Design, Fabrication, and Testing of Mechanical Hinges with Snap-Fit Locking Mechanisms in Rigid Origami Structures

The ancient art of ‘origami’ has recently become the source of inspiration for engineers to create structures that can unfold from a compact state to a fully deployed one. For instance, researchers have currently adopted origami designs in various engineering disciplines, including aerospace engineering, robotics, biomedical engineering, and architecture. In particular, architects have been interested in designing origami-inspired rigid walled structures that can be deployed as disaster-relief shelters. This type of design has three main advantages: transportability, constructability, and rigidity. Although there has been increased interests in deployable structures, limited research has been conducted on evaluating their structural performance, specifically the mechanical performance of the hinges that allow for the rotation of the rigid panels. To address the limitation, this thesis proposes a novel design of hinge connections for rigid origami structures. The hinges utilize snap fit connections to allow for the structure to achieve and maintain a locked state once unfolded without the need for any additional connections. Prototypes of the hinge design were fabricated using a 3D printer and their flexural strength was experimentally and computationally studied. It was concluded that the design could resist typical flexural loads for residential structures, and future research should be performed to minimize deflection

Study of the flexibility of a learning analytics tool to evaluate teamwork competence acquisition in different contexts

Learning analytics tools and methodologies aim to facilitate teachers and/or decision makers with information and knowledge about what is happening in virtual learning environments in a straightforward and effortless way. However, it is necessary to apply these tools and methodologies in different contexts with a similar success, that is, that they should be flexible and portable enough. There exist several learning analytics tools that only works properly with very specific versions of learning platforms. In this paper, the authors aim to evaluate the flexibility and portability of a methodology and a learning analytics tool that supports individual assessment of teamwork competence. In order to do so the methodology and the tool are applied in a similar course from two different academic contexts. After the experiment, it is possible to see that the learning analytics tool seems to work properly and the suggested new functionalities are similar in both contexts. The methodology can be also applied but results could be improved if some meetings are carried out to check how team works are progressing with their tasks

Pervasive and Connected Digital Twins for Edge Computing Enabled Industrial Applications

A digital twin (DT) is a digital representation of a physical asset that serves as its counterpart — or twin. DTs differ from static, three-dimensional models in that they are continuously updated with data from numerous sources. In one continually changing world of pervasive computing, where computational and human intelligence are expanding everywhere, DTs can be regarded as the backbone for addressing the synergy of software, devices, movable objects, networks, and people. In this paper, we present a novel perspective for designing, prototyping and testing pervasive and connected DTs for edge computing enabled industrial applications. The provided paradigm allows for the creation of computational models for cloud computing as well as the transmission of data and computational intelligence through analytic platforms. A case study is presented to demonstrate the possibilities of the suggested framework. According to the outlined findings, the proposed architecture contributes to effective maintenance and management of infrastructures and facilities

Synthetic Jet Actuator-Based Aircraft Tracking Using a Continuous Robust Nonlinear Control Strategy

A robust nonlinear control law that achieves trajectory tracking control for unmanned aerial vehicles (UAVs) equipped with synthetic jet actuators (SJAs) is presented in this paper. A key challenge in the control design is that the dynamic characteristics of SJAs are nonlinear and contain parametric uncertainty. The challenge resulting from the uncertain SJA actuator parameters is mitigated via innovative algebraic manipulation in the tracking error system derivation along with a robust nonlinear control law employing constant SJA parameter estimates. A key contribution of the paper is a rigorous analysis of the range of SJA actuator parameter uncertainty within which asymptotic UAV trajectory tracking can be achieved. A rigorous stability analysis is carried out to prove semiglobal asymptotic trajectory tracking. Detailed simulation results are included to illustrate the effectiveness of the proposed control law in the presence of wind gusts and varying levels of SJA actuator parameter uncertainty

Antidisturbance Vibration Suppression of the Aerial Refueling Hose during the Coupling Process

In autonomous aerial refueling (AAR), the vibration of the flexible refueling hose caused by the receiver aircraft’s excessive closure speed should be suppressed once it appears. This paper proposed an active control strategy based on the permanent magnet synchronous motor (PMSM) angular control for the timely and accurate vibration suppression of the flexible refueling hose. A nonsingular fast terminal sliding-mode (NFTSM) control scheme with adaptive extended state observer (AESO) is proposed for PMSM take-up system under multiple disturbances. The states and the “total disturbance” of the PMSM system are firstly reconstituted using the AESO under the uncertainties and measurement noise. Then, a faster sliding variable with tracking error exponential term is proposed together with a special designed reaching law to enhance the global convergence speed and precision of the controller. The proposed control scheme provides a more comprehensive solution to rapidly suppress the flexible refueling hose vibration in AAR. Compared to other methods, the scheme can suppress the flexible hose vibration more fleetly and accurately even when the system is exposed to multiple disturbances and measurement noise. Simulation results show that the proposed scheme is competitive in accuracy, global rapidity, and robustness

Measuring the impact of haptic feedback in collaborative robotic scenarios

[EN] In recent years, the interaction of a human operator with teleoperated robotic systems has been much improved. One of the factors influencing this improvement is the addition of force feedback to complement the visual feedback provided by traditional graphical user interfaces. However, the users of these systems performing tasks in isolated and safe environments are often inexperienced and occasional users. In addition, there is no common framework to assess the usability of these systems, due to the heterogeneity of applications and tasks, and therefore, there is a need for new usability assessment methods that are not domain specific. This study addresses this issue by proposing a measure of usability that includes five variables: user efficiency, user effectiveness, mental workload, perceived usefulness, and perceived ease of use. The empirical analysis shows that the integration of haptic feedback improves the usability of these systems for non-expert users, even though the differences are not statistically significant; further, the results suggest that mental workload is higher when haptic feedback is added. The analysis also reveals significant differences between participants depending on gender.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL