Differential game theory for versatile physical human-robot interaction

The last decades have seen a surge of robots working in contact with humans. However, until now these contact robots have made little use of the opportunities offered by physical interaction and lack a systematic methodology to produce versatile behaviours. Here, we develop an interactive robot controller able to understand the control strategy of the human user and react optimally to their movements. We demonstrate that combining an observer with a differential game theory controller can induce a stable interaction between the two partners, precisely identify each other’s control law, and allow them to successfully perform the task with minimum effort. Simulations and experiments with human subjects demonstrate these properties and illustrate how this controller can induce different representative interaction strategies

Insulinomas may present with normoglycemia after prolonged fasting but glucose-stimulated hypoglycemia.

BACKGROUND: Insulinomas are rare but are the most common cause of hyperinsulinemic hypoglycemia in the adult population. Diagnosis of this pathology relies on clinical features along with laboratory tests and imaging investigations to aid in localization. One of the most robust standard tests used for establishing a biochemical diagnosis is the prolonged (72 h) fast. Currently, it is recommended that a prolonged supervised fast be performed, at least for 48 h if not for 72 h, and many would take the absence of hypoglycemia after a 72-h fast as evidence excluding the diagnosis. METHODS: We employed prolonged fasts and standard glucose tolerance tests, plus imaging studies and surgical pathology, in two patients with suspected insulinomas. RESULTS: The prolonged 72-h fast was normal in both the patients, whereas in both cases a prolonged oral glucose tolerance test clearly demonstrated the induction of severe hyperinsulinemia followed by significant hypoglycemia. Surgical removal confirmed the presence of insulinomas in each case. CONCLUSIONS: Although the sensitivity of the 72-h fast is high and still plays an important role in the diagnosis of an insulinoma, we suggest that a "normal" test result should be interpreted in the light of clinical symptoms

Mechanical Characterization of Prosthetic Feet and Shell Covers Using a Force Loading Apparatus

To assist in the redirection of kinetic energy many modern prosthetic feet often utilize a so called energy storing and return (ESAR) design that is achieved through dorsiflexion and elastic bending to facilitate forward propulsion during push-off. Consequently, the proper selection of the foot stiffness and mechanical response for an individual amputee is significant; however, the component stiffness and mechanical properties between manufactures remains largely unreported. This study reports independent characterization of TLM Prosthetics TaiLor Made foot with interchangeable springs and Freedom Innovations Renegade foot using mechanical testing techniques to determine the stiffness, viscoelasticity, and localized material strain in prosthetic feet and their cosmetic covers. Mechanical data are acquired during the compressive loading of the prosthetic foot via force-deflection sensors and digital image correlation. In doing so, this contribution demonstrates a curtailed characterization process that can be used to quantify properties for other modern foot prosthetics