Abstract: A linear electromagnetic machine for generating a force acting between two members relatively movable along an axis, one of which is capable of producing a magnetic field the direction of at least part of which extends substantially radially of the said axis and the other of which comprises or includes a conductor, conveniently in the form of a coil, in which an electric current can flow substantially perpendicularly of the magnetic field so as to generate a force between the two members substantially parallel to the axis. The radial magnetic field is generated by permanent magnets orientated with their direction of magnetization axially, the pole pieces acting to concentrate the magnetic flux to follow a radial path through the coils.

Abstract: A linear electromagnetic machine for generating a force acting between two members relatively movable along an axis, one of which is capable of producing a magnetic field the direction of at least part of which extends substantially radially of the said axis and the other of which comprises or includes a conductor, conveniently in the form of a coil, in which an electric current can flow substantially perpendicularly of the magnetic field so as to generate a force between the two members substantially parallel to the axis. The radial magnetic field is generated by permanent magnets orientated with their direction of magnetisation axially, the pole pieces acting to concentrate the magnetic flux to follow a radial path through the coils.

Abstract: An apparatus for imparting motion to a load comprises means for applying a force to the load and a compliant support for the load, in which there are provided means for effecting dynamic variation of the compliance of the support during operation of the apparatus so as to optimise the power efficiency. The apparatus may be capable of controlling relative motion in a plurality of degrees of freedom between a platform and a reference plane, the compliant means acting to support the weight of the platform, and the force-applying means being one or more actuators for applying perturbing forces between the platform and the reference plane. Control means act to control one or more actuators to move in one direction or the other to displace the platform with respect to the reference plane. At least part of the compliant supports may be a gas spring and in one embodiment this is in the form of a bellows supporting the platform.

Abstract: Electromagnetic apparatus for producing an axially directed force comprising a stator having a plurality of axially spaced coils around a working volume within which an armature in the form of a free piston is axially displaceable, the armature having means for producing a magnetic field a substantially radially directed part of which intersects at least some of the coils of the stator such that a resultant axially directed force is generated when a current flows in the coils.

Abstract: Sealed telescoping tubes are electromagnetically and fluidly actuated to provide linear motion and withstand loading. One of the tubes may be connected to a pressure or vacuum source, and the other sealed to a fixture to provide variable volume load augmentation in addition to electromagnetic actuation. Alternatively, both tubes may be sealed to provide a pneumatic or hydraulic spring with electromagnetic actuation, and the sealed tubes may also be connected to a pressure or vacuum source for load augmentation. A bearing may be used in conjunction with the seal between the tubes to provide resistance to traversal loads. The electromagnetic actuation includes a helical arrangement of coils or permanent magnets to provide linear motion or resistance. The coils can be arranged to be connected to a conventional multi-phase motor drive.