A patient support apparatus includes a frame, wheels, a patient support surface, a motor, a power assist control, a sensor, and a controller. The power assist control detects a force applied to it. The sensor detects an angular orientation of the patient support apparatus with respect to a generally horizontal plane. The controller drives the motor at different levels for a particular force applied to the power assist control depending upon the angular orientation sensed by the sensor. The controller may control the motors such that the patient support apparatus accelerates at substantially the same rate, regardless of the angle of the patient support apparatus. The controller may also limit the driving of the motor to less than a maximum value based upon the angular orientation of the patient support apparatus.
