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This paper presents a definition of human thermal comfort that can be used for control purposes. A control strategy and architecture based on a Proportional Integral Derivative (PID) controller format is developed. Problems and limitations are discussed and the results from both simulations and experiments are used to demonstrate the practicality of the comfort definition.

The duration and frequency of extravehicular activity (EVA) is expected to increase with the anticipation of challenging missions ahead. This necessitates the development of an automatic controller for astronaut thermal comfort regulation. A reliable human thermal model is essential in order to predict the thermal response of subjects under various conditions to aid in automatic controller development. This paper examines thermal response sensitivity to several parameters and input modifications using a popular human thermal model. These parameter and input variations are based either on values reported in the literature or realistic estimates.

Novel mechatronic designs for the automation and control of an all-terrain vehicle for operation by a C-5/6 quadriplegic are described. As part of a project at the University of Missouri, a Kawasaki Mule 2010 all-terrain vehicle was purchased and fully automated and interfaced with a computer for control using novel automation designs. This computer controlled all-terrain vehicle (CCATV) is primarily intended to be used for recreational off-road locomotion. A ‘drive-by-wire’ computer control system has been designed, tested and installed on a utility vehicle and delivered to the sponsor. A very user-friendly and high-tech control panel was developed with 2 joysticks, 15 push buttons and 3 LCD displays for interfacing with the CCATV systems.

This paper presents the quantified effects of uncertainties and errors relating to typical human thermoregulatory experiments involving liquid cooled garments in suit calorimeters. It reports on-going efforts to develop a state-of-the art facility to perform human thermal testing for space suit thermal comfort control. A systematic methodology using sensitivity derivatives combined with instrument uncertainties is applied to develop a bound of accuracy on measured experimental variables. As for unmeasured experimental variables, methods used to estimate and minimize these uncertainties are also included. During actual experimentation with human subjects, the variability in experiments associated with subjects is modeled; steps taken to minimize errors and ensure repeatability are also reported. Results from this analysis will suggest specific improvements to the experimental setup in the most effective manner from the experimental accuracy and cost standpoint.

The prospect of using automatic control for astronaut thermal comfort regulation during extravehicular activity (EVA) requires an investigation of issues concerning the current state of the art of human thermal models. The analysis presented includes, but is not limited to, the discussion of assumptions and the accuracy, range and relative significance of parameters (e.g., thermal properties, physical dimensions, etc.) of transient human thermal models. The Wissler 1D model attracts primary consideration; however, there exists the appropriate inclusion of the 41-Node Man model for reflection and study.

This study investigates the complexities associated with quantifying human thermal comfort using indices. A detailed review of the literature is first performed. The uncertainties associated with comfort modeling are then highlighted. Possible indices are developed and evaluated using integrated human-suit-PLSS (Portable Life Support System) simulations developed at the University of Missouri. The study forms part of a larger project aimed at developing automatic thermal controllers for NASA space suits.

Automatic thermal comfort control for the minimum consumables PLSS is undertaken using several control approaches. Accuracy and performance of the strategies using feedforward, feedback, and gain scheduling are evaluated through simulation, highlighting their advantages and limitations. Implementation issues, consumable usage, and the provision for the extension of these control strategies to the cryogenic PLSS are addressed.