A seat-damping device for damping vibrations transmitted to a seat of a vehicle, the seat-damping device comprising: a housing having an interior, an upper interior chamber, and a lower interior chamber; a piston shaft that extends into the interior of the housing; a piston head disposed within the interior of the housing for axial displacement within the housing, wherein the piston head subdivides the housing to define the upper interior chamber and the lower interior chamber on opposing sides of the piston head, the piston head comprising: a top pole disposed within the interior of the housing, on a same side of the piston head as the upper interior chamber; a bottom pole disposed within the interior of the housing, on a same side of the piston head as the lower interior chamber; at least one permanent magnet, which is configured to generate a permanent magnetic field and is a disk magnet attached to the bottom pole; and at least one coil, which is disposed adjacent to, and circumferentially about, the top pole and is configured to generate a current-induced magnetic field proportional to a magnitude of an electrical current supplied to the coil, a polarity of the current-induced magnetic field being based upon a direction of the electrical current; and a magnetorheological fluid disposed within and filling substantially all of the upper and lower interior chambers (202A, 202B) of the housing, wherein the MR fluid is movable between the upper and lower interior chambers (202A, 202B) upon the axial displacement of the piston head within the housing, wherein the MR fluid has a predetermined magnetically responsive property, and wherein a state of the predetermined magnetically responsive property of the MR fluid is selectively adjustable by subjecting the MR fluid to a net magnetic field, which is defined as a sum of the current-induced magnetic field and the permanent magnetic field, and wherein the seat-damping device is configured to generate a damping force proportional to the net magnetic field. a housing having an interior, an upper interior chamber, and a lower interior chamber; a piston shaft that extends into the interior of the housing; a piston head disposed within the interior of the housing for axial displacement within the housing, wherein the piston head subdivides the housing to define the upper interior chamber and the lower interior chamber on opposing sides of the piston head, the piston head comprising: a top pole disposed within the interior of the housing, on a same side of the piston head as the upper interior chamber; a bottom pole disposed within the interior of the housing, on a same side of the piston head as the lower interior chamber; at least one permanent magnet, which is configured to generate a permanent magnetic field and is a disk magnet attached to the bottom pole; and at least one coil, which is disposed adjacent to, and circumferentially about, the top pole and is configured to generate a current-induced magnetic field proportional to a magnitude of an electrical current supplied to the coil, a polarity of the current-induced magnetic field being based upon a direction of the electrical current; and a top pole disposed within the interior of the housing, on a same side of the piston head as the upper interior chamber; a bottom pole disposed within the interior of the housing, on a same side of the piston head as the lower interior chamber; at least one permanent magnet, which is configured to generate a permanent magnetic field and is a disk magnet attached to the bottom pole; and at least one coil, which is disposed adjacent to, and circumferentially about, the top pole and is configured to generate a current-induced magnetic field proportional to a magnitude of an electrical current supplied to the coil, a polarity of the current-induced magnetic field being based upon a direction of the electrical current; and a magnetorheological fluid disposed within and filling substantially all of the upper and lower interior chambers (202A, 202B) of the housing, wherein the MR fluid is movable between the upper and lower interior chambers (202A, 202B) upon the axial displacement of the piston head within the housing, wherein the MR fluid has a predetermined magnetically responsive property, and wherein a state of the predetermined magnetically responsive property of the MR fluid is selectively adjustable by subjecting the MR fluid to a net magnetic field, which is defined as a sum of the current-induced magnetic field and the permanent magnetic field, and wherein the seat-damping device is configured to generate a damping force proportional to the net magnetic field.