An Antisaturating Adaptive Preaction and a Slide Surface to Achieve Soft Landing Control for Electromagnetic Actuators

Real-control applications of any nature can be affected by saturation limits that generate windup. When saturation occurs in a device its performance deteriorates. Electromagnetic actuators for industrial applications are being utilized ever more frequently for positioning and tracking control problems. One of the most important requirements in tracking trajectories is to achieve a soft landing, which guarantees reliable functionality and a longer component life. This paper presents an application of a typical electromagnetic actuator through a hardware-in-the-loop structure in which a soft landing is required in the tracking trajectory. To avoid saturation, which prevents soft landings, a specific new control law is developed. The proposed technique is based on a cyclic adaptive current preaction combined with a sliding surface. The technique consists of building a control law so that the position of the valve at which its velocity assumes its minimum is as close as possible to the landing point. At this time point, the magnetic force compensates for the elastic force and the preaction component is switched off. An experimental setup using a hardware-in-the-loop to allow a pilot investigation, model validation, and testing before implementation is considered. Real measurements of the proposed method are shown.