Development of a three-degrees-of-freedom moveable platform for providing postural perturbations

AbstractThe purpose of this study was to design and develop a three-degrees-of-freedom moveable platform to provide postural perturbations for balance assessment and training. The platform consists of three motion mechanisms, which can provide forward—backward translation, upward—downward tilt, and clockwise—counterclockwise rotation. This platform can move in any of its degrees of freedom separately or simultaneously. The precision and accuracy of the platform movement were examined by calculating the standard deviations in repeated trials and comparing the real amplitude and velocity of the movement with the preset values. All the standard deviations in repeated trials were small in that the variation coefficients were less than 2 per cent, except that in the highest-velocity test, and all the mean differences were less than 1 mm for translational and 1° for tilt or rotational perturbations. The results demonstrated that the platform is a reliable and valid instrument for providing postural perturbation...