Control System Design of Inertial Moment Actuator using Gyroscopic Spindle for Robotic Machining

Abstract

This study presents the controller design procedure and method for inertial moment actuator suppressing robot vibrations during machining. The gyroscopic spindle actuator was introduced for vibration suppression in robotic machining and the experimental validation demonstrated significant suppression of low-frequency vibrations alongside reductions in higher-frequency structural vibrations in our previous work. The actuator utilizes a rotating flywheel, driven by an air-pressure turbine, to generate stabilizing gyroscopic moments, enhancing machining precision and stability. Key design features include a lightweight structure, a wireless optical angular speed sensor, and an electro-pneumatic proportional valve for flywheel speed control. In this work firstly the formulating equation procedures for geometric relation among motor driving axes, actuator axes and machining head axes are presented. And the procedures for formulating proposed controller structure are shown with considering dynamic working principle and some assumptions. For control stability and efficiency a band-pass filter was adopted and the procedure for formulating discrete time filter equation is shown. And in order to tune the controller gain an experimentally tuning method is presented with considering dynamic relations. Experimental validation confirmed substantial attenuation of low-frequency vibrations, with the most pronounced reduction observed near 6 Hz, together with clear suppression of higher-frequency structural modes. These outcomes indicate that the proposed actuator improves machining stability and surface finish while maintaining robust and reliable performance. The results demonstrate the effectiveness of the gyroscopic spindle actuator in mitigating vibration-induced limitations in robotic machining and provide a practical foundation for further advances in robotic manufacturing systems.