Matching Items (2)
Description
The ultimate goal of human movement control research is to understand how natural movements performed in daily activities, are controlled. Natural movements require coordination of multiple degrees of freedom (DOF) of the arm. Here, patterns of arm joint control during daily functional tasks were examined, which are performed through rotation of the shoulder, elbow, and wrist with the use of seven DOF: shoulder flexion/extension, abduction/adduction, and internal/external rotation; elbow flexion/extension and pronation/supination; wrist flexion/extension and radial/ulnar deviation. Analyzed movements imitated two activities of daily living: combing the hair and turning the page in a book. Kinematic and kinetic analyses were conducted. The studied kinematic characteristics were displacements of the 7 DOF and contribution of each DOF to hand velocity. The kinetic analysis involved computation of 3-dimensional vectors of muscle torque (MT), interaction torque (IT), gravity torque (GT), and net torque (NT) at the shoulder, elbow, and wrist. Using a relationship NT = MT + GT + IT, the role of active control and the passive factors (gravitation and inter-segmental dynamics) in rotation of each joint was assessed by computing MT contribution (MTC) to NT. MTC was computed using the ratio of the signed MT projection on NT to NT magnitude. Despite the variety of joint movements required across the different tasks, 3 patterns of shoulder and elbow coordination prevailed in each movement: 1) active rotation of the shoulder and predominantly passive rotation of the elbow; 2) active rotation of the elbow and predominantly passive rotation of the shoulder; and 3) passive rotation of both joints. Analysis of wrist control suggested that MT mainly compensates for passive torque and provides adjustment of wrist motion according to requirements of both tasks. The 3 shoulder-elbow coordination patterns during which at least one joint moves largely passively represent joint control primitives underlying performance of well-learned arm movements, although these patterns may be less prevalent during non-habitual movements. The advantage of these control primitives is that they require minimal neural effort for joint coordination, and thus increase neural resources that can be used for cognitive tasks.
ContributorsMarshall, Dirk (Author) / Dounskaia, Natalia (Thesis advisor) / Schaefer, Sydney (Thesis advisor) / Buneo, Christopher (Committee member) / Arizona State University (Publisher)
Created2018
Description
The purpose of this study was to utilize quantitative results gained through surveys to determine the effect of hands-on engineering activities and a poster study on improving understanding and awareness of engineering disciplines in high school students. There was a focus on increasing participation of women and minorities in engineering to improve diversity, and this study utilized biomedical engineering as a means of achieving these goals. The analysis of this thesis focused on the results of the pre-assessment and post-assessment taken by a group of high school students before and after a program using presentations in combination with engineering activities tackling real-world problems. These assessments objectively ranked both the awareness and interest level in various engineering activities across a number of disciplines. The results were analyzed using percentages of the engineering statements that the students recognized as engineering and were interested in, as well as using t-tests. Statistical significance was found for the percentage of statements that the students expressed the highest interest level in between the initial and final survey. The other factors analyzed did not produce statistical significance, but the increase in interest level does meet one of the primary goals of the project. Since the percentages of all the positive factors did increase between the pre- and post- assessment, the study can be considered a success overall; more data is simply needed to indicate significance in these other factors. Future studies will focus on implementing this program as an after-school activity that can be led by members of the engineering community at ASU.
ContributorsLum, Kenna (Co-author) / Marshall, Dirk (Co-author) / Ganesh, Tirupalavanam (Thesis director) / Parker, Hope (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05