Figure 8.

Tactile pressure sensors for e-skin and robotics. (a) Photograph of the large area flexible active-matrix (AM) MOS₂ tactile sensor array (left). Photograph of the AM MoS₂ tactile sensor on the human palm (right). (b) Primary design concept of flexible e-skin sensor based on polyaniline hollow nanosphere composite films (PANI-HNSCF) (left). Optical image of a wearable ultrathin e-skin sensor array on the wrist and under various mechanical deformations (right). (c) Cross-section of the skin of the fingertip depicting key sensory structures and soft biomimetic e-skin (left). Optical image showing carbon nanotube-polyurethane (CNT-PU) interconnects for signal recording with inductance/capacitance ratio (LCR) meter and SEM picture of the top e-skin layer with molded pyramids (right), showing CNT-PU and PU areas (inset). Tactile feedback prevented flattening of the raspberry. Without tactile feedback, the fruit was crushed (bottom). (d) Digital image of the flexible tactile array sensor attached to the tip of an index finger as an artificial fingertip (left). Digital image of a braille sign stating “restroom for handicapped males” (middle). Illustration denoting the dimensions of the scanned braille (right). Current profiles obtained from the artificial fingertip while scanning the braille (bottom). (e) The scalable tactile glove (STAG) consists of a sensor array with 548 elements covering the entire hand, attached to a custom knit glove. An electrical readout circuit is used to acquire the normal force recorded by each sensor at approximately 7.3 fps. Using this setup allows recording of a dataset of 135,187 tactile maps while interacting with 26 different objects. A deep convolutional neural network trained purely on tactile information can be used to identify or weigh objects and explore the tactile signatures of the human grasp. The glove shown at the center is a rendering. (a) Reproduced with permission [117]. Copyright 2019, American Chemical Society. (b) Reproduced with permission [118]. Copyright 2017, Elsevier. (c) Reproduced with permission [119]. Copyright 2018, American Association for the Advancement of Science. (d) Reproduced with permission [120]. Copyright 2018, John Wiley and Sons. (e) Reproduced with permission [121]. Copyright 2019, Springer Nature.