Disclosed is a method for improving a printing speed of a printer. The reformer can be designed to generate a fluid comprising sufficient thermal energy, hydrogen, and carbon monoxide. A first sensor and a second sensor for reading the position information from the scale are provided as the position-detection means, and the first sensor and the second sensor are provided in order to be separated by a distance which is more than or equal to a gap width of the scale seam. An integral controller is provided for receiving data from sensors and controlling the fluid powered rotary actuator to actively assist gait of a user.