Assembly cell controls using flexible software tools and high level control configuration language
In the Technical Research Centre of Finland a flexible, automatic assembly cell has been built for research and development of automatic assembly systems and for feasibility studies of industrial assemblies. The main components of the cell are two industrial robots with dedicated microprocessor controllers, a conveyor system and a hydraulic press with multi-purpose microprosessor controllers and a vertical carousel storage with Programmable Logic Controller (PLC). In addition the cell includes auxiliary equipment like automatic tool changers, feeders and screwdrivers which are mainly controlled by binary signals. The cell controller is a common 80186-based controller system for automation with some software extensions to cover also manufacturing cell controls. The control software in the cell controller consists of a real time database with software blocks to handle controls, machine communications, operator communications and data-management.
In order to manage many small production tests with different assemblies and equipment with minimal effort the cell control software must be parameter based so that new configurations can be defined without changes in the software. Control definitions i.e. control sequences, error handling, operator displays and syntax for machine communications are given by configuration tools using high level configuration language. Communications between the cell computer and different machines are carried out using serial links and line-by-line character based communications (terminal type communications). By setting parameters and describing communication strings in a description file it is possible to cover most of the machines having some kind of terminal connection for the operator. With the terminal type communications it is easy to realize the Virtual Terminal Protocol i.e. to connect directly the operator’s terminal to the machines. The VTP and the terminal type communications together with the description files give us an opportunity to build up hierarchical control systems with almost unlimited number of control levels.
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- Ä1A Lempiäinen J., Temmes J, Temmes J., “Flexible assembly cell realization for feasibility studies of industrial assemblies.” Proc. of the 7th Int. Conference on Assembly Automation, Zurich 4–6 Feb. 1986, pp. 227–232. IFS (Publications) Ltd, 1986.Google Scholar