This paper details the design principles of operation of a pneumatic proximity-to-tactile sensing device for part handling and recognition in a flexible manufacturing environment. The sensing device utilises a densely packed line array of piezoresistive pressure sensors, providing continuous variable outputs. The sensing plane of the device incorporates a corresponding line array of air jets which develop an air cushion when striking a target of interest. The back pressure levels from these air jets form the basis for the task of target detection and recognition.

Interactive robot systems are under active investigation as aids for people with impaired manipulating ability. Under the direction of a disabled operator, a robot can manipulate objects, thereby increasing the independence of the operator in home, school and work activities. This paper describes a high-level control language CURL developed to facilitate communication between a disabled operator and the task environment. CURL is a Windows-based application. Interactive robotics requires a different approach from mainstream robotics where humans are kept out of the robot's work area.

A prototype robot for picking citrus is described which utilized real-time, color machine vision to vision-servo the robot on a targeted fruit. A programming technique is presented which simplified development of the task-level, robot control program. An economic evaluation of robotic harvesting in Florida determined that robotic harvesting would be approximately 50 percent more expensive than conventional hand harvesting. Harvest inefficiency was identified as the most influential factor affecting robotic harvesting economics. Field trial performance is summarized and the potential of commercial robotic harvesting discussed.

A computationally fast inverse kinematic scheme is derived which solves robot's end-effector (EE) trajectories in terms of joint trajectories. The inverse kinematic problem (IKP) is cast as a control problem for a simple dynamic system. The resulting closed-loop algorithms are shown to guarantee satisfactory tracking performance. Differently from previous first-order schemes which only solve for joint positions and velocities, we propose here new second order tracking schemes which allow the on-line generation of joint position + velocity + acceleration (PVA) reference trajectories for any computed torque-like controller in sensor-based robot applications. The algorithms do explicitly solve the IKP for both EE position and orientation. Simulation results for a six-degree-of-freedom PUMA-like geometry demonstrate the effectiveness of the scheme, even near singularities.

This paper considers the use of the Taguchi method as a means to identify the optimum design of a robot sensor. The sensor is modelled by a complex set of equations which makes optimisation using traditional calculusbased methods difficult. The Taguchi method is employed as a systematic method to understand the performance of the sensor whilst using a limited number of model evaluations. The Taguchi method is based on the experimental design technique and the results of using a full factorial design, 1/2 and 1/4 fractional factorial designs are compared. The advantage of using the Taguchi method over traditional experimental techniques is also discussed.

In this paper a control law, which consists of a fuzzy logic controller plus a nonlinear effects negotiator for a flexible robot manipulator, is presented. The nonlinear effects negotiator is used to enhence the control system's ability in dealing with the uncertainty of the mathematical model. The control algorithm is simple and easy to tune as opposed to conventional control law which requires time consuming gains selections. To obtain fuzzy control rules, an error response plane method is proposed.

Robots in the 20th century have been valued mainly for their enhancement of productivity. According to Professor Ichiro Kato of Waseda University, 21st-century robots will be valued because they enhance amenity. The development of robot systems for health care, detailed in this special issue of Robotica, is an affirmation of this forecast.

Several factors have combined to cause this development, although economic factors are paramount. Industrialised countries, where robots are most likely to be used, face an ageing population-a result of lower birth rates, reduced infant mortality and increased life expectancy. This ‘ageing society' is expected to have enormous impact upon these countries’ health and social security systems which devote a large proportion of their resources to the care of older people.

A robot simulation system has been developed to assist in the design of robots, layouts and robot task planning. A general type of robot manipulator can be stimulated taking into consideration the geometrical and kinematical model of the robot. The work cell with multiple robots and its industrial environment is displayed on CRT by a 3-D computer graphic system. Examples and a description of the mathematical algorithm for the kinematic modelling are also included.

This work describes a hierarchically structured geometric database in an off-line robot programming system. The data structure contains the numerical definition of the frame variables, as well as an indicator of the respective reference frames. Moreover, the physical relations between the objects in the environment are included. The database is implemented such that it continuously reflects the actual structure of the environment. As a result, all calculations of the frame locations are carried out automatically. Moreover, the programming system is capable to autonomously updating the numerical information after changes in the environment. Making this database the heart of a robot programming system greatly simplifies the off-line programming of complex robot tasks, like f.i. assembly tasks.

Robotic peg-hole insertion operations can play a very important role in manufacturing industry because it is a common requirement in the manufacturing process and, it requires high precision and high speed.

In general, this operation can be divided into two processes: Search process to engage the peg and the hole and, insertion process.

The search process is critical in the assembly operation. It can be defined as a process where the angular.and the translational errors between the peg and the hole are reduced until insertion can occur.

In this paper, an efficient method for computing the Jacobian matrix for robot manipulators on a single processor computer is developed. Compared with the existing methods, the number of required numerical operations is considerably smaller, making the proposed technique the fastest, or the least expensive, one for any general N degrees-of-freedom manipulator.

A simple general model for learning, using a fuzzy set theoretic approach and fuzzy decision in an automaton which has nonfuzzy input/output, is proposed. The process has been modelled somewhat in the fashion of general biological systems, which may be viewed as a fuzzy decision process where learning consists in taking a tentative action and reinforcing the membership values on the basis of the results of that action. The model is tested on an automaton whose sole purpose is to follow the boundary on an object with which it makes contact during its movements. The automaton is simulated by a computer. it has standard 8–neighbourhood configuration with binary sense capability and three action capabilities. The automaton has been found to learn to take correct action in a large number of possible input situations within only a few thousand moves.

A manipulator regressor is an n x l matrix function in the dynamic expression τ = Y r or τ = Wr, which linearizes the robotic dynamics with respect to a properly defined inertia parameter vector ζr є R1. Many modern adaptive controllers require on-line computation of a regressor to estimate the unknown inertia parameters and ensure robustness of the closed-loop system.

While the computation of Y is studied by Atkeson, An and Hollerbach1 and Khosla and Kanade,2 the computation of W for a general n–link robot has not been reported in the literature. This paper presents an algorithm to compute W for a general n–link robotic manipulator. The variables used to construct the regressor matrix are directly available from the outward iteration of a Newton-Euler algorithm; some additional arithmetic operations and first-order, low-pass filtering are needed. The identification of unknown inertia parameters is also discussed.