Active material actuation utilizing tunable magnetic overload protection

摘要

A system for and method of providing overload protection for an active material actuator and composing assembly, including a magnetically functioning mechanism comprising one or more permanent magnet, electromagnet, and/or magnetorheological fluid reservoir cooperatively configured to produce a tunable holding force.

主权项

1. An active material actuation system adapted for driving a load over an actuation cycle, and preventing an overload condition during the cycle, the system comprising:
an active material actuator operable to undergo a reversible transformation in fundamental property when exposed to or occluded from an activation signal, having a work output end and a securing end, and configured to apply a driving force to the load; a fixed structure coupled to the actuator; and a magnetically functioning mechanism intermediate and physically coupled to the securing end and structure, and configured to produce a selected holding force opposite the driving force and operable to retain the securing end and structure in a relatively fixed condition over the cycle; wherein the mechanism is tunable, so as to produce a plurality of differing holding forces, including the selected holding force, the mechanism being configured such that the structure and securing end are disconnected when the driving force is greater than the selected holding forces, so as to provide a secondary work output path; and wherein the mechanism includes a combination of at least one electromagnet, permanent magnet, and ferrous material communicatively coupled to the magnets cooperatively producing the selected holding force.