Matthias Scherrer, Erwin Hauser, Rudolf Scheidl,
"Simulation study of permanent magnetic actuation for a hydraulic valve with hysteresis response behavior"
: Proceedings of the 2020 ASME on Fluid Power and Motion Control FPMC2020 September 9-11, 2020, University of Bath, Bath, United Kingdom, 9-2020
Simulation study of permanent magnetic actuation for a hydraulic valve with hysteresis response behavior
Sprache des Titels:
Proceedings of the 2020 ASME on Fluid Power and Motion Control FPMC2020 September 9-11, 2020, University of Bath, Bath, United Kingdom
For the realization of compact and lightweight digital hydraulic
cylinder drives for exoskeleton actuation the hydraulic
binary counter concept was proposed. This counter principle is
based on hydraulically piloted switching valves which feature a
hysteretic response with respect to the pilot pressure. In first prototypes
of that counter bistable mechanical buckling beams realized
the hysteretic response. Their performance suffered from
high friction in the hinges and high local stresses. Furthermore,
they require tight manufacturing tolerances not only of themselves
but also of their bearing structure.
In this paper, the usage of permanent magnet concept to realize
the hysteresis function in an alternative way is studied. The
valve spool is made of a ferromagnetic material and is attracted
or repelled by a permanent magnet made of a Neodymium-Iron-
Bor. The expected benefits are lower friction, lower demands on
manufacturing tolerances, and an easier assembly of the valve.
To find an advantageous embodiment of this functioning principle
ring or disc shaped magnets of different sizes are analyzed.
The magnetic forces exhibited by these different magnetic circuit
designs are simulated with the Magnetic Finite Element code
?FEMM?. The quasi-static magnetic forces at different spool positions
are computed. Magnetic saturation and remanence are
considered in this analysis. The aim is to achieve the required
force on the piston and, thus, ensure the valve?s functionality. At
the same time, however, the valve should be designed as compact
and light as possible. The Finite element simulations are
compared with an analytical model which provides a compact
understanding of the influence of the design parameters on the
functional and non functional performance criteria.