Abstract
In this study, an advance method for enhancing chatter stability in robotic arm milling systems is proposed and validated numerically. A dynamic model incorporating both rigid–flexible coupling and time-delay effects is developed by means of a parameterized delay differential equation. Stability boundaries under fixed control parameters and specific postures of the robotic arm are initially determined using a full-discretization approach. To further enlarge the stable operating region, the control parameters and postures of the robotic arm are optimized simultaneously by maximizing the spectral radius of the state transition matrix through a tracking-based particle swarm optimization algorithm. As a result, the optimized stability boundaries are demonstrated to enclose and significantly extend the original boundaries. To validate the proposed strategy, time-domain nonlinear simulations are carried out at representative cutting conditions, where chatter is shown to be effectively eliminated and the tool-tip vibrations are significantly reduced. It is demonstrated that an unstable chatter regime can be converted into a stable periodic vibration state by the optimized parameters, but does not always guarantee a reduction in vibration amplitude, especially at large cutting depths. This work suggests that greater machining accuracy and increased material removal rates can be achieved through the parameter optimization strategy presented herein.
Get full access to this article
View all access options for this article.