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  1. Madden, John D. ; Anderson, Iain A. ; Shea, Herbert R. (Ed.)
    Current robotic sensing is mainly visual, which is useful up until the point of contact. To understand how an object is being gripped, tactile feedback is needed. Human grasp is gentle yet firm, with integrated tactile touch feedback. Ras Labs makes Synthetic Muscle™, which is a class of electroactive polymer (EAP) based materials and actuators that sense pressure from gentle touch to high impact, controllably contract and expand at low voltage (battery levels), and attenuate force. The development of this technology towards sensing has provided for fingertip-like sensors that were able to detect very light pressures down to 0.01 N and even 0.005 N, with a wide pressure range to 25 N and more and with high linearity. By using these soft yet robust Tactile Fingertip™ sensors, immediate feedback was generated at the first point of contact. Because these elastomeric pads provided a soft compliant interface, the first point of contact did not apply excessive force, allowing for gentle object handling and control of the force applied to the object. The Tactile Fingertip could also detect a change in pressure location on its surface, i.e., directional glide provided real time feedback, making it possible to detect and prevent slippage by then adjusting the grip strength. Machine learning (ML) and artificial intelligence (AI) were integrated into these sensors for object identification along with the determination of good grip (position, grip force, no slip, no wobble) for pick-and-place and other applications. Synthetic Muscle™ is also being retrofitted as actuators into a human hand-like biomimetic gripper. The combination of EAP shape-morphing and sensing promises the potential for robotic grippers with human hand-like control and tactile sensing. This is expected to advance robotics, whether it is for agriculture, medical surgery, therapeutic or personal care, or in extreme environments where humans cannot enter, including with contagions that have no cure, as well as for collaborative robotics to allow humans and robots to intuitively work safely and effectively together. 
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  2. Bar-Cohen, Yoseph ; Anderson, Iain A. ; Shea, Herbert R. (Ed.)
    Ras Labs makes Synthetic Muscle™, which is a class of electroactive polymer (EAP) based materials and actuators that controllably contract and expand at low voltage (1.5 V to 50 V, including use of batteries), potentially sense pressure (gentle touch to high impact), and attenuate force. This offers biomimetic movement by contracting similar to human muscles, but also exceeds natural biological capabilities by expanding under reversed electric polarity. These EAPs are affordable and robust. They have been tested in many harsh environments, including extreme temperatures, high pressure underwater environments, and in space on the International Space Station. Potential load bearing applications are feasible, with significant mechanical strength when tested in compression. Selected EAP samples were tested and survived 3,000,000 cycles at 4 Hz from 5 psi to 30 psi, followed by a 50-psi compression. Human grasp is gentle yet firm, with tactile touch feedback. In conjunction with shape-morphing abilities, these EAPs also are being explored to intrinsically sense pressure due to the correlation between mechanical force applied to the EAP and its electronic signature. We are continuing to advance EAP technology and apply this technology towards robotic grippers. The robotic field is experiencing phenomenal growth in this fourth phase of the industrial revolution, the robotics era. The combination of Ras Labs’ EAP shape-morphing and sensing features promises the potential for robotic grippers with human hand-like control and tactile sensing. This work is expected to advance both robotics and prosthetics, particularly for collaborative robotics to allow humans and robots to intuitively work safely and effectively together. 
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