| Abstract [eng] |
The dissertation presents the development of a human postural control assessment system: from investigations of suspended-platform mechanics to an automated prototype. The work comprises five parts: mechanical investigations, modelling, biomechanical and neurobiomechanical analyses, and prototype development. Experimental studies established the platform’s horizontal stiffness and oscillation damping as quantitative descriptors of different instability levels. Modelling established how suspension geometry affects force distribution and the dynamics of human–platform interaction. The biomechanical analysis characterised how the interaction between the centre of mass and the base of support changes throughout sway at different instability levels. The neurobiomechanical analysis established that combinations of instability levels and sensory information strategies produce controllable postural destabilisation, ranging from barely perceptible to critical levels that require the recruitment of other compensatory strategies. After evaluating the informativeness of the biomechanical measures, mean centre-of-pressure velocity was selected for real-time assessment of task difficulty and determination of a safety threshold. The prototype developed from these findings automatically adjusts instability levels, records biomechanical measures, and terminates the test when the threshold is exceeded. The system provides a basis for a new generation of postural control studies in which the intensity of natural body sway is modulated in a controlled manner by combining sensory information strategies and mechanical instability levels, without additional external perturbations. |
