A comprehensive review on the state-of-the-art of piezoelectric energy harvesting

Hybrid vibration and wind energy harvesting using combined piezoelectric and electromagnetic conversion for bridge health monitoring applications

A nonlinear two-degree-of-freedom electromagnetic energy harvester for ultra-low frequency vibrations and human body motions

Development of biomimetic actuators has been an essential motivation in the study of smart materials. However, few materials are capable of controlling complex twisting and bending deformations simultaneously or separately using a dynamic control system. Here, we report an ionic polymer-metal composite actuator having multiple-shape memory effect, and is able to perform complex motion by two external inputs, electrical and thermal. Prior to the development of this type of actuator, this capability only could be realized with existing actuator technologies by using multiple actuators or another robotic system. This paper introduces a soft multiple-shape-memory polymer-metal composite (MSMPMC) actuator having multiple degrees-of-freedom that demonstrates high maneuverability when controlled by two external inputs, electrical and thermal. These multiple inputs allow for complex motions that are routine in nature, but that would be otherwise difficult to obtain with a single actuator. To the best of the authors' knowledge, this MSMPMC actuator is the first solitary actuator capable of multiple-input control and the resulting deformability and maneuverability.

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A multiple-shape memory polymer-metal composite actuator capable of programmable control, creating complex 3D motion of bending, twisting, and oscillation

Soft actuator materials change their shape or size in response to stimuli like electricity, heat, light, chemical or pH. These actuator materials are compliant and well suited for soft mechatronics and robots. This paper introduces the definition of soft materials and the position of soft actuator materials in comparison with conventional actuators and other solid state actuator materials. A thorough review of selected soft actuator materials is carried out, including responsive gels/hydrogels, ionic polymer metal composites, conducting polymers, carbon nanotubues/graphenes, dielectric elastomers, shape memory polymers and biopolymers. This review will give insights for applications of soft actuator materials via better understanding of the materials in terms of their preparation, performance and limitation.

Review of Soft Actuator Materials

Energy harvesting from a piezoelectric biomimetic fish tail

Ionic polymer metal composites (IPMCs) are an emerging class of soft active materials that are finding growing application as underwater propulsors for miniature biomimetic swimmers Understanding the hydrodynamics generated by an IPMC vibrating under water is central to the design of such biomimetic swimmers In this paper, we propose the use of time-resolved particle image velocimetry to detail the fluid kinematics and kinetics in the vicinity of an IPMC vibrating along its fundamental structural mode The reconstructed pressure field is ultimately used to estimate the thrust produced by the IPMC The vibration frequency is systematically varied to elucidate the role of the Reynolds number on the flow physics and the thrust production Experimental results indicate the formation and shedding of vortical structures from the IPMC tip during its vibration Vorticity shedding is sustained by the pressure gradients along each side of the IPMC, which are most severe in the vicinity of the tip The mean thrust is found to robustly increase with the Reynolds number, closely following a power law that has been derived from direct three-dimensional numerical simulations A reduced order distributed model is proposed to describe IPMC underwater vibration and estimate thrust production, offering insight into the physics of underwater propulsion and aiding in the design of IPMC-based propulsors

Woojin Chae

Papers

Energy harvesting from a piezoelectric biomimetic fish tail

Flow measurement and thrust estimation of a vibrating ionic polymer metal composite