Sensitive robust tactile fingertips and shape-morphing actuation for robotic grippers

Abstract

Human grasp is gentle yet firm, with integrated tactile touch feedback. 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. 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. EAP development towards sensing provided for fingertip-like sensors that were able to detect very light pressures to 0.005 N and with a wide pressure range over 45 N with high linearity. Algorithms, machine learning (ML), and artificial intelligence (AI) were integrated into these sensors for object and grip determination (position, grip force, any slip or wobble) and immediate correction for pick-and-place and other applications. High tack EAPs also have good adhesion to a variety of substances and had self-healing properties. Using these adhesive EAPs and other strategies, sensors and actuators were created where all components stay together. Synthetic Muscle™ was also being retrofitted as actuators into a partial human hand-like biomimetic gripper that focused on the pincer grip. 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 hazardous environments where humans cannot enter, as well as for collaborative robotics to allow humans and robots to intuitively work safely and effectively together.