Optimal Design of Soft Continuum Magnetic Robots under Follow-the-leader Shape Forming Actuation

Lloyd, Peter; Pittiglio, Giovanni; Chandler, James H.; Valdastri, Pietro

doi:10.1109/ismr48331.2020.9312943

Cited by 13 publications

(23 citation statements)

References 23 publications

(35 reference statements)

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“…An algorithm for the selection of a magnetization profile and actuating fields for a fully shape forming catheter was demonstrated, in a virtual environment, in Lloyd et al (2020b) . The contribution of this work was to develop an optimization routine to derive specific magnetization profiles and time variant actuating fields to achieve follow-the-leader motion without imparting contact forces on the surrounding environment during navigation.…”

Section: Problem Definitionmentioning

confidence: 99%

“…The reinforced sample on the right constrains the unstable twisting mode of actuation resulting in larger magnetic torque in the desired, bending, mode of deflection. FIGURE 2 | A minimal reproducible example of the impact of magnetic instability arising during manipulator navigation [as introduced in Lloyd et al (2020b)]. Specific magnetization profiles and time variant actuating fields achieve follow-the-leader motion without imparting contact forces on the surrounding environment.…”

Section: Introductionmentioning

confidence: 99%

“…supporting video). A combination of diverse magnetic signatures Lum et al (2016) and time-variant actuating fields Lloyd et al (2020b) will inevitably create obtuse angles of actuation. Such obtuse angles will also unavoidably occur in the case that actuation is generated via external permanent magnets [e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Key to the development of the shape forming magnetic CM is the ability to support unstable combinations of magnetization and applied field (illustrated in Figure 1 and demonstrated in the supporting video). A combination of diverse magnetic signatures Lum et al (2016) and time-variant actuating fields Lloyd et al (2020b) will inevitably create obtuse angles of actuation. Such obtuse angles will also unavoidably occur in the case that actuation is generated via external permanent magnets [e.g.…”

Section: Introductionmentioning

confidence: 99%

“… A minimal reproducible example of the impact of magnetic instability arising during manipulator navigation [as introduced in Lloyd et al (2020b) ]. Specific magnetization profiles and time variant actuating fields achieve follow-the-leader motion without imparting contact forces on the surrounding environment.…”

Section: Introductionmentioning

confidence: 99%

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Feasibility of Fiber Reinforcement Within Magnetically Actuated Soft Continuum Robots

et al. 2021

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Soft continuum manipulators have the potential to replace traditional surgical catheters; offering greater dexterity with access to previously unfeasible locations for a wide range of interventions including neurological and cardiovascular. Magnetically actuated catheters are of particular interest due to their potential for miniaturization and remote control. Challenges around the operation of these catheters exist however, and one of these occurs when the angle between the actuating field and the local magnetization vector of the catheter exceeds 90°. In this arrangement, deformation generated by the resultant magnetic moment acts to increase magnetic torque, leading to potential instability. This phenomenon can cause unpredictable responses to actuation, particularly for soft, flexible materials. When coupled with the inherent challenges of sensing and localization inside living tissue, this behavior represents a barrier to progress. In this feasibility study we propose and investigate the use of helical fiber reinforcement within magnetically actuated soft continuum manipulators. Using numerical simulation to explore the design space, we optimize fiber parameters to enhance the ratio of torsional to bending stiffness. Through bespoke fabrication of an optimized helix design we validate a single, prototypical two-segment, 40 mm × 6 mm continuum manipulator demonstrating a reduction of 67% in unwanted twisting under actuation.

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Section: Problem Definitionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Feasibility of Fiber Reinforcement Within Magnetically Actuated Soft Continuum Robots

et al. 2021

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Patient-Specific Magnetic Catheters for Atraumatic Autonomous Endoscopy

et al. 2022

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Despite increasing interest in minimally invasive surgical techniques and related developments in flexible endoscopes and catheters, follow-the-leader motion remains elusive. Following the path of least resistance through a tortuous and potentially delicate environment without relying on interaction with the surrounding anatomy requires the control of many degrees of freedom. This typically results in large-diameter instruments. One viable solution to obtain dexterity without increasing size is via multiple-point magnetic actuation over the length of the catheter. The main challenge of this approach is planning magnetic interaction to allow the catheter to adapt to the surrounding anatomy during navigation. We design and manufacture a fully shape-forming, soft magnetic catheter of 80 mm length and 2 mm diameter, capable of navigating a human anatomy in a follow-the-leader fashion. Although this system could be exploited for a range of endoscopic or intravascular applications, here we demonstrate its efficacy for navigational bronchoscopy. From a patient-specific preoperative scan, we optimize the catheters’ magnetization profiles and the shape-forming actuating field. To generate the required transient magnetic fields, a dual-robot arm system is employed. We fabricate three separate prototypes to demonstrate minimal contact navigation through a three-dimensional bronchial tree phantom under precomputed robotic control. We also compare a further four separate optimally designed catheters against mechanically equivalent designs with axial magnetization profiles along their length and only at the tip. Using our follow-the-leader approach, we demonstrate up to 50% more accurate tracking, 50% reduction in obstacle contact time during navigation over the state of the art, and an improvement in targeting error of 90%.

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Magnetic-Actuated Flexible Instruments with Enhanced Bending Capability through Magnetic Distribution Optimization

Huang,

Ma,

et al. 2023

2023 IEEE 19th International Conference on Automation Science and Engineering (CASE)

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Optimal Design of Soft Continuum Magnetic Robots under Follow-the-leader Shape Forming Actuation

Abstract: This is a repository copy of Optimal Design of Soft Continuum Magnetic Robots under Follow-the-leader Shape Forming Actuation.

Cited by 13 publications

References 23 publications

Feasibility of Fiber Reinforcement Within Magnetically Actuated Soft Continuum Robots

Feasibility of Fiber Reinforcement Within Magnetically Actuated Soft Continuum Robots

Patient-Specific Magnetic Catheters for Atraumatic Autonomous Endoscopy

Magnetic-Actuated Flexible Instruments with Enhanced Bending Capability through Magnetic Distribution Optimization

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