Revistas
Revista:
APPLIED SCIENCES
ISSN:
2076-3417
Año:
2021
Vol.:
11
N°:
4
Págs.:
1443
Featured Application Comparison two digital solutions (tablet based and Augmented Reality based) for bus maintenance against the traditional solution based on paper. This paper shows two developed digital systems as an example of intelligent garage and maintenance that targets the applicability of augmented reality and wearable devices technologies to the maintenance of bus fleets. Both solutions are designed to improve the maintenance process based on verification of tasks checklist. The main contribution of the paper focuses on the implementation of the prototypes in the company's facilities in an operational environment with real users and address the difficulties inherent in the transfer of a technology to a real work environment, such as a mechanical workshop. The experiments have been conducted in real operation thanks to the involvement of the public transport operator DBUS, which operates public transport buses in the city of Donostia-San Sebastian (Spain). Two solutions have been developed and compared against the traditional process: one based on Tablet and another one based on Microsoft HoloLens. The results show objective metrics (Key Performance Indicators, KPI) as well as subjective metrics based on questionnaires comparing the two technological approaches against the traditional one based on manual work and paper.
Revista:
LECTURE NOTES IN COMPUTER SCIENCE
ISSN:
0302-9743
Año:
2018
Vol.:
10796
Págs.:
149 - 158
As urbanization increases, mobility becomes more complex and supposes a major challenge for public transportation authorities. An approach to tackle this problem is to introduce systems that ease vehicle operation and monitoring. However, these systems are hard to maintain and integrate. On this paper, a new information technology (IT) architecture is introduced. Developed by the ITxPT association, the architecture aims to improve the cost-effective implementation of the IT modules in public transport fleets. This architecture has capitalized the work of several European projects to create a solid standard ready to test on field. Finally, a use case of the introduction of an eco-driving assistance system that employs this architecture in real operation is presented.
Revista:
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
ISSN:
1615-147X
Año:
2014
Vol.:
49
N°:
1
Págs.:
169 - 183
In this paper an optimization-based hybrid dynamic motion prediction method is presented. The method is hybrid as the prediction relies both on actually performed motions for reference (following a data-based approach) and on the definition of appropriate performance measures (following a knowledge-based approach). The prediction is carried out through the definition of a constrained non-linear optimization problem, in which the objective function is composed of a weighted combination of data-based and knowledge-based contributions. The weights of each contribution are varied in order to generate a battery of hybrid predictions, which range from purely data-based to purely knowledge-based. The results of the predictions are analyzed and compared against actually performed motions both qualitatively and quantitatively, using a measure of realism defined as the distance of the predicted motions from the mean of the actually performed motions. The method is applied to clutch pedal depression motions and the comparison between the different approaches favors the hybrid solution, which seems to combine the strengths of both data- and knowledge-based approaches, enhancing the realism of the predicted motion.
Revista:
MULTIBODY SYSTEM DYNAMICS
ISSN:
1384-5640
Año:
2014
Vol.:
32
N°:
1
Págs.:
27 - 53
In this paper, we present a novel method to predict human motion, seeking to combine the advantages of both data-based and knowledge-based motion prediction methods. Our method relies on a database of captured motions for reference and introduces knowledge in the prediction in the form of a motion control law, which is followed while resembling the actually performed reference motion. The prediction is carried out by solving an optimization problem in which the following conditions are imposed to the motion: must fulfill the goals of the task; resemble the reference motion selected from the database; follow a knowledge-based dynamic motion control law; and ensure the dynamic equilibrium of the human model, considering its interactions with the environment. In this work, we apply the proposed method to a database of clutch pedal depression motions, and we present the results for three predictions. The method is validated by comparing the results of the prediction to motions actually performed in similar conditions. The predicted motions closely resemble the motions in the validation database and no significant differences have been noted either in the motion's kinematics or in the motion's dynamics.
Revista:
TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES
ISSN:
0968-090X
Año:
2014
Vol.:
43
Págs.:
222 - 229
This paper shows that agent based simulation can evaluate the performance of different bus layout designs from passengers' perspective, thus helping bus manufacturers to design new layouts that are more attractive for passengers. Including agent-based simulation in the bus design process is an inexpensive and efficient procedure to evaluate new design concepts (wheel-well position, number of doors, etc.) in relation to the preferences, needs and expectations of current and future passengers. Its main advantage is that these new design concepts are evaluated well before manufacturing the first physical prototype. Bus passengers are modelled and simulated as autonomous agents. Eight different types of passengers, which were elaborated from observations of actual passengers, have been modelled. Passengers' preferences and features have been implemented using a calibrated making decision algorithm. The paper also presents two case-studies to analyse the sensitivity of the performance of two different bus layouts with different number and distributions of passengers.
Autores:
Rexfelt, O. (Autor de correspondencia); Schelenz, T.; Karlsson, M.; et al.
Revista:
TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES
ISSN:
0968-090X
Año:
2014
Vol.:
38
Págs.:
16 - 27
In this paper, we propose an agent-based simulation approach that is capable of simulating the flow of passengers on board buses and at bus stops. The intention is that it will be applied during vehicle development to analyze how vehicle design affects passenger flow, and thus also how it affects system performance such as dwell time. In turn, this could aid the developers in making design decisions early in the development process. Besides introducing the simulation tool itself, the paper explores the realism of the data generated by the tool. A number of passenger flow experiments featuring a full-scale bus mockup and 50 participants were carried out. The setup of these experiments mirrored a number of 'bus journeys' (regarding vehicle design, number of passengers boarding/alighting at each stop and so on) that had previously been simulated using the simulation tool. When the data from the simulations were compared with the data from the passenger flow experiments, it could be concluded that the tool is indeed able to generate realistic passenger flows, although with some errors when a large number of passengers board/alight. The simulated dwell times were rationally affected by the tested bus layout aspects. It was concluded that the tool makes it possible to evaluate how variations in bus layouts affect passenger flow, providing data of sufficiently high quality to be useful in early phases of vehicle design.
Revista:
VIRTUAL REALITY
ISSN:
1359-4338
Año:
2014
Vol.:
18
N°:
3
Págs.:
161 - 171
This paper focuses on the simulation of bimanual assembly/disassembly operations for training or product design applications. Most assembly applications have been limited to simulate only unimanual tasks or bimanual tasks with one hand. However, recent research has introduced the use of two haptic devices for bimanual assembly. We propose a more natural and low-cost bimanual interaction than existing ones based on Markerless motion capture (Mocap) systems. Specifically, this paper presents two interactions based on a Markerless Mocap technology and one interaction based on combining Markerless Mocap technology with haptic technology. A set of experiments following a within-subjects design have been implemented to test the usability of the proposed interfaces. The Markerless Mocap-based interactions were validated with respect to two-haptic-based interactions, as the latter has been successfully integrated into bimanual assembly simulators. The pure Markerless Mocap interaction proved to be either the most or least efficient depending on the configuration (with 2D or 3D tracking, respectively). Usability results among the proposed interactions and the two-haptic based interaction showed no significant differences. These results suggest that Markerless Mocap or hybrid interactions are valid solutions for simulating bimanual assembly tasks when the precision of the motion is not critical. The decision on which technology to use should depend on the trade-off between the precision requested to simulate the task, the cost, and inner features of the technology.
Autores:
Velaz, Yaiza; Rodriguez Arce, Jorge; Gutierrez, T.; et al.
Revista:
JOURNAL OF COMPUTING AND INFORMATION SCIENCE IN ENGINEERING
ISSN:
1530-9827
This paper focuses on the use of virtual reality (VR) systems for teaching industrial assembly tasks and studies the influence of the interaction technology on the learning process. The experiment conducted follows a between-subjects design with 60 participants distributed in five groups. Four groups were trained on the target assembly task with a VR system, but each group used a different interaction technology: mouse-based, Phantom Omni (R) haptic, and two configurations of the Markerless Motion Capture (Mmocap) system (with 2D or 3D tracking of hands). The fifth group was trained with a video tutorial. A post-training test carried out the day after evaluated performance in the real task. The experiment studies the efficiency and effectiveness of each interaction technology for learning the task, taking in consideration both quantitative measures (such as training time, real task performance, evolution from the virtual task to real one), and qualitative data (user feedback from a questionnaire). Results show that there were no significant differences in the final performance among the five groups. However, users trained under mouse and 2D-tracking Mmocap systems took significantly less training time than the rest of the virtual modalities. This brings out two main outcomes: (1) the perception of collisions using haptics does not increase the learning transfer of procedural tasks demanding low motor skills and (2) Mmocap-based interactions can be valid for training this kind of tasks.
Revista:
TRANSPORT POLICY
ISSN:
0967-070X
Año:
2013
Vol.:
25
Págs.:
178 - 185
This paper presents a bus passenger decision making algorithm that can be applied to evaluate a new bus design using agent-based simulation techniques. For each single passenger, the algorithm builds a ranked list of available targets (seats and standing areas) according to their preferences and selects the most convenient one. The algorithm is fitted to work with a generic parametric passenger model and allow differentiating several passenger types managing their preferences regarding the entry door, seat location and standing area, among others. The differences in these preferences allow us to distinguish the types of bus passenger. The algorithm also takes into account the variation of preferences according to the amount of passengers onboard. Four fill-in modes from a nearly empty bus to maximum capacity have been implemented. To evaluate the performance of the algorithm, two case studies have been implemented within the XJTEK AnyLogic simulation environment. The decision making algorithm has been used to model the behaviour of the eight types of passengers in two different bus layouts, one with three doors and the other with five. The types of passengers were defined by Chalmers University of Technology in a previous work from 100 observations at bus stops and onboard buses in Gothenburg, Bremerhaven and Rome. The results prove that the passenger decision making algorithm can be effectively used to evaluate a new design of a bus layout using agent-based simulation techniques estimating the parameters that measure quality of service (passengers' satisfaction and dwell time among others). (C) 2012 Elsevier Ltd. All rights reserved.
Revista:
COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING
ISSN:
1093-9687
Año:
2013
Vol.:
28
N°:
6
Págs.:
465 - 480
Simulators provide significant advantages in training operators of concrete spraying machinery, such as economic savings, the practical absence of safety risks, and environmental and educational benefits. The main challenge in developing a real-time training simulator for concrete spraying machinery lies in the modeling of shotcrete application. This article presents a novel method that models and simulates in real time the three main factors influencing shotcrete sprayability: adhesion, cohesion, and rebound. Furthermore, thanks to the addition of an obstacle model, the method makes it possible to spray onto additional supporting elements, which is a typical shotcrete application. The proposed method considers a wet-mix thick flow spraying process and is based on experiments that were run with a real concrete spraying machine and complemented by expert advice. The method was developed and evaluated using a user-centered methodology, resulting in realistic shotcrete application modeling that meets the needs for training concrete spraying machinery operators.
Revista:
MULTIBODY SYSTEM DYNAMICS
ISSN:
1384-5640
Año:
2011
Vol.:
26
N°:
4
Págs.:
397 - 410
In this paper, we present an optimization method for solving the nonlinear constrained optimization problem arising from a motion reconstruction problem formulated with natural coordinates. A motion reconstruction problem consists in a kinematic analysis of a rigid multibody system whose motion is usually overdetermined by an excess of data. The method has been applied to the analysis of human motion which is a typical case of an overdetermined kinematic problem as a large number of markers are usually placed on a subject to capture its movement. The efficiency of the method has been tested both with computer-simulated and real experimental data using models that include open and closed kinematic loops.
Revista:
INTERNATIONAL JOURNAL OF CRASHWORTHINESS
ISSN:
1358-8265
Año:
2010
Vol.:
15
N°:
1
Págs.:
39 - 48
This paper evaluates the consequences of the impact of an unrestrained object against the head of vehicle occupant during a frontal crash by means of a computational head-neck biomechanical model. The correct positioning of head restraints can partially protect the rear side of the head, but there is still a significant probability of being injured. However, because head restraints are typically not properly adjusted as whiplash studies have shown, the probability of being impacted by an unrestrained object during a frontal crash is noticeably high and hence the risk of being injured is also high. In this work, head injury risk is evaluated through the Head Injury Criterion (HIC), by simulating a complete head-neck biomechanical model with realistic motion under frontal crash condition. The model developed includes all cervical vertebrae, intervertebral discs, ligaments and muscles. The model was validated against experimental data. Results have shown that the risk of severe head injury in frontal collision due to unrestrained objects cannot be neglected. The risk is directly related to the mass of the impact object, the relative velocity between the object and the head and the incorrect use of the head restraint.