Adaptive Control of a Gantry System
Computer numerical control (CNC) machines used in automated manufacturing are indeed mechatronic systems. Control plays a crucial role in their operation. This chapter presents a comprehensive virtual simulation model of a realistic and modular CNC system. The Virtual CNC architecture represents an actual CNC, but with modular feed drives, sensors, motors, and amplifiers. The CNC software library includes a variety of trajectory interpolation and axis control laws. Constant, trapezoidal, and cubic acceleration profiles can be selected as a trajectory generation module. The control laws can be selected ranging from a simple proportional-integral-derivative (PID) to complex pole placement, generalized predictive control, or sliding mode control with friction compensation. When the Virtual CNC is assembled, its performance can be tested using frequency- and time-domain response analyses, which are automated. The Virtual CNC includes both analytical tuning methods for linear controllers, as well as fuzzy logic–based expert auto-tuning system for adaptive sliding mode control. Tool-path and feed-rate optimization strategies have also been implemented for accurate high-speed cornering applications. The chapter includes detailed experimental verification of the developed algorithms.