The work presented here is the description of the control strategy of two cooperating robots. A two–finger hand is an example of such a System. The control method allows for position control of the contact point by one of the robots while the other robot controls the contact force. The stability analysis of two robot manipulators has been investigated using unstructured models for dynamic behavior of robot manipulators. For the stability of two robots, there must be some initial compliance in either robot. The initial compliance in the robots can be obtained by a non-zero sensitivity function for the tracking controller or a passive compliant element such as an RCC.

This paper describes the Robotics and Intelligent Systems Program (RISP) at the Oak Ridge National Laboratory (ORNL). RISP is a focal point at ORNL for studies in robotics, teleoperations, and related aspects of intelligent machines, such as artificial intelligence, neural networks, and parallel computing. RISP research is intended to minimize human error through automation of repetitive, dull, and routine tasks; to minimize human risk by allowing effective remote operation in hazardous environments; to optimize cooperation of humans and machines; and to cope effectively with emergency situations where fast response is essential.

Robotic vehicles have a wide field of applications in the civilian and military industry including manufacturing, assembly lines, security, operation in hostile environment, and testing. In the defense area, robotic vehicles have the potential for force multiplication and removing the soldier from hazardous environments on the battlefield. To make such vehicles avaialable requires research, development, testing and demonstration of advanced robotics and artificial intelligence (AI) technologies and systems. A realistic effort towards that objective requires the establishment of an advanced laboratory responsible for evaluation and development of subsystems and integration of the various elements into vehicles for field tests. Hence, requirements for the laboratory are given including a layout design and link analysis of the different components. As the first part of planning the laboratory, the technology was assessed to assure inclusion of the state-of-the-art equipment. Then, equipment requirements were defined, including interactions between pieces of equipment and providing for support, recording and monitoring equipment.

This is a concise survey of the activities carried out by the Robotics Laboratory of the “J. Stefan” Institute, University of E. Kardelj, Ljubljana (Yugoslavia) on the field of robotics research and development of robots. A list of research themes is given with a brief explanation of each containing the objectives, the obtained results, the history and the future outlook. Besides, the main projects concerned with the development of industrial robots are described, as well as the equipment which enables practical work and experimentations as a major element of the laboratory research and educational activities.

This paper examines a tactile slip sensor based on photoelastic effects. Photoelastic patterns are obtained using a Dynamic Ram with a resolution of 256 by 128 pixels. Software is developed to detect changes in the stress patterns when an object moves relative to the surface of the sensor. It is suggested that the stress patterns can be used to detect slippage at the object/gripper interface.

In this paper a pneumatic vibratory wrist operated with a PWM controller is developed for robotic assembly. In the vibratory assembly system, the vibratory wrist can perform random search motion of a hole to compensate the position error at the early stage of an insertion process. Since the vibration characteristics of the wrist, such as the amplitude and trajectory of the vibration, are critical to assembly performance, they are experimentally investigated for various system controller parameters. In addition, a series of insertion experiments are performed to evaluate the assembly performance of the proposed wrist. The results show that within a wide range of operating conditions the wrist vibration can effectively compensate for large positioning errors when this wrist is used for a chamferless peg-in-hole task.

This paper is concerned with the design of intelligent subsystems that interface actuators and sensors to intelligent supervisors for robot work-cells. Benefits of our approach include removal of low level computation and stringent real-time constraints from the superviser, potential for combining and interpreting information from sensor combinations, and provision of a uniform information interface for disparate devices. Our approach to the design and organisation of these subsystems is based on the concept of virtual devices. We demonstrate the applicability of the concept by describing the design and implementation of an intelligent controller for a sensory gripper.

This paper reports on a continuation of research activities at the Loughborough University of Technology (LUT) which are aimed at evolving second generation pneumatic drives and provides an introduction to various aspects which must be considered in the design and use of industrial pneumatic servo-driven robots. The paper illustrates how a new generation of fast and accurate pneumatic servo drives, demonstrating excellent performance/cost characteristics, will become available and will rival electric and hydraulic counterparts in many areas of industrial control.

This paper proposes a method for finding an optimal geometric robot trajectory to perform a specified point-to-point motion without violating joint displacement limits or interference constraints. The problem is discretised, and a quantitative measure of interference is proposed. Constraint violations are represented by exterior penalty functions, and the problem is solved by iteratively improving an initial estimate of the trajectory. This is accomplished by numerically minimizing a cost functional using a modified Newton–Raphson method.

The problem of constructing a smooth path with respect to time through N given points in configuration space is considered. Two variants of an algorithm suggested by Paul are presented and evaluated. It is shown that the algorithms suggested in this paper yield in general considerable improvements in two respects: Firstly, the deviation of the resulting path from the given points is reduced markedly and secondly, the overall time needed for the movement is reduced significantly and consequently, is closer to the true minimum-time. The price to be paid for these improvements is a moderate increase of computation time allowing still online use of the algorithm.

An approach for collision–free trajectory planning along designated paths of two robots in a common workspace is presented. Specifically, in order to describe potential collision between the links of two robots along the designated paths, explicit forms of virtual obstacle are adopted, according to which links of one robot are made to grow while the other robot is forced to shrink as a point on the path. Then, a notion of virtual coordination space is introduced to visualize all the collision–free coordinations of two trajectories. Assuming that a collision–free coordination curve between the two robots is given via a virtual coordination space, the minimum time collision–free trajectory pair for the two robots is sought considering dynamic constraints of torque and velocity bounds of actuators of the two robots.

In this paper, a new splines–based control method for robot manipulators is presented and discussed. The above method can be effectively used for path planning and control of rigid and flexible robots. The computational simplicity of the proposed algorithm, together with its flexibility and its high–level intelligence built in, can be considered as promising tools for achieving the goals of modem robot manipulator design.

The need for fault tolerant mechanisms in flexible manufacturing systems is described and previous work on diagnosis in robotics and other areas is considered. Fundamental difficulties in the analysis of robot cell malfunctions are described and a glossary of terms useful in this area is presented. Limited observational data on the occurrence of faults in assemblies are reported. Finally a proposal for an experimental mechanism for diagnosis within a knowledge rich supervisory system is explored.

The paper present a model of the kinematics of a rotary, redundant manipulator, in the form of a Finite State Machine, this is in fact, an example of AI production systems. This model is able to supply us with succesive configurations, calculated immediately in Cartesian space and allowing at the same time to considerably simplify the computations engaged in the graph searching. For an automaton-type model of the manipulator kinematics, diverse strategies of searching for a collision-free trajectory, reduced to a search of an appropriate path in the state-transition graph of FSM, are analyzed.

An active force control system for robotic deburring based on an active end effector is developed. The system utilizes a PUMA-560 six axis robot. The robot's structural dynamics, positioning errors, and the deburring cutting process are examined in detail. Based on ARMAX plant models identified using the least squares method, a discrete PID controller is designed and tested in real-time. The control system is shown to maintain the force within l N of the reference, and reduce chamfer depth errors to 0.12 mm from the 1 mm possible without closed-loop control.