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.

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 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 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.

This paper presents a new method to generate a smooth collision-free path of a mobile robot. The path is generated as follows: First, the obstacle spaces are artificially contracted to obtain an initial collision-free path which leads the mobile robot from the start point to the goal; then the path is iteratively modified to avoid the obstacle spaces which are gradually restored (this is carried out in consideration of the index introduced to evaluate the correctness of the path), in the final step, all the obstacle spaces are fully restored and the obtained path becomes a desirable collision-free one. The proposed method is effectively applied to an example of planning planar movements of a mobile robot.

A practical architecture, using a four-bar-linkage, is considered for the University of Minnesota direct drive rotot. This statically-balanced direct drive robot has been constructed for stability analysis of the robot in constrained maneuvers.2–6 As a result of the elimination of the gravity forces (without any counter weights), smaller actuators and consequently smaller amplifiers were chosen. The motors yield acceleration of 5 g at the robot end point without overheating. High torque, low speed, brush-less AC synchronous motors are used to power the robot. Graphite-epoxy composite material is used for the construction of the robot links. A 4-node parallel processor has been used to control the robot. The dynamic tracking accuracy-with the feedforward torque method as a control law- has been derived experimentally.

In this paper the authors present a mathematical model of geometric and kinematic behaviour of an original passive compliant device provided with two rotation centres, called DCR–LAI system. This device is designed for a robotic assembly of parts with very small tolerances including a chamfer at the hole. The given modélisation may be used as a decision aid for the choice of a compliant device with regard to characteristics of parts being assembled.

An extension of the inverse kinematics algorithm by Gupta and Kazerounian is presented. The robot kinematics is formulated by using the Zero Reference Position Method. Euler parameters and the related vector forms of the spatial rotation concatenation have been used to improve the efficiency of the velocity Jacobian computation. The joint rates are formally integrated by using a modified predictor-corrector method particularized to robot inverse kinematics – it is a strict descending, p(1)c(0 – n), variable step algorithm. The definitions of the rotational error and overall error measure have been revised. Depending upon the convergence criteria used, these modifications reduce the overall computational time by 20%.

A method was developed that takes into account flexibility of robot links in the inverse dynamics calculations. This method uses the Newton-Euler equations and is applicable for special case systems that allow for only a small degree of flexibility. Application of the method should improve the accuracy of the position of the end effector during motion of the robot.

The results of this study show that the method can be based entirely on an existing rigid-link model with only minimal changes required as additions. The computational complexity of the method is discussed briefly as well and indicates an increase of computations of slightly more than a factor of two as compared to a rigid-link model for the same robot geometry.