An untethered soft chemo-mechanical robot with composite structure and optimized control

Endowing the animals with agile actions, natural muscle functions as a soft actuator, which is powered by chemical reactions of metabolism and controlled by electrical nerve-signals. Inspired by natural muscle, various types of soft chemical machines (SCM) have been recently developed, possessing advantages of light weight, fast actuation, compact integration, high power and low noise. In this paper, we propose a composite structure as a soft chemical engine (SCE), which is driven by the chemical decomposition of hydrogen peroxide (H2O2). The SCE directly converts chemical energy into mechanical work, achieving excellent performance of large actuation (∼33% volume expansion) and fast response (∼1 s). We advance the SCE with excellent performance to a soft chemical machine (SCM) with well-controlled functions, as a mechatronic control system. The soft robot possesses robust control with untethered operation and stable actuating cycles. We develop a model for the locomotion mechanisms, revealing that optimized mechatronic controls can significantly enhance the performance of SCM.