 Users may download and print one copy of any publication from the public portal for the purpose of private study or research.  You may not further distribute the material or use it for any profit-making activity or commercial gain  You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

No abstract

The use of exoskeletons as an aid for people with musculoskeletal disorder is the subject to an increasing interest in the research community. These devices are expected to meet the specific needs of users, such as children with cerebral palsy (CP) who are considered a significant population in pediatric rehabilitation. Although these exoskeletons should be designed to ease the movement of people with physical shortcoming, their design is generally based on data obtained from healthy adults, which leads to oversized components that are inadequate to the targeted users. Consequently, the objective of this study is to custom-size the lower limb exoskeleton actuators based on dynamic modeling of the human body for children with CP on the basis of hip, knee, and ankle joint kinematics and dynamics of human body during gait. For this purpose, a multibody modeling of the human body of 3 typically developed children (TD) and 3 children with CP is used. The results show significant differences in gait patterns especially in knee and ankle with respectively 0.39 and -0.33 (Nm/kg) maximum torque differences between TD children and children with CP. This study provides the recommendations to support the design of actuators to normalize the movement of children with CP.

No abstract

The complexity of an engineering product is based in part on the number of components and their dependencies, where the latter can be desired or undesired. In some cases, where those dependencies exist concurrently, engineers can be misled regarding the design challenge at hand due to ill-adapted representation methods, especially when managing various abstraction levels. To overcome this issue, a new modeling method to concurrently handle positive and negative dependencies is proposed. This paper suggests modeling the dependencies using a complex number notation within a design structure matrix. Using the proposed representation to simultaneously model positive and negative dependencies, shown through an illustrative example, it is possible to differentiate and make use of more information when dealing with different abstraction levels. Finally, the paper discusses implications related to using the modeling method regarding the system analysis.