Integrated Electromagnetic Actuator With Adaptable Zero Power Gravity Compensation

This article presents a novel integrated electromagnetic actuator with a position-independent zero power gravity compensation mechanism for variable masses. Gravity is actively compensated by a variable reluctance actuator with a seamlessly tunable electropermanent magnet. To counteract the negative stiffness of the variable reluctance actuator, Lorentz actuators are used to stabilize the position of a magnetically levitated mover in two DoFs. A local search algorithm tunes the electropermanent magnet, providing a variable force between 0 and 25 N. Experimental results demonstrate a reduction of the power consumption by at least four orders of magnitude in comparison to the purely Lorentz actuated system and a gravity compensation tuning rate of 2.6 N/s, verifying the utilization of the actuator for energy efficient positioning systems or vibration isolation systems with variable effective loads.