An LMI-based machining logic fusion

This paper discusses the issues of robust machining process controller synthesis. In practical cases, operating conditions have strong effects on the process dynamics, and it is very difficult to use a fixed controller to achieve a satisfactory performance. Here, a fuzzy logic inference mechanism is introduced to adjust the controller according to the on-line measurements of operating variables which define the operating conditions or operating points of the processes, and a linear matrix inequality (LMI) based hybrid approach is developed to achieve robust properties against modelling errors, uncertainties, disturbances, and inaccuracy of on-line measurements. The simulation results of a design example (an end milling process control) shows that robust stability and satisfactory performance have been achieved.