Development of a 2-DOF Controlled Magnetic Drive Actuator for Laser Beam Cutting

Abstract

Laser beam cutting (LBC) is a non-contact machining method that is widely used in industry. In order to improve cutting speed and reduce the consumption of assist gas, it is necessary to employ a machining method that applies a suitable eccentricity between the laser beam axis and the assist gas nozzle axis. This paper describes the development of a high-speed, high-precision, magnetic drive actuator, which can be attached to a conventional LBC machine to control the relative displacement between the laser beam axis and the assist gas nozzle axis in two orthogonal directions. First, a magnetic drive actuator is designed and fabricated. In the actuator, the motions of the lens in the radial directions are controlled by electromagnets, and the motions in the other directions are constrained by elastic hinges. Second, a compensation method for the zero point of the displacement sensors that are used to measure the displacements of the lens in the radial direction and an adaptive control method for the actuator are presented. Finally, the effectiveness of the presented control method is verified, and the positioning performance of the actuator is evaluated through experiments. The experimental results showed that the vibration of the lens was reduced using the presented control method, and the actuator had a positioning resolution of 0.75 µm, a bandwidth greater than 133 Hz, and a positioning stroke of 1 mm.

Improvement in Position Response of Laser Focus Controlled Magnetic Actuator Based on Mixed Sensitivity Robust Control

“…Electromagnetic drive technology has the characteristics of a simple structure, compact structure, and no need for lubrication [20][21][22][23][24][25][26], which can meet the needs of non-coaxial laser cutting actuators. Zhang X. et al designed a high-speed, high-precision electromagnetic actuator that can be connected with traditional laser cutting machine tools to control the relative position of the laser beam's axis and the auxiliary gas's axis [27]. He D. et al proposed a 6-DOF (degrees of freedom) magnetically levitated lens-driven actuator for off-axis laser cutting control [28,29].…”

Improvement of EDM Machining Speed by Using Magnetic/Piezoelectric Hybrid Drive Actuator

“…As the local actuators, a piezoelectric actuator [2], a voice coil motor [3], and a magnetic bearing [4] have been used to improve the positioning response of the electrode.…”