111 research outputs found
Improved estimation of elbow flexion angle from IMU measurements using anatomical constraints
No full textObjectives:
Inertial Measurement Units (IMUs) are a valid alternative to optical tracking systems for human motion capture, but they are subject to several disturbances that limit their accuracy. We aim to improve the accuracy of elbow joint angle estimation from IMU measurements by introducing a novel postprocessing algorithm that uses anatomical constraints and does not require any prior calibration or knowledge of anthropometric parameters.
Materials and Methods:
We propose a new error model that addresses sensor misalignment and fusion errors. We use an error state extended Kalman filter (ESEKF) with state constraints to integrate the anatomical constraints. We validate the proposed algorithm by testing it in different scenarios and comparing it with a state-of-the-art optical tracking system.
Results:
The research results highlight the superior performance of the proposed method compared with existing techniques. The study demonstrates a significant reduction in errors, particularly in complex arm movements and under strong external disturbances. The results obtained in the three different tested scenarios underscore the robustness and effectiveness of the developed algorithm, reaching half the error committed by the existing calibration-free correction algorithms proposed in the literature.
Conclusions:
The developed technique provides highly accurate estimates of joint angles in several challenging real-world scenarios
Intrinsic Contact Sensing for Soft Fingers
No full textThe basic mathematic relationships of intrinsic (or force based) contact sensing are discussed. While conventional tactile sensing devices are designed to provide information about local phenomena caused by contact, intrinsic contact sensing detects a few global quantities relating to the interactions of two bodies in contact. The author addresses the geometric-mathematical problem of detecting these quantities starting from force/torque measurements and from the geometric description of one of the contacting surfaces. Two methods for solving the intrinsic contact sensing problem are discussed. The first method is able to give exact results for contacts of the hard-finger type, while it is shown to be only approximate for soft-finger contacts. A formula for estimating the extent of such approximation error is provided. A second, novel solution method is presented, which applies to soft fingers with ellipsoidal surface and is capable of yielding exact solutions to the problem. Some implementation issues and applications of intrinsic tactile sensing to fine manipulation operations are reviewe
Towards Robotic Transseptal Puncture: A Preliminary Study Investigating the Influence of Puncture Velocity in Minimally Invasive Cardiovascular Surgery
No full textMinimally invasive cardiac surgery (MI CS) has revolutionized cardiovascular interventions. A crucial step during many MI CS targeting the left side of the heart is the transeptal puncture (TP) performed in the fossa ovalis (FO). Performing a manual TP poses challenges, requiring a high level of expertise and a steep learning curve. This has motivated interest in the exploration of robotic transseptal puncture, aiming to improve the accuracy of execution. This study conducts a comprehensive analysis of the impact of puncture speed on TP safety using a robotic implementation system and a specially designed FO simulator. Specifically, a 7 Degree of Freedoms (DoFs). manipulator was used to perform the puncture using the standard transseptal kit commonly used in manual TP. Moreovere, to measure the interaction forces between the needle and the tissue, a load cell was attached to the base of the end effector of the manipulator. The simulator was built and validated against existing models proposed in the literature, successfully replicating the anatomical features and mechanical properties of the fossa ovalis tissue. Experimental results demonstrate that higher puncture velocities are associ-ated with reduced needle shear forces, improving the overall safety of the procedure
Left invertibility of output-quantized systems: an application to cryptography
No full textIn this paper a secure communication method is proposed, based on left invertibility of output-quantized dynamical systems. The sender uses an output-quantized linear system with a feedback function to encode messages, which are sequences of inputs of the system. So left invertibility property enables the receiver to recover the messages. The secret key is formed by the system’s parameters, including the feedback function. The use of quantization makes the cryptographic system work exactly, and without asymptotic estimates. Simulations of encoding-decoding procedure and results about security of the method are finally shown
Phytochemical Study of the Ecuadorian Species Lepechinia mutica (Benth.) Epling and High Antifungal Activity of Carnosol against Pyricularia oryzae
No full textThe plant Lepechinia mutica (Benth.) Epling (family Lamiaceae) is endemic to Ecuador. In the present study, we report some major non-volatile secondary metabolites from the leaves and the chemistry of the essential oil distilled from the flowers. The main identified compounds were carnosol, viridiflorol, ursolic acid, oleanolic acid, chrysothol, and 5-hydroxy-4′,7-dimethoxy flavone. Their structures were determined by X-ray diffraction and NMR and MS techniques. The essential oil showed a chemical composition similar to that distilled from the leaves, but with some qualitative and quantitative differences regarding several minor compounds. The main constituents (>4%) were: δ-3-carene (24.23%), eudesm-7(11)-en-4-ol (13.02%), thujopsan-2-α-ol (11.90%), β-pinene (7.96%), valerianol (5.19%), and co-eluting limonene and β-phellandrene (4.47%). The volatile fraction was also submitted to enantioselective analysis on a β-cyclodextrin column, obtaining the separation and identification of the enantiomers for α-thujene, β-pinene, sabinene, α-phellandrene, limonene and β-phellandrene. Furthermore, the anti-fungal activity of non-volatile secondary metabolites was tested in vitro, with carnosol resulting in being very active against the “blast disease” caused by the fungus Pyricularia oryzae
La comunità che cura: una ricerca azione partecipata per promuovere salute nella zona di Pescarola.
No full textRicerca-azione partecipata e promozione della salute nella zona di Pescarola (Bologna)
Trombosi venosa profonda degli arti inferiori durante varicella in bambino con mutazione del fattore V di Leiden e deficit familiare di proteina S
No full textModeling Human Motor Skills to Enhance Robots’ Physical Interaction
No full textThe need for users’ safety and technology acceptability has incredibly increased with the deployment of co-bots physically interacting with humans in industrial settings, and for people assistance. A well-studied approach to meet these requirements is to ensure human-like robot motions and interactions. In this manuscript, we present a research approach that moves from the understanding of human movements and derives usefull guidelines for the planning of arm movements and the learning of skills for physical interaction of robots with the surrounding environment.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Learning & Autonomous Contro
Imitation Learning for Path Planning in Cardiac Percutaneous Interventions
No full textObjective: Mitral regurgitation is a valvular heart disease particularly affecting the aging population. Minimally invasive transcatheter procedures offer benefits over traditional open-chest surgery but require significant operator skill and hand-eye coordination, making the learning curve steeper and limiting accessibility. To address these challenges, there is growing research interest in automating these procedures, making it crucial to define safe navigable routes within anatomical structures for robotic operation. This study introduces a tailored learning-based framework for path planning in cardiac percutaneous interventions, specifically adapted to the dynamically constrained and safety-critical environment of mitral valve repair. Methods: We compared generative adversarial imitation learning and behavioral cloning techniques to traditional path planning algorithms like rapidly-exploring random trees. Using patient-specific anatomical data, a faithful digital twin was created, with dynamic motions to replicate real-time cardiac movements of the mitral valve. Results: Learning approaches significantly reduced target position errors and improved path smoothness with greater clearance from obstacles compared to state-of-the-art methods. Conclusion: Learning methodologies provided consistent and repeatable routes in cardiac anatomy, both in pre-operative static and intra-operative dynamic scenarios. Significance: Embedding task demonstrations in the learning process shows the potential to automate and optimize catheter navigation, promoting standardization of minimally invasive cardiac procedures
Towards autonomous robotic procedure for ultrasound-guided percutaneous cardiac interventions for mitral valve repair
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