Manipulation Capabilities Research Articles

Realization of multi-transverse-mode squeezed optical frequency combs with Gouy phase compensation

Multimode quantum light fields significantly enhance quantum state manipulation and communication capabilities by expanding the dimensionality of the Hilbert space. In this work, we elaborately design a non-horizontal cavity suitable for a Gouy phase-compensated synchronously pumped optical parametric oscillator. By injecting an optical frequency comb in HG10 mode into the cavity as the seed, we demonstrate the simultaneous generation of a bright squeezed optical frequency comb in HG10 mode and a vacuum squeezed optical frequency comb in HG01 mode. The coexistence of amplitude quadrature squeezed fields in these two orthogonal first-order Hermite-Gaussian transverse modes also suggest the presence of quadrature entanglement between the two first-order Laguerre-Gaussian modes, LG0 + 1 and LG0 - 1. This research underscores the capability of one-step generation of multi-transverse-mode squeezed optical frequency combs using a single cavity, marking a significant stride in the realm of quantum optics.

Survey of learning-based approaches for robotic in-hand manipulation

Human dexterity is an invaluable capability for precise manipulation of objects in complex tasks. The capability of robots to similarly grasp and perform in-hand manipulation of objects is critical for their use in the ever changing human environment, and for their ability to replace manpower. In recent decades, significant effort has been put in order to enable in-hand manipulation capabilities to robotic systems. Initial robotic manipulators followed carefully programmed paths, while later attempts provided a solution based on analytical modeling of motion and contact. However, these have failed to provide practical solutions due to inability to cope with complex environments and uncertainties. Therefore, the effort has shifted to learning-based approaches where data is collected from the real world or through a simulation, during repeated attempts to complete various tasks. The vast majority of learning approaches focused on learning data-based models that describe the system to some extent or Reinforcement Learning (RL). RL, in particular, has seen growing interest due to the remarkable ability to generate solutions to problems with minimal human guidance. In this survey paper, we track the developments of learning approaches for in-hand manipulations and, explore the challenges and opportunities. This survey is designed both as an introduction for novices in the field with a glossary of terms as well as a guide of novel advances for advanced practitioners.

Metabarriers for mitigating traffic-induced surface waves: Mechanism dependence on buried arrangements

Locally resonant metamaterials provide exceptional wave manipulation capabilities in the low-frequency regime. This study introduces a buried metabarrier, which can simultaneously harness both resonant and geometric scatterings, to attenuate surface Rayleigh waves at both low and high frequencies induced by traffic. In particular, how the buried arrangements of metabarriers influence their resonant- and geometric-scattering mechanisms is investigated by considering the metabarrier units buried vertically and horizontally in the ground. To this purpose, a numerical finite element model, which is verified through comparisons with existing studies, is developed to analyze the attenuation performance of the metabarrier. Using this model, we perform parametric studies to examine the effects of the material properties and dimensions of the metabarriers on their attenuation behavior. Due to resonant scattering, low-frequency Rayleigh waves are mainly reflected by the vertical metabarriers; in contrast, they are predominantly converted into refracted bulk waves by the horizontal metabarriers. Additionally, the geometric scattering of horizontal metabarriers yields Bragg effects, which can reflect more high-frequency Rayleigh waves and induce a partial mode conversion to transverse bulk waves. Our systematic investigations will, to some extent, facilitate the future design of a well-performing metabarrier attenuating broadband Rayleigh waves.

Electromagnetic Manipulation Evolution from Stacked Meta‐Atoms to Spatially Cascaded Metasurfaces

AbstractMetasurfaces, known as planar two‐dimensional (2D) metamaterials, are proposed to overcome obstacles like high loss and bulky volume occurring with three‐dimensional (3D)metamaterials. Single‐layer structures face limited degrees of freedom, and cannot satisfy the growing functional demands for meta‐devices. To simplify the design process and gain more controllability, quasi‐2D structures are introduced into metasurfaces in the form of stacked meta‐atoms design or spatially cascaded metasurfaces. These configurations greatly expand the manipulation capability of metasurfaces and spawn a variety of functions and applications. In this review, the progress of metasurfaces with multi‐layer stacked meta‐atoms and spatially cascaded metasurfaces is presented. Progress is presented from metasurfaces with multi‐layer stacked meta‐atom configurations to spatially cascaded metasurfaces, focusing on the development of versatile applications for these quasi‐2D configurations. Special attentions are paid to the diffractive deep neural networks(D2NNs), and a category of recently developed cascaded metasurfaces introduces a brand‐new method into metasurface inverse designing as well as paves paths to all‐optical computing. Finally, the promising avenues for such metasurfaces are discussed.

Bionic Fluorine-Free Multifunctional Photothermal Surface for Anti/de/Driving-Icing and Droplet Manipulation.

Due to safety concerns associated with ice accumulation, there is a need to develop a durable surface with anti/de-icing properties. Inspired by Gecko skin and Nepenthes, a superhydrophobic photothermal surface (SH-PS) with micro-nano hierarchical structure based on carbon nanotube composites is prepared by one-step laser method. It can be switchable to a slippery photothermal surface (S-PS) by injecting silicone oil. S-PS can effectively delay icing at -20 °C/-30 °C, and maintain excellent dynamic anti-icing capabilities following 28 times supercooled droplet impact (-30 °C). Under near-infrared (NIR) irradiation, S-PS exhibits high-efficiency photothermal deicing and excellent ice droplet control capabilities. Furthermore, S-PS also exhibits remarkable droplet manipulation capabilities under NIR irradiation, even anti-gravity transport (8°) and programmable track manipulation. Notably, after 20m abrasion, the S-PS still maintains good performances of anti/de-icing and droplet manipulation after infusing lubricant. All these excellent performances can promote its application in a wider range of fields.

Tunable Acoustic Tweezer System for Precise Three-Dimensional Particle Manipulation

This study introduces a tunable acoustic tweezer system designed for precise three-dimensional particle trapping and manipulation. The system utilizes a dual-liquid-layer acoustic lens, which enables the dynamic control of the focal length through the adjustable curvature of a latex membrane. This tunability is essential for generating the acoustic forces necessary for effective manipulation of particles, particularly along the direction of acoustic wave propagation (z-axis). Experiments conducted with spherical particles as small as 1.5 mm in diameter demonstrated the system’s capability for stable trapping and manipulation. Performance was rigorously evaluated through both z-axis and 3D manipulation tests. In the z-axis experiments, the system achieved a manipulation range of 33.4–53.4 mm, with a root-mean-square error and standard deviation of 0.044 ± 0.045 mm, which highlights its precision. Further, the 3D manipulation experiments showed that particles could be accurately guided along complex paths, including multilayer rectangular and helical trajectories, with minimal deviation. A visual feedback-based particle navigation system significantly enhanced positional accuracy, reducing errors relative to open-loop control. These results confirm that the tunable acoustic tweezer system is a robust tool for applications requiring precise control of particles with diameter of 1.5 mm in three-dimensional environments. Considering its ability to dynamically adjust the focal point and maintain stable trapping, this system is well suited for tasks demanding high precision, such as targeted particle delivery and other applications involving advanced material manipulation.

Experimental validation of anomalous acoustic wave refraction using Double layered acoustic gratings

Acoustic metasurfaces (AMSs) have garnered increasing attention over the past decade due to their remarkable capability for wave manipulation. AMSs have been widely applied in diverse domains, including anomalous refraction and extraordinary sound absorption/isolation, among others. However, typical AMS designs, such as Helmholtz resonator-like or labyrinthine structures, are often geometrically complex, limiting their practical usability. In this paper, we introduce an ultracompact Double Layered Acoustic Grating (DLAG) to achieve anomalous acoustic wave refraction. The DLAG comprises double-layered rigid panels with multiple perforated subwavelength slits. By optimizing the positions of these slits on the rigid panels, the acoustic energy of an obliquely incident plane wave can be concentrated within a predetermined region in an arbitrary direction. The paper will first review the theoretical background to predict the wave propagation controlled by DLAGs based on the surface coupling approach. Subsequently, the underlying principle to achieve anomalous refraction using DLAGs will be discussed. A 3D-printed DLAG with the optimized slit positions is used for demonstration. In the experiment, the acoustic energy of a plane wave with an incident angle of 36 degrees was successfully collimated within a predetermined focusing region with a negative refracted angle of -36 degrees.

1-bit absorption-diffusion acoustic coding metasurface

Acoustic metasurfaces demonstrate unprecedented potential for flexible capabilities of the acoustic wavefront manipulation. Especially, acoustic diffusers and absorbers via acoustic metasurfaces have garnered significant attention of researchers due to the excellent performance. However, although these diffusers and absorbers have achieved excellent acoustic scattering suppression, it still remains a significant challenge to obtain higher scattering suppression. Here, a 1-bit absorption-diffusion acoustic coding metasurface (ADM) is proposed, which can achieve high-performance acoustic backward scattering reduction in the operating frequency by combining the advantages of acoustic diffusers and absorbers. In order to realize the proposed ADM, two kinds of subwavelength dual-layer unit cells with opposite reflection phases and low amplitudes are introduced. Both simulated and experimental results demonstrate that the proposed ADM can achieve the pre-designed backward acoustic scattering reduction. The proposed integrated mechanism can provide a new method for designing high-performance acoustic metasurfaces, which can have potential applications in stealth technology, noise control and other relevant applications.

A hybrid gripper with electro-adhesive film for variable friction

In recent years, gripper technology has gained attention in robotics for reliably handling objects with delicate and complex shapes. Electro-adhesive grippers, in particular, have received significant attention due to their role in enhancing object grasping and manipulation capabilities. While much of the existing research has focused on improving electro-adhesion through advancements in EA film and nanoparticle modifications, this study takes a different approach by integrating electro-adhesion as an auxiliary function within a mechanical gripper. This integration allows for a novel hybrid gripper that uses electro-adhesive force to reduce the required normal force during gripping, thereby improving the handling of challenging objects. We thoroughly analyzed the gripper’s geometric design, along with its kinematic and mechanical properties. Our study also examined crucial performance parameters, such as nanoparticle content, composition, and electrode design, to optimize the generation and maintenance of electro-adhesion. To confirm performance, the developed gripper was affixed to a UR3 robotic manipulator from Universal Robotics, and gripping experiments on assorted objects, as well as anti-slip control experiments, were carried out. The results demonstrated that the integration of electro-adhesive force with a mechanical gripper significantly enhances gripping capability, particularly in terms of slip control and friction variation. This indicates that the Electro-Adhesive (EA) film hybrid gripper presents a novel and effective approach to advancing gripping and manipulation technologies.

Nonlinear elasticity tailoring and failure mode manipulation of functionally graded honeycombs under large deformation

Design of lattice metamaterials with tailored mechanical properties at a relatively higher (macro) length scale by architecting lower (micro) length scale geometric and material configurations leads to achieving unprecedented mechanical properties for fulfilling advanced multi-functional structural demands. In the design space of innovative microstructural configurations, we propose a novel class of lattice metamaterials with cell walls made of optimally designed functionally graded intrinsic materials. Under different modes of remotely applied mechanical stresses, two different intuitive architectures of functional gradations for the intrinsic cell wall materials are proposed. The large-deformation nonlinear lattices result in broadband modulation of effective stiffness, and an unprecedented manipulation capability of failure modes and corresponding strengths covering ductile and brittle types depending on architected material gradation. For estimating the nonlinear elasticity and microstructural stresses as a measure of failure mode for the proposed functionally graded lattices undergoing large deformation, a multi-scale mechanics-based semi-analytical framework is developed. Geometrically nonlinear functionally graded beams with generalized material gradation, integrated with unit cell architectures, are analyzed through iterative variational energy principle-based Ritz approach. Based on the developed physically insightful computational framework, effective nonlinear elastic properties and failure modes of the functionally graded honeycomb lattices are tailored as a function of the intrinsic material gradation at the lower length scale. The proposed novel class of lattices with optimally designed functionally graded intrinsic materials and coupled unit cell architectures would open up innovative avenues for designing advanced multi-functional engineering structures and mechanical systems.

Au Nanorings/TiO2 NPs@MXene-Based Metasurfaces with a Magnetic Mirror-Modulated ECL Strategy for Extracellular Vesicle Detection.

A metasurface as an artificial electromagnetic structure can concentrate optical energy into nanometric volumes to strongly enhance the light-matter interaction, which has been becoming a powerful platform for optical sensing, nonlinear effects, and quantum optics. Herein, we developed a novel hybrid plasmonic-dielectric metasurface consisting of Au nanorings (Au NRs) and TiO2 nanoparticles derived from MXene (TiO2 NPs@MXene). The hybrid metasurface simultaneously benefited from the high near-field enhancement effect of plasmonic materials and the low loss of dielectric materials. Furthermore, the optical modulation efficiency of the hybrid metasurface can be regulated by a magnetic mirror configuration. The magnetic mirror acted like a mirror, confining the electrons to a limited region and increasing the density of the surface plasmon. Moreover, the electrochemiluminescence (ECL) of the Cu2BDC metal-organic framework (Cu2BDC-MOF) served as a light source for the Au NRs/TiO2 NPs@MXene metasurface. Due to the exceptional light manipulation capability of the hybrid metasurface and the coordination of the magnetic mirror, the isotropic ECL signal can be dynamically amplified and converted into polarized emission. Finally, a metasurface-regulated ECL (MECL)-based biosensor with a dual-positive membrane protein recognition strategy was developed for the accurate identification of gastric cancer-derived extracellular vesicles. The novel MECL research opened up a new route in the realization of dynamically tunable metasurfaces for optical sensing and novel nanophotonic devices.

Increasing Horizontal Controlled Force Delivery Capabilities of Aerial Manipulators by Leveraging the Environment

Delivering large horizontal controlled forces for long periods with aerial manipulators is not an easy task to accomplish; several factors including disturbances, reaction forces from the on-board arm or actuator’s limitations might diminish their horizontal force delivery capabilities. Aiming to mitigate these drawbacks, this paper presents a comprehensive study of the force delivery capabilities of aerial manipulators leveraging the environment. The methodology to evaluate the aforementioned capabilities is the Generalized-Jacobian-based force ellipsoid, which was applied to different types of both free-flying and attached-to-the-environment aerial manipulators. In addition, large controlled force delivery experiments with the mentioned manipulators were conducted on physics-engine-based robotics simulation software. The obtained results categorically demonstrate that aerial manipulators leveraging the environment are capable of delivering larger forces than their free-flying counterparts, which has not been proved in the literature so far in the field of aerial robotics.

Design and batch fabrication of anisotropic microparticles toward small-scale robots using microfluidics: recent advances.

Small-scale robots with shape anisotropy have garnered significant scientific interest due to their enhanced mobility and precise control in recent years. Traditionally, these miniature robots are manufactured using established techniques such as molding, 3D printing, and microfabrication. However, the advent of microfluidics in recent years has emerged as a promising manufacturing technology, capitalizing on the precise and dynamic manipulation of fluids at the microscale to fabricate various complex-shaped anisotropic particles. This offers a versatile and controlled platform, enabling the efficient fabrication of small-scale robots with tailored morphologies and advanced functionalities from the microfluidic-derived anisotropic microparticles at high throughput. This review highlights the recent advances in the microfluidic fabrication of anisotropic microparticles and their potential applications in small-scale robots. In this review, the term 'small-scale robots' broadly encompasses micromotors endowed with capabilities for locomotion and manipulation. Firstly, the fundamental strategies for liquid template formation and the methodologies for generating anisotropic microparticles within the microfluidic system are briefly introduced. Subsequently, the functionality of shape-anisotropic particles in forming components for small-scale robots and actuation mechanisms are emphasized. Attention is then directed towards the diverse applications of these microparticle-derived microrobots in a variety of fields, including pollution remediation, cell microcarriers, drug delivery, and biofilm eradication. Finally, we discuss future directions for the fabrication and development of miniature robots from microfluidics, shedding light on the evolving landscape of this field.

Mechanochromic Suction Cups for Local Stress Detection in Soft Robotics

Advancements in smart soft materials are enhancing the capabilities of robotic manipulators in object interactions and complex tasks. Mechanochromic materials, acting as lightweight sensors, offer easily interpretable visual feedback for localized stress detection, structural health monitoring, and energy‐efficient robotic skins. Herein, an innovative mechanochromic soft end‐effector capable of discerning local contact stresses during mechanical interactions with objects is presented and their relative position is ascertained. This system utilizes a reversible force‐induced color switch in a thin layer of spiropyran‐functionalized polydimethylsiloxane, which coats a silicone‐made suction cup. The mechanochromic suction cup is integrated with a 3D‐printed compact load‐transferring system and electronic color‐changing detection elements. The assembly may serve as a synthetic receptor for robotic actuators, discerning localized interaction forces down to 3 N. The system's resilience to varying environmental factors, including illumination, tilting, and interaction with objects of various shapes is verified. The results indicate potential for exteroceptive solutions in reconfigurable manipulation tasks without compromising the overall softness of the manipulator.

Wide-angle reflection control with a reflective digital coding metasurface for 5G communication systems

Abstract Metasurfaces have attracted widespread attention in recent years due to their powerful electromagnetic wave manipulation capabilities. This paper proposes and validates a single-polarized, angle-adjustable reflective digital coding metasurface. Each unit cell achieves independent reflection phase control by loading a PIN diode for on-off switching. The unit’s design and coding scheme are carefully optimized to ensure the performance of the proposed reconfigurable metasurface. As a validation, a prototype consisting of 16×16 elements is fabricated and measured, with a control signal provided by a field-programmable gate array controller. Experimental results demonstrate angle control of up to ±60° in the frequency range of 3.4 GHz–3.6 GHz, a peak gain of 24.9 dBi in a single channel, and gain exceeding 10 dBi across a 200 MHz operational bandwidth. Furthermore, the performance is validated in a communication system, yielding positive results. The proposed reflective digital coding metasurface contributes to the advancement of reconfigurable intelligent surfaces and holds promise for widespread adoption in various communication scenarios.

Magnetic Torque-Driven All-Terrain Microrobots.

All-terrain microrobots possess significant potential in modern medical applications due to their superior maneuverability in complex terrains and confined spaces. However, conventional microrobots often struggle with adaptability and operational difficulties in variable environments. This study introduces a magnetic torque-driven all-terrain multiped microrobot (MTMR) to address these challenges. By coupling the structure's multiple symmetries with different uniform magnetic fields, such as rotating and oscillating fields, the MTMR demonstrates various locomotion modes, including rolling, tumbling, walking, jumping, and their combinations. Experimental results indicate that the robot can navigate diverse terrains, including flat surfaces, steep slopes (up to 75°), and gaps over twice its body height. Additionally, the MTMR performs well in confined spaces, capable of passing through slits (0.1 body length) and low tunnels (0.25 body length). The robot shows potential for clinical applications like minimally invasive hemostasis in internal bleeding and thrombus removal from blood vessels through accurate cargo manipulation capability. Moreover, the MTMR can carry temperature sensors to monitor environmental temperature changes in real time while simultaneously manipulating objects, displaying its potential for in-situ sensing and parallel task implementation. This all-terrain microrobot technology demonstrates notable adaptability and versatility, providing a solid foundation for practical applications in interventional medicine.

A passive convex optimal control algorithm for teleoperating a redundant robotic arm in minimally invasive surgery

AbstractIn recent years, the remote center of motion (RCM) constraint has moved from purely mechanical to software implementation, enabling the use of serial manipulators in robotic‐assisted minimal invasive surgery. However, ensuring safety with software‐based RCM presents challenges. This article addresses this issue by introducing a novel control algorithm for a 7‐DOF redundant robotic arm, taking into account a software RCM while considering system passivity and kinematic constraints. The algorithm is both a control optimizer and a robot kinematics inversion, enabling precise and dexterous control for various surgical tasks and other control applications. By formulating a quadratic optimization problem under linear constraints, the algorithm guarantees the robotic arm's performance, safety, and stability under communication delay. Experimental validation demonstrates the effectiveness and accuracy of the control algorithm in executing a surgical training task (peg‐and‐ring) during bilateral teleoperation. The results highlight the successful implementation of the RCM constraint, ensuring patient safety and optimizing the manipulation capabilities of the robotic arm.

Phase-modulated pulsing coherent acoustic tweezers for dynamic adjustable spaced particle patterning

Abstract Acoustic tweezer technique with non-contact micro-object manipulation capability has been widely utilized for particle patterning in the fields of cell arraying, target drug delivery, and functional composite fabrication. However, the manipulation resolution of acoustic tweezer device is decided by the configuration of interdigital transducers (IDTs), which is half the wavelength of surface acoustic waves (SAWs). This limitation severely reduces the manipulation versatility of acoustic tweezer devices. To address this limitation, we propose a novel approach that employs phase-modulated pulsing coherent SAWs. This method can halve the patterning spacing and allows for customization of the spacing based on specific manipulation demands. Our proposed technique increases the flexibility and manipulation resolution of acoustic tweezer device, and thus can be widely applied to reconfigurable assembly and precise manipulation of particles and cells.

Addictive manipulation: a perspective on the role of reproductive parasitism in the evolution of bacteria-eukaryote symbioses.

Wolbachia bacteria encompass noteworthy reproductive manipulators of their arthropod hosts. which influence host reproduction to favour their own transmission, also exploiting toxin-antitoxin systems. Recently, multiple other bacterial symbionts of arthropods have been shown to display comparable manipulative capabilities. Here, we wonder whether such phenomena are truly restricted to arthropod hosts. We focused on protists, primary models for evolutionary investigations on eukaryotes due to their diversity and antiquity, but still overall under-investigated. After a thorough re-examination of the literature on bacterial-protist interactions with this question in mind, we conclude that such bacterial 'addictive manipulators' of protists do exist, are probably widespread, and have been overlooked until now as a consequence of the fact that investigations are commonly host-centred, thus ineffective to detect such behaviour. Additionally, we posit that toxin-antitoxin systems are crucial in these phenomena of addictive manipulation of protists, as a result of recurrent evolutionary repurposing. This indicates intriguing functional analogy and molecular homology with plasmid-bacterial interplays. Finally, we remark that multiple addictive manipulators are affiliated with specific bacterial lineages with ancient associations with diverse eukaryotes. This suggests a possible role of addictive manipulation of protists in paving the way to the evolution of bacteria associated with multicellular organisms.

Engineering artificial non-coding RNAs for targeted protein degradation.

Targeted protein degradation has become a notable drug development strategy, but its application has been limited by the dependence on protein-based chimeras with restricted genetic manipulation capabilities. The use of long non-coding RNAs (lncRNAs) has emerged as a viable alternative, offering interactions with cellular proteins to modulate pathways and enhance degradation capabilities. Here we introduce a strategy employing artificial lncRNAs (alncRNAs) for precise targeted protein degradation. By integrating RNA aptamers and sequences from the lncRNA HOTAIR, our alncRNAs specifically target and facilitate the ubiquitination and degradation of oncogenic transcription factors and tumor-related proteins, such as c-MYC, NF-κB, ETS-1, KRAS and EGFR. These alncRNAs show potential in reducing malignant phenotypes in cells, both in vitro and in vivo, offering advantages in efficiency, adaptability and versatility. This research enhances knowledge of lncRNA-driven protein degradation and presents an effective method for targeted therapies.