A Simple Dynamic Characterization Method for Thin Stacked Dielectric Elastomer Actuators by Suspending a Weight in Air and Electrical Excitation

A Soft Electro-Hydraulic Pneumatic Actuator with Self-Sensing Capability toward Multi-Modal Haptic Feedback

Haptic feedback is appealing for achieving the realistic perception of environmental changes for human bodies in human–computer interaction fields. However, existing haptic actuators have some hurdles such as single mode, poor compatibility, or incomplete tactile information. In this study, we proposed a novel way to generate haptic feedback by designing a soft electro-hydraulic pneumatic actuator (SEHPA) with dual drive modes. The SEHPA was structured with silicone films, a silicone air chamber, flexible electrodes, and an insulating liquid dielectric for good human–machine compatibility. The SEHPA had the advantages of high output force (1.5 N at 10 kPa) and displacement (4.5 mm at 5 kPa), as well as various haptic notifications (0~400 Hz vibration). The electro-hydraulic drive method realized smooth output force changes at the millinewton level (0~40 mN) and output displacement changes at the micron level (0~800 μm), which further enriched the details of the tactile experience. In addition, the self-sensing capability of the SEHPA can be dedicated to monitoring and ensuring precise output. The SEHPAs can be potentially mounted on the fingertips to provide accurate tactile sensation once the manipulator touches an object through teleoperation. More invisible information can also be obtained by customizing various haptic notifications. The excellent response behavior and accurate tactile haptic feedback demonstrate the candidate for teleoperation fields.

A DIY Fabrication Approach of Stretchable Sensors Using Carbon Nano Tube Powder for Wearable Device

Soft robotics and wearable devices are promising technologies due to their flexibility. As human-soft robot interaction technologies advance, the interest in stretchable sensor devices has increased. Currently, the main challenge in developing stretchable sensors is preparing high-quality sensors via a simple and cost-effective method. This study introduces the do-it-yourself (DIY)-approach to fabricate a carbon nanotube (CNT) powder-based stretchable sensor. The fabrication strategy utilizes an automatic brushing machine to pattern CNT powder on the elastomer. The elastomer ingredients are optimized to increase the elastomer compatibility with the brushing method. We found that polydimethylsiloxane-polyethyleneimine (PDMS-PEIE) is 50% more stretchable and 63% stickier than previously reported PDMS 30-1. With these improved elastomer characteristics, PDMS-PEIE/multiwalled CNT (PDMS-PEIE/MWCNT-1) strain sensor can realize a gauge factor of 6.2-8.2 and a responsivity up to 25 ms. To enhance the compatibility of the powder-based stretchable sensor for a wearable device, the sensor is laminated using a thin Ecoflex membrane. Additionally, system integration of the stretchable sensors are demonstrated by embedding it into a cotton-glove and a microcontroller to control a virtual hand. This cost-effective DIY-approach are expected to greatly contribute to the development of wearable devices since the technology is simple, economical, and reliable.