Abstract
Shape memory alloys (SMAs) are an attractive technology in actuators and sensors because of their versatile geometry, low weight, high energy density, and low cost. The design of an SMA actuator system is generally tuned to the desired application criteria during development. Due to the thermal actuation, SMA applications are currently only considered in the frequency ranges below 10 Hz. Replacing cross-sectionally ‘thick’ SMA elements can achieve higher actuation frequencies. The concept of using ‘thin’ elements, thus improving the surface-to-volume ratio, is known from the literature and was translated into applications.
Such a system’s efficient and reliable operation requires the precise combination of the used SMA elements in one system. Replacing the time-consuming and error-prone adjustment process of single SMA elements, a novel bundle concept is developed and presented. One continuous SMA wire is used to build the hole antagonistic system and reaches a cyclic actuation frequency of up to 20 Hz.
This work presents the investigation of the improved bundle concept. Massively reducing the surface-to-volume ratio using very thin SMA wires with a diameter of 25 μm enables the cyclic actuation of up to 66 Hz. In detail, different actuation parameters are discussed to evaluate the cyclic actuation performance.
