Bioinspired Electromechanically Active Polymer-Based Robotics

Electromechanically Active Polymers (EAPs) are ‘smart materials’ that exhibit a mechanical response (deformation/force) to an electrical stimulus. They are referred to as ‘artificial muscle materials’, as they can emulate the main functional properties of natural muscles, in that they can combine biomimetic motion with self-sensing ability and variable stiffness operation. They also show additional attractive properties, such as light weight, mechanical compliance, compact size, simple structure, low power consumption, acoustically silent operation, and low cost. Among the various types of EAPs available, this chapter focuses on the special kind known as ‘dielectric elastomers’ (DEs), which show today the greatest potential for various mechatronic applications. When used as actuators (i.e. transducers of electrical energy into mechanical work) DEs are capable of large electrically-induced strains and stresses, in some cases even exceeding mammalian muscles performance, although fully harnessing such performance of those materials in actual devices remains challenging. In comparison with traditional electromagnetic motors, DE actuators (DEAs) have low specific weight, high energy density and efficiency, intrinsic mechanical compliance and don’t generate acoustic noise. In the field of robotics, DE actuation is being extensively studied for bioinspired machines. This chapter revises the most significant uses demonstrated so far.