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Developing a Mono-Actuated Compliant GeoGami Robot

Webster, Archie, Skull, Lee, Tafrishi, Seyed Amir

arXiv.org Artificial Intelligence

This paper presents the design of a new soft-rigid robotic platform, "GeoGami". We leverage origami surface capabilities to achieve shape contraction and to support locomotion with underactuated forms. A key challenge is that origami surfaces have high degrees of freedom and typically require many actuators; we address repeatability by integrating surface compliance. We propose a mono-actuated GeoGami mobile platform that combines origami surface compliance with a geometric compliant skeleton, enabling the robot to transform and locomote using a single actuator. We demonstrate the robot, develop a stiffness model, and describe the central gearbox mechanism. We also analyze alternative cable-driven actuation methods for the skeleton to enable surface transformation. Finally, we evaluate the GeoGami platform for capabilities, including shape transformation and rolling. This platform opens new capabilities for robots that change shape to access different environments and that use shape transformation for locomotion.


Compound Fault Diagnosis for Train Transmission Systems Using Deep Learning with Fourier-enhanced Representation

Rico, Jonathan Adam, Raghavan, Nagarajan, Jayavelu, Senthilnath

arXiv.org Artificial Intelligence

Abstract--Fault diagnosis prevents train disruptions by ensuring the stability and reliability of their transmission systems. Data-driven fault diagnosis models have several advantages over traditional methods in terms of dealing with non-linearity, adaptability, scalability, and automation. However, existing data-driven models are trained on separate transmission components and only consider single faults due to the limitations of existing datasets. These models will perform worse in scenarios where components operate with each other at the same time, affecting each component's vibration signals. T o address some of these challenges, we propose a frequency domain representation and a 1-dimensional convolutional neural network for compound fault diagnosis and applied it on the PHM Beijing 2024 dataset, which includes 21 sensor channels, 17 single faults, and 42 compound faults from 4 interacting components, that is, motor, gearbox, left axle box, and right axle box. Our proposed model achieved 97.67% and 93.93% accuracies on the test set with 17 single faults and on the test set with 42 compound faults, respectively. Fault diagnosis plays a crucial role in maintaining the stability and reliability of transmission components, helping to prevent disruptions in train operations.


Video games are taking longer to make, but why?

BBC News

Video games are taking longer to make, but why? It's been 84 years... or so says the meme. For video game fans, it can certainly feel like it, as the gap between big releases gets longer. Earlier this month Silksong, the highly anticipated sequel to 2017's Hollow Knight, was finally released . And don't get us started on Grand Theft Auto 6.


Design of a 3-DOF Hopping Robot with an Optimized Gearbox: An Intermediate Platform Toward Bipedal Robots

Choe, JongHun, Kim, Gijeong, Kim, Hajun, Kang, Dongyun, Kim, Min-Su, Park, Hae-Won

arXiv.org Artificial Intelligence

-- This paper presents a 3-DOF hopping robot with a human-like lower-limb joint configuration and a flat foot, capable of performing dynamic and repetitive jumping motions. T o achieve both high torque output and a large hollow shaft diameter for efficient cable routing, a compact 3K compound planetary gearbox was designed using mixed-integer nonlinear programming for gear tooth optimization. T o meet performance requirements within the constrained joint geometry, all major components--including the actuator, motor driver, and communication interface--were custom-designed. The robot weighs 12.45 kg, including a dummy mass, and measures 840 mm in length when the knee joint is fully extended. A reinforcement learning-based controller was employed, and the robot's performance was validated through hardware experiments, demonstrating stable and repetitive hopping motions in response to user inputs. These experimental results indicate that the platform serves as a solid foundation for future bipedal robot development. A supplementary video is available at: https://youtu.be/BZ2H0dQBcXc


Design and Performance Evaluation of an Elbow-Based Biomechanical Energy Harvester

Huang, Hubert, Huang, Jeffrey

arXiv.org Artificial Intelligence

Carbon emissions have long been attributed to the increase in climate change. With the effects of climate change escalating in the past few years, there has been an increased effort to find green alternatives to power generation, which has been a major contributor to carbon emissions. One prominent way that has arisen is biomechanical energy, or harvesting energy based on natural human movement. This study will evaluate the feasibility of electric generation using a gear and generator-based biomechanical energy harvester in the elbow joint. The joint was chosen using kinetic arm analysis through MediaPipe, in which the elbow joint showed much higher angular velocity during walking, thus showing more potential as a place to construct the harvester. Leg joints were excluded to not obstruct daily movement. The gear and generator type was decided to maximize energy production in the elbow joint. The device was constructed using a gearbox and a generator. The results show that it generated as much as 0.16 watts using the optimal resistance. This demonstrates the feasibility of electric generation with an elbow joint gear and generator-type biomechanical energy harvester.


Design and Control of a Compact Series Elastic Actuator Module for Robots in MRI Scanners

He, Binghan, Zhao, Naichen, Guo, David Y., Paxson, Charles H., Fearing, Ronald S.

arXiv.org Artificial Intelligence

In this study, we introduce a novel MRI-compatible rotary series elastic actuator module utilizing velocity-sourced ultrasonic motors for force-controlled robots operating within MRI scanners. Unlike previous MRI-compatible SEA designs, our module incorporates a transmission force sensing series elastic actuator structure, with four off-the-shelf compression springs strategically placed between the gearbox housing and the motor housing. This design features a compact size, thus expanding possibilities for a wider range of MRI robotic applications. To achieve precise torque control, we develop a controller that incorporates a disturbance observer tailored for velocity-sourced motors. This controller enhances the robustness of torque control in our actuator module, even in the presence of varying external impedance, thereby augmenting its suitability for MRI-guided medical interventions. Experimental validation demonstrates the actuator's torque control performance in both 3 Tesla MRI and non-MRI environments, achieving a settling time of 0.1 seconds and a steady-state error within 2% of its maximum output torque. Notably, our force controller exhibits consistent performance across low and high external impedance scenarios, in contrast to conventional controllers for velocity-sourced series elastic actuators, which struggle with steady-state performance under low external impedance conditions.


Take-Two plans to lay off 5 percent of its employees by the end of 2024

Engadget

Take-Two Interactive plans to lay off 5 percent of its workforce, or about 600 employees, by the end of the year, as reported in an SEC filing Tuesday. The studio is also canceling several in-development projects. These moves are expected to cost 160 million to 200 million to implement, and should result in 165 million in annual savings for Take-Two. As the owner of Grand Theft Auto and the parent company of Rockstar Games, 2K, Private Division, Zynga and Gearbox, Take-Two is a juggernaut in the video game industry. It reported 5.3 billion in revenue in 2023, a nearly 2 billion increase over the previous year.


Model-Based Sensor Diagnostics for Robotic Manipulators

Kukreja, Astha

arXiv.org Artificial Intelligence

This paper introduces a methodology for formulating model-based constraints tailored for sensor diagnostics, featuring analytical relationships extending across mechanical and electrical domains. While applicable to various robotic systems, the study specifically centers on a robotic joint employing a series elastic actuator. Three distinct constraints are imposed on the series elastic actuator: the Torsional Spring Constraint, Joint Dynamics Constraint, and Electrical Motor Constraint. Through a simulation example, we demonstrate the efficacy of the proposed model-based sensor diagnostics methodology. The study addresses two distinct types of sensor faults that may arise in the torque sensor of a robot joint, and delves into their respective detection methods. This insightful sensor diagnostic methodology is customizable and applicable across various components of robots, offering fault diagnostic and isolation capabilities. This research contributes valuable insights aimed at enhancing the diagnostic capabilities essential for the optimal performance of robotic manipulators in collaborative environments.


Domain knowledge-informed Synthetic fault sample generation with Health Data Map for cross-domain Planetary Gearbox Fault Diagnosis

Ha, Jong Moon, Fink, Olga

arXiv.org Artificial Intelligence

Extensive research has been conducted on fault diagnosis of planetary gearboxes using vibration signals and deep learning (DL) approaches. However, DL-based methods are susceptible to the domain shift problem caused by varying operating conditions of the gearbox. Although domain adaptation and data synthesis methods have been proposed to overcome such domain shifts, they are often not directly applicable in real-world situations where only healthy data is available in the target domain. To tackle the challenge of extreme domain shift scenarios where only healthy data is available in the target domain, this paper proposes two novel domain knowledge-informed data synthesis methods utilizing the health data map (HDMap). The two proposed approaches are referred to as scaled CutPaste and FaultPaste. The HDMap is used to physically represent the vibration signal of the planetary gearbox as an image-like matrix, allowing for visualization of fault-related features. CutPaste and FaultPaste are then applied to generate faulty samples based on the healthy data in the target domain, using domain knowledge and fault signatures extracted from the source domain, respectively. In addition to generating realistic faults, the proposed methods introduce scaling of fault signatures for controlled synthesis of faults with various severity levels. A case study is conducted on a planetary gearbox testbed to evaluate the proposed approaches. The results show that the proposed methods are capable of accurately diagnosing faults, even in cases of extreme domain shift, and can estimate the severity of faults that have not been previously observed in the target domain.


Airborne Sound Analysis for the Detection of Bearing Faults in Railway Vehicles with Real-World Data

Kreuzer, Matthias, Schmidt, David, Wokusch, Simon, Kellermann, Walter

arXiv.org Artificial Intelligence

In this paper, we address the challenging problem of detecting bearing faults in railway vehicles by analyzing acoustic signals recorded during regular operation. For this, we introduce Mel Frequency Cepstral Coefficients (MFCCs) as features, which form the input to a simple Multi-Layer Perceptron classifier. The proposed method is evaluated with real-world data that was obtained for state-of-the-art commuter railway vehicles in a measurement campaign. The experiments show that with the chosen MFCC features bearing faults can be reliably detected even for bearing damages that were not included in training.