Aerosol Jet Printing of Strain Sensors for Soft Robotics

Abstract

The field of soft robotics is rapidly progressing toward applications including; wearable electronics, prosthetics, and biomedical devices. This is leading to demand for flexible, embedded high‐performance strain sensors to deliver real‐time feedback on the static configurations and dynamic motions of these robotic devices, to ultimately enable the levels of autonomous control and structural monitoring required for intelligent manipulation. Herein, aerosol jet printing (AJP) technology is utilized to generate arbitrary piezoresistive strain sensor layouts on fibrous paper suitable for direct integration into elastomeric soft robots. A custom graphene nanoplatelet ink with a viscosity of around 2.70 cP has been formulated for optimized atomization and patterning of conductive traces via AJP. Single and multilayer printing onto different paper substrates are explored; with the nominal resistance of the printed tracks varying from 272 to 4900 kΩ depending on paper type and number of layers. Maximum gauge factors of 24.2 ± 1.8 and 56.5 ± 4.5 are determined for sensor surfaces under tensile and compression modes, respectively. To demonstrate the possibility for direct integration of this approach for soft robotics, strain sensors are directly printed onto the strain‐limiting layer of a pneumatic soft robotic gripper, to provide continuous feedback of the gripper over curvatures up to 80 m−1.

Development of Silicone Rubber-Multiwalled Carbon Nanotube Composites for Strain-Sensing Applications: Morphological, Mechanical, Electrical, and Sensing Properties

“…Elastomeric strain sensors represent an advanced class of smart materials that has gathered significant interest across a diverse range of applications, including structural health monitoring, − human body movement detection, − personalized health monitoring, − soft robotics, − and electronic skin. − Elastomer strain sensors belong to the category of conductive polymer composites (CPC). These composites operate based on the electrical resistance change when exposed to mechanical deformation, including tensile (strain) and compressive (pressure) forces, namely piezoresistive mechanism. ,, In this mechanism, the strain sensor detects mechanical stimuli and converts them into electrical signals.…”

Polymeric piezoelectric accelerometers with high sensitivity, broad bandwidth, and low noise density for organic electronics and wearable microsystems

“…On the one hand, many new polymer processing methods simplify the sensor manufacturing process by omitting the traditional micromachining methodology based on cycles of material deposition, lithography, and anisotropic etching. As typical examples in this respect, many studies have combined direct processing methods, such as roll-to-roll adhesive lamination 4 , 5 , laser micromachining 6 , aerosol jet printing 7 , 8 , and 3D printing 9 , to manufacture polymeric sensors for wearable microsystems. On the other hand, most of these direct machining methods cannot compete with classic micromachining techniques for resolution and throughput.…”

Flexible Strain Sensor Based on Nickel Microparticles/Carbon Black Microspheres/Polydimethylsiloxane Conductive Composites for Human Motion Detection

“…Flexible wearable devices, − electronic skin, − soft robots, − and intelligent control , are rapidly developing. Among them, strain sensors play a crucial role in the field of flexible electronics, and flexible stretchable sensors prepared using nanocomposites have been widely studied .…”