Due to the complexity of teleoperation tasks, human operators figure in the teleoperator perception-decision-control loop. The operator needs an interactive system to handle the huge flow of data between himself and the teleoperator.

The scene represented by the robot and its environment is viewed by one or more cameras. However, the video image may be degraded in extreme environments (underwater, space, etc.) or simply inadequate (2-D image).

In this paper we describe the visual perception aids based of the scene, and more specifically how these are generated by the method we put forward. The system developed at the LRE superimposes a 3-D synthetic image onto the video picture, and animates the scene in real-time on the basis of sensor information feedback. The graphic image can be generated from models, if the objects are known, otherwise interactively, with the cooperation of the operator if the objects are completely unknown. Experiments show that these graphic aids improve the operator's performance in task execution.

The purpose of this paper is to show how one can use entropies of deterministic functions (as previously defined by the author) in order to analyze some questions related to machine vision. The main advantage of this approach is that it provides information theoretic methods for solving problems which basically do not refer to probability distributions. After a short qualitative background on deterministic functions, one applies this theory to edge finding, image segmentation, transfer of information defined by brightness functions, and image processing. Some more theoretical details on the entropies of deterministic functions are given in the appendix.

This paper describes a revised version of ROBOPLAN, a goal-oriented robot task planning system for automatic generation, decomposition and execution of high-level robot plans for assembly. It emphasizes its new features, i.e., modularity, formal definition of the task, robust plan synthesis, and execution of each assembly step. A task definition language allows a formal description of the robot universe and the assembly task to be input to ROBOPLAN. The expert task planner is a non-linear backward chaining problem solver, using a goal driven depth-first strategy. The implemented search strategy has been tested in the assembly domain, but it could be used in other domains where planning is needed. The motion planner provides a non-optimal, safe robot trajectory; collision free path planning has not been included yet. A robot executable code is generated for each assembly step and monitored in real time. The error detection and recovery capability of the system is rather limited at present, since no sensors are used. The initial implementation of the system has been tested and evaluated on the assembly of a DC motor. The potential of extending this planning framework to other applications is also discussed.

The paper describes a free space modeling method by multivalue coding. Each code defines some numerical values representing a set of cells from a grid. The idea consists in using the grid as a Karnaugh board whose rows and columns are binary coded rather than Gray coded. This operating method allows to define, for each code, its grid location and allows numerical comparison in order to locate a code relatively to another. This aspect is helpful for path planning. The free space model is represented by a switching function or a tree to which boolean algebra rules and mathematic operations are applied. We describe an application to mobile robot path planning.

This paper focuses on the implementation of a dual-mode controller for the maneuver of a single link flexible robotic arm. The joint angle trajectory tracking is accomplished by a proportional and derivative PD and a feedforward controller. Based on the pole placement technique, a linear stabilizer is designed for elastic mode stabilization. The stabilizer is switched on when the trajectory reaches the vicinity of the terminal state, and the effect of switching time on arm vibration is investigated. An optical deflection sensor is used for on-line measurements of elastic deflections, and also used for the prediction of the static deflection of the arm in the target position. The robustness of the linear stabilizer at varying pay loads is presented.

This paper describes the structure of the program package for manipulator modeling, control law synthesis and simulation SYM. While the underlying algorithms have been explained elsewhere, this paper puts emphasis on SYM as a program environment with both research and educational purposes. The control law synthesis in symbolic form, as well as system simulation, are given in more details since those features have been introduced into SYM recently. As an illustration we present few instances of SYM outputs which depict main steps in manipulator control system creation process: manipulator structure as a 3D scheme, control law definition form and system simulation results as 2D plots.

This paper outlines a method for control of robotic systems for part sorting operations in unstructured manufacturing environments. The sorting is accomplished simply and without any change in the kinematic structure of the robot or any need for inclusion of complicated external sensory systems. The method developed is based on the inherent relationship between the mass of parts to be carried and the maximum velocity of the tool centre point attainable along certain specified paths.

The actuators' maximum velocity is detected and is communicated to a devised expert system. The expert system uses this maximum velocity as a part of its matching procedure for the purpose of part sorting.

The problem of determining energy optimal walking motions for a bipedal walking robot is considered. A full dynamic model of a planar seven-link biped with feet is derived including the effects of impact of the feet with the ground. Motions of the hip and feet during a regular step are then modelled by 3rd order polynomials, the coefficients of which are obtained by numerically minimising an energy cost function. Results are given in the form of walking profiles and energy curves for the specific cases of motion over level ground, motion up and down an incline, and varying payload.

Collision-Avoidance is a key issue in planning trajectories for dual robots whose workspaces overlap. In this paper, we develop a new trajectory planning method by proposing a traffic control schemes. The traffic controller determines the next positions for each robot based on the motion priority and path direction subject to the collision-avoidance conditions and the robots' physical limits. The problem of determining the next positions is formulated and optimized. Algebraic expressions for collision avoidance between every-pair of links – one from the first robot and the other from the second robot – are derived in configuration space. These algebraic expressions are then used to solve the problem of determining “optimal” (in the sense of path direction and motion priority) robots' trajectories. A solution procedure is developed using a nonlinear programming (NLP) solver. The main advantage of our approach is that the two robots' trajectories can be determined simultaneously without requiring any a priori path information. Several numerical examples are presented to demonstrate the validity and effectiveness of the proposed approach.

This paper illustrates means by which the techniques of compliance and electroadhesion can, using electror-heological, and other fluids, be combined to provide very effective shape adaptive robot end-effectors and similar holding surface.