Development And Initial Analysis Of A Mini Cnc Rapid Development System

This paper describes the development of a mini Computer Numerical Control (CNC) Rapid Development System (RDS). The mini CNC RDS, which is based on Matlab Simulink, provides the student, within the context of a semester long course, with a tool to automate the major components of a table top three–axis machine tool. The major components of the mini CNC include three linear axes and a spindle. The mini CNC RDS allows the student to model and analyze the dynamics of the major components, design and analyze controllers for these components, and design and analyze interpolators for the linear axes. The analyses are done both virtually and experimentally. With this tool the student is able to explore all phases of automation development (i.e., simulation, emulation, and implementation). The student encodes their dynamic models, controllers, and interpolators as subsystems in Matlab Simulink. The inputs and outputs of each subsystem, along with their engineering units, are carefully specified. The student then utilizes the mini CNC RDS to analyze the performance of their dynamic models, controllers, and interpolators. The mini CNC RDS has three modes: simulation, emulation, and implementation. In the simulation mode the student simulates the three linear axis and spindle system dynamic responses for a variety of command voltage signals. The student can specify the magnitude and frequency of square, triangle, and sinusoidal command voltage signals, or they can create their own command voltage signal. In this mode the student can check their dynamic model for obvious errors (e.g., instability). In the simulation mode the student can also simulate the equipment controllers and interpolators with their dynamic models. In this case, the command voltage signals are not specified. Rather, they are generated by the controllers based upon the reference signals sent from the interpolators and the simulated linear axis position and spindle velocity measurements from the dynamic models. In the emulation mode, the simulation is executed on the target computer to ensure timing requirements are met. In the implementation mode, the controllers and interpolators are executed on the real linear axis system, while the simulation is executed in parallel. Simulation and experimental data are gathered and compared. This paper describes the development of the mini CNC RDS.