An actuator having an output slidable between extended and retracted positions is provided. The actuator includes a primary module having a power drive, power screw rotatable by the power drive, and a nut operable to translate rotation of the power screw to linear motion of the nut across the power screw. The actuator includes a secondary module having a power drive, a shaft rotatable by the power drive, a power screw, and a nut. The power screw is slidably coupled to and rotatable by the shaft, and coupled to the output. The nut is coupled to the power screw and is operable to slide linearly across the shaft by rotating through the nut. Both the primary nut and secondary power screw are operable to move the output to the extended position or the retracted position depending on the rotational direction of the primary power screw and secondary power screw.

In exemplary implementations, a target rod is actuated. The target rod is part of a set of threaded, elongated rods, the longitudinal axes of which are substantially parallel to each other. The set of rods has an interior region and a perimeter region. Actuators induce vibrations in a set of perimeter rods. These vibrations are substantially perpendicular to the longitudinal axes. Furthermore, the vibrations are transmitted to interior rods, causing a target rod in the interior region to rotate about, and translate along, the longitudinal axis of the target rod. The target rod undergoes stick-slip motion relative to adjacent rods.

In exemplary implementations, a target rod is actuated. The target rod is part of a set of threaded, elongated rods, the longitudinal axes of which are substantially parallel to each other. The set of rods has an interior region and a perimeter region. Actuators induce vibrations in a set of perimeter rods. These vibrations are substantially perpendicular to the longitudinal axes. Furthermore, the vibrations are transmitted to interior rods, causing a target rod in the interior region to rotate about, and translate along, the longitudinal axis of the target rod. The target rod undergoes stick-slip motion relative to adjacent rods.

In exemplary implementations, a target rod is actuated. The target rod is part of a set of threaded, elongated rods, the longitudinal axes of which are substantially parallel to each other. The set of rods has an interior region and a perimeter region. Actuators induce vibrations in a set of perimeter rods. These vibrations are substantially perpendicular to the longitudinal axes. Furthermore, the vibrations are transmitted to interior rods, causing a target rod in the interior region to rotate about, and translate along, the longitudinal axis of the target rod. The target rod undergoes stick-slip motion relative to adjacent rods.

A projectile including: a body having an internal space; and a mechanical stepper motor disposed in the body, the mechanical stepper motor including: a shuttle having one of a plurality of pockets and movable pins offset from each other with a first spacing; a body portion having the other of the plurality of pockets and movable pins offset from each other with a second spacing, where the first spacing is different from the second spacing; and actuation means for engaging at least one of the movable pins into a corresponding pocket to step one of the shuttle and body portion a predetermined linear and/or rotary displacement; wherein the mechanical stepper motor outputs the predetermined linear and/or rotary displacement to an actuated device operatively connected to the shuttle.

A projectile including: a body having an internal space; and a mechanical stepper motor disposed in the body, the mechanical stepper motor including: a shuttle having one of a plurality of pockets and movable pins offset from each other with a first spacing; a body portion having the other of the plurality of pockets and movable pins offset from each other with a second spacing, where the first spacing is different from the second spacing; and actuation means for engaging at least one of the movable pins into a corresponding pocket to step one of the shuttle and body portion a predetermined linear and/or rotary displacement; wherein the mechanical stepper motor outputs the predetermined linear and/or rotary displacement to an actuated device operatively connected to the shuttle.