It is, indeed, a pleasure to edit this special issue of Robotica entitled Design and Applications. This consists of revised and updated papers presented during the 26th International Symposium on Industrial Robots (ISIR), which was held on 4–6 October, 1995, in Singapore. The theme of the symposium was “Competitive Automation: New Frontiers, New Opportunities”. Ninety-six papers were presented by authors from twenty-five countries around the world. Three keynote presentations were made by Dr. Joseph Engelberger, best known as the ‘Father of Industrial Robots', Prof. Yukio Hasegawa, a world renowned professor from Japan and Mr. Walter Reis, from Germany (then the Chairman of the International Federation of Robotics).

Industrial robots have a high positioning accuracy and stiffness but their work spaces are limited because their bases are fixed to the ground. To enlarge the work spaces, this paper proposes a novel mechanism, a wire suspended manipulator with three degrees of freedom. First, the kinematics of the mechanism is derived from both force and geometric constraints. Second, the volume of the work space is numerically calculated. After the evaluation of manipulability of the wire suspended system, guidelines for designing parameters are studied.

This paper presents some problems dealing with the transportation of bulk and liquid materials. The robotization of the transport process by an elastic manipulator of an elephant trunk type is proposed. The design of an experimental stand and some results of statical and dynamical analysis are presented. In conclusion, some proposals describing the possibilities of utilising elastic manipulators for transport purposes are given.

For securing and increasing the quality of various material processing technologies a flexible sensor data integration is indispensable. Hence, a powerful and configurable sensor-robot-system was designed and implemented, integrating sensor data into industrial robot controls within the interpolation or the position control clock rate. Different controllers were designed and the system responses of the control loops were simulated and optimized by an efficient control design tool. Experimental results on the achievable path accuracy are presented. Finally, some application for the developed sensor control loops are introduced.

In co-operation with an Austrian small sized company, the Institute for Handling Devices and Robotics at the Vienna University of Technology started a project with the goal to reduce the time necessary for planning, programming and set-up of robot equipped manufacturing cells. In this contribution a modular, object-oriented control system for robotized cells is presented. This system ‘C_CTRL' is responsible for all necessary tasks, like sequencing, supervising, controlling of basic functions, error handling, and recording of statistic data. The control system is ‘self-generating' during program start-up – using hardware information from a simple ASCII configuration file. Regardless which and how many components used in a particular cell, there is no additional programming effort for generation of the entire control software.

To increase operator safety in robotic working cells, a capacitive sensor for the detection of humans has been developed. The sensor consists of two electrically conducting planes, insulated electrically from the ambient. When the dielectric or conductive conditions in the space between the planes are altered, e.g. a person enters, the sensor will indicate the presence of the person. The strength of the electric field caused by the sensor is kept low by lock-in amplifier technique. In the article the basic detection principle, the sensor electronics and the sensor signal handling are described and some practical experiments are presented.

In this paper, a mathematical representation of constrained robot systems in the form of a differential-algebraic equation model is first considered. This model in modified further to include the joint flexibility between the linkages of the robot, and the actuator dynamics. The objective is to design a feedback control law for the system so that the position output variables (typically the end-effector position) and the force output variables (typically the contact force between the robot's end-effector and the contact surface) of the robot follows the desired position and the desired force trajectories, respectively, despite the presence of joint flexibility and actuator dynamics. A systematic procedure is developed for designing a feedback control law which ensures that the position variables track the desired position trajectories exponentially, and the force variables track the desired force trajectories exponentially. Since the development of the control law is based on the model of a constrained robot system which includes the effects of actuator dynamics and joint flexibility, it is possible to achieve better tracking performance using the force/position control law developed in this paper in cases where such effects are significant.

A six axis robot has been connected to the World Wide Web at http://telerobot.mech.uwa.edu.au/. The robot was made available on the World Wide Web in September 1994 and has been through many revisions since that time. The remote user receives static images of the robot's work space and can manipulate wooden blocks.

The implementation and application of this interface to telerobotics is discussed. Useability and operator behaviour are investigated through analysis of movement records. Questions addressed are: What is the level of interest in this technique and is it a practical interface for telerobotics.

A mathematic model is developed for a quadruped walking robot to investigate the dynamic stability considering all the inertial effects in the system including those of legs. The dynamic model is derived based on Lagrange's equation using matrix-vector notations for the simpler expression. Then an instant gait stability measure is proposed to apply to dynamic gait as well as static gait. The gait stability measure is obtained from the angular momentum of the system about the supporting edges in the quadrupedal gait of +x type. The validity of the gait stability measure is examined along with the gait stability analysis for several representative gait parameters using the developed dynamic model.

In this paper, tip tracking control of a single-link flexible robot is studied through computer simulations. The controller investigated is of a two-loop PD type, which is deduced from a control approach originally developed for elastic joint robots. A very simple model, with the flexible link of the robot being lumped to a spring-mass unit, is employed for the controller design. Bounded Input and Bounded Output (BIBO) stable tip tracking performance is guaranteed. The controller is robustly stable under system parameter uncertainties, and is comparatively easy to implement. In the simulations, different payloads are considered, and the system performance is compared with the traditional Singular Perturbation (SP) method. The simulation results show that the PD type controller designed based on the simple lumped model is able to provide quite satisfactory performance.

In this paper, the wall-following problem of an AGV is characterized by keeping a constant distance from a wall. Four Polaroid ultrasonic range sensors (sonar) are used to obtain information of the distance between the AGV and the wall. Four sonars are divided into two groups being placed at the front and back end on the right side of the AGV, respectively. A digital filter is used to get rid of disturbance and wrong readings. The former results mainly from the door and the latter from the specular reflection and accidental scattering. To obtain good dynamic and steady performances, a new compound fuzzy-I control algorithm is presented. Our methods have been verified by following a 15-meter-long wall with one door by using our TIT-1 AGV (TIT: Tianjin Institute of Technology). The results show a good performance with an error of ±2 cm from the desired distance to the wall.

The motion planner presented in this paper enables the user to design movements in an interactive way, and to integrate sensor signals efficiently. In addition to the usual movements bound to a path, which can now be combined like lego pieces, smooth and fast reactions to arbitrary changes of the target are also provided. This motion planner opens new possibilities for flexible and sensor-oriented robotics, as examples from its implementation on two robots show.

An adaptive control of multiple robot compliant manipulation of a dynamical environment is synthesized. It may be implemented when: (i) there is no good understanding of all physical effects incorporated in the multiple robots/object/environment system to be controlled; (ii) the parameters of the system are not precisely known, (iii) the system parameters do vary in a known region about their nominal values. The proposed adaptive control law has the inverse dynamics controller structure and is composed of an identification part (parameter update law), and a control law part. It is proved that the proposed adaptive controller is asymptotically stable. The simulation results verify the proposed approach to coordinated adaptive control of multiple robot manipulators in constrained motion tasks. They also verify that the multiple robots/object/environment system can track a step parameter change.