Flexible Liquid‐Filled Fiber Adapter Enabled Wearable Optical Sensors

Yang

IEEE Trans. Med. Robot. Bionics

2021

The emerging applications of collaborative robots (cobots) are spilling out from product manufactories to service industries for human care, such as patient care for combating the coronavirus disease 2019 (COVID-19) pandemic and in-home care for coping with the aging society. There are urgent demands on equipping cobots with safe collaboration, immersive teleoperation, affective interaction, and other features (e.g., energy autonomy and self-learning) to make cobots capable of these application scenarios. Robot skin, as a potential enabler, is able to boost the development of cobots to address these distinguishing features from the perspective of multimodal sensing and self-contained actuation. This review introduces the potential applications of cobots for human care together with those demanded features. In addition, the explicit roles of robot skin in satisfying the escalating demands of those features on inherent safety, sensory feedback, natural interaction, and energy autonomy are analyzed. Furthermore, a comprehensive review of the recent progress in functionalized robot skin in components level, including proximity, pressure, temperature, sensory feedback, and stiffness tuning, is presented. Results show that the codesign of these sensing and actuation functionalities may enable robot skin to provide improved safety, intuitive feedback, and natural interfaces for future cobots in human care applications. Finally, open challenges and future directions in the real implementation of robot skin and its system synthesis are presented and discussed.

Section: ) Functional Materialsmentioning

confidence: 99%

Review of Robot Skin: A Potential Enabler for Safe Collaboration, Immersive Teleoperation, and Affective Interaction of Future Collaborative Robots

Yang

IEEE Trans. Med. Robot. Bionics

2021

“…[14,26] By comparison, optical conduction-based tactile sensors not only generally have the advantages of fast response and good flexibility, but also are easy to realize the miniaturization and the integration. [24,25] The principle of optical conduction-based tactile sensors can be briefly illustrated as follows. When the sensor is touched, the light transmission pathway is influenced, and as a result, the light intensity or optical wavelength reached on the photosensor is changed.…”

Section: Introductionmentioning

confidence: 99%

Liquid Lens‐Based Optical Tactile Sensor with a Touch‐Sensing Separable Structure

Yang

Liu

et al. 2022

Adv Materials Inter

Optical tactile sensing plays an important role in the tactile sensing field, due to its high sensitivity, fast response, and prominent interference immunity. Herein, based on the liquid lens, a low‐cost optical tactile sensor with a touch‐sensing separable structure is designed and fabricated, and it contains a touch unit and an optics sensing unit. The touch unit is a chamber structure with good integration, and the optics sensing unit is designed with a liquid‐membrane structure. Different from the existed optical tactile sensors, the principle of the proposed sensor is that the focal length of the optics sensing unit is changed with an external contact force, and then the directional light propagation direction produces change, which affects the perceived light intensity of the silicon photocell. From the sensing performance test results, this tactile sensor has good statics and dynamics performance, which embodies in the rapid response time (about 0.048 s), stable output, high sensitivity (the max sensitivity is about 7.1338 V/N), and resolution (0.01 N), low hysteresis ratio (less than 6.5%), and good linearity (R2 ≈ 0.98). In addition, some application experiments are conducted and the results demonstrate the application feasibility of the proposed sensor in health monitoring and multichannel sensing.

Adv Materials Technologies

“…For example, optical micro/nanofiber with diameter down to several hundreds of nanometers, which exhibits strong evanescent field, can be fabricated as wearable tactile sensors, and strain/stress sensing have been realized in these flexible optical sensors. [28][29][30] However, the research on bio-inspired or biomimetic optical sensors with advanced sensing capabilities such as slip/friction detection is still lacking. It is an inspiring yet challenging topic of developing a flexible tactile sensor possessing skin-like structural and functional characteristics toward robotic grasping applications.…”

Section: Introductionmentioning

confidence: 99%

Finger‐Skin‐Inspired Flexible Optical Sensor for Force Sensing and Slip Detection in Robotic Grasping

Jiang

Zhang

Pan

et al. 2021

Self Cite

by nanoengineering and flexible electronics, [4][5][6][7][8] accurate detection of physical stimuli such as pressure, temperature, and humidity has been realized in flexible tactile sensors, rendering them both high sensitivity and excellent flexibility comparable to human skin (hence the name "artificial skin"). [4,9] To allow for applications in robotics, slip detection during the grasping and manipulation of objects is a critical function that should be included in the flexible tactile sensor when used in robotic hand or manipulator. [10][11][12] Widerange force sensing and fast-response slip detection are needed in robotic grasping and dexterous manipulation for the purpose of measuring the contact force and preventing object slippage. For example, home robots and nursing robots would be expected to safely deliver objects and operate instruments, while manufacturing robots and industrial robots would be assigned to perform manipulation and assembly tasks in high precision. [11,13] However, the development of flexible tactile sensor with simultaneous force sensing and slip detection for robotic grasping still remain difficult due to considerations on sensor design, sensor performance, and sensor integration with robotic system. [13][14][15] From the application perspective, flexible tactile sensor capable of detecting the contact force and obtaining friction/slip information is desirable for intelligent robotic manipulators, if they are anticipated to adjust grasping force and posture in accordance with the shape, weight, and friction coefficient of the grasped objects for achieving dexterous manipulation and automatic grasping in scenarios such as human-machine interface, robotic surgery, intelligent manufacturing, etc.Flexible tactile sensors based on electrical sensing scheme, including capacitive, resistive, piezoelectric, and triboelectric mechanisms, have already been widely reported over the past decade. These electronic tactile sensors usually mimic the biological features of the delicate tactile sensation in human skin, such as the epidermis-dermis interface, sensory receptors, fingerprint patterns, and ionic stimuli in afferent neuron. [16][17][18][19][20] Multimodal sensing capabilities and other special properties ranging from self-healing, self-powering, energy harvesting, stimuli visualization, to environmental adaptation, have also been attempted in these electronic tactile sensors, but several drawbacks including high fabrication cost, parasite effect, complicated circuitry, and signal crosstalk may place constraints on their practical applications in robotics. [15,[21][22][23][24] AsThe finger skin of human plays a key role in amplifying and transferring tactile signals to sensory receptors, and it provides design guidelines for next-generation flexible tactile sensors. To enable robotic applications such as dexterous manipulation and tactile feedback, the functions of force sensing and slip detection are crucial for flexible tactile sensors. Here, a finger-skin inspired flexible optical (FIFO...