A controllable rotary brake includes two non-magnetically permeable isolating rings, a shaft, an even number of magnetic field generating portions, at least one resistance disc, and at least one magneto-rheological fluid layer. The non-magnetically permeable isolating rings are spaced apart from each other in an axial direction, and each has a bottom wall. An even number of penetrating holes are formed on the bottom wall. The shaft is rotatably inserted in and adapted to pivot relative to the non-magnetically permeable isolating rings. Two ends of each magnetic field generating portion are tightly fitted to the corresponding penetrating holes. The resistance disc is sleeved on the shaft and is spaced apart from one of the non-magnetically permeable isolating rings. The magneto-rheological fluid layer fills between the resistance disc and one of the non-magnetically permeable isolating rings and contacts the resistance disc and one end of each magnetic field generating portion.

Provided are a reliable high-voltage system and a failure diagnosis method thereof, in which a vibration damping mechanism using an electrorheological fluid as a working fluid is a load, and can prevent electric shock due to leakage current and the influence on surrounding electronic devices. There are provided a first circuit that includes a power source and a ground, a second circuit that is magnetically coupled to the first circuit via a transformer and includes a load connected to the ground, a controller that is connected to the ground, a third circuit that is connected to the second circuit and the ground, a first resistor that is provided between a connection point at a high potential end of the second circuit and the ground, and a second resistor that is provided between a connection point at a low potential end of the second circuit and the ground, and has a resistance value different from a resistance value of the first resistor.

A magnetorheological damper, wherein the damper comprises a housing that is at least partially filed with a magnetorheological fluid, and a magnetorheological valve disposed within the housing. The valve includes a magnetically permeable core having at least one coil reservoir formed therein, and at least one conductor coil, wherein each conductor coil is disposed around a portion of the core within a respective one of the coil reservoir(s). The valve additionally includes a fluid flow path adjacent the conductor coil(s). The fluid flow path is structured and operable to allow the magnetorheological fluid to flow adjacent the conductor coil(s). The valve further includes at least one coil cover, wherein each coil cover is disposed over a respective one of the coil(s) such that the respective coil is protected from exposure to magnetorheological fluid flowing through the fluid flow path.

Provided are an electroviscous fluid exhibiting a high ER effect and having sufficient durability, and a cylinder device. An electroviscous fluid of the present invention includes a fluid and polyurethane particles containing metal ions. The polyurethane particles have a phase separation structure of a hard segment and a soft segment, and contain an additive increasing a urethane bond forming the hard segment.

A magnetorheological apparatus includes a flexible body formed of an elastomer material, a plurality of cell cavities defined by the flexible body, a magnetorheological (MR) fluid disposed within each cell cavity of the plurality of cell cavities, and a magnetic field inductor positioned adjacent to at least one of the cell cavities. Each cell cavity of the plurality of cell cavities is fluidly encapsulated within the flexible body. The magnetic field inductor is selectively operable to vary a magnetic field, and the MR fluid within the at least one cell cavity is configured to vary a stiffness of the at least one cell cavity in response to the magnetic field.

A method for controlling an elastic mount configured to support a propulsion device with respect to a marine vessel, wherein the elastic mount contains an electromagnetic fluid and an electromagnet and is configured such that adjusting an amount of electricity applied to the electromagnet changes a shear strength of the electromagnetic fluid in the elastic mount and thereby controls an elasticity of the elastic mount. The method includes applying a first amount of electricity to the electromagnet to produce an initial elasticity of the elastic mount measuring an oscillation of the propulsion device with a motion sensor, determining that the oscillation of the propulsion device exceeds a threshold oscillation, and adjusting the amount of electricity applied to the electromagnet to change the elasticity of the elastic mount to reduce the oscillation.

A head unit device for controlling motion of an object includes shear thickening fluid (STF), an alternative STF (ASTF), and a chamber configured to contain a portion of the STF and the ASTF. The chamber further includes a piston compartment and an alternative reservoir. The head unit device further includes a reservoir injector configured within the chamber, and a piston housed at least partially radially within the piston compartment. The chamber further includes a set of fluid flow sensors and a set of fluid manipulation emitters to control the reservoir injector to adjust flow of the ASTF from the alternative reservoir to the piston compartment to cause selection of one of a variety of shear rates for a mixture of the STF and the STF within the piston compartment.

A head unit device for controlling motion of an object includes shear thickening fluid (STF), an alternative STF (ASTF), and a chamber configured to contain a portion of the STF and the ASTF. The chamber further includes a piston compartment and an alternative reservoir. The head unit device further includes a reservoir injector configured within the chamber, and a piston housed at least partially radially within the piston compartment. The chamber further includes a set of fluid flow sensors and a set of fluid manipulation emitters to control the reservoir injector to adjust flow of the ASTF from the alternative reservoir to the piston compartment to cause selection of one of a variety of shear rates for a mixture of the STF and the STF within the piston compartment.

An object of the present invention is to provide a torsion damper excellent in dynamic damping effect even when a vibration frequency fluctuates. A craft damper (torsion damper) of the present invention includes a crankshaft (shaft member) to be input with a torsion vibration, a disc member coaxially attached to the crankshaft, a ring-shaped inertia mass body connected to an outer peripheral side of the disc member via a magneto-rheological elastomer member so as to be coaxial with the crankshaft, and an electromagnetic coil for applying a magnetic field to the magneto-rheological elastomer member.

An object of the present invention is to provide a torsion damper excellent in dynamic damping effect even when a vibration frequency fluctuates. A craft damper (torsion damper) of the present invention includes a crankshaft (shaft member) to be input with a torsion vibration, a disc member coaxially attached to the crankshaft, a ring-shaped inertia mass body connected to an outer peripheral side of the disc member via a magneto-rheological elastomer member so as to be coaxial with the crankshaft, and an electromagnetic coil for applying a magnetic field to the magneto-rheological elastomer member.