Advancements and recent trends in shape memory alloy actuators: position control and emerging applications

Shape memory alloy (SMA) is a class of intelligent materials that have gained significant attention in recent years due to their unique capabilities, including a high force-to-weight ratio, considerable recovery stress with high strain capacity, compact size, and durability, making them potential applications in various fields. However, effective position control of SMA actuators remains challenging because SMA possesses nonlinear behavior, large hysteresis, slow response, and lower bandwidth. This systematic review presents an overview of position control techniques and emerging applications for SMA actuator systems and identifies research directions for further advancements. The review encompasses a comprehensive literature analysis focusing on the position control techniques employed in SMA actuator systems. Various control techniques, including linear, nonlinear, intelligent, and optimal control, are discussed based on their effectiveness in achieving precise and reliable position control of SMA. This review offers a roadmap for advancing the position control capabilities in identified research directions and enabling their broader applications in biomedical, robotics, aerospace and aviation, automobile industry, and strategical sectors.