Search Results

In this review study, information on efficiencies and characteristics of different exercises is presented with the goal of using the information for modeling extra-vehicular activity (EVA). Muscle activation is reported for running, walking, and cycling. The deviation and uncertainties in efficiency will be assessed along with effects of workload, rate of exercise, training, and various physiological parameters. The uncertainty involved in using VO2 consumption as a measure of metabolic rate is discussed. The information reported will be related to efforts to analyze exercises to simulate EVA on Earth.

A directional dynamic model of a partially filled liquid tank vehicle is developed to investigate its dynamic characteristics during typical straight-line braking maneuvers. The computer simulation model is developed by integrating the fluid slosh model of a partially filled tank to the pitch plane vehicle model. The dynamic behavior of liquid within the tank is modeled using an equivalent mass-spring system. The analogous mechanical system model for the partially filled cleanbore cylindrical tank is developed by utilizing the potential flow theory for longitudinal oscillations. An approximate summation method is developed in order to obtain the mechanical system parameters and are validated against experimental results available in literature. Computer simulation of the tank vehicle for typical braking maneuvers is then performed by incorporating the slosh forces and moments computed using the mechanical analogy model into the vehicle model.