Integrating digital human modeling into virtual environment for ergonomic oriented design

International audienceVirtual human simulation integrated into virtual reality applications is mainly used for virtual representation of the user in virtual environment or for interactions between the user and the virtual avatar for cognitive tasks. In this paper, in order to prevent musculoskeletal disorders, the integration of virtual human simulation and VR application is presented to facilitate physical ergonomic evaluation, especially for physical fatigue evaluation of a given population. Immersive working environments are created to avoid expensive physical mock-up in conventional evaluation methods. Peripheral motion capture systems are used to capture natural movements and then to simulate the physical operations in virtual human simulation. Physical aspects of human's movement are then analyzed to determine the effort level of each key joint using inverse kinematics. The physical fatigue level of each joint is further analyzed by integrating a fatigue and recovery model on the basis of physical task parameters. All the process has been realized based on VRHIT platform and a case study is presented to demonstrate the function of the physical fatigue for a given population and its usefulness for worker selection

Fatigue evaluation in maintenance and assembly operations by digital human simulation

Virtual human techniques have been used a lot in industrial design in order to consider human factors and ergonomics as early as possible. The physical status (the physical capacity of virtual human) has been mostly treated as invariable in the current available human simulation tools, while indeed the physical capacity varies along time in an operation and the change of the physical capacity depends on the history of the work as well. Virtual Human Status is proposed in this paper in order to assess the difficulty of manual handling operations, especially from the physical perspective. The decrease of the physical capacity before and after an operation is used as an index to indicate the work difficulty. The reduction of physical strength is simulated in a theoretical approach on the basis of a fatigue model in which fatigue resistances of different muscle groups were regressed from 24 existing maximum endurance time (MET) models. A framework based on digital human modeling technique is established to realize the comparison of physical status. An assembly case in airplane assembly is simulated and analyzed under the framework. The endurance time and the decrease of the joint moment strengths are simulated. The experimental result in simulated operations under laboratory conditions confirms the feasibility of the theoretical approach

Virtual Human Hand: Autonomous Grasping Strategy

La mà humana és l'eina més completa, capaç d'adaptar-se a superfícies diferents i formes i tocar i agafar. Es presenten i es desenvolupa un algoritme nou per agafar qualsevol objecte en un entorn virtual (VE). L'objectiu és presentar una teoria nova per agafar qualsevol objecte en un VE amb l'humà virtual (VH).Postprint (published version

Multi-Objective Optimisation Method for Posture Prediction and Analysis with Consideration of Fatigue Effect and its Application Case

Automation technique has been widely used in manufacturing industry, but there are still manual handling operations required in assembly and maintenance work in industry. Inappropriate posture and physical fatigue might result in musculoskeletal disorders (MSDs) in such physical jobs. In ergonomics and occupational biomechanics, virtual human modelling techniques have been employed to design and optimize the manual operations in design stage so as to avoid or decrease potential MSD risks. In these methods, physical fatigue is only considered as minimizing the muscle or joint stress, and the fatigue effect along time for the posture is not considered enough. In this study, based on the existing methods and multiple objective optimisation method (MOO), a new posture prediction and analysis method is proposed for predicting the optimal posture and evaluating the physical fatigue in the manual handling operation. The posture prediction and analysis problem is mathematically described and a special application case is demonstrated for analyzing a drilling assembly operation in European Aeronautic Defence & Space Company (EADS) in this paper

Re-design of drivers’ car seat using three dimensional reverse engineering

Automobile seat design in current practice requires satisfying the ergonomics guidelines as well as considers the comfort expectation of the population. The main aim is to re-examine the existing car seat designs and to propose a novel seat design for better comfort. The number of cars reviewed for drivers’ seat features and user comfort are based on the analysis using a statistical tool. The statistical tool analysis is defined using data from the survey conducted. The proposed design is obtained using the 3-D Reverse Engineering procedure on the selected car seat models. The result is assessed to show that the modified car seat design is superior in terms of form, shape, seat features, usability and comfort. Through this work, the basic seat needs while driving, for example pain preclusion aspects and comfort weightage are defined. The survey done can expunge the expenditure for test experimentations in the future and the proposed methodology can be useful in establishing new design standards for the seat

Valoración del daño corporal en personas afectadas de secuelas neurológicas

Objetivo: Mostrar un nuevo sistema para simular la recuperación inicial de las funciones de la extremidad superior los primeros días después del ictus y simular la recuperación funcional de los pacientes bajo los programas de rehabilitación. Pacientes y metodología: Seleccionamos 29 pacientes en los primeros cuatro días después de padecer un ictus, valorados a los tres y siete días y uno, tres y seis meses, recogiendo tipo de ictus, clasificación (escala de Oxford), déficit neurológico (escala de NIHSS), medidas de discapacidad, valoración de la función motora de la extremidad superior (escala de Fugl-Meyer), tono muscular y balance muscular de la extremidad superior. Resultados: Los pacientes que presentaron un tono muscular disminuido tuvieron más dificultad en mejorar el control motor de las articulaciones de la extremidad superior. Los pacientes TACI presentaron mayor déficit neurológico, mientras que los tipos de ictus POCI y LACI tenían una función motora mejor con mayor independencia para el desarrollo de sus actividades de la vida diaria. Conclusión: La simulación virtual del brazo y la mano en pacientes afectados por un ictus proporciona a los médicos y fisioterapeutas una nueva herramienta que permite simular la evolución de los déficits en algunos pacientes.Postprint (published version

Robotic Grippers for Large and Soft Object Manipulation

Grasping has always been considered a key domain of cyber-physical systems, through which action physical interaction can be achieved. This paper presents a systematic review of the state-of-the-art robotic soft object gripping solutions aimed for the food-industry, focusing on red meat handling. A categorized analysis about the currently used grippers is provided, that could be used or adapted to robotic meat-processing. The paper enlists various solutions and gripping principles for low-payload applications too, although the emphasis is on the classic shapelocking and force-locking grippers that are potentially capable of grasping and manipulating heavier specimens. The purpose of the scientific literature survey is mainly to identify exceptional and/or remarkable gripper-designs, or completely new gripping concepts, while the patent research presents complete, commercially available solutions

Neural Network for Large-Scale Problems, with Application to Human Motion

As the potential applications for artificial intelligence, and thus neural networks expand, and as the prevalence of big data increases, the need for improved training in neural networks that leverage data sets efficiently will soon surface. In addition, research in the field of human simulation has led to significant advancements in quality, time, and cost management for products like military and athletic equipment and vehicles. There is, however, a critical need for human simulation models to run in real time, especially those with large-scale problems like motion prediction (a single motion problem involves prediction of between 500-700 outputs). Hence, this work addresses both challenges by introducing a modified training process for an artificial neural network (ANN) that is capable of mitigating memory issues and improving accuracy with large scale problems that involve minimal taring data. The new modified ANN design is successfully tested on two common human-motion tasks, walking and going prone. Through comparison with a benchmark ANN, the results of the new network are shown to be accurate objectively and subjectively

Planificación de movimientos para conjuntos mano-brazo con numerosos grados de libertad

Con el objetivo de avanzar hacia la emulaci ´on de las capacidades y destreza de la mano humana se est ´an desarrollando manos rob´oticas con prestaciones muy superiores a las tradicionales pinzas usadas en la rob´otica industrial. El uso de estas manos rob´oticas conlleva asociados nuevos retos, y entre ellos est ´a el de la planificaci ´on eficiente de sus movimientos, ya que aunque algunos m´etodos de planificaci ´on tradiciones podr´ıan ser v´alidos, su aplicaci ´on pr´actica es limitada debido sobre todo al elevado n´umero de grados de libertad que tiene un sistema rob´otico que incluya una mano antropomorfa montada sobre un brazo manipulador. Este art´ıculo presenta un enfoque que permite soluciones suficientemente eficientes para ser utilizadas en la pr´actica. El enfoque propuesto est ´a basado en la reducci ´on de la dimensi ´on del espacio de b´usqueda y en la utilizaci ´on de t´ecnicas de muestreo para generar movimientos del conjunto mano-brazo en entornos con obst ´aculos que pueden imponer fuertes restricciones en la b´usqueda de movimientos sin colisi ´on, como sucede normalmente cuando la mano se acerca a un objeto para su sujeci ´on y manipulaci ´on. Los desarrollos te´oricos han sido implementados tanto en simulaci ´on como en un sistema f´ısico real, por lo que se incluyen resultados experimentales reales.Postprint (published version

The development and applications of serious games in the public services: defence and health

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.The latest advances of Virtual Reality technologies and three-dimensional graphics, as well as the developments in Gaming Technologies in the recent years, have stemmed the proliferation of Serious Games in a broader spectrum of research applications. Among the most popular areas of application are public services such as Defence and Health, where digital technologies realise new challenges and opportunities for research and development of Serious Games and for a variety of contexts. As with all games, the user engagement is elevated and apart from the entertaining aspect, Serious Games serve as a novel and promising alternative experience to knowledge transfer. Furthermore, Serious Games bring to the end user and the overall society a series of attractive benefits. These benefits include safety, cost-effectiveness, increased motivation and personalisation. Hence, this Thesis aims to investigate novel approaches of developing Serious Games that utilise the recent advances of Virtual Reality and Gaming Technology and facilitate the aforementioned benefits. The process of design and development of the novel tools and applications follow an iterative manner and are driven by the review of the available literature as well as end-user feedbackEPSRC (Engineering and Physical Sciences Research Council ) , MOD (UK), NHS (UK