Goto

Collaborating Authors

 bead



Computing forward statics from tendon-length in flexible-joint hyper-redundant manipulators

Feng, Weiting, Walker, Kyle L., Yang, Yunjie, Giorgio-Serchi, Francesco

arXiv.org Artificial Intelligence

Hyper-redundant tendon-driven manipulators offer greater flexibility and compliance over traditional manipulators. A common way of controlling such manipulators relies on adjusting tendon lengths, which is an accessible control parameter. This approach works well when the kinematic configuration is representative of the real operational conditions. However, when dealing with manipulators of larger size subject to gravity, it becomes necessary to solve a static force problem, using tendon force as the input and employing a mapping from the configuration space to retrieve tendon length. Alternatively, measurements of the manipulator posture can be used to iteratively adjust tendon lengths to achieve a desired posture. Hence, either tension measurement or state estimation of the manipulator are required, both of which are not always accurately available. Here, we propose a solution by reconciling cables tension and length as the input for the solution of the system forward statics. We develop a screw-based formulation for a tendon-driven, multi-segment, hyper-redundant manipulator with elastic joints and introduce a forward statics iterative solution method that equivalently makes use of either tendon length or tension as the input. This strategy is experimentally validated using a traditional tension input first, subsequently showing the efficacy of the method when exclusively tendon lengths are used. The results confirm the possibility to perform open-loop control in static conditions using a kinematic input only, thus bypassing some of the practical problems with tension measurement and state estimation of hyper-redundant systems.



Dynamic and Generalizable Process Reward Modeling

Yin, Zhangyue, Sun, Qiushi, Zeng, Zhiyuan, Cheng, Qinyuan, Qiu, Xipeng, Huang, Xuanjing

arXiv.org Artificial Intelligence

Process Reward Models (PRMs) are crucial for guiding Large Language Models (LLMs) in complex scenarios by providing dense reward signals. However, existing PRMs primarily rely on heuristic approaches, which struggle with cross-domain generalization. While LLM-as-judge has been proposed to provide generalized rewards, current research has focused mainly on feedback results, overlooking the meaningful guidance embedded within the text. Additionally, static and coarse-grained evaluation criteria struggle to adapt to complex process supervision. To tackle these challenges, we propose Dynamic and Generalizable Process Reward Modeling (DG-PRM), which features a reward tree to capture and store fine-grained, multi-dimensional reward criteria. DG-PRM dynamically selects reward signals for step-wise reward scoring. To handle multifaceted reward signals, we pioneeringly adopt Pareto dominance estimation to identify discriminative positive and negative pairs. Experimental results show that DG-PRM achieves stunning performance on prevailing benchmarks, significantly boosting model performance across tasks with dense rewards. Further analysis reveals that DG-PRM adapts well to out-of-distribution scenarios, demonstrating exceptional generalizability.


Contactless Precision Steering of Particles in a Fluid inside a Cube with Rotating Walls

Amoudruz, Lucas, Karnakov, Petr, Koumoutsakos, Petros

arXiv.org Artificial Intelligence

Contactless manipulation of small objects is essential for biomedical and chemical applications, such as cell analysis, assisted fertilisation, and precision chemistry. Established methods, including optical, acoustic, and magnetic tweezers, are now complemented by flow control techniques that use flow-induced motion to enable precise and versatile manipulation. However, trapping multiple particles in fluid remains a challenge. This study introduces a novel control algorithm capable of steering multiple particles in flow. The system uses rotating disks to generate flow fields that transport particles to precise locations. Disk rotations are governed by a feedback control policy based on the Optimising a Discrete Loss (ODIL) framework, which combines fluid dynamics equations with path objectives into a single loss function. Our experiments, conducted in both simulations and with the physical device, demonstrate the capability of the approach to transport two beads simultaneously to predefined locations, advancing robust contactless particle manipulation for biomedical applications.


Fourier-Based 3D Multistage Transformer for Aberration Correction in Multicellular Specimens

Alshaabi, Thayer, Milkie, Daniel E., Liu, Gaoxiang, Shirazinejad, Cyna, Hong, Jason L., Achour, Kemal, Görlitz, Frederik, Milunovic-Jevtic, Ana, Simmons, Cat, Abuzahriyeh, Ibrahim S., Hong, Erin, Williams, Samara Erin, Harrison, Nathanael, Huang, Evan, Bae, Eun Seok, Killilea, Alison N., Drubin, David G., Swinburne, Ian A., Upadhyayula, Srigokul, Betzig, Eric

arXiv.org Artificial Intelligence

High-resolution tissue imaging is often compromised by sample-induced optical aberrations that degrade resolution and contrast. While wavefront sensor-based adaptive optics (AO) can measure these aberrations, such hardware solutions are typically complex, expensive to implement, and slow when serially mapping spatially varying aberrations across large fields of view. Here, we introduce AOViFT (Adaptive Optical Vision Fourier Transformer) -- a machine learning-based aberration sensing framework built around a 3D multistage Vision Transformer that operates on Fourier domain embeddings. AOViFT infers aberrations and restores diffraction-limited performance in puncta-labeled specimens with substantially reduced computational cost, training time, and memory footprint compared to conventional architectures or real-space networks. We validated AOViFT on live gene-edited zebrafish embryos, demonstrating its ability to correct spatially varying aberrations using either a deformable mirror or post-acquisition deconvolution. By eliminating the need for the guide star and wavefront sensing hardware and simplifying the experimental workflow, AOViFT lowers technical barriers for high-resolution volumetric microscopy across diverse biological samples.


Lattice Protein Folding with Variational Annealing

Khandoker, Shoummo Ahsan, Inack, Estelle M., Hibat-Allah, Mohamed

arXiv.org Artificial Intelligence

Understanding the principles of protein folding is a cornerstone of computational biology, with implications for drug design, bioengineering, and the understanding of fundamental biological processes. Lattice protein folding models offer a simplified yet powerful framework for studying the complexities of protein folding, enabling the exploration of energetically optimal folds under constrained conditions. However, finding these optimal folds is a computationally challenging combinatorial optimization problem. In this work, we introduce a novel upper-bound training scheme that employs masking to identify the lowest-energy folds in two-dimensional Hydrophobic-Polar (HP) lattice protein folding. By leveraging Dilated Recurrent Neural Networks (RNNs) integrated with an annealing process driven by temperature-like fluctuations, our method accurately predicts optimal folds for benchmark systems of up to 60 beads. Our approach also effectively masks invalid folds from being sampled without compromising the autoregressive sampling properties of RNNs. This scheme is generalizable to three spatial dimensions and can be extended to lattice protein models with larger alphabets. Our findings emphasize the potential of advanced machine learning techniques in tackling complex protein folding problems and a broader class of constrained combinatorial optimization challenges.


JAMMit! Monolithic 3D-Printing of a Bead Jamming Soft Pneumatic Arm

Yao, Yao, Westermann, Maximilian, Pontin, Marco, Albini, Alessandro, Maiolino, Perla

arXiv.org Artificial Intelligence

3D-printed bellow soft pneumatic arms are widely adopted for their flexible design, ease of fabrication, and large deformation capabilities. However, their low stiffness limits their real-world applications. Although several methods exist to enhance the stiffness of soft actuators, many involve complex manufacturing processes not in line with modern goals of monolithic and automated additive manufacturing. With its simplicity, bead-jamming represents a simple and effective solution to these challenges. This work introduces a method for monolithic printing of a bellow soft pneumatic arm, integrating a tendon-driven central spine of bowl-shaped beads. We experimentally characterized the arm's range of motion in both unjammed and jammed states, as well as its stiffness under various actuation and jamming conditions. As a result, we provide an optimal jamming policy as a trade-off between preserving the range of motion and maximizing stiffness. The proposed design was further demonstrated in a switch-toggling task, showing its potential for practical applications.


CES 2025: Smart lighting brand Govee goes all-in with AI

PCWorld

Sure, Govee has some new smart lights to unveil at CES this year, but what this smart lighting manufacturer really wants to talk about is, of course, the buzzword of the show: AI. From its AI-powered gaming lights to its light-scene-creating AI chatbot, Govee clearly sees its budding AI efforts as the best way to set itself apart in the crowded smart lighting market, and the company isn't being timid about putting AI front and center. The star of the show is Govee's smart lighting-focused AI model, newly upgraded to 12 billion parameters, up from just 0.86B parameters in the previous version Trained on more than 10,000 lighting effects, Govee's model is the brains behind its text-to-image AI Lighting Bot, which allows users to create and edit smart light effects using natural-language text prompts. There's also AI Dreamview, a Govee technology that applies their newly created effects across groups of smart lights. To be clear, Govee does have some actual smart lights to show off at CES, including a new and portable table lamp that doubles as a Bluetooth speaker.


Efficient Generation of Molecular Clusters with Dual-Scale Equivariant Flow Matching

Subramanian, Akshay, Qu, Shuhui, Park, Cheol Woo, Liu, Sulin, Lee, Janghwan, Gómez-Bombarelli, Rafael

arXiv.org Artificial Intelligence

Amorphous molecular solids offer a promising alternative to inorganic semiconductors, owing to their mechanical flexibility and solution processability. The packing structure of these materials plays a crucial role in determining their electronic and transport properties, which are key to enhancing the efficiency of devices like organic solar cells (OSCs). However, obtaining these optoelectronic properties computationally requires molecular dynamics (MD) simulations to generate a conformational ensemble, a process that can be computationally expensive due to the large system sizes involved. Recent advances have focused on using generative models, particularly flow-based models as Boltzmann generators, to improve the efficiency of MD sampling. In this work, we developed a dual-scale flow matching method that separates training and inference into coarse-grained and all-atom stages and enhances both the accuracy and efficiency of standard flow matching samplers. We demonstrate the effectiveness of this method on a dataset of Y6 molecular clusters obtained through MD simulations, and we benchmark its efficiency and accuracy against single-scale flow matching methods.