This paper deals with the first transatlantic experiment of robotic telesurgery. A robot in Milan (Italy) performed an operation on a model of a pig, and the surgeon controller was in JPL, Pasadena (USA). By means of two communication satellites and of an optical fibre network, the robot performed a biopsy and a preliminary cut for a laparoscopic mini-invasive surgery operation.

A fundamental study on the control of hydraulically actuated robots is presented. Dynamic modelling is performed in both time-domain and frequency-domain. It is shown that the inclusion of hydraulic elements increases the order of the system. Hydraulic compliance is the most effective factor in this regard.

Three distinct control strategies are applied. Their performances are evaluated and compared. All three methods are exemplified with a two link hydraulic robot in a computer simulation. The robot has the same hydraulic configuration as many existing industrial manipulators. The simulation program is written in ACSL (Advanced Continuous Simulation Language) running on a VAX 11/750.

A rigid body dynamical model and control architecture are developed for the closed chain motion of two structurally dissimilar manipulators holding a rigid object in a three-dimensional workspace. The model is first developed in the joint space and then transformed to obtain reduced order equations of motion and a separate set of equations describing the behavior of the generalized contact forces. The problem of solving the joint space and reduced order models for the unknown variables is discussed. A new control architecture consisting of the sum of the outputs of a primary and secondary controller is suggested which, according to the model, decouples the force and position-controlled degrees of freedom during motion of the system. The proposed composite controller enables the designer to develop independent, non-interacting control laws for the force and position control of the complex closed chain system.

This paper presents a new method for solving the inverse kinematics of robot manipulators. The method defines incremental units in joint and Cartesian spaces, which represent the position resolutions in each space. Based on these units, the incremental computation of the DDA integrator is used to solve the direct kinematics. The repetitive calculation of the inverse Jacobian matrix is replaced by a simple look-up table. By using an iterative procedure with convergence rules, the inverse kinematics algorithm is established. A 3 DOF robot is considered as the combination of two types of a 2 DOF robot. Simulation and experiment are performed to test the algorithm.

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.

A method is presented for generating the path which significantly reduces residual vibration. The desired path is optimally designed so that the system completes the required move with minimum residual vibration. The dynamic model and optimal path are effectively formulated and computed by using special moving coordinates, called virtual rigid link coordinates, to represent the link flexibilities. Also joint compliances are included in the model. Characteristics of residual vibration are identified from the linearized equations of motion. From these results, the performance index is selected to reduce residual vibration effectively. The path to be designed is developed by a combined Fourier series and polynomial function to satisfy both the convergence and boundary condition matching problems. The concept of correlation coefficients is used to select the minimum number of design variables, i.e. Fourier coefficients, the only ones which have a considerable effect on the reduction of residual vibration. A two-link manipulator is used to evaluate this method. Results show that residual vibration can be drastically reduced by selecting an appropriate manipulator path.

A proximity sensor using a mechanical contact principle is under development for robotic applications. Good discrimination between contact loads and inertial windage loads is essential. Rugged design and easy replacement of sensing elements is also necessary. The sensor is under consideration for use on the feet of the Adaptive Suspension Vehicle.