System and method to control a rotary-linear actuator

An integrated rotary-linear actuator system, comprising:

• a plunger movable along and rotatable about a longitudinal axis extending through the plunger, the plunger is supported against a motor support via bearings, the plunger comprises an array of magnets arranged on one of an outside surface of the plunger and an inside surface of the motor support, which supports the plunger to permit movement thereof;
• a coil system having two sets of coils arranged to, when energized, interact with the plunger, the first set of coils being operative to provide an electric field to effect movement of the plunger in a linear mode, the second set of coils being operative to effect movement of the plunger in a rotational mode;
• an amplifier coupled to the coils and operative to provide electrical energy to energize the coils;
• and
• a thin sheet carrying an encoder scale affixed to a surface of the array of magnets, the encoder scale is etched with a pattern of reflective and non-reflective regions that are scanned by optical pickups to register movement of the plunger, wherein the optical pickups project light at and sense reflected light from an elongated detection region, such that when the plunger moves successive columns of reflective and non-reflective patches pass through the detected area and are averaged.

A method for controlling an integrated rotary-linear actuator system, comprising:

• providing a plunger movable along and rotatable about a longitudinal axis extending through the plunger, the plunger comprises an array of magnets arranged on one of an outside surface of the plunger and an inside surface of the motor support, which supports the plunger to permit movement thereof;
• controlling an amplifier to selectively energize two sets of coils to interact with the plunger, such that the plunger, which is moveable linearly and rotationally about a longitudinal axis thereof, moves in at least one of a linear and rotational direction, the linear direction in response to the energization of a first set of coils, and the rotational direction in response to the energization of a second set of coils;
• and
• affixing a thin sheet carrying an encoder scale to a surface of the array of magnets, the encoder scale is etched with a pattern of reflective and non-reflective regions that are scanned by optical pickups to register movement of the plunger, wherein the optical pickups project light at and sense reflected light from an elongated detection region, such that when the plunger moves successive columns of reflective and non-reflective patches pass through the detected area and are averaged.

An integrated rotary-linear actuator system, comprising:

• means for supporting a plurality of motors including means for supporting a bearing, the means for supporting the plurality of motors and the means for supporting the bearing defining a well;
• means for providing a plunger movable along and rotatable about a longitudinal axis extending through the plunger, the plunger is supported against a motor support via the bearings, the plunger comprises an array of magnets arranged on one of an outside surface of the plunger and an inside surface of the motor support, which supports the plunger to permit movement thereof;
• means for controlling an amplifier to selectively energize two sets of coils to interact with the plunger, such that the plunger, which is moveable linearly and rotationally about a longitudinal axis thereof, moves in at least one of a linear and rotational direction, the linear direction in response to the energization of a first set of coils, and the rotational direction in response to the energization of a second set of coils;
• means for affixing a thin sheet carrying an encoder scale to a surface of the array of magnets, the encoder scale is etched with a pattern of reflective and non-reflective regions that are scanned by optical pickups to register movement of the plunger, wherein the optical pickups project light at and sense reflected light from an elongated detection region, such that when the plunger moves successive columns of reflective and non-reflective patches pass through the detected area and are averaged;
• and
• means for restricting extension and retraction of the plunger beyond selected levels that might damage the actuator.