Research on two-dimensional external magnetic drive method of maglev ball based on force imbalance

Abstract

In this paper, an external magnetic driving method of a maglev ball based on force imbalance is first proposed to meet the requirement that the maglev ball is moved linearly in the axis direction of the electromagnetic actuator in the non-liquid environment. This method is expected to be better applied in the fields of industrial and medical miniature curved tube. The maglev ball is a magnetic levitated object. Based on the interpolation algorithm, the two-dimensional stepwise levitation motion trajectory of the maglev ball is designed as the target curve of the motion. The maglev ball can be driven with a large range along a specified motion path. Compared with the 1.0 mm step input, the overshoot of a 0.2 mm step input is decreased by 73.7% and 73.6% in the descending phase and the ascending phase, respectively. Therefore, fluctuation of the step response of the maglev ball is improved by smaller step control. However, the larger the step input, the faster the speed and the larger the levitation gap. Under the condition of a 1.0 mm step input, the maximum levitation gap can be up to 20.487 mm, and the speed of the maglev ball can reach 3.086 mm/s. Compared with static levitation control, the position of the maglev ball is fluctuated severely due to radial runout under motion control conditions, and the position accuracy can reach ±0.03 mm.

Close-Loop Current Control With Current-Sensing Resistor for Electromagnet Driven by Full-Bridge PWM Inverter

“…The full-bridge pulse-width-modulation (PWM) inverter is wildly applied to drive the electromagnet and enables advanced technologies, such as the active magnetic bearing (AMB) [1] and the permanent-electro magnetic suspension (PEMS) [2]. AMB is famous for no contact and eliminates unwanted friction and lubrication so that AMB significantly promotes the high-speed rotating machinery [3].…”