Optimal control for chatter mitigation in milling—Part 1: Modeling and control design

• Prototype spindle with integrated active system is used for chatter mitigation.
• Active structural controls for chatter suppression are divided into two approaches.
• Behavior of mechatronic structure coupled with milling process is modeled.
• Optimal control theory is used for formulation of both approaches.
• Both approaches are compared with simulation.

Active structural methods constitute a promising way to mitigate chatter vibrations in milling. This paper presents an active system integrated into a spindle unit. Two different optimal control strategies are investigated. The first one only considers the dynamics of the machine structure in the controller design and minimizes the influence of cutting forces on tool tip deviations. The second one takes explicitly the process interaction into account and attempts to guarantee the stability of the overall closed-loop system for specific machining conditions. The modeling and formulation used for both strategies are presented in this first part. A simulation allows the comparison of their respective working principle. The validation of the proposed concept in experimental conditions is described in the second part.