The paper deals with a three axis reaction force and displacement sensor. The design procedure of the strain gauges sensor for its intended application as a tactile proble is described. The deformable sensor body with strain gauges arrangement allows all three output voltage readings to be directly related with rectangular components of the force displacement vector in a remote contact reference system. The structural orthogonalisation that results in minimal cross component couplings is briefly outlined. The practical use of the designed probe is exemplified by seam following in a robotic welding system.

An expression is derived for the combined flexural-joint stiffness matrix and the elastic deformation field of a servo-controlled two-link robot manipulator. Such expressions are needed in dealing with light weight high-speed flexible robot manipulators. The approach employs a strain energy invariance principle with respect to the elemental and the system reference coordinate frames to derive the desired 9 × 9 combined flexural joint stiffness matrix.

For the past several years, industrial robots are being used extensively. These robots are generally equipped with relatively simple control systems. Such control systems have proved adequate, but with increased demand on robot performance, there is need for advanced and sophisticated controllers. One of the probelms in the control of robots is that system dynamics change due to several factors such as the orientation of arms and their effective inertia.

Adaptive controllers have the advantage that the system is continuously modelled and controller parameters are evaluated on-line, thus resulting in superior performance. Adaptive controllers can be realized in several ways.

This paper describes the design and performance of an explicit self tuning regulator for a robot arm.

This paper is concerned with the problem of keeping contact with a fixed object during the motion of a manipulator gripper along the contour of an object, i.e. along a constraint. The theory of the existence and the stability of stationary regimes of motion along a straight line and a circle is studied.

The numerical complexity of robot dynamic models, inverse control structures and decentralized control laws is analyzed in a systematic fashion. Dynamic models of actuators (DC motors and hydraulic cylinders) are taken into account, too. The exact number of floating-point multiplications and additions/subtractions for an n−link manipulator is determined. The results are applied to several typical industrial manipulators. Measuring of computation time for various control structures is realized on an up-to-date 16-bit microcomputer, widely used in robot controllers. Thereby, the real-time applicability and effectively the “price” of different control laws are estimated.

The dynamics of “simple, redundant robots” are developed. A “redundant” robot is a robot whose degrees of freedom are greater than those needed to perform a given kinetmatic task. A “simple” robot is a robot with all joints being revolute joints with axes perpendicular or parallel to the arm segments. A general formulation, and a solution algorithm, for the “inverse kinematics problem” for such systems, is presented. The solution is obtained using orthogonal complement arrays which in turn are obtained from a “zero-eigenvalues” algorithm. The paper concludes with an assertion that this solution, called the “natural dynamics solution,” is optimal in that it requires the least energy to drive the robot.

This paper briefly describes actual robot level programming languages, focusing on their intrinsic limitations when compared with traditional concurrent programming languages or when used for robotic systems/flexible production workshops programming, and not only for an isolated manipulator control.

To reduce such limitations, a suggestion is made to base the development of robotic programming systems on already existing concurrent languages (Concurrent Pascal, Modula-2), taking into account their built-in extension facilities for fastening the incorporation of (or easy interfacing with) existing packages or products already developed in robotics (robot models, CAD systems, vision systems, etc).

Using such languages as a support base for a robotic station programming environment, with access to different components developed separately, will allow a better understanding of the inter-relations among components and their limitations when faced with an integration perspective.