A geometrical methodology for automatic machine tool command generation is introduced. The geometric entities relevant to machine tool operation are unambiguously defined by volume models. A vector sum operator is used to determine regions of the configuration space of the machine tool which correspond to undesired collisions, cavity access and material removal. Some indication of how cutter paths are generated is given and a practical implementation for the case of machining two and a half dimensional components under two and a half axis control is discussed in more detail.

The author stresses the need for relevant empirical data concerning the organizational and human factors resulting from the introduction of robots. After discussing automation in industry and business, as well as military and space applications, the author identifies the problems and consequences arising out of robotization in industry. He concludes with a plea for meshing the robot and social technologies in order to bring about economic and technological revitalization.

Actual positions of industrial robot end-effectors differ from those commanded off-line. Consequently, it is then difficult for robots to fulfill certain tasks, such as automated assembly sequences or tasks where high performance accuracy is required. This paper shows that the accuracy of robot performance can be improved by introducing deviation matrices which are functions of many possible error sources. As a first approach, an experiment was carried out where structural elastic deflections, one of the many error sources, of a robot ASEA Irb 6/2 were taken into account. The experiment showed that using the improved model, the positioning accuracy of an ASEA Irb 6/2 robot carrying a weight of 5.6kg was improved from 2.5mm to 0.25mm and the orientation accuracy was improved from 0·45° to 0·3°.

A low cost tactile sensor using commercially available conductive silicone rubber has been developed. It comprises a two dimensional array arranged in 3 mm centre-to-centre distance. Each sensor element has a zero-force resistance of about 0.3 kohm and it has a logarithmic characteristic curve of resistance versus force. An 8 × 8 prototype tactile sensor array over an area of 3 cm × 3 cm has been fabricated and mounted on the gripper of a robot for testing and evaluation. The associated software has also been developed. The limitations of the sensor are also discussed.

This paper presents some aspects of the behavior of hydraulically actuated heavy duty manipulators. This category of manipulators is used extensively in large resource based industries and any improvement in efficiency may result in major financial benefits. In this paper an adaptive control algorithm is used for a two rigid link manipulator driven by hydraulic actuators. The dynamic model of the manipulator is derived as well as the models of the hydraulic actuators including compliance, dead time and full dynamics of the servo valves. An adaptive control algorithm is considered since changes occur on-line in the system's parameters. The adaptive algorithm used is Generalized Predictive Control (GPC). The GPC uses a controlled autoregressive integrated moving average (CARIMA) type model and a cost function that minimizes a predicted future output error and future weighted control inputs to the plant, resulting in a sequence of future control increments. The procedure, in this work, does not separate the hydraulic actuator and the link dynamics into separate sub-systems, but controls them as one system. The changes in the system's parameters due to the hydraulics or the link dynamics can be estimated and the coefficients of the model adjusted without the necessity of identifying the exact cause of the changes.

It was found in this work that the variations of the GPC control horizon can lead to faster response during transients and significantly reduced overshoot in the nonlinear hydraulic actuation system. An on-line change of the maximum output horizon is also introduced.

This work shows the analysis and results of a two link manipulator with hydraulic actuators. It can be implemented on any hydraulically actuated manipulator with any number of links and actuators.

Numerical simulations are performed on a Vax 3200 computer and the results are presented.

In this paper a control strategy for a redundant PUMA robot is presented. This robot is obtained from the conventional PUMA robot by addition of a joint parallel to the elbow joint. For redundancy resolution the following approach is chosen. From the position and pointing direction of the end effector of the PUMA robot the position and orientation of the fourth link of a 4R-manipulato? is calculated and the redundancy is resolved for this manipulator. This is done by adding an equation to the relationship between the joint angles and position and orientation of the fourth link. By this approach a control strategy is derived that allows motions of the end effector of the PUMA robot in a large part of its work space and shows repeatable behaviour. Furthermore, the redundancy is utilized so that the fiexture of the wrist is kept small.

The flexible turning cell developed at CETIM has enabled us, among other things, to investigate how the movement of workpieces could be organized in flexible production cells.

The very design of flexible cells leads to the following questions about the manufacturing process to be considered: – type of product, – type of operational side, – type of management/control, – type of data transmission.

These questions are answered by calling upon group technology for both the product and operational sides, and upon simulation to define precisely the operational side, and the type of management/control and data transmission system to be used.

For simple cells (i.e. those with few work-stations) the system can be analyzed in detail without resorting to simulation. Thus equipment limitations such as those set by robot control can be taken into account to analyze the possibilities to interlink numerous different paths.

With this approach simpler real-time operation can be implemented. It also permits handling operations on different types of workpieces (i.e. of different shape and sequence) simultaneously.

This paper presents a trajectory generation method using smooth functions for an automatic guidance system of an autonomous vehicle with two differentially driven wheels within structured environments. A control algorithm based on an incrementally generated smooth trajectory gives a good performance when implemented on an experimental vehicle.