Aiming at the efficiency and precision in micro electrical discharge machining (micro-EDM) is affected because the interpole voltage is unstable in conventional micro-EDM. This paper describes a five-degrees-of-freedom (5-DOF) controlled, wide-bandwidth, and high-precision magnetic levitation actuator. The conventional micro-EDM can install the actuator to maintain a stable interpole voltage between the electrode and workpiece to realize the high-speed micro-EDM. In this paper, the structure of the magnetic levitation actuator is designed, and the magnetic field characteristics are analyzed. On this basis, an integrator and regulator are used along with a controller with local current feedback to eliminate steady-state errors, stabilize the control system, and improve the bandwidth and positioning accuracy of the magnetic levitation actuator, and the dynamic performance of the actuator is evaluated. The experimental results show that the developed actuator has excellent positioning performance with micron-level positioning accuracy to meet the demand for the real-time, rapid, and accurate adjustment of the interpole gap during micro-EDM.

Electrical discharge machining (EDM) is not limited to the strength and hardness of conductive materials, and is a non-contact special processing technology. In micro-EDM, there are problems such as untimely axial positioning, unstable inter-electrode machining voltage, and difficulty in discharging inter-electrode electric erosion products. This paper considers a magnetic actuator with fast response and high accuracy as the local actuator for a micro-EDM. By introducing a domain adjustment mechanism, a variable domain fuzzy PID controller was designed to control the inter-electrode voltage control system of the magnetic actuator for micro-EDM using an intelligent control strategy. During the micro-EDM machining process, the controlled magnetic actuator drives the tool electrode in the axial direction for rapid micro-positioning, thus maintaining effective inter-electrode machining voltage and achieving a high-speed and high precision EDM. Simulation and experimental results showed that compared with traditional micro-EDM, the machining efficiency of the variable domain fuzzy PID control magnetic actuator, and traditional micro-EDM cooperative control, was increased by 40%, the machining process was more stable, and the quality of the machined surface was better.

The efficiency and accuracy of conventional electrical discharge machining (EDM) is limited by the stability of the voltage between the poles. To improve the efficiency of EDM, this paper proposes a machining method that combines a self-developed 5-degree-of-freedom (5-DOF) controllable magnetic levitation actuator with a conventional EDM machine tool. The stability of the inter-pole voltage is improved by the actuator micro-adjustment the electrodes of the EDM machine tool. Firstly, an EDM control system with local current feedback and decoupling control elements is designed based on the EDM servo drive principle to improve the response speed and positioning accuracy of the actuator. Secondly, the actuator was connected to the spindle of a conventional EDM machine tool, and machining experiments were carried out. The experimental results showed that the EDM machine tool connected to the actuator could control the electrode position more quickly, adjust the discharge state quickly, and increase the number of discharges per unit time. The average machining speed increased from 1.108µm/s to 3.925µm/s, which is 3.54 times faster than conventional EDM. Finally, complex shape machining experiments were carried out and the machining results showed that by adjusting the target value of the radial direction of the actuator, the various trajectories of the electrode could be controlled to depict arbitrary shapes.

In this paper, a novel permanent magnet magnetic levitation system is proposed. First, the structure and dimensions of this magnetic levitation system are designed, and determine the optimal combination of magnetic poles for the two permanent magnetic sticks. Second, the optimal rotation angles of the two permanent magnet sticks are determined for different positions of the iron ball, and the dynamics model of the magnetic levitation system is established. Then, the control system of the magnetic levitation system is designed using the LQR(Linear Quadratic Regulator) control method. Finally, the vertical levitation experiment of the iron ball was carried out, and the experimental results showed that the levitation position of the levitated iron ball changed as the rotation angles of the double permanent magnet sticks changed.