A method for controlling an angular orientation of a person support apparatus including a bladder portion containing fluidized particulate material, an upper frame, and a base frame may include adjusting a height of the upper frame with respect to the base frame with at least one of a first and second actuator at respective speeds, determining a dynamic angular orientation of the upper frame with respect to the base frame based on at least one of a respective operating characteristic of the first and second actuator, determining a corrected angular orientation based on the dynamic angular orientation and a floor angle indicative of the orientation of the base frame with respect to horizontal, comparing the corrected angular orientation with an orientation reference range, and adjusting at least one actuator speed when the corrected angular orientation is outside the orientation reference range until it is within the orientation reference range.