Development of a theoretical model for upright postural control in lower limb prosthesis users

Methods used to assess quiet standing in unilateral prosthesis users often assume validity of an inverted pendulum model despite this being shown as invalid in some instances. The aim of the current study was to evaluate the validity of a proposed unilaterally-constrained pin-controller model in explaining postural control in unilateral prosthesis users. Prosthesis users were contrasted against the theoretical model as were able-bodied controls that stood on a platform which unilaterally constrained movement of the CoP. All participants completed bouts of quiet standing with eyes open, eyes closed and with feedback on inter-limb weight bearing asymmetry. Correlation coefficients were used to infer inverted pendulum behavior in both the anteroposterior and mediolateral directions and were derived from both kinematic (body attached markers) and kinetic (centre of pressure) experimental data. Larger, negative correlation coefficients reflected better model adherence, whilst low or no correlation reflected poorer model adherence. Inverted pendulum behavior derived from kinematic data, indicated coefficients of high magnitude in both mediolateral (all cases range 0.71–0.78) and anteroposterior (0.88–0.91) directions, irrespective of groups. Inverted pendulum behavior derived from kinetic data in the anteroposterior direction indicated validity of the model with large negative coefficients associated with the unconstrained/intact limbs (prosthesis users: − 0.45 to − 0.65, control group: − 0.43 to − 0.72), small coefficients in constrained/prosthetic limbs (prosthesis users: − 0.02 to 0.07, control group: 0.13–0.26) and large negative coefficients in combined conditions (prosthesis users: − 0.36 to − 0.56, control group: − 0.71 to − 0.82). For the mediolateral direction, coefficients were negligible for individual limbs (0.03–0.17) and moderate to large negative correlations, irrespective of group (− 0.31 to − 0.73). Data suggested both prosthesis users’ and able-bodied individuals’ postural control conforms well to that predicted by a unilaterally-constrained pin-controller model, which has implications for the fundamental control of posture in transtibial prosthesis users

GROUP MODEL BUILDING WITH CAUSAL LOOP DIAGRAMS TO FOSTER CAPABILITIES FOR SUSTAINABLE DESIGN AND PRODUCT DEVELOPMENT

AbstractThis research proposes a group model building workshop method that uses causal loop diagrams to foster capabilities for sustainable product development based on feedback and observations from several cases. The method's potential to enhance sustainability system thinking skills and to identify relationships between sustainability criteria and traditionally identified requirements is evaluated. The method can trigger discussion, visualize complexity and dependencies of sustainable design problems. Other application areas are e.g., sustainability training for practicing engineers and students.</jats:p

APPROACH FOR SUSTAINABILITY CRITERIA AND PRODUCT LIFE-CYCLE DATA SIMULATION IN CONCEPT SELECTION

AbstractCompanies struggle with identifying relevant sustainability aspects strategically, assessing alternative solutions quantitatively, and making trade-offs. This paper reports results from a prescriptive study with an aerospace company, and presents the Sustainability Criteria And product life-cycle Data Simulation (SCADS) approach. Based on strategic integration of sustainability indicators, this approach aims to enable visualisation and comparison of the sustainability implications of different concepts in early design phases of product development.</jats:p

HOW CAN INFORMATION AND COMMUNICATIONS TECHNOLOGY SUPPORT THE LINK BETWEEN CIRCULAR ECONOMY AND PRODUCT LIFE CYCLE MANAGEMENT? – A REVIEW

AbstractLinear production is related to resource scarcity and negative environmental impacts. Circular Economy (CE) emerged for society transition towards sustainability, based on regenerative systems and multiple life cycle products. Product Life cycle Management (PLM) supports the whole life cycle with the aid of Information and Communication Technology (ICT). A literature review analyzed the role of ICT enabling CE based on PLM, identifying challenges and opportunities, active and passive PLM, system perspective, stakeholder's role, and sustainability. Concluding that ICT enables the CE transition.</jats:p

Industry trends to 2040

The engineering design community needs to development tools and methods now to support emerging technological and societal trends. While many forecasts exist for technological and societal changes, this paper reports on the findings of a workshop, which addressed trends in engineering design to 2040. The paper summarises the key findings from the six themes of the workshop: societal trends, ways of working, lifelong learning, technology, modelling and simulation and digitisation; and points to the challenge of understanding how these trends affect each other

RAISING VALUE AND SUSTAINABILITY AWARENESS FOR CRITICAL MATERIALS: A SERIOUS GAME FOR THE AEROSPACE SECTOR

AbstractAviation strives today to include environmental and social considerations as drivers for decision making in design. This paper proposes a serious game to raise awareness of the value and cost implications of being ‘sustainability compliant’ when developing aerospace sub-systems and components. After describing the development of the game, from needfinding to prototyping and testing, the paper discusses the results from verification activities with practitioners, revealing the ability of the game to raise sustainability awareness and support negotiation across disciplinary boundaries in design.</jats:p