Controlling harmful milling vibration for robotic milling system based on the optimization of milling posture and spindle speed

Harmful machining vibration including milling chatter and resonance are easily generated during robotic milling process, and it seriously restrict the machining ability of the robot. To address this problem, a harmful machining vibration-controlled method based on the combined optimization of milling posture and spindle speed is proposed for robotic milling system in this paper. With this context, firstly, the robot stiffness model is established based on the theory of the multi-body with small-deformation, and the stiffness ellipsoid at the tool cutting point is used to optimize the milling posture, so that the structure stiffness of the robot can be enhanced; Then, the robot chatter stability model is constructed considering the modal coupling effect, and the spindle speed is optimized to restrain the milling chatter and resonance. Finally, with the optimized milling posture and spindle speed, the milling process is planned and performed with a Staubli TX-200 robot, and two experiments for workpiece with steel and aluminum are implemented to verify the proposed method. The experiment results demonstrate that the comprehensive optimization of milling posture and spindle speed can efficiently control the harmful machining vibration for the robotic milling system, thus, the machining quality of the workpiece can be improved.