UBC Theses and Dissertations
A dynamically reconfigurable system architecture and FPGA based servo controller for distributed machine tool control Oldknow, Kevin David
This thesis presents the design and analysis of a novel system and protocol for the automatic configuration and dynamic reconfiguration of distributed machine tool control systems. The basis for the system is the UBC Open Architecture Control System reference model. A virtual machine abstraction of the underlying machine tool controller is implemented in an object-oriented extension to the ANS Forth programming language, and used to facilitate hardware independence. A reconfigurable binding table translates virtual machine method calls into appropriate hardware dependent routines. These hardware dependent routines are established in the system via the interpretive translation of a stream of tokenized code, retrieved from device firmware. The tokenizing scheme used is based on the IEEE 1275 Open Firmware standard. A Field-Programmable Gate Array based servo controller, designed to be compatible with the Open Configuration System, is also presented. The servo controller is implemented on a prototyping board incorporating a 20,000 gate Xilinx FPGA and 32 kiloByte RAM chip, with the addition of a filter to convert a pulse-width modulated signal to an analog amplifier reference signal. The controller is capable of driving a single machine tool (or robotic) axis, and has been integrated into a laboratory test-stand comprising a current-controlled DC motor loop and incremental quadrature position feedback.
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