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.

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 example actuator control system includes a variable differential transformer (VDT) configured to measure displacement of a motor, and a motor controller configured to control the motor based on displacement data from the VDT. A circuit card assembly (CCA) interconnects the VDT to the motor controller. The CCA includes memory storing configuration data of the VDT, and the CCA is configured to provide the configuration data to the motor controller to calibrate the motor controller for use of the VDT. A method of configuring a motor controller is also disclosed.

An example actuator control system includes a variable differential transformer (VDT) configured to measure displacement of a motor, and a motor controller configured to control the motor based on displacement data from the VDT. A circuit card assembly (CCA) interconnects the VDT to the motor controller. The CCA includes memory storing configuration data of the VDT, and the CCA is configured to provide the configuration data to the motor controller to calibrate the motor controller for use of the VDT. A method of configuring a motor controller is also disclosed.

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.

A displacement device includes a stator having non-parallel stator-x and stator-y elongated traces. The device also 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 includes a first pair of adjacent first magnetization segments made up of 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.

A displacement device comprises a stator comprising non-parallel stator-x and stator-y elongated traces. The device comprises a moveable stage comprising a first magnet array comprising 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 comprises a first pair of adjacent first magnetization segments comprising 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.

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.