26,030 research outputs found
Key technologies for safe and autonomous drones
Drones/UAVs are able to perform air operations that are very difficult to be performed by manned aircrafts. In addition, drones' usage brings significant economic savings and environmental benefits, while reducing risks to human life. In this paper, we present key technologies that enable development of drone systems. The technologies are identified based on the usages of drones (driven by COMP4DRONES project use cases). These technologies are grouped into four categories: U-space capabilities, system functions, payloads, and tools. Also, we present the contributions of the COMP4DRONES project to improve existing technologies. These contributions aim to ease drones’ customization, and enable their safe operation.This project has received funding from the ECSEL Joint Undertaking (JU) under grant agreement No 826610. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and Spain, Austria, Belgium, Czech Republic, France, Italy, Latvia, Netherlands. The total project budget is 28,590,748.75 EUR (excluding ESIF partners), while the requested grant is 7,983,731.61 EUR to ECSEL JU, and 8,874,523.84 EUR of National and ESIF Funding. The project has been started on 1st October 2019
Serving to secure "Global Korea": Gender, mobility, and flight attendant labor migrants
This dissertation is an ethnography of mobility and modernity in contemporary South Korea (the Republic of Korea) following neoliberal restructuring precipitated by the Asian Financial Crisis (1997). It focuses on how comparative “service,” “security,” and “safety” fashioned “Global Korea”: an ongoing state-sponsored project aimed at promoting the economic, political, and cultural maturation of South Korea from a once notoriously inhospitable, “backward” country (hujin’guk) to a now welcoming, “advanced country” (sĹŹnjin’guk). Through physical embodiments of the culturally-specific idiom of “superior” service (sĹŹbisĹ), I argue that aspiring, current, and former Korean flight attendants have driven the production and maintenance of this national project.
More broadly, as a driver of this national project, this occupation has emerged out of the country’s own aspirational flights from an earlier history of authoritarian rule, labor violence, and xenophobia. Against the backdrop of the Korean state’s aggressive neoliberal restructuring, globalization efforts, and current “Hell Chosun” (Helchosŏn) economy, a group of largely academically and/or class disadvantaged young women have been able secure individualized modes of pleasure, self-fulfillment, and class advancement via what I deem “service mobilities.” Service mobilities refers to the participation of mostly women in a traditionally devalued but growing sector of the global labor market, the “pink collar” economy centered around “feminine” care labor. Korean female flight attendants share labor skills resembling those of other foreign labor migrants (chiefly from the “Global South”), who perform care work deemed less desirable. Yet, Korean female flight attendants elude the stigmatizing, classed, and racialized category of “labor migrant.” Moreover, within the context of South Korea’s unique history of rapid modernization, the flight attendant occupation also commands considerable social prestige.
Based on ethnographic and archival research on aspiring, current, and former Korean flight attendants, this dissertation asks how these unique care laborers negotiate a metaphorical and literal series of sustained border crossings and inspections between Korean flight attendants’ contingent status as lowly care-laboring migrants, on the one hand, and ostensibly glamorous, globetrotting elites, on the other. This study contends the following: first, the flight attendant occupation in South Korea represents new politics of pleasure and pain in contemporary East Asia. Second, Korean female flight attendants’ enactments of soft, sanitized, and glamorous (hwaryŏhada) service help to purify South Korea’s less savory past. In so doing, Korean flight attendants reconstitute the historical role of female laborers as burden bearers and caretakers of the Korean state.U of I OnlyAuthor submitted a 2-year U of I restriction extension request
Meso-scale FDM material layout design strategies under manufacturability constraints and fracture conditions
In the manufacturability-driven design (MDD) perspective, manufacturability of the product or system is the most important of the design requirements. In addition to being able to ensure that complex designs (e.g., topology optimization) are manufacturable with a given process or process family, MDD also helps mechanical designers to take advantage of unique process-material effects generated during manufacturing. One of the most recognizable examples of this comes from the scanning-type family of additive manufacturing (AM) processes; the most notable and familiar member of this family is the fused deposition modeling (FDM) or fused filament fabrication (FFF) process. This process works by selectively depositing uniform, approximately isotropic beads or elements of molten thermoplastic material (typically structural engineering plastics) in a series of pre-specified traces to build each layer of the part. There are many interesting 2-D and 3-D mechanical design problems that can be explored by designing the layout of these elements. The resulting structured, hierarchical material (which is both manufacturable and customized layer-by-layer within the limits of the process and material) can be defined as a manufacturing process-driven structured material (MPDSM). This dissertation explores several practical methods for designing these element layouts for 2-D and 3-D meso-scale mechanical problems, focusing ultimately on design-for-fracture. Three different fracture conditions are explored: (1) cases where a crack must be prevented or stopped, (2) cases where the crack must be encouraged or accelerated, and (3) cases where cracks must grow in a simple pre-determined pattern. Several new design tools, including a mapping method for the FDM manufacturability constraints, three major literature reviews, the collection, organization, and analysis of several large (qualitative and quantitative) multi-scale datasets on the fracture behavior of FDM-processed materials, some new experimental equipment, and the refinement of a fast and simple g-code generator based on commercially-available software, were developed and refined to support the design of MPDSMs under fracture conditions. The refined design method and rules were experimentally validated using a series of case studies (involving both design and physical testing of the designs) at the end of the dissertation. Finally, a simple design guide for practicing engineers who are not experts in advanced solid mechanics nor process-tailored materials was developed from the results of this project.U of I OnlyAuthor's request
Vision- and tactile-based continuous multimodal intention and attention recognition for safer physical human-robot interaction
Employing skin-like tactile sensors on robots enhances both the safety and
usability of collaborative robots by adding the capability to detect human
contact. Unfortunately, simple binary tactile sensors alone cannot determine
the context of the human contact -- whether it is a deliberate interaction or
an unintended collision that requires safety manoeuvres. Many published methods
classify discrete interactions using more advanced tactile sensors or by
analysing joint torques. Instead, we propose to augment the intention
recognition capabilities of simple binary tactile sensors by adding a
robot-mounted camera for human posture analysis. Different interaction
characteristics, including touch location, human pose, and gaze direction, are
used to train a supervised machine learning algorithm to classify whether a
touch is intentional or not with an F1-score of 86%. We demonstrate that
multimodal intention recognition is significantly more accurate than monomodal
analyses with the collaborative robot Baxter. Furthermore, our method can also
continuously monitor interactions that fluidly change between intentional or
unintentional by gauging the user's attention through gaze. If a user stops
paying attention mid-task, the proposed intention and attention recognition
algorithm can activate safety features to prevent unsafe interactions. We also
employ a feature reduction technique that reduces the number of inputs to five
to achieve a more generalized low-dimensional classifier. This simplification
both reduces the amount of training data required and improves real-world
classification accuracy. It also renders the method potentially agnostic to the
robot and touch sensor architectures while achieving a high degree of task
adaptability.Comment: 11 pages, 8 figures, preprint under revie
Recommended from our members
Ensuring Access to Safe and Nutritious Food for All Through the Transformation of Food Systems
Model Parameter Identification via a Hyperparameter Optimization Scheme for Autonomous Racing Systems
In this letter, we propose a model parameter identification method via a
hyperparameter optimization scheme (MI-HPO). Our method adopts an efficient
explore-exploit strategy to identify the parameters of dynamic models in a
data-driven optimization manner. We utilize our method for model parameter
identification of the AV-21, a full-scaled autonomous race vehicle. We then
incorporate the optimized parameters for the design of model-based planning and
control systems of our platform. In experiments, MI-HPO exhibits more than 13
times faster convergence than traditional parameter identification methods.
Furthermore, the parametric models learned via MI-HPO demonstrate good fitness
to the given datasets and show generalization ability in unseen dynamic
scenarios. We further conduct extensive field tests to validate our model-based
system, demonstrating stable obstacle avoidance and high-speed driving up to
217 km/h at the Indianapolis Motor Speedway and Las Vegas Motor Speedway. The
source code for our work and videos of the tests are available at
https://github.com/hynkis/MI-HPO.Comment: 6 pages, 8 figures. Published in IEEE Control Systems Letters (L-CSS
NF-Atlas: Multi-Volume Neural Feature Fields for Large Scale LiDAR Mapping
LiDAR Mapping has been a long-standing problem in robotics. Recent progress
in neural implicit representation has brought new opportunities to robotic
mapping. In this paper, we propose the multi-volume neural feature fields,
called NF-Atlas, which bridge the neural feature volumes with pose graph
optimization. By regarding the neural feature volume as pose graph nodes and
the relative pose between volumes as pose graph edges, the entire neural
feature field becomes both locally rigid and globally elastic. Locally, the
neural feature volume employs a sparse feature Octree and a small MLP to encode
the submap SDF with an option of semantics. Learning the map using this
structure allows for end-to-end solving of maximum a posteriori (MAP) based
probabilistic mapping. Globally, the map is built volume by volume
independently, avoiding catastrophic forgetting when mapping incrementally.
Furthermore, when a loop closure occurs, with the elastic pose graph based
representation, only updating the origin of neural volumes is required without
remapping. Finally, these functionalities of NF-Atlas are validated. Thanks to
the sparsity and the optimization based formulation, NF-Atlas shows competitive
performance in terms of accuracy, efficiency and memory usage on both
simulation and real-world datasets
Stable Real-Time Feedback Control of a Pneumatic Soft Robot
Soft actuators offer compliant and safe interaction with an unstructured
environment compared to their rigid counterparts. However, control of these
systems is often challenging because they are inherently under-actuated, have
infinite degrees of freedom (DoF), and their mechanical properties can change
by unknown external loads. Existing works mainly relied on discretization and
reduction, suffering from either low accuracy or high computational cost for
real-time control purposes. Recently, we presented an infinite-dimensional
feedback controller for soft manipulators modeled by partial differential
equations (PDEs) based on the Cosserat rod theory. In this study, we examine
how to implement this controller in real-time using only a limited number of
actuators. To do so, we formulate a convex quadratic programming problem that
tunes the feedback gains of the controller in real time such that it becomes
realizable by the actuators. We evaluated the controller's performance through
experiments on a physical soft robot capable of planar motions and show that
the actual controller implemented by the finite-dimensional actuators still
preserves the stabilizing property of the desired infinite-dimensional
controller. This research fills the gap between the infinite-dimensional
control design and finite-dimensional actuation in practice and suggests a
promising direction for exploring PDE-based control design for soft robots
Event-based tracking of human hands
This paper proposes a novel method for human hands tracking using data from
an event camera. The event camera detects changes in brightness, measuring
motion, with low latency, no motion blur, low power consumption and high
dynamic range. Captured frames are analysed using lightweight algorithms
reporting 3D hand position data. The chosen pick-and-place scenario serves as
an example input for collaborative human-robot interactions and in obstacle
avoidance for human-robot safety applications. Events data are pre-processed
into intensity frames. The regions of interest (ROI) are defined through object
edge event activity, reducing noise. ROI features are extracted for use
in-depth perception. Event-based tracking of human hand demonstrated feasible,
in real time and at a low computational cost. The proposed ROI-finding method
reduces noise from intensity images, achieving up to 89% of data reduction in
relation to the original, while preserving the features. The depth estimation
error in relation to ground truth (measured with wearables), measured using
dynamic time warping and using a single event camera, is from 15 to 30
millimetres, depending on the plane it is measured. Tracking of human hands in
3D space using a single event camera data and lightweight algorithms to define
ROI features (hands tracking in space)
Learning Over All Contracting and Lipschitz Closed-Loops for Partially-Observed Nonlinear Systems
This paper presents a policy parameterization for learning-based control on
nonlinear, partially-observed dynamical systems. The parameterization is based
on a nonlinear version of the Youla parameterization and the recently proposed
Recurrent Equilibrium Network (REN) class of models. We prove that the
resulting Youla-REN parameterization automatically satisfies stability
(contraction) and user-tunable robustness (Lipschitz) conditions on the
closed-loop system. This means it can be used for safe learning-based control
with no additional constraints or projections required to enforce stability or
robustness. We test the new policy class in simulation on two reinforcement
learning tasks: 1) magnetic suspension, and 2) inverting a rotary-arm pendulum.
We find that the Youla-REN performs similarly to existing learning-based and
optimal control methods while also ensuring stability and exhibiting improved
robustness to adversarial disturbances
- …