V.G. Kortman
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13 records found
1
Adaptable by design
Encoding complex deformation profiles in mckibben artificial muscles
The octopus achieves intricate arm deformations through local muscle interactions rather than centralized coordination. Inspired by this principle, this study aims to develop embodied intelligent McKibben Artificial Muscles (AMs), in which global deformation is encoded directly into their physical structure. The key design parameter explored is the braiding angle, which governs the type and magnitude of motion. By spatially varying this angle along the actuator, we demonstrate embedded capabilities for local extension and contraction within a single AM. Additionally, a mismatch in braiding angles between opposing wire sets generates a twisting motion. To implement these variations, traditional braiding techniques were adapted for localized angle control. Within a single McKibben AM, a maximum strain of +0.06 and minimum strain of −0.19 was measured. A twist angle of 100° was achieved using a 50.4° angle difference at 50 kPa actuation pressure. A final modular prototype demonstrated the integration of multiple motion modes within a single actuator body. These results highlight the potential of mechanically intelligent AMs to simplify actuation systems in soft robotics. Applications include wearable technologies such as exoskeletons and prosthetics, as well as bioinspired systems like artificial hearts or continuum robotic arms, where compact and adaptive actuation is essential.
Soft robots are intrinsically capable of adapting to different environments by changing their shape in response to interaction forces. However, sensory feedback is still required for higher level decisions. Most sensing technologies integrate separate sensing elements in soft actuators, which presents a considerable challenge for both the fabrication and robustness of soft robots. Here we present a versatile sensing strategy that can be retrofitted to existing soft fluidic devices without the need for design changes. We achieve this by measuring the fluidic input that is required to activate a soft actuator during interaction with the environment, and relating this input to its deformed state. We demonstrate the versatility of our strategy by tactile sensing of the size, shape, surface roughness and stiffness of objects. We furthermore retrofit sensing to a range of existing pneumatic soft actuators and grippers. Finally, we show the robustness of our fluidic sensing strategy in closed-loop control of a soft gripper for sorting, fruit picking and ripeness detection. We conclude that as long as the interaction of the actuator with the environment results in a shape change of the interval volume, soft fluidic actuators require no embedded sensors and design modifications to implement useful sensing.
Unlocking Versatility
Magnetic-Actuated Deployable Suction Gripper for Complex Surface Handling
Suction grippers offer a distinct advantage in their ability to handle a wide range of items. However, attaching these grippers to irregular and rough surfaces presents an ongoing challenge. To address this obstacle, this study explores the integration of magnetic intelligence into a soft suction gripper design, enabling fast external magnetic actuation of the attachment process. Additionally, miniaturization options are enhanced by implementing a compliant deploying mechanism. The resulting design is the first-of-its-kind magnetically-actuated deployable suction gripper featuring a thin magnetic membrane (Ø 50 mm) composed of carbonyl iron particles embedded in a silicone matrix. This membrane is supported by a frame made of superelastic nitinol wires that facilitate deployment. During experiments, the proof-of-principle prototype demonstrates successful attachment on a diverse range of curved surfaces in both dry and wet environments. The gripper achieves attachment on curved surfaces with radii of 50-75 mm, exerting a maximum attachment force of 2.89 ± 0.54 N. The current gripper design achieves a folding percentage of 75%, enabling it to fit into a Ø 12.5 mm tube and access hard-to-reach areas while maintaining sufficient surface area for attachment forces. The proposed prototype serves as a foundational steppingstone for further research in the development of reliable and effective magnetically-actuated suction grippers across various configurations. By addressing the limitations of attachment to irregular surfaces and exploring possibilities for miniaturization and precise control, this study opens new avenues for the practical application of suction grippers in diverse industries and scenarios.
Advancements in aspiration catheter tip design for thrombectomy
A comprehensive patent review
Magnetic Stimulation for Programmed Shape Morphing
Review of Four-Dimensional Printing, Challenges and Opportunities
In the field of Additive Manufacturing, four-dimensional (4D) printing has emerged as a promising technique to fabricate smart structures capable of undergoing shape morphing in response to specific stimuli. Magnetic stimulation offers a safe, remote, and rapid actuation mechanism for magnetically responsive structures. This review provides a comprehensive overview of the various strategies and manufacturing approaches employed in the development of magnetically stimulated shape morphing 4D-printed structures, based on an extensive literature search. The review explores the use of magnetic stimulation either individually or in combination with other stimuli. While most of the literature focuses on single-stimulus responsive structures, a few examples of multistimuli responsive structures are also presented. We investigate the influence of the orientation of magnetic particles in smart material composites, which can be either random or programmed during or after printing. Finally, the similarities and differences among the different strategies and their impact on the resulting shapemorphing behavior are analyzed. This systematic overview functions as a guide for readers in selecting a manufacturing approach to achieve a specific magnetically actuated shape-morphing effect.
Gripping slippery and flexible tissues during minimal invasive surgery (MIS) is often challenging using a conventional tissue gripper. A force grip has to compensate for the low friction coefficient between the gripper’s jaws and the tissue surface. This study focuses on the development of a suction gripper. This device applies a pressure difference to grip the target tissue without the need to enclose it. Inspiration is taken from biological suction discs, as these are able to attach to a wide variety of substrates, varying from soft and slimy surfaces to rigid and rough rocks. Our bio-inspired suction gripper is divided into two main parts: (1) the suction chamber inside the handle where vacuum pressure is generated, and (2) the suction tip that attaches to the target tissue. The suction gripper fits through a ∅ 10 mm trocar and unfolds in a larger suction surface when being extracted. The suction tip is structured in a layered manner. The tip integrates five functions in separate layers to allow for safe and effective tissue handling: (1) foldability, (2) air-tightness, (3) slideability, (4) friction magnification and (5) seal generation. The contact surface of the tip creates an air-tight seal with the tissue and enhances frictional support. The suction tip’s shape grip allows for the gripping of small tissue pieces and enhances its resistance against shear forces. The experiments illustrated that our suction gripper outperforms man-made suction discs, as well as currently described suction grippers in literature in terms of attachment force ( 5.95 ± 0.52 N on muscle tissue) and substrate versatility. Our bio-inspired suction gripper offers the opportunity for a safer alternative to the conventional tissue gripper in MIS.
Tissue extraction plays a crucial role in various medical disciplines, with aspiration catheters serving as the prevailing method. Unfortunately, these catheters face limitations such as clogging and dependence on tissue properties and device dimensions. Therefore, there is a pressing need for an improved tissue extraction device that enables efficient and reliable tissue removal during Minimally Invasive Surgery (MIS).
Methods
In this study, we present a novel tissue transport system that utilizes a cylindrical conveyor belt mechanism for reliable tissue transportation. We conducted experiments using a proof-of-principle prototype to explore the influence of tissue elasticity, rotational velocity, instrument orientation, and tissue shape on the transportation rate, efficiency, and reliability. Tissue phantoms with gelatine concentrations of 3, 9, and 12 wt% were employed to simulate a range of Young’s moduli from 1 to 110 kPa.
Results
The mean transportation rates for these phantoms were 7.75±0.48, 8.43±1.50, and 8.90±0.56 g/min, respectively. Notably, all phantoms were transported successfully. The perfect reliability exhibited underscores the potential of our instrument as an alternative to aspiration catheters.
Conclusion
This research presents a significant step forward in the field of tissue extraction, offering a promising approach for MIS with enhanced efficiency and reliability.
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Tissue extraction plays a crucial role in various medical disciplines, with aspiration catheters serving as the prevailing method. Unfortunately, these catheters face limitations such as clogging and dependence on tissue properties and device dimensions. Therefore, there is a pressing need for an improved tissue extraction device that enables efficient and reliable tissue removal during Minimally Invasive Surgery (MIS).
Methods
In this study, we present a novel tissue transport system that utilizes a cylindrical conveyor belt mechanism for reliable tissue transportation. We conducted experiments using a proof-of-principle prototype to explore the influence of tissue elasticity, rotational velocity, instrument orientation, and tissue shape on the transportation rate, efficiency, and reliability. Tissue phantoms with gelatine concentrations of 3, 9, and 12 wt% were employed to simulate a range of Young’s moduli from 1 to 110 kPa.
Results
The mean transportation rates for these phantoms were 7.75±0.48, 8.43±1.50, and 8.90±0.56 g/min, respectively. Notably, all phantoms were transported successfully. The perfect reliability exhibited underscores the potential of our instrument as an alternative to aspiration catheters.
Conclusion
This research presents a significant step forward in the field of tissue extraction, offering a promising approach for MIS with enhanced efficiency and reliability.