The Science

The key to Ras Labs’ Tactile Fingertip sense of touch comes from our compliant electroactive polymers (EAPs). Ras Labs makes Synthetic Muscle™, which is a patented class of EAP-based materials and actuators that sense pressure (gentle touch to high impact), controllably contract and expand at low voltage (including battery levels), and attenuate force [1,2]. Synthetic Muscle is a durable, manmade material capable of life-like, tactile, touch-sensing feedback and biomimetic motion, and able to withstand harsh environments, including extreme temperatures, pressures, radiation (samples successfully flown on the International Space Station), and areas with chemical and biological hazards. Ras Labs’ EAPs are scalable and can be made in a variety of shapes, sizes, thicknesses, and durometers. This is a strong platform business that can lead to many applications; however, our current focus is providing human-like touch and feedback to robotic gripper end-of-arm tooling (EOAT), automation, cobots, and humanoids (especially humanoid hands).  

Ras Labs’ Tactile Fingertips have been integrated into traditional marketplace grippers and hand-centric designs. These touch-sensing systems generate immediate feedback at the first point of contact.  The sensing pads provide a soft, compliant interface (they feel like human fingertips) and the point of contact is gentle, yet firm. The Tactile Fingertip also detects change in pressure location on its surface, making it possible to detect and prevent slippage by then adjusting the grip strength, proportionally in real time without stuttering, due to both feedback and the sensing pad’s compliance. The soft, gentle nature of our Tactile Fingertips naturally hold gripped objects, even delicate glassware and ripe fruit, with no droppage, slippage, damage, or marks.

The sensitivity of our touch-sensing EAP showcases a unique capability: the Tactile Fingertip has the ability to detect heartbeat pulses when humans hold the sensor with their fingers or against pulse points.  In addition, the sensor can distinguish the four cardiac components within one heartbeat.  These soft sensors are extremely responsive, with a broad pressure range from at least 0.05 N (0.005 N in max sensitivity mode) to over 45 N with high linearity, and with a spatial resolution of 1 mm².  Human touch is around 0.1 N of force over a fingertip [3] with a resolution of 2 mm [4].  We were aiming for human tactile touch and have surpassed this, including response speed! Ras Labs’ soft, compliant Tactile Fingertips are robust (20,000,000+ cycles with full functionality) while incredibly sensitive and with a wide pressure range.  Ras Labs makes touch easy.

Ras Labs has the power to replicate human grasp. Ras Labs' unique, EAP-based Tactile Fingertip touch-sensing allows for the gentle handling of objects without having to sacrifice time. This integration reduces the need for costly visualization and is bringing robots with human hand-like tactile touch and dexterous control. This is transforming robots, whether it is for e-commerce, unstructured bin sorting, healthcare, agriculture, or manufacturing, as well as for collaborative and humanoid robotics. This will allow humans and robots to work together intuitively and safely, expanding humanity's effectiveness and capabilities while safeguarding human health and life.  

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1. L. Rasmussen, Editor, “Smart Materials: Considerations in Space and on Earth,” Springer, GmbH & Co. KG, pre-publication © 2021. 

2. L. Rasmussen, Editor, “Electroactivity in Polymeric Materials,” Springer-Verlag, GmbH & Co. KG © 2012. 

3. Patel B., Synthetic Skin Sensitive to the Lightest Touch, https://spectrum.ieee.org/biomedical/bionics/synthetic-skin-sensitive-to-the-lightest-touch © 2010.

4. Bickley, L. and Szilagui, P., “Bates' Guide to Physical Examination and History Taking (9th ed.),” Lippincott Williams & Wilkins, ISBN 978-0-7817-6718-7, ASIN B0028IKRYG © 2007.