Shape Memory Alloy Monolithic Micro-meso Scale Manipulator: Conceptual Design, Manufacturing, Modeling

The need for low-cost robust meso-scale ¿smart¿ robots (manipulators) that have no discrete parts (monolithic), no sensors (¿self-sensing¿) and can be used in space-constrained systems, e. g., in microfactories, biomedical applications, etc., was the motivation for the current research. This study describes the design, fabrication and analysis of such a smart robot ¿ a monolithic Micro/Meso Scale Manipulator (mMM), fabricated from Shape Memory Alloy powders (NiTi) by means of the laser-based Direct Metal Deposition (DMD) process. A first prototype, a functional part of the mMM ¿ a SMA accordion spring type actuator was manufactured by DMD. The actuator provides a linear movement for the mMM due to the Shape Memory Effect (SME) property of SMAs. A new mathematical model describing the phase transformation kinetics in SMAs and a new analytical phase transformation function was developed. In the current work a ¿self-sensing¿ concept was explored and evaluated in an SMA wire actuator and applied to the SMA spring based actuator. A new mathematical model of the motion of the SMA wire- and spring- based actuators was developed.