(Dr. Thomas Kurfess, advisor)

"Design of a PC-Based Open Architecture Machine Tool Controller"

Abstract

Commercial machine tool controllers today are powerful and robust pieces of equipment. However, because they are largely based on proprietary hardware, these controllers are also expensive and relatively inflexible. The focus of this thesis is to present an alternative for machine tool controllers that is based largely in software, and capable of running on standard hardware. A software-based system is less expensive and more flexible than the current hardware based systems. Three primary objectives in conducting the research for this thesis were: specification of an open-architecture standard for machine tool controllers; implementation of the specified standard in software; and testing of the software on a cylindrical grinder.
In broad terms, the job of a machine tool controller is to map input from the user to output for the machine, and to map input from the machine to output for the user. The nature of this mapping varies from one machine tool to another, and from one controller to another on the same machine. A specification for implementing this mapping must therefore provide a large degree of flexibility. To this end, the controller specification supports division of control tasks into modules, such as a user-interface module, hardware-interface module, control algorithm module, and an interpolation module. The modules interact with one another in a fixed manner, so that modules may be added, modified, or removed to alter the functionality of the overall controller. The focus of this research is defining the manner of interaction between modules. A minimum set of modules was created and assembled into a machine tool controller to form a proof of concept.