The evolution of mechanical actuation: from conventional actuators to artificial muscles

Abstract

Mechanical actuators are defined as mechanical devices that convert an input energy into motion. Since the 1990s, advancements in the fields of robotics and automation have produced a critical need for the development of lightweight and efficient actuators capable of human-like motion. In the past few decades, extensive research activities in the fields of materials science and smart materials have led to the development of a novel type of actuator known as artificial muscles. This review paper describes the evolution of mechanical actuators from conventional technologies such as electric, hydraulic, and pneumatic actuators, to bioinspired artificial muscles. The working mechanism, manufacturing process, performance, and applications of different artificial muscles are described and compared with those of conventional actuators. Details on the cost, input sources, activation modes, advantages, and drawbacks of each artificial muscle technology are also provided to guide the reader through the intricate selection process of the bestsuited actuator for a specific application.

Skeletal Muscle Fibers Inspired Polymeric Actuator by Assembly of Triblock Polymers

“…40 kJ m −3 ). [ 3 , 18 , 54 ] However, its P (4.5 W kg −1 ) remains lower than that of human skeletal muscles. [ 18 ] pH‐driven actuation is a diffusion‐controlled process.…”

“…[ 57 ] The development of an artificial actuators that can achieve the energy transfer efficiency of skeletal muscle both highly desirable and a great challenge. [ 3 , 18 ]…”

“…Actuators are controllable work-producing devices that use thermal, electrical, light, or chemical energy to achieve propulsion and manoeuvrability. [1][2][3][4][5][6][7][8][9][10][11][12] Steam engines, combustion engines, and electric motors are classical actuators that have driven the industrial revolution and shaped modern society. [13] DOI: 10.1002/advs.…”

“…Actuators are controllable work‐producing devices that use thermal, electrical, light, or chemical energy to achieve propulsion and manoeuvrability. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ] Steam engines, combustion engines, and electric motors are classical actuators that have driven the industrial revolution and shaped modern society. [ 13 ] Different materials have been applied in the design of actuators, including stimulus‐responsive gels, liquid crystal elastomers, dielectric elastomers, shape memory polymers, conductive polymers, carbon nanotubes (CNTs), graphene, and polymer/inorganic nanocomposites.…”

Light‐Driven Actuation in Synthetic Polymers: A Review from Fundamental Concepts to Applications

“…[ 28–32 ] In fact, natural materials are often inspire research activities to create synthetic alternatives. [ 33–37 ] The intention is to design synthetic actuators either by mimicking nature or to get inspiration from nature to create synthetic alternatives. Nature based actuators is a vast and specialized domain with some excellent reviews available, [ 28–32 ] and therefore it was excluded from the review.…”