Model-based Design Framework for Shape Memory Alloy Wire Actuation Devices.

Abstract

While Shape Memory Alloys (SMAs) have exceptional actuation characteristics such as high energy density, silent operation, flexible packaging, etc., they have not found widespread use in commercial applications because of the significant learning curve required of engineers before they are capable of designing actuation devices using this unique material. An SMA actuation device design framework consisting of grammar, design methods, and design process enables engineers of different backgrounds to make efficient and appropriate design decisions in different stages of the design process. A reference SMA actuation device structure built on a generalized actuation device hierarchical structure using the actuation device grammar works as a reference structure to identify and populate device design options, and to model and analyze the device actuation performance as well as to enlighten non-expert engineers about the essential elements of SMA actuation devices. Design methods consisting of modular modeling, model aggregation and performance prediction, and visualization approaches support design decisions to serve diverse stakeholders of actuation device design by exposing the effects of individual device elements not only for SMA actuation devices, but also for a wide range of actuation devices. A multi-stage design process is formalized to help engineers create a detailed design including a three-step decoupled equilibrium design procedure which prevents potential iteration by decoupling the force and deflection of actuation output behavior, and hides the complexity of material and SMA architectural models from engineers while still exposing the impact of design parameters. The design framework makes SMA design knowledge more accessible to engineers with different levels of expertise and roles in device development by systematically organizing and presenting the device grammar, design methods, and design process. A design tool software platform based on the framework enables the creation of computer-aided design tools to support a variety of design tasks, which were demonstrated in two use case examples. By having the SMA actuation device design framework, the acceptance of the SMA actuation technology into both research and commercial applications can be increased to utilize promising SMA actuation benefits, and the device development cycle leading to these applications can be streamlined.