Filling 'gaps' in strength data for design

Data on the physical strength capabilities of users are fundamental to the safe and usable design of products. It is recognised, however, that there are many 'gaps' in the ergonomics data available to designers. Whilst considerable research on human capabilities and limitations has already been carried out, few data exist which are directly applicable in the design process. This paper describes a two-stage research project which was undertaken to try to address some of these data 'gaps'. Potential needs for design-relevant data were identified in Stage 1 of the research and in Stage 2 new data were collected to meet some of those needs. Data were collected on children through to the older adult on a series of six strength measurements, all of which were intended to be directly applicable to design: (1) finger push strength, (2) pinch-pull strength, (3) hand grip strength, (4) wrist-twisting strength, (5) opening strength, and (6) push and pull strength. The methodology, findings and data from this research are presented and discussed.     

面向康复工程的助行可穿戴外骨骼机器人的人类工效学设计

中国社会正在逐渐进入老龄化,肢体残疾人群数也在不断增加,这逐渐加剧了我国康复专业人才的供需矛盾。为了缓解该矛盾,针对下肢运动功能完全或部分丧失的偏瘫及截瘫患者,设计了PRMI助行外骨骼机器人。该外骨骼系统对其穿戴者提供运动补偿以帮助其自然和有效地独立行走。介绍了PRMI助行外骨骼机器人设计目的。通过对外骨骼的人类工效学设计的分析,对PRMI外骨骼的可调范围、关节的运动范围、最大力矩、运动学上的一致性以及人机交互进行了介绍。     

单片机系统的电磁兼容设计

给出了电磁兼容性的基本含义,对单片机系统中普通存在的电样兼容问题作了简要的论述,并就如何进行单片机系统电磁兼容设计作了较为全面和详细的叙述。文中介绍了电磁兼容设计方法同样适用于微机控制系统、家用电器、工业自动测控装置、电子测量装置、移动通信设备等的开发和设计,具有较大的实用价值和经济价值。     

Axiomatic design principles in analysing the ergonomics design parameter of a virtual environment

One of the negative side effects experienced by users when interacting with virtual environment is visual symptoms. This paper explores the ergonomics design parameters of the virtual environment to minimize such negative side effect by applying axiomatic design principles. Axiomatic design is a method to provide a systematic way for designing products and large systems. The independence axiom is used to map customer domain (CAs) to functional domain (FRs) and physical domain (DPs). A paper based survey was conducted to identify and define customers' preference in the virtual environment. A virtual robot manufacturing system was developed as a case study to explore ergonomic design parameters that satisfy the independence of FRs and CAs. Results of this study shows that the ergonomic design parameters of virtual environment identified (DP₁₆₁-DP₁₆₂-DP₁₂₁-DP₁₁₁-DP₁₃₁-DP₁₄₁-DP₁₅₁-DP₁₅₂) have satisfied the independence functional requirement and desired visual comfort for users. By uncoupling the design it provides an efficient and effective sequence of design activities FR₁₆₁-FR₁₆₂-FR₁₂₁-FR₁₁₁-FR₁₃₁-FR₁₄₁-FR₁₅₁-FR₁₅₂.     

A task based ‘design for all’ support tool

The ‘design for all’ philosophy promotes the development of products that meet the requirements of a broader section of the population, including those who are older or disabled, to minimise the need for bespoke designs and individual customisations. Such an approach begins to meet the needs of a population containing an ever increasing proportion of these excluded groups, whilst providing opportunities to manufacturers to maximise the available market for any given product.Most design activity embodies some form of task analysis that involves identifying users and the tasks they perform. Computer based human modelling systems are becoming increasingly important in this task analysis role combined with the established ergonomics technique of fitting trials, in which a product or environment is evaluated through trials using a carefully selected user group.This research addresses the lack of existing data necessary for the accurate representation of human form and capability in the older and disabled populations for use in these modelling systems. A small-scale survey is being undertaken to collect this important information. In addition, existing modelling systems in this area rely on expert ergonomics knowledge in performing task based analysis, which in addition can be a time consuming and repetitive task. Methods are being developed to streamline this process and to place the emphasis on good design and ergonomics principles as opposed to ‘driving’ the system. These methods involve the development of a simplified process for computer based task analysis and a means of determining the percentage accommodated by any given design.Further research will eventually focus on extending the data collection, refining the task model and look at a means of suggesting design solutions in response to the analysis results.     

Computer aided design of the sitting workplace

This paper demonstrates the use of personal micro-computers to individualize the design of the sitting workplace. Engineering static and functional anthropometry as well as ergonomic design principles are implemented. Computer outputs and a case study are presented.     

Issues in the design and use of wearable computers

Wearable computers are fully functional, self-powered, self-contained computers that allow the user to access information anywhere and at any time. In this paper, design issues for wearable computers are discussed, including power considerations, use of input devices, image registration, and the use of wearable computers for the design of smart spaces. Application areas for wearable computers are presented, including medicine, manufacturing, maintenance, and as personal assistants. Finally, future research directions for wearable computers are indicated.     

Applying a fusion of wearable sensors and a cognitive inspired architecture to real-time ergonomics analysis of manual assembly tasks

High value manufacturing systems still require ergonomically intensive manual activities. Examples include the aerospace industry where the fitting of pipes and wiring into confined spaces in aircraft wings is still a manual operation. In these environments, workers are subjected to ergonomically awkward forces and postures for long periods of time. This leads to musculoskeletal injuries that severely limit the output of a shopfloor leading to loss of productivity. The use of tools such as wearable sensors could provide a way to track the ergonomics of workers in real time. However, an information processing architecture is required in order to ensure that data is processed in real time and in a manner that meaningful action points are retrieved for use by workers.In this work, based on the Adaptive Control of Thought—Rational (ACT-R) cognitive framework, we propose a Cognitive Architecture for Wearable Sensors (CAWES); a wearable sensor system and cognitive architecture that is capable of taking data streams from multiple wearable sensors on a worker’s body and fusing them to enable digitisation, tracking and analysis of human ergonomics in real time on a shopfloor. Furthermore, through tactile feedback, the architecture is able to inform workers in real time when ergonomics rules are broken. The architecture is validated through the use of an aerospace case study undertaken in laboratory conditions. The results from the validation are encouraging and in the future, further tests will be performed in an actual working environment.     

Wheelchair ergonomics and physiological testing of prototypes

Abstract

Two hand rim propelled wheelchairs, a daily-use (active) wheelchair (R) and a marathon sports wheelchair (S), were compared to a three-wheeled crank (C) and a (synchronic) lever (L) propelled wheelchair. All wheelchairs were analysed with respect to cardio-respiratory parameters ([Vdot] _E, [Vdot] _O2 , HR, RER), power output and gross mechanical efficiency during a continuous exercise test (speed of the treadmill V = 0·96 ms^-1; every third minute a one degree increase of the slope). Non-wheelchair users (NW: N = 10) were compared to wheelchair sportsmen (WS: N = 3).

The cardio-respiratory strain of hand rim propulsion increases more swiftly for both R and S wheelchairs than for the C and L systems. Mechanical efficiency is significantly lower for the hand rim wheelchairs with a remarkably low efficiency for the S wheelchair. The S wheelchair however showed the lowest energy losses and a lower [Vdot]_{O 2} compared to the R wheelchair, these being important modalities for high speed and long distance wheeling. The trend in the data was similar for the C and L wheelchairs. These systems showed a 2–3% higher mechanical efficiency in the NW group than for R and S wheelchairs. The trend in the data between wheelchairs for both groups is more or less identical, although the WS group showed lower cardiorespiratory responses and a higher mechanical efficiency. It is concluded that physiological testing of prototypes is useful and should be extended to biomechanical and anatomical aspects to learn more about the optimizing factors for efficiency and energy expenditure in the wheelchair/user interface.     

Improving sustainability in combined manual material handling through enhanced lot-sizing models

Lot-sizing models play an important role in optimizing the performance of internal logistics systems that involve a large amount of manual material handling (MMH) tasks. The performance of MMH tasks should be assessed using multiple criteria rather than being merely cost-oriented, considering the fact that the lot size affects the workload and can result in work-related musculoskeletal disorders (WMSDs). This study aims to integrate biomechanical and physiological guidelines into a cost-based performance optimization model of MMH tasks. In this study, we consider the impact of lot size on lifting frequency, which is reflected in the Composite Lifting Index (CLI), an extension of the National Institute for Occupational Safety and Health (NIOSH). In addition, the energy expenditure rates of operators are estimated by applying an established physiological method. The energy expenditure results are used to calculate rest allowance during a handling process that help keep workload levels acceptable. To make the model more general, we consider different manual material shipping scenarios and intermodal replenishment cases. Finally, a sustainable lot-sizing model is applied in a two-stage intermodal replenishment case and several numerical experiments to determine the influence of item weight, speed, distance, and opportunity cost. The results indicate that the proposed model can ease the ergonomic strain of operators without compromising economic efficiency.     

Integration of the human factor into the design and construction of fishing vessels

Sea fishing is an extremely hazardous occupation. Since the eighties, several studies and reports have been made in an attempt to further the integration of safe working conditions into the design of fishing vessels. This paper presents various ergonomical interventions, performed on several very different projects: one industrial vessel, and smaller vessels built in co-operation with small firms. The ergonomical follow-up on the design and construction of a large halieutic research vessel was performed along standard principles: work analysis in typical situations, definition and simulation of possible future activity, and input from future users. The experience of work with smaller firms (when they were either the owner or the contractor) has shown the limitations of these principles. The difficulties were mainly related to the projects’ lack of structure (no specifications, no plans), the lack of availability of the different actors, and the lack of any real demand as far as safety was concerned.

Multi-position ergonomic computer workstation design to increase comfort of computer work

This paper presents a new design of computer workstation that is aimed at increasing the comfort of a user working for long periods at a computer. As we have become a society that spends a lot of time working on computers, the computer workstation needs to provide comfort to users. Discomfort and an improper position can negatively affect overall health and productivity. A new type of ergonomic computer workstation, which allows users to sit in multiple working positions, is proposed in order to provide better comfort to people who spend a long time sitting at their workstations. We have designed and developed a new multi-position ergonomic computer workstation which has 19 degrees of freedom and which can accommodate from 5th to 95th percentile human size. Four types of working position (upright, lean-back, zero-gravity and lean-forward) are preset by choosing different angular positions of the workstation parts. Positions of the workstation parts can be changed by controlling the actuators. These four positions were used to evaluate the comfort of the workstation. Subjective and objective evaluations, including comparison of the prototype and standard computer setup, were carried out using human subjects and ergonomic principles. Results showed that the new workstation is much more comfortable, supporting the body in a balanced way. Users have the freedom to stretch and relax in different working positions before they feel any noticeable discomfort; as a result, it lets users work for a longer period without strain, thus resulting in higher productivity.     

Forty years of IEA: some reflections on the evolution of ergonomics

This paper is the IEA Presidential Address to the 1997 IEA Triennial Congress in Tampere, Finland. The evolution of ergonomics prior to and after the foundation of the International Ergonomics Association in 1957 is reviewed. Ergonomics has broadened from considering work activities to include all types of human activities. The recent introduction of computers has changed many of the premises for work and leisure activities, and cognitive ergonomics is now as important as the ‘biological’ emphasis that was mentioned in the founding documents of IEA. Ergonomics is a science of design. There are three important targets for ergonomics design activity: to improve safety, productivity and operator satisfaction. A systems approach is presented to define how these parameters interact and how they can be measured.     

Ergonomics and human factors: the paradigms for science,engineering, design,technology and management of human-compatible systems

This paper provides a theoretical perspective on human factors and ergonomics (HFE), defined as a unique and independent discipline that focuses on the nature of human-artefact interactions, viewed from the unified perspective of the science, engineering, design, technology and management of human-compatible systems. Such systems include a variety of natural and artificial products, processes and living environments. The distinguishing features of the contemporary HFE discipline and profession are discussed and a concept of ergonomics literacy is proposed. An axiomatic approach to ergonomics design and a universal measure of system-human incompatibility are also introduced. It is concluded that the main focus of the HFE discipline in the 21st century will be the design and management of systems that satisfy human compatibility requirements.     

移动代理在可穿戴计算机数据处理中的应用

计算能力的便携化已成为微小型计算机的发展趋势之一,人们期望能够随时随地对主动和被动数据进行处理。可穿戴计算机为满足这种无处不在的计算提供了硬件可能,对其软件的研究主要分为无线网络包括单跳和多跳网络的底层通信机制和基于其上的计算模式如移动代理和远程过程求值等。文章介绍了移动计算和移动代理的关系及其实现方式,移动代理在可穿戴计算机数据处理中的应用及在这方面进行的工作。     

Enhancing the impact of ergonomics interventions

The aim of this paper was to provide recommendations for ergonomists involved in project design and evaluation. Twelve research and consultancy projects involving ergonomics interventions in a variety of settings in The Netherlands were analysed to identify factors important to success. Projects included participatory and non-participatory cases. Eight factors were identified for successful project design and for demonstrating project effectiveness.     

Improving engineering design- contributions of cognitive ergonomics

Engineering design is analysed in terms of design problem-solving. Engineering designers of differing productivity hardly differ in mental abilities, especially their tested intelligence. However, they differ in their strategies concerning the analysis of requirements and of the problem, in their search for general principles solving the relevant problem, and in the procedures used for developing specific solutions. Experimental and interview results stress that the interrelationship of thinking and sketching, as well as other kinds of an early low-cost prototyping are of crucial importance for the efficiency of the problem-solving procedure and the result. Possibilities for assisting design problem-solving and to improve the training of designers are discussed.     

工业设计中的抗疲劳研究

西方工业革命迫使产品使用者与设计者由同一化分离,形成了崭新的社会分工格局。在这样的社会背景下,使用期望与产品设计间的断层往往会引发设计缺陷。设计缺陷将会引起使用者的不适与疲劳,而疲劳积累则是造成事故的主要原因之一。因此在设计多元化的今天,我们依然不可忽视"适用于使用者"这一设计的根本出发点。文章通过对生理疲劳与心理疲劳的产生因素、作用机理等方面进行分析,提出了改进设计以缓解疲劳的措施。