The disclosure relates to a drug delivery device having a drive unit includes a stator comprising a plurality of coils consecutively arranged in an axial direction, and an armature axially movable within the stator, the armature including a number of magnets and pole shoes consecutively arranged in the axial direction. A respective pole shoe is arranged between respectively neighbouring magnets. At least one axial end of the armature comprises a terminal pole shoe.

The disclosure relates to a drug delivery device having a drive unit includes a stator comprising a plurality of coils consecutively arranged in an axial direction, and an armature axially movable within the stator, the armature including a number of magnets and pole shoes consecutively arranged in the axial direction. A respective pole shoe is arranged between respectively neighbouring magnets. At least one axial end of the armature comprises a terminal pole shoe.

An X-Y movable stage with rotation is described. A fixed base comprises a magnetic bed with a checkerboard, hexagonal or pseudo-random pattern of alternating north and south poles on a grid. A movable puck moves and rotates on the base. The puck comprises three or more nodes where each node may be energized for a north, south, or off magnetic field, with varying field strength. Methods of mapping node locations, controllers, and applications are described. Embodiments for specific applications are described.

An X-Y movable stage with rotation is described. A fixed base comprises a magnetic bed with a checkerboard, hexagonal or pseudo-random pattern of alternating north and south poles on a grid. A movable puck moves and rotates on the base. The puck comprises three or more nodes where each node may be energized for a north, south, or off magnetic field, with varying field strength. Methods of mapping node locations, controllers, and applications are described. Embodiments for specific applications are described.

An X-Y movable stage with rotation and tilt is described. A fixed base comprises a magnetic bed with a checkerboard, hexagonal or pseudo-random pattern of alternating north and south poles on a grid. A movable puck moves, rotates and tilts on the base. The base and puck system is free of any other moving parts. The puck comprises three or more nodes where each node may be energized for a north, south, or off magnetic field, with varying field strength. Embodiments include use in a vacuum or fluid. Light from the base to the puck may be used to charge or power a puck. Methods of mapping node locations, controllers, and applications are described. Embodiments for specific applications are described.

An X-Y movable stage with rotation and tilt is described. A fixed base comprises a magnetic bed with a checkerboard, hexagonal or pseudo-random pattern of alternating north and south poles on a grid. A movable puck moves, rotates and tilts on the base. The base and puck system is free of any other moving parts. The puck comprises three or more nodes where each node may be energized for a north, south, or off magnetic field, with varying field strength. Embodiments include use in a vacuum or fluid. Light from the base to the puck may be used to charge or power a puck. Methods of mapping node locations, controllers, and applications are described. Embodiments for specific applications are described.

A displacement device includes a stator having non-parallel stator-x and stator-y elongated traces. The device includes a moveable stage having a first magnet array with first magnetization segments linearly elongated in a stage-x direction and having magnetization directions generally orthogonal to the stage-x direction. The first magnet array incorporates a first pair of adjacent first magnetization segments having two first magnetization segments adjacent to one another in a stage-y direction non-parallel to the stage-x direction. Each first magnetization segment in the first pair has a corresponding magnetization direction oriented at a corresponding angle .sub.n about a corresponding stage-x axis as measured from a positive stage-z direction that is generally orthogonal to both the stator-x and stator-y directions. The corresponding angle .sub.n is one of 45+n90 where n is any integer. Each first magnetization segment in the first pair has a different magnetization direction.

Provided is a linear motor control apparatus capable of improving estimation accuracy of a resonance frequency immediately after start, and a compressor equipped with the linear motor control apparatus. A linear motor control apparatus includes a winding to which an AC voltage is applied and a mover which is connected to an elastic body, in which the linear motor control apparatus includes an operation mode (1) which monotonously increases amplitude of the AC voltage while keeping a frequency of the AC voltage substantially constant, and an operation mode (2) which changes the frequency of the AC voltage while keeping the amplitude of the AC voltage substantially constant, and executes the operation mode (1) and the operation mode (2) in this order.

Provided is a linear motor control apparatus capable of improving estimation accuracy of a resonance frequency immediately after start, and a compressor equipped with the linear motor control apparatus. A linear motor control apparatus includes a winding to which an AC voltage is applied and a mover which is connected to an elastic body, in which the linear motor control apparatus includes an operation mode (1) which monotonously increases amplitude of the AC voltage while keeping a frequency of the AC voltage substantially constant, and an operation mode (2) which changes the frequency of the AC voltage while keeping the amplitude of the AC voltage substantially constant, and executes the operation mode (1) and the operation mode (2) in this order.

The disclosure relates to a drug delivery device having a drive unit includes a stator comprising a plurality of coils consecutively arranged in an axial direction, and an armature axially movable within the stator, the armature including a number of magnets and pole shoes consecutively arranged in the axial direction. A respective pole shoe is arranged between respectively neighbouring magnets. At least one axial end of the armature comprises a terminal pole shoe.