optical fiber
A Flexible FBG-Based Contact Force Sensor for Robotic Gripping Systems
Lai, Wenjie, Nguyen, Huu Duoc, Liu, Jiajun, Chen, Xingyu, Phee, Soo Jay
Soft robotic grippers demonstrate great potential for gently and safely handling objects; however, their full potential for executing precise and secure grasping has been limited by the lack of integrated sensors, leading to problems such as slippage and excessive force exertion. To address this challenge, we present a small and highly sensitive Fiber Bragg Grating-based force sensor designed for accurate contact force measurement. The flexible force sensor comprises a 3D-printed TPU casing with a small bump and uvula structure, a dual FBG array, and a protective tube. A series of tests have been conducted to evaluate the effectiveness of the proposed force sensor, including force calibration, repeatability test, hysteresis study, force measurement comparison, and temperature calibration and compensation tests. The results demonstrated good repeatability, with a force measurement range of 4.69 N, a high sensitivity of approximately 1169.04 pm/N, a root mean square error (RMSE) of 0.12 N, and a maximum hysteresis of 4.83%. When compared to a commercial load cell, the sensor showed a percentage error of 2.56% and an RMSE of 0.14 N. Besides, the proposed sensor validated its temperature compensation effectiveness, with a force RMSE of 0.01 N over a temperature change of 11 Celsius degree. The sensor was integrated with a soft grow-and-twine gripper to monitor interaction forces between different objects and the robotic gripper. Closed-loop force control was applied during automated pick-and-place tasks and significantly improved gripping stability, as demonstrated in tests. This force sensor can be used across manufacturing, agriculture, healthcare (like prosthetic hands), logistics, and packaging, to provide situation awareness and higher operational efficiency.
- Asia > Singapore (0.05)
- North America > United States (0.04)
- North America > Canada > Ontario > Toronto (0.04)
- Europe > Switzerland (0.04)
- Health & Medicine (0.88)
- Energy (0.71)
Towards the Development of a Tendon-Actuated Galvanometer for Endoscopic Surgical Laser Scanning
Yamamoto, Kent K., Zachem, Tanner J., Moradkhani, Behnam, Chitalia, Yash, Codd, Patrick J.
There is a need for precision pathological sensing, imaging, and tissue manipulation in neurosurgical procedures, such as brain tumor resection. Precise tumor margin identification and resection can prevent further growth and protect critical structures. Surgical lasers with small laser diameters and steering capabilities can allow for new minimally invasive procedures by traversing through complex anatomy, then providing energy to sense, visualize, and affect tissue. In this paper, we present the design of a small-scale tendon-actuated galvanometer (TAG) that can serve as an end-effector tool for a steerable surgical laser. The galvanometer sensor design, fabrication, and kinematic modeling are presented and derived. It can accurately rotate up to 30.14 degrees (or a laser reflection angle of 60.28 degrees). A kinematic mapping of input tendon stroke to output galvanometer angle change and a forward-kinematics model relating the end of the continuum joint to the laser end-point are derived and validated.
- North America > United States > North Carolina > Durham County > Durham (0.04)
- North America > United States > Nevada > Clark County > Las Vegas (0.04)
- North America > United States > Kentucky > Jefferson County > Louisville (0.04)
- North America > United States > Illinois > DuPage County > Elmhurst (0.04)
- Health & Medicine > Therapeutic Area > Neurology (1.00)
- Health & Medicine > Surgery (1.00)
Single-Fiber Optical Frequency Domain Reflectometry Shape Sensing of Continuum Manipulators with Planar Bending
Tavangarifard, Mobina, Ovalle, Wendy Rodriguez, Alambeigi, Farshid
Abstract-- To address the challenges associated with shape sensing of continuum manipulators (CMs) using Fiber Bragg Grating (FBG) optical fibers, we feature a unique shape sensing assembly utilizing solely a single Optical Frequency Domain Reflectometry (OFDR) fiber attached to a flat nitinol wire (NiTi). Integrating this easy-to-manufacture unique sensor with a long and soft CM with 170 mm length, we performed different experiments to evaluate its shape reconstruction ability. Results demonstrate phenomenal shape reconstruction accuracy for both C-shape (< 2 mm tip error, < 1.2 mm shape error) and J-shape (< 3.4 mm tip error, < 2.3 mm shape error) experiments. I. INTRODUCTION Instead of using rigid instrumentation in minimally invasive surgeries that limit access and dexterity of clinicians, continuum manipulators (CMs) have been proposed to provide more flexibility and access within confined and tortuous paths of anatomical spaces [1]. SSA. Figure also shows the SSA structure modeled as a composite Particularly, having an appropriate integrated sensing modality and pertinent algorithm to estimate their shape and end effector position at any time would be of Paramount importance for cannot completely address this poor accuracy and may increase the accurate control of these robots [1], [4].
AI-Based Energy Transportation Safety: Pipeline Radial Threat Estimation Using Intelligent Sensing System
Zhu, Chengyuan, Yang, Yiyuan, Yang, Kaixiang, Zhang, Haifeng, Yang, Qinmin, Chen, C. L. Philip
The application of artificial intelligence technology has greatly enhanced and fortified the safety of energy pipelines, particularly in safeguarding against external threats. The predominant methods involve the integration of intelligent sensors to detect external vibration, enabling the identification of event types and locations, thereby replacing manual detection methods. However, practical implementation has exposed a limitation in current methods - their constrained ability to accurately discern the spatial dimensions of external signals, which complicates the authentication of threat events. Our research endeavors to overcome the above issues by harnessing deep learning techniques to achieve a more fine-grained recognition and localization process. This refinement is crucial in effectively identifying genuine threats to pipelines, thus enhancing the safety of energy transportation. This paper proposes a radial threat estimation method for energy pipelines based on distributed optical fiber sensing technology. Specifically, we introduce a continuous multi-view and multi-domain feature fusion methodology to extract comprehensive signal features and construct a threat estimation and recognition network. The utilization of collected acoustic signal data is optimized, and the underlying principle is elucidated. Moreover, we incorporate the concept of transfer learning through a pre-trained model, enhancing both recognition accuracy and training efficiency. Empirical evidence gathered from real-world scenarios underscores the efficacy of our method, notably in its substantial reduction of false alarms and remarkable gains in recognition accuracy. More generally, our method exhibits versatility and can be extrapolated to a broader spectrum of recognition tasks and scenarios.
- Europe > United Kingdom > England > Oxfordshire > Oxford (0.28)
- North America > United States (0.28)
- Asia > China > Zhejiang Province (0.14)
A novel approach to measuring patent claim scope based on probabilities obtained from (large) language models
This work proposes to measure the scope of a patent claim as the reciprocal of the self-information contained in this claim. A probability of occurrence of the claim is obtained from a language model and this probability is used to compute the self-information. Grounded in information theory, this approach is based on the assumption that an unlikely concept is more informative than a usual concept, insofar as it is more surprising. In turn, the more surprising the information required to defined the claim, the narrower its scope. Five language models are considered, ranging from simplest models (each word or character is assigned an identical probability) to intermediate models (using average word or character frequencies), to a large language model (GPT2). Interestingly, the scope resulting from the simplest language models is proportional to the reciprocal of the number of words or characters involved in the claim, a metric already used in previous works. Application is made to multiple series of patent claims directed to distinct inventions, where each series consists of claims devised to have a gradually decreasing scope. The performance of the language models is assessed with respect to several ad hoc tests. The more sophisticated the model, the better the results. I.e., the GPT2 probability model outperforms models based on word and character frequencies, which themselves outdo the simplest models based on word or character counts. Still, the character count appears to be a more reliable indicator than the word count.
- Europe > Switzerland > Zürich > Zürich (0.14)
- Europe > Netherlands > North Brabant > Eindhoven (0.04)
- North America > United States > New York (0.04)
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- Research Report > Promising Solution (0.63)
- Overview > Innovation (0.40)
Polymer-Based Self-Calibrated Optical Fiber Tactile Sensor
Chen, Wentao, Yan, Youcan, Zhang, Zeqing, Yang, Lei, Pan, Jia
Human skin can accurately sense the self-decoupled normal and shear forces when in contact with objects of different sizes. Although there exist many soft and conformable tactile sensors on robotic applications able to decouple the normal force and shear forces, the impact of the size of object in contact on the force calibration model has been commonly ignored. Here, using the principle that contact force can be derived from the light power loss in the soft optical fiber core, we present a soft tactile sensor that decouples normal and shear forces and calibrates the measurement results based on the object size, by designing a two-layered weaved polymer-based optical fiber anisotropic structure embedded in a soft elastomer. Based on the anisotropic response of optical fibers, we developed a linear calibration algorithm to simultaneously measure the size of the contact object and the decoupled normal and shear forces calibrated the object size. By calibrating the sensor at the robotic arm tip, we show that robots can reconstruct the force vector at an average accuracy of 0.15N for normal forces, 0.17N for shear forces in X-axis , and 0.18N for shear forces in Y-axis, within the sensing range of 0-2N in all directions, and the average accuracy of object size measurement of 0.4mm, within the test indenter diameter range of 5-12mm.
The secret role of undesired physical effects in accurate shape sensing with eccentric FBGs
Roodsari, Samaneh Manavi, Freund, Sara, Angelmahr, Martin, Rauter, Georg, Schade, Wolfgang, Cattin, Philippe C.
Fiber optic shape sensors have enabled unique advances in various navigation tasks, from medical tool tracking to industrial applications. Eccentric fiber Bragg gratings (FBG) are cheap and easy-to-fabricate shape sensors that are often interrogated with simple setups. However, using low-cost interrogation systems for such intensity-based quasi-distributed sensors introduces further complications to the sensor's signal. Therefore, eccentric FBGs have not been able to accurately estimate complex multi-bend shapes. Here, we present a novel technique to overcome these limitations and provide accurate and precise shape estimation in eccentric FBG sensors. We investigate the most important bending-induced effects in curved optical fibers that are usually eliminated in intensity-based fiber sensors. These effects contain shape deformation information with a higher spatial resolution that we are now able to extract using deep learning techniques. We design a deep learning model based on a convolutional neural network that is trained to predict shapes given the sensor's spectra. We also provide a visual explanation, highlighting wavelength elements whose intensities are more relevant in making shape predictions. These findings imply that deep learning techniques benefit from the bending-induced effects that impact the desired signal in a complex manner. This is the first step toward cheap yet accurate fiber shape sensing solutions.
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Light in the Larynx: a Miniaturized Robotic Optical Fiber for In-office Laser Surgery of the Vocal Folds
Chiluisa, Alex J., Pacheco, Nicholas E., Do, Hoang S., Tougas, Ryan M., Minch, Emily V., Mihaleva, Rositsa, Shen, Yao, Liu, Yuxiang, Carroll, Thomas L., Fichera, Loris
This letter reports the design, construction, and experimental validation of a novel hand-held robot for in-office laser surgery of the vocal folds. In-office endoscopic laser surgery is an emerging trend in Laryngology: It promises to deliver the same patient outcomes of traditional surgical treatment (i.e., in the operating room), at a fraction of the cost. Unfortunately, office procedures can be challenging to perform; the optical fibers used for laser delivery can only emit light forward in a line-of-sight fashion, which severely limits anatomical access. The robot we present in this letter aims to overcome these challenges. The end effector of the robot is a steerable laser fiber, created through the combination of a thin optical fiber (0.225 mm) with a tendon-actuated Nickel-Titanium notched sheath that provides bending. This device can be seamlessly used with most commercially available endoscopes, as it is sufficiently small (1.1 mm) to pass through a working channel. To control the fiber, we propose a compact actuation unit that can be mounted on top of the endoscope handle, so that, during a procedure, the operating physician can operate both the endoscope and the steerable fiber with a single hand. We report simulation and phantom experiments demonstrating that the proposed device substantially enhances surgical access compared to current clinical fibers.
- Asia > Japan > Honshū > Kantō > Tokyo Metropolis Prefecture > Tokyo (0.14)
- North America > United States > Massachusetts > Worcester County > Worcester (0.04)
- North America > United States > Pennsylvania > Delaware County > Chester (0.04)
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- Health & Medicine > Surgery (1.00)
- Health & Medicine > Therapeutic Area > Ophthalmology/Optometry (0.82)
Army of robots pushes the limits of astrophysics
One thousand newly-minted microrobots created in EPFL labs will soon be deployed at two large-scale telescopes in Chile and the United States. These high-precision instruments, capable of positioning optical fibers to within a micron, will vastly increase the quantity of astrophysics data that can be gathered – and expand our understanding of the Universe.
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- North America > United States > Ohio (0.05)
- North America > United States > New Mexico (0.05)
- North America > United States > Michigan (0.05)
This Light-based Nervous System Helps Robots 'Feel'
Last night, way past midnight, I stumbled onto my porch blindly grasping for my keys after a hellish day of international travel. Lights were low, I was half-asleep, yet my hand grabbed the keychain, found the lock, and opened the door. Thanks to the intricate wiring between our brain and millions of sensors dotted on--and inside--our skin, we know exactly where our hand is in space and what it's touching without needing visual confirmation. But this combined sense of the internal and the external is completely lost to robots, which generally rely on computer vision or surface mechanosensors to track their movements and their interaction with the outside world. What if, instead, we could give robots an artificial nervous system?