This article focuses on research at the MEC, giving three examples of areas of concerted activities at the Centre: intelligent manufacturing, concurrent engineering and rapid manufacturing.

A method is presented that compensates for manipulator end-point errors in order to achieve very high position accuracy. The measured end-point error is decomposed into generalized geometric and elastic error parameters that are used in an analytical model to calibrate the system as a function of its configuration and the task loads, including any payload weight. The method exploits the fundamental mechanics of serial manipulators to yield a non-iterative compensation process that only requires the identification of parameters that are function only of one variable. The resulting method is computationally simple and requires far less measured data than might be expected. The method is applied to a six degrees-of-freedom (DOF) medical robot that positions patients for cancer proton therapy to enable it to achieve very high accuracy. Experimental results show the effectiveness of the method.

The use of Clifford or geometric algebra for dealing with three dimensional geometry is discussed. One issue is the representation of the rigid body motions of rotations and translations as elements within the algebra. The approach used is to work with projective geometry and choose the square of an additional basis element to be large (infinite). This allows Euclidean points to be represented as vectors in the algebra and transforms on these to be handled using bivectors. This paper looks at the use of Clifford algebra for handling the types of transforms required in robotic applications. A number of example applications are given.

Construction is of great interest in the application of practical and theoretical results in the field of robotics. The economic efficiency potential of using robots is defined by construction quantities, a high level of manual work, and hard and unfavorable working conditions. Mounting and finishing operations are the main focus for the practical use of robots. This paper describes technological characteristics of such operations, suggests kinematic structures for mounting and finishing operations, and provides kinematic model designs as examples. Taking into consideration the management details of mounting and finishing operations, this paper also makes recommendations on movement planning and on the formation of the laws of drive control. In the conclusion, recommendations on applying the results and using computer technologies in the development of control programs are presented.

In order to handle a material with either a delicate surface or an air permeable structure, a novel nozzle was designed and developed. This nozzle utilises the phenomena of the radial air outflow. It is envisaged that this new nozzle will handle materials by eliminating surface marking and air permeable structure problems.

15th TRIENNIAL WORLD CONGRESS OF THE INTERNATIONAL FEDERATION OF AUTOMATIC CONTROL (IFAC), BARCELONA, SPAIN, 21st–26th JULY, 2002

The World Congress under the Spanish presidency (Prof. P. Albertos) brought together about 2000 researchers and practitioners of control theory, technology and applications. The famous Gran Teatro del Liceo of Barcelona was the right location for the opening ceremony, whereas the congress sessions were held at the campus of the Universidad Politecnica de Catalunia.

A Wall-Climbing Robot (WCR) with magnetic tracks is presented in this paper. The robot is designed for labeling the scale of oil tank.5 The Wall-Climbing Robot (WCR) uses a permanent magnet sucker as its sucking mode, and a track as its moving mode. We designed an elastic brace mechanism, a load-scatter mechanism and parallelogram mechanism to improve the robot's adaptability on the steel wall surface. The control system utilizes two-level computer control systems, achieving control of the robot's moving track and processing data collected by the robot.

A new approach to the design of a fuzzy continuous gain scheduled H∞ controller based on Taylor series fitting for n-joint rigid robotic manipulators, which guarantees satisfactory dynamic characteristics in the whole movement range, is presented. This scheme combines the gain scheduled H∞ theory with the Linear Matrix Inequalities (LMI) approach to design a continuous gain scheduled H∞ controller, which is applicable to systems with fast state variations so that the deficiency of the coventional gain scheduled controllers is overcome, with the use of Taylor series fitting. Fuzzy control is then incorporated so that the design controller possesses the characteristics of a fast response for large errors and a well-damped response for small errors. The system thus always has a good dynamic performance along with the variations of the system states. Simulations and experiments demonstrate the effectiveness of the designed controller.

INTERKAMA AUTOMATION FAIR

Düsseldorf (Germany); February 16–20, 2003.

Enquiries to:

Messe Düsseldorf GmbH

(Frank Hartmann)

Postfach 101006

Stockumer Kirchstrasse 61

40474 DÜSSELDORF

GERMANY

(Tel. +49(0)211/4560-407; fax +49(0)211/4560-87407)

www.messe-duesseldorf.de

E-mail: [email protected]

KNOWLEDGE IN ACTION: LOGICAL FOUNDATIONS FOR SPECIFYING AND IMPLEMENTING DYNAMICAL SYSTEMS, by Raymond Reiter, MIT Press, Cambridge, Mass., 2001, xx + 424 pp., ISBN 0-262-18218-l (Hardback, £34.50)

A control structure for the bilateral teleoperation of mobile robots, with tactile feedback and visual information of the interaction force is proposed in this paper. Also an impedance controller is implemented in the mobile robot structure that guarantees the linear velocity be within a desired fixed range without saturation in the actuators. To illustrate the performance of the proposed control structure, experiments on a Pioneer 2 mobile robot teleoperated with a commercial joystick with force feedback are shown.

Based on the author's knowledge the paper gives a brief account of some of the scientific achievements of robotics that were of crucial importance to its development.

In a rough chronological order these are: zero-moment concept and semi-inverse method; recursive formulation of robot dynamics; computer-aided derivation of robot dynamics in symbolic form; dynamic approach to generation of trajectories of robotic manipulators; centralized feedforward control in robotics; robot dynamic control; decentralized control and observer applied to strongly coupled active mechanisms; force feedback in dynamic control of robots; decentralized control stability tests for robotic mechanisms; underactuated robotic systems; practical stability tests in robotics; unified approach to control laws synthesis for robot interacting with dynamic environment; modeling and control of multi-arm cooperating robots interacting with environment; connectionist algorithms for advanced learning control of robots interacting with dynamic environment; fuzzy logic robot control with model-based dynamic compensation, and internal redundancy – a new way to improve robot dynamic performance.

Techniques for tele-operated robots have played for more than 30 years a major role in the context of space missions, as well as in monitoring and handling of hazardous materials. Recent progress in telecommunication and information processing technologies offers now an infrastructure for enabling the provision of services at remote locations with an enormous economic potential. The aim of this first IFAC-conference in telematics (= telecommunications+informatics) was to survey the state-of-the-art with emphasis on applications in automation and robotics. It was organised by the VDI/VDE Gesellschaft Mess-und Automatisierungstechnik (GMA) and the University of Applied Sciences FH Ravensburg-Weingarten.