Abstract : This paper analyzes the control structure of a non-circular section machining system with a high-frequency servo tool post directly driven by a linear motor as its core. Starting from the small gain theorem, the relationship between the maximum dynamic flexibility of the servo tool post and the system stability is explained. The influence of single-loop speed control and dual-loop speed-position control on performance is analyzed. In the design of the dual-loop controller, H-control theory is applied, comprehensively considering factors such as tracking performance, dynamic flexibility, and control energy. The designed controller shows significant improvement over traditional lead-lag networks. Keywords : Controller; H-control; Servo; Flexibility 1 Introduction In recent years, research on machining using direct linear motor drive has flourished. It is widely used in applications requiring high-speed reciprocating motion, such as piston non-circular turning. Direct linear motor drive overcomes many shortcomings of traditional "rotary motor-nut/screw" type drives, such as backlash, large friction, and large inertia, thereby improving machining speed and accuracy. However, direct-drive tools and the cutting process have strong dynamic feedback, causing tool chatter and leaving chatter marks on the workpiece surface, thus reducing the surface quality of the workpiece and, in severe cases, even damaging the workpiece or tool. Without servo feedback control, direct drive lacks sufficient stiffness to avoid tool chatter. Therefore, in order to apply high-speed, high-response linear motor direct drive to actual cutting processes, the servo control system must achieve the highest possible tracking performance and, at the same time, maximize its dynamic stiffness to reduce the impact of cutting force interference on tool positioning. [b][align=center]For more details, please click: Research on Servo Tool Post Controller for Direct-Driven Linear Motors[/align][/b]