Stage devices are disclosed for holding an object such as a reticle for use in microlithography. An exemplary stage device includes a movable object-holder that holds the object. At least one actuator moves the object-holder. A position-detector determines a position of the object-holder, wherein the position-detector produces a first position signal whenever the object-holder is not holding the object and produces a second position signal whenever the object-holder is holding the object. A controller, connected to the position-detector and to the at least one actuator, produces a first control signal upon receiving the first position signal and a second control signal upon receiving the second position signal. These control signals cause the at least one actuator to place or hold the object-holder at a pre-determined position whether the object-holder is not holding or is holding the object. The controller also determines whether the object is not being held or is being held by the object-holder based on whether the controller is receiving the first position signal or the second position signal, respectively.

 
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> Assistive walking device

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