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 multi-stimuli 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 shape-morphing 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.

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.

Soft Robotics: A Route to Equality, Diversity, and Inclusivity in Robotics.

Robotics is entering our daily lives. The discipline is increasingly crucial in fields such as agriculture, medicine, and rescue operations, impacting our food, health, and planet. At the same time, it is becoming evident that robotic research must embrace and reflect the diversity of human society to address these broad challenges effectively. In recent years, gender inclusivity has received increasing attention, but it still remains a distant goal. In addition, awareness is rising around other dimensions of diversity, including nationality, religion, and politics. Unfortunately, despite the efforts, empirical evidence shows that the field has still a long way to go before achieving a sufficient level of equality, diversity, and inclusion across these spectra. This study focuses on the soft robotics community-a growing and relatively recent subfield-and it outlines the present state of equality and diversity panorama in this discipline. The article argues that its high interdisciplinary and accessibility make it a particularly welcoming branch of robotics. We discuss the elements that make this subdiscipline an example for the broader robotic field. At the same time, we recognize that the field should still improve in several ways and become more inclusive and diverse. We propose concrete actions that we believe will contribute to achieving this goal, and provide metrics to monitor its evolution.

A retrofit sensing strategy for soft fluidic robots.

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.

A bio-inspired expandable soft suction gripper for minimal invasive surgery-an explorative design study.

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.