The present invention relates to an actuator capable of operating in three dimensions, having more than two actuating arms and being driven by a piezo or other smart material device, and which may be adapted for use as an actuator, an energy capture device, or a sensor. In certain embodiments, the smart material actuator can also operate as the driver for an audio speaker.
Smart material actuators are known in the art. However, such actuators have one or two actuating arms. Known actuators have limited applications as the actuator-driven arms are intended to move in a single plane and are not well adapted to applications such as grapplers that require compression on multiple planes or in applications where motion in a plane orthogonal to that of the arms is desired. The present invention overcomes such limitations by providing an actuator with more than two arms in which the arms move in independent planes but are operated by a common smart material device. The result is an actuator apparatus that is not only adaptable for use in applications for which one-arm or two-arm smart material actuators were not suitable and which also can be more efficient than one- or two-arm actuators in terms of work output.
A further objective of the present invention is to provide an actuator apparatus capable of operation at high frequencies. Known smart material actuators tend to fail when operated at very high frequencies of repeated activation and deactivation. One reason for such failures is that the actuating arms tend to overextend during high speed operation and especially when operating at resonant frequencies. Certain embodiments of the actuator of the present invention, however, are designed to overcome such limitations both by reducing the weight of the actuating arms and by providing dampeners adapted to prevent such overextensions without hindering high speed operation. The result is a multi-arm actuator capable of operation at very high frequencies, including, without limitation, embodiments capable of operating at frequencies that allow the actuator to serve as a driver of an efficient audio speaker.
A still further objective of the present invention is to provide a smart material actuator capable of being operated with actuating arms at a variety of angles. Allowing use of actuating arms of varying angles allows for great flexibility as arm angles can be selected to meet physical constraints imposed by differing applications. At the same time, it is disclosed that certain ranges of arm angles result in more efficient operation than others in terms of actuator work output. Accordingly, by providing an actuator apparatus capable of use with multiple arm angles, it becomes possible to optimize efficiency by adjusting arm angles.
In addition, the present invention is adapted such that common components can be utilized to assemble actuators of several configurations. This allows for flexibility and efficiency in manufacturing, as common components may be manufactured in bulk and then assembled in wide range of configurations adapted to different applications.