Design Of Active Sensing Smart Skin For Incipient Slip Detection In Robotic Applications

Design of Active Sensing Smart Skin for Incipient Slip Detection in Robotic Applications

Tactile sensing is paramount for robots operating in human-centered environments to help in understanding interaction with objects. To enable robots to have sophisticated tactile sensing capability, researchers have developed different kinds of tactile sensors for robotic hands to realize the 'sense of touch'. In this study, we are focused on the incipient slip detection problem for robots which is known as one of the most challenging issues in robotic tactile sensing. Currently, most of the slip detection sensors are passive sensors which provide limited information about the sensing parameters. Therefore, this will usually require large amount of data and extra computation effort in accurately classifying slip conditions of robotic hands. Other sensing mechanisms such as optical approaches which can provide enriched sensing parameters for slip detection often suffer from complex sensor configurations and being inflexible in terms of customization. Active sensing, on the other hand, has the advantage of simple sensor configurations, and in the meantime can provide more sensing parameters which will improve the overall efficiency of the tactile sensing capabilities for incipient slip detection. In this thesis, by using the active sensing method, a novel active sensing smart skin technique is developed for incipient slip detection which leverages piezoelectric transducers as actuators/sensors. With this method, a robotic fingertip with the embedded actuator and sensor were created in which the actuator generates ultrasonic guided waves received by the sensor during a slip scenario. By analyzing the received signal using an attenuation-based method, we can monitor the entire contact area evolution during a slip scenario. Therefore, this method can serve as an excellent indicator for early slip detection with the advantage of accurately monitoring the contact condition. In addition, the frustrated total internal reflection method was used to validate the signal attenuation increases with the growing of the contact area. Built on these results, a unique robotic skin was then designed and fabricated which demonstrated robust and sensitive response for incipient slip detection. Finally, an LED slip alert system on a real gripper was developed to demonstrate the capability of our method to be applicable to real robotic finger situations.

International Aerospace Abstracts

Robotic Tactile Sensing

Future robots are expected to work closely and interact safely with real-world objects and humans alike. Sense of touch is important in this context, as it helps estimate properties such as shape, texture, hardness, material type and many more; provides action related information, such as slip detection; and helps carrying out actions such as rolling an object between fingers without dropping it. This book presents an in-depth description of the solutions available for gathering tactile data, obtaining aforementioned tactile information from the data and effectively using the same in various robotic tasks. The efforts during last four decades or so have yielded a wide spectrum of tactile sensing technologies and engineered solutions for both intrinsic and extrinsic touch sensors. Nowadays, new materials and structures are being explored for obtaining robotic skin with physical features like bendable, conformable, and stretchable. Such features are important for covering various body parts of robots or 3D surfaces. Nonetheless, there exist many more hardware, software and application related issues that must be considered to make tactile sensing an effective component of future robotic platforms. This book presents an in-depth analysis of various system related issues and presents the trade-offs one may face while developing an effective tactile sensing system. For this purpose, human touch sensing has also been explored. The design hints coming out of the investigations into human sense of touch can be useful in improving the effectiveness of tactile sensory modality in robotics and other machines. Better integration of tactile sensors on a robot’s body is prerequisite for the effective utilization of tactile data. The concept of semiconductor devices based sensors is an interesting one, as it allows compact and fast tactile sensing systems with capabilities such as human-like spatio-temporal resolution. This book presents a comprehensive description of semiconductor devices based tactile sensing. In particular, novel Piezo Oxide Semiconductor Field Effect Transistor (POSFET) based approach for high resolution tactile sensing has been discussed in detail. Finally, the extension of semiconductors devices based sensors concept to large and flexile areas has been discussed for obtaining robotic or electronic skin. With its multidisciplinary scope, this book is suitable for graduate students and researchers coming from diverse areas such robotics (bio-robots, humanoids, rehabilitation etc.), applied materials, humans touch sensing, electronics, microsystems, and instrumentation. To better explain the concepts the text is supported by large number of figures.