifest the pain tolerance. |
Object Zone Detection with Omni-Directional Vision Sensors
SRR-No.33-4 |
Kyoko HAMAJIMA, Jian LU and Koji ISIHARA |
: The purpose of this research is to develop the camera monitoring device which is applicable to safety protection devices used in mechanical safety, especially in human-machine cooperation systems. This kind of device is usually called Vision Based Protective Devices (VBPD). By using VBPD, the machines are stopped while people intrude the dangerous area of the machine monitored by video cameras.
Keywords; Camera monitoring system, Image processing, Safety, Omni-directional vision sensor |
The Communication Method for Mobile Robots by Recognizing Gestures of Operators
SRR-No.33-5 |
Jian LU, Wei JIANG and Kyoko HAMAJIMA |
: When the gesture recognition is used in robot control, as a new method for human-robot communication, it is required to do the risk analysis and the safety assessment for the method. Because the requirements on safety and on reliability are strict, only those simple and easily-recognizable gestures could be used in the current stage of gesture recognition technologies. In this paper, the gestures considered are restricted to those inputed from still images and those formed only by two arms. A three dimensional (3D) model is established for expressing gestures quantitatively in three dimensional space, and a quantity analysis model based on the distance between gestures, which we call the Gesture Distance Model (GDM), are proposed for evaluating about the possibility of gesture miss-recognition(or simply the miss-recognition risk). By applying to the GDM the average body-sizes in the Japanese Body-size Database, an analysis table about the standard distances between 16 basic gestures is obtained. In addition, an implementation for gesture recognition based on the GDM, by using the standard body-size as the one side in GDM and the gesture to be recognized as the other, is also proposed. Finally an explanation is also given about the gesture design method which causes small miss-recognition risk.
Keywords;Human-machine Communication, Pattern Recognition, Gesture Recognition, Robot Safety, Risk Assessment |
Analysis of Fatal Accident Caused by Industrial Machines
SRR-No.33-6 |
Shigeo UMEZAKI and Syoken SHIMIZU |
: When the fatal accident arises, many people declare that we never repeat more accident. However, it is forgotten as the time passes and a resemble accident repeat again. The reason why such problem arises seems to be because not only original causes are not perfectly investigated to each accident, but also information on the accident are not universalized as a general engineering knowledge. |
The Basic Consideration on Accident Prevention Strategy ofthe Hazardous Point Nearby Operation
SRR-No.33-7 |
Shigeo UMEZAKI and Syoken SHIMIZU |
:It is a common knowledge for safety engineers to perform machine safe measures based on the risk reduction process described in ISO 12100. Its process consists of the "inherently safe design measure", "safeguarding" and other supplemental countermeasures. However, there are many "hazardous point nearby operations", that is the operation of process confirmation, adjustment, prepairing, trouble-shooting, maintenance, inspection, repairing, cleaning of the machine etc.. It is very difficult to apply above safe measures for these operations because a operator is close to machine moving parts without stopping it.
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The Basic Consideration on Accident Prevention Strategy for the Operation Executed by Multiple Operators Cooperating in Large Production Lines
SRR-No.33-8 |
Shigeo UMEZAKI and Syoken SHIMIZU |
: There are many hazardous operations executed in large production lines such as the operation of trouble-shooting, maintenance or cleaning of machines. An operator enters in its line for these operations while a machine is stopped. In this case, when other operator restarts the machine by mistake, the accidental start of the machine could cause a serious disaster.
These results can be useful to the supplement of ISO11161 standard. |