A theoretical approach is developed to deal with man-machine interactive systems requiring advanced decision making in unpredictable environments. The hierarchical method consists of a three-layer control of "increasing intelligence and decreasing precision." The lowest level consists of several controllers designed for effective control with existing hardware using an approximation theory of optimal control. The next level is that of a coordinator which utilizes new computer architectures to effectively control the overall hardware system. The highest level is the organizer which supervises the performance of the overall system. Both highest levels are computer implemented and the research involved is in developing the appropriate architecture and software to accommodate others. The lowest level, aimed for end-point control tasks, is dominated by typical hardware control methods. The coexistence of the two approaches makes the method novel. Application of intelligent control techniques to robotics and manipulative systems is considered.

Intelligent robotic control

In this paper, we discuss a human-robot (H-R) coexistent system which allows H-R contact actions in the safeguarding space mechanically bounded by the human pain tolerance limit. The first half of this paper describes our study on the evaluation of the human pain tolerance limit which determines an individual's safeguarding space. We also show the human-safety-oriented design of a robot. The robot is covered with a viscoelastic material to achieve both impact force attenuation and contact sensitivity, keeping within the human pain tolerance limit. The robot, with simple direct-drive (DD) motor torque detection and emergency stop capabilities, automatically stops whenever any severe H-R contact occurs. In the second half of the paper, we propose a more efficient H-R system, which allows H-R contact for improving work efficiency, as long as the contact does not exceed the human pain tolerance limit. For this purpose, a robot is controlled to reduce its velocity with high reliability at an incipient stage of its contact with a human. Through experiments, we demonstrate the validity and efficient utility of the safeguarding space. The first experiment verifies that the developed robot exerts a contact force less than the human pain tolerance limit establishing the safeguarding space. The second experiment comparatively shows the robot's velocity reduction to accept a safe contact with the human in the space.

Human-robot contact in the safeguarding space

Analytic formulation of the principle of increasing precision with decreasing iNtelligence for intelligent machines

Analytical design of intelligent machines

A Petri net model of the coordination level of an intelligent mobile robot system (IMRS) is presented. The purpose of this model is to specify the integration of the individual efforts on path planning, supervisory motion control, and vision system that are necessary for the autonomous operation of a mobile robot in a structured dynamic environment. This is achieved by analytically modeling the various units of the system as Petri net transducers and explicitly representing the task precedence and information dependence among them. The model can be used to simulate the task processing and evaluate the efficiency of operations and the responsibility of decisions in the coordination level of the intelligent mobile robot system. Some simulation results of the task processing and learning are presented. >

A Petri-net coordination model for an intelligent mobile robot

Brief paper: Linguistic decision schemata for intelligent robots

As more and more robots are installed in the industrial sector, the statistical likelihood for accidents involving robots increases unless careful design and implementation of safety features occurs. Some worker deaths related to robot accidents have been reported in Japan. Most workers and users of robots have embarked on a safety program depending on personnel training, preventative maintenance, and perimeter barriers and/or interlocks. Most of these necessary methods still do not address the issue of personnel required to be close to a robot during teaching, maintenance, and troubleshooting. The results of a research project underway at Rensselaer Polytechnic Institute to develop a computer controlled sensor system that will monitor the working envelope of a robot are discussed. If an dangerous situation occurs, this system will cause the robot to take corrective action to avoid personnel injury or damage to the robot or equipment.

James H. Graham

Papers

Brief paper: Linguistic decision schemata for intelligent robots

A Safety and Collision Avoidance System for Industrial Robots

Book review: Interaction with the environment