Actuation Mechanisms and Applications for Soft Robots: A Comprehensive Review

Soft robots, which exhibit distinguishing features in terms of compliance, adaptability, and safety, have been expansively adopted in various niche applications. For soft robots, innovative actuators have been designed based on smart materials enabling the robots to perform flexible and versatile functions, whereas extra spaces and accessories to accommodate motors and power devices have been eliminated to achieve structural optimisation. Herein, different types of actuation mechanisms for soft robots are summarised to reflect the state-of-the-art research and applications. Major characteristics of the actuation mechanisms are updated. Design methodologies of the actuation mechanisms are discussed in detail. Furthermore, their advantages, disadvantages, and application potential are compared and summarised. In the end, based on our knowledge and understanding, new thoughts and recommendations to further develop the actuation mechanisms are put forward. This review is useful to support the conclusion that, through incorporating actuation mechanisms and advanced intelligent technologies, soft robots tend to create disruptive innovations in applications.