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Force from Shape --- Estimating the Location and Magnitude of the External Force on Flexible Instruments

Journal Contribution - Journal Article

Abstract—Force sensing is highly desirable in minimally invasive medical applications, since this feature shows great potential for reducing tissue damage and enhancing manipulation safety. However, embedding force sensors in medical devices is challenging and costly. This paper explores the possibility to use shape sensing as a measure to extract force information. In this work, a model-based approach that allows simultaneous shape and force sensing is proposed. Shape information is reconstructed employing a multi-core Fiber Bragg Grating fiber with multiple sensing locations. This fiber is capable of distributed 3D shape sensing. It is shown how by making use of Extended Kalman Filter and a mechanics model of the flexible instrument it becomes possible to estimate both the magnitudes and locations of externally applied forces. Experiments were carried out to validate the proposed method for both one and two external forces applied at arbitrary locations in different directions on a flexible instrument. Results show that one-directional force magnitude and location can be estimated with an average error of 23.08 mN (15.39%) and 11.06 mm (6.51%), respectively. For two-directional forces, results of the load near the base show an average error of 52.01 mN (30.59%) for magnitude and 29:24 mm (17.20%) for the location. For the load applied simultaneously near the tip, the mean magnitude error is 16:79 mN (11.19%) and the average location error is 10:18 mm (5.99%). The force sensing algorithm can run in real-time with an approximate frequency of 59 Hz. In these experiments it can be observed that force-sensing accuracy, which depends on the sensitivity of the shape of flexible instruments with respect to the external force, can vary drastically
Journal: IEEE Transactions on Robotics
ISSN: 1552-3098
Issue: 5
Volume: 37
Pages: 1 - 8
Publication year:2021
BOF-keylabel:yes
IOF-keylabel:yes
BOF-publication weight:3
CSS-citation score:1
Authors from:Higher Education
Accessibility:Open