Magnetorheological damper–based positioning system with power generation

Abstract

This study investigates a newly developed positioning system based on a rotary magnetorheological damper with power generation capability, comprising an electromagnetic power generator (energy extractor) generating electrical power, an magnetorheological damper which alters the damping characteristics of the system and an electrical interface, connected in between the coil of the generator and the damper control coil, which conditions the voltage output from the generator. Structural configurations of the damper and the generator are outlined, and the results of their testing and the testing done on the entire system are summarised, covering the tests conducted with and without the interface, under the idle run and under load in the assumed velocity range. The objective of the work is to examine the performance of the proposed positioning system through experiments. Results of the system testing in the uncontrolled case (passive system) and in the controlled one (semi-active system) in a purpose-built test rig are compared and discussed. Three design options of the electrical system controlling the damper are explored. In the first option, the damper is assumed to be controlled starting from the initial moment of the motor shaft’s motion, and in the second option, the control action begins at the instant when the motor shaft assumes the present position. The third variant is similar to the first one except that an additional condenser is connected behind the Graetz bridge. The results confirm the adequacy of the developed positioning system and demonstrate an improvement in control of the system’s dynamic behaviour.

Investigation of Velocity Sensing in Harvesters for Magnetorheological Dampers

“…For example, Jung et al 2010 studying a sensing capability of the harvester incorporated in the MR damper-based vibration control system showed that a harvester could well serve as a velocity sensor for common control methods in such systems. The present study recalls former works of the first author investigating energy harvesting MR dampers (Sapiński 2008, Sapiński 2014), exploring their applications in vibration reduction systems (Sapiński et al 2016) and in positioning systems (Sapiński et al 2018). The objective of the work is to demonstrate ability of the considered magnetic harvesters to act as velocity sensors.…”

Advanced Prototype of an Electrical Control Unit for an MR Damper Powered by Energy Harvested from Vibrations

“…The experiments were carried out with excitation z with an amplitude A = 3.5 mm and frequency f changed from 2 Hz to 10 Hz with a 0.1 Hz step. In each experiment lasting 20 s, three time intervals were distinguished: increasing the amplitude (0, 5) s, maintaining a constant amplitude (5, 15) s, and reducing the amplitude (15,20) s. The results of experiments performed at a constant amplitude of excitation z are shown in Figures 11 and 12. The plots in Figure 11 show the powers generated by the harvester P h , supplied to the MR damper control coil P d , and consumed by the ECU P el vs. frequency f. The power values P h , P d , and P el were calculated according to the Equations ( 3)- (5).…”

“…The study [19] reports an H-bridge Graetz rectifier with a smoothing capacitor to convert AC current generated in a resonant electromagnetic vibration harvester into DC current supplying resistance load. The work [20] demonstrates a measurement and control unit with an H-bridge Graetz rectifier for conditioning the energy recovered from an object's oscillations in an MR rotary damper-based positioning system.…”

Innovative variable stiffness and variable damping magnetorheological actuation system for robotic arm positioning

“…Tomori et al (2013) developed a one-degree-of-freedom manipulator using an artificial muscle and an MR brake to control the vibration and overshoot of the manipulator. Sapin´ski et al (2018) reported a magnetorheological damper-based positioning system. The overshoot and settling time of the system were reduced by the controlling of an MR damper.…”