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 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. The nodes are arranged on an X-Y motion grid on the puck that are rotated 45° from the magnetic base grid. A first set of node locations on the puck may be each centered between a pair of opposite poles on the magnetic base. One arrangement of nodes is at the corners of a rectangle aligned with the motion grid. An optional second set of one node locations on the puck may be each centered between a pair of opposite poles on the magnetic base, when the first set of nodes is aligned over poles. Methods of mapping node locations, controllers, and applications are described.

An X-Y movable stage with rotation is described. A fixed base comprises a magnetic bed with a checkerboard 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. The nodes are arranged on an X-Y motion grid on the puck that are rotated 45° from the magnetic base grid. A first set of node locations on the puck may be each centered between a pair of opposite poles on the magnetic base. One arrangement of nodes is at the corners of a rectangle aligned with the motion grid. An optional second set of one node locations on the puck may be each centered between a pair of opposite poles on the magnetic base, when the first set of nodes is aligned over poles. Methods of mapping node locations, controllers, and applications are described.

A linear motion control device for use in a linear control system is presented. The linear motion control device includes a coil driver to drive a coil that, when driven, effects a linear movement by a motion device having a magnet. The linear motion control device also includes a magnetic field sensor to detect a magnetic field associated with the linear movement and an interface to connect an output of the magnetic field sensor and an input of the coil driver to an external controller. The interface includes a feedback loop to relate the magnetic field sensor output signal to the coil driver input.

A stepping motor includes a rotor, a stator and three coils. The rotor is two-pole magnetized in a radius direction. The stator is provided with a rotor receiving section for receiving the rotor. The three coils are magnetically connected with the stator. At least one of the three coils is an integrated coil which is integrally formed with the stator by winding a coil around a part of the stator.

A stepping motor includes a rotor, a stator and three coils. The rotor is two-pole magnetized in a radius direction. The stator is provided with a rotor receiving section for receiving the rotor. The three coils are magnetically connected with the stator. At least one of the three coils is an integrated coil which is integrally formed with the stator by winding a coil around a part of the stator.

Aspects of the invention provide methods and systems for moving a plurality of moveable stages relative to a stator. The stator comprises a plurality of coils shaped to provide pluralities of coil trace groups where each coil trace group comprises a corresponding plurality of generally linearly elongated coil traces which extend across a stator tile. Each moveable stage comprises a plurality of magnet arrays. Methods and apparatus are provided for moving the moveable stages relative to the stator, where a magnet array from a first moveable stage and a magnet array from a second moveable stage both overlap a shared group of coil traces. For at least a portion of the time that the magnet arrays from the first and second moveable stages overlap the shared group of coil traces, currents are controllably driven in the shared coil trace group based on the positions of both the first and second moveable stages. The positions of the first and second moveable stages may be ascertained by feedback.

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.