A hierarchical open architecture multiprocessor (ROAM) implementation of a computer numerical controller (CNC) is presented. An advanced control system consisting of a hierarchy of independent buses is developed and tested for the purposes of providing unattended intelligent machining systems.

Loosely coupled subsystems, which handle process monitoring and control, are located on a primary bus structure. An advanced digital signal processing (DSP) subsystem acts as the HOAM-CNC master processor for a secondary CNC bus. Inexpensive embedded axis controllers on the CNC bus perform interpolation, control and data collection tasks. The axis controllers have high speed communications with the HOAM-CNC master by using dual ported memory. Within the HOAM-CNC subsystem, data collection, process control and monitoring tasks are executed in a real-time multitasking environment, which also performs position control.

This system demonstrates an open architecture controller, which allows any process control and monitoring task in the system to manipulate the feed, acceleration, control parameters and position commands in real time. This open approach also allows the easy integration of new process control, monitoring and position control algorithms or subsystems.