real experiment
reviewers raised, and then respond to some reviewers individually. 2 Synthetic vs. real experiments. R1 and R4 questioned how well our analysis for the synthetic experiments in Section
We thank the reviewers for their careful consideration of our work. R2 suggested that an analysis on non-toy models would be interesting to see. R3 believed that the synthetic experiment was not suited to the model class. We expect our analysis on smaller models to extrapolate to larger ones (R2). We regret that we were not clearer about how our aim differs from these studies [McMurray et al. (2012), ME would aid downstream learning as we propose or as is observed in humans in lifelong learning settings.
Augmented Structure Preserving Neural Networks for cell biomechanics
Olalla-Pombo, Juan, Badรญas, Alberto, Sanz-Gรณmez, Miguel รngel, Benรญtez, Josรฉ Marรญa, Montรกns, Francisco Javier
Cell biomechanics involve a great number of complex phenomena that are fundamental to the evolution of life itself and other associated processes, ranging from the very early stages of embryo-genesis to the maintenance of damaged structures or the growth of tumors. Given the importance of such phenomena, increasing research has been dedicated to their understanding, but the many interactions between them and their influence on the decisions of cells as a collective network or cluster remain unclear. We present a new approach that combines Structure Preserving Neural Networks, which study cell movements as a purely mechanical system, with other Machine Learning tools (Artificial Neural Networks), which allow taking into consideration environmental factors that can be directly deduced from an experiment with Computer Vision techniques. This new model, tested on simulated and real cell migration cases, predicts complete cell trajectories following a roll-out policy with a high level of accuracy. This work also includes a mitosis event prediction model based on Neural Networks architectures which makes use of the same observed features. Introduction Cell migration mechanisms are known to be present in many fundamental processes throughout the evolution of living organisms. As cells are living units that perform complex tasks, undergo constant reactions and transformations, interact with other cells and can respond to their surroundings, their migration can be presented as the result of a large number of internal and external factors. The influence of many environmental factors such as chemical gradients that can be created with biomaterials [6] or that might appear in organic environments [7], density gradients caused by cell accumulation [8], or even the presence of dead cells (which can be of interest in wound healing or tumor growth processes) [9] has been thoroughly studied. Other external factors related to cell collective movement and the tensile forces that can appear between them have also been analyzed [10, 11], with several works in this field showing that cells can use protuberances to attach themselves to other cells, which later exert pulling or pushing forces to guide their movement [12]. Despite the precision that the proposed models can achieve while explaining the relation between these factors and cell movements, there is a general lack of a global approach to the problem. Due to the possible interrelations between environmental properties, many studies simplify the problem by creating conditions where the studied gradient or feature is the dominant source of instability, and thus the main reason behind cell migration [13].
Reviews: Probabilistic Inference with Generating Functions for Poisson Latent Variable Models
The idea of probability generating function achieving similar forms of "conjugacy" as Gaussian random variables and (finite) discrete random variables is very interesting. This enables a fast and exact inference algorithm on Poisson latent variable models. The formulation involving probability generating function does not seem to be constrained to Poisson random variables but all the simulations and real application pertain to Poisson HMM. It is unclear if there's anything special with Poisson that enables better parameter estimates. It is also unclear if there are other Poisson latent variable models other than Poisson HMMs with wide applications.
Learning for Deformable Linear Object Insertion Leveraging Flexibility Estimation from Visual Cues
Manipulation of deformable Linear objects (DLOs), including iron wire, rubber, silk, and nylon rope, is ubiquitous in daily life. These objects exhibit diverse physical properties, such as Young$'$s modulus and bending stiffness.Such diversity poses challenges for developing generalized manipulation policies. However, previous research limited their scope to single-material DLOs and engaged in time-consuming data collection for the state estimation. In this paper, we propose a two-stage manipulation approach consisting of a material property (e.g., flexibility) estimation and policy learning for DLO insertion with reinforcement learning. Firstly, we design a flexibility estimation scheme that characterizes the properties of different types of DLOs. The ground truth flexibility data is collected in simulation to train our flexibility estimation module. During the manipulation, the robot interacts with the DLOs to estimate flexibility by analyzing their visual configurations. Secondly, we train a policy conditioned on the estimated flexibility to perform challenging DLO insertion tasks. Our pipeline trained with diverse insertion scenarios achieves an 85.6% success rate in simulation and 66.67% in real robot experiments. Please refer to our project page: https://lmeee.github.io/DLOInsert/
WiFi-CSI Sensing and Bearing Estimation in Multi-Robot Systems: An Open-Source Simulation Framework
Dijkstra, Brendan, Jadhav, Ninad, Sloot, Alex, Marcantoni, Matteo, Jayawardhana, Bayu, Gil, Stephanie, Haghighat, Bahar
Development and testing of multi-robot systems employing wireless signal-based sensing requires access to suitable hardware, such as channel monitoring WiFi transceivers, which can pose significant limitations. The WiFi Sensor for Robotics (WSR) toolbox, introduced by Jadhav et al. in 2022, provides a novel solution by using WiFi Channel State Information (CSI) to compute relative bearing between robots. The toolbox leverages the amplitude and phase of WiFi signals and creates virtual antenna arrays by exploiting the motion of mobile robots, eliminating the need for physical antenna arrays. However, the WSR toolbox's reliance on an obsoleting WiFi transceiver hardware has limited its operability and accessibility, hindering broader application and development of relevant tools. We present an open-source simulation framework that replicates the WSR toolbox's capabilities using Gazebo and Matlab. By simulating WiFi-CSI data collection, our framework emulates the behavior of mobile robots equipped with the WSR toolbox, enabling precise bearing estimation without physical hardware. We validate the framework through experiments with both simulated and real Turtlebot3 robots, showing a close match between the obtained CSI data and the resulting bearing estimates. This work provides a virtual environment for developing and testing WiFi-CSI-based multi-robot localization without relying on physical hardware. All code and experimental setup information are publicly available at https://github.com/BrendanxP/CSI-Simulation-Framework
BoFire: Bayesian Optimization Framework Intended for Real Experiments
Dรผrholt, Johannes P., Asche, Thomas S., Kleinekorte, Johanna, Mancino-Ball, Gabriel, Schiller, Benjamin, Sung, Simon, Keupp, Julian, Osburg, Aaron, Boyne, Toby, Misener, Ruth, Eldred, Rosona, Costa, Wagner Steuer, Kappatou, Chrysoula, Lee, Robert M., Linzner, Dominik, Walz, David, Wulkow, Niklas, Shafei, Behrang
Our open-source Python package BoFire combines Bayesian Optimization (BO) with other design of experiments (DoE) strategies focusing on developing and optimizing new chemistry. Previous BO implementations, for example as they exist in the literature or software, require substantial adaptation for effective real-world deployment in chemical industry. BoFire provides a rich feature-set with extensive configurability and realizes our vision of fast-tracking research contributions into industrial use via maintainable open-source software. Owing to quality-of-life features like JSON-serializability of problem formulations, BoFire enables seamless integration of BO into RESTful APIs, a common architecture component for both self-driving laboratories and human-in-the-loop setups. This paper discusses the differences between BoFire and other BO implementations and outlines ways that BO research needs to be adapted for real-world use in a chemistry setting.
Data-driven Explainable Controller for Soft Robots based on Recurrent Neural Networks
Chen, Zixi, Ren, Xuyang, Ciuti, Gastone, Stefanini, Cesare
The nonlinearity and hysteresis of soft robot motions have posed challenges in accurate soft robot control. Neural networks, especially recurrent neural networks (RNNs), have been widely leveraged for this issue due to their nonlinear activation functions and recurrent structures. Although they have shown satisfying accuracy in most tasks, these black-box approaches are not explainable, and hence, they are unsuitable for areas with high safety requirements, like robot-assisted surgery. Based on the RNN controllers, we propose a data-driven explainable controller (DDEC) whose parameters can be updated online. We discuss the Jacobian controller and kinematics controller in theory and demonstrate that they are only special cases of DDEC. Moreover, we utilize RNN, the Jacobian controller, the kinematics controller, and DDECs for trajectory following tasks. Experimental results have shown that our approach outperforms the other controllers considering trajectory following errors while being explainable. We also conduct a study to explore and explain the functions of each DDEC component. This is the first interpretable soft robot controller that overcomes the shortcomings of both NN controllers and interpretable controllers. Future work may involve proposing different DDECs based on different RNN controllers and exploiting them for high-safety-required applications.
Collective Bayesian Decision-Making in a Swarm of Miniaturized Robots for Surface Inspection
Siemensma, Thiemen, Chiu, Darren, Ramshanker, Sneha, Nagpal, Radhika, Haghighat, Bahar
Robot swarms can effectively serve a variety of sensing and inspection applications. Certain inspection tasks require a binary classification decision. This work presents an experimental setup for a surface inspection task based on vibration sensing and studies a Bayesian two-outcome decision-making algorithm in a swarm of miniaturized wheeled robots. The robots are tasked with individually inspecting and collectively classifying a 1mx1m tiled surface consisting of vibrating and non-vibrating tiles based on the majority type of tiles. The robots sense vibrations using onboard IMUs and perform collision avoidance using a set of IR sensors. We develop a simulation and optimization framework leveraging the Webots robotic simulator and a Particle Swarm Optimization (PSO) method. We consider two existing information sharing strategies and propose a new one that allows the swarm to rapidly reach accurate classification decisions. We first find optimal parameters that allow efficient sampling in simulation and then evaluate our proposed strategy against the two existing ones using 100 randomized simulation and 10 real experiments. We find that our proposed method compels the swarm to make decisions at an accelerated rate, with an improvement of up to 20.52% in mean decision time at only 0.78% loss in accuracy.
Tell and show: Combining multiple modalities to communicate manipulation tasks to a robot
Vanc, Petr, Skoviera, Radoslav, Stepanova, Karla
As human-robot collaboration is becoming more widespread, there is a need for a more natural way of communicating with the robot. This includes combining data from several modalities together with the context of the situation and background knowledge. Current approaches to communication typically rely only on a single modality or are often very rigid and not robust to missing, misaligned, or noisy data. In this paper, we propose a novel method that takes inspiration from sensor fusion approaches to combine uncertain information from multiple modalities and enhance it with situational awareness (e.g., considering object properties or the scene setup). We first evaluate the proposed solution on simulated bimodal datasets (gestures and language) and show by several ablation experiments the importance of various components of the system and its robustness to noisy, missing, or misaligned observations. Then we implement and evaluate the model on the real setup. In human-robot interaction, we must also consider whether the selected action is probable enough to be executed or if we should better query humans for clarification. For these purposes, we enhance our model with adaptive entropy-based thresholding that detects the appropriate thresholds for different types of interaction showing similar performance as fine-tuned fixed thresholds.
Dynamic Manipulation of a Deformable Linear Object: Simulation and Learning
Chen, Qi Jing, Bretl, Timothy, Vuong, Nghia, Pham, Quang-Cuong
We show that it is possible to learn an open-loop policy in simulation for the dynamic manipulation of a deformable linear object (DLO) -- e.g., a rope, wire, or cable -- that can be executed by a real robot without additional training. Our method is enabled by integrating an existing state-of-the-art DLO model (Discrete Elastic Rods) with MuJoCo, a robot simulator. We describe how this integration was done, check that validation results produced in simulation match what we expect from analysis of the physics, and apply policy optimization to train an open-loop policy from data collected only in simulation that uses a robot arm to fling a wire precisely between two obstacles. This policy achieves a success rate of 76.7% when executed by a real robot in hardware experiments without additional training on the real task.