OPTIMAL CONTROL OF NONLINEAR MILLING TIME-DELAY SYSTEMS
Aiming at the time-delay phenomenon in milling process of milling cutter,in order to reduce chatter,the optimal control model of the time-delay system was established with the balance force applied by the actuator as the decision variable and the balance force and milling displacement as the performance index.Firstly,the unfixed terminal moment was transformed into fixed terminal moment by time scale transformation.Secondly,using the control parameter method,it was equivalent to the parameter optimization problem.Thirdly,using the costate method,the gradient of the performance index and constraint on the optimization variable was obtained.Finally,a SQP-based algorithm was established to solve the approximate optimization problem.
optimal controltime delaycontrol parameterizationmilling system