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The human ankle provides a significant amount of net positive work during the stance period of walking, especially at moderate to fast walking speeds. On the contrary, conventional ankle-foot prostheses are completely passive during stance, and consequently , cannot provide net positive work. Clinical studies indicate that transtibial amputees using(More)
This paper addresses the issues of energy efficiency in mechanisms for underwater locomotion and its accomplishment using a more robust class of mechanical structures. We present a design methodology for fabricating a continuous mechanical fish body such that its kinematic behavior matches parametric models of fish swimming with minimum energy cost. It is(More)
In this paper, a solution to the control problem of dual actuation in atomic force microscopes (AFMs) is presented. The use of two actuators to balance the trade-off between bandwidth, range, and precision has been recently extended to nano-positioning systems. Despite existing demands, this concept undergoes fundamental limitations towards its extension to(More)
The self-propelled swimming performance of two prototypes designed to mimic the kinematics of real fish swimming at high Reynolds numbers is presented. The design methodology uses structural compliance instead of discrete assemblies to achieve desired kinematics. Experiments took place at Reynolds numbers between 15×103 and 90×103. A prototype(More)
Utilizing a newly developed atomic-force-microscopy-based wide-frequency rheology system, we measured the dynamic nanomechanical behavior of normal and glycosaminoglycan (GAG)-depleted cartilage, the latter representing matrix degradation that occurs at the earliest stages of osteoarthritis. We observed unique variations in the frequency-dependent stiffness(More)