Dead reckoning of an automated guided vehicle by differential odometers

This paper describes a method of dead reckoning for an automated guided vehicle by using rotary encoders attached on main wheels. The method provides position and direction of the vehicle on real time basis by integrating angular variations of the wheels. The result is used in the Target Point Following algorithm which navigates the vehicle. In order to obtain precise estimation, a rotation measuring unit has been developed. The unit includes pulse signal enhancer which increase by four times the precision of the rotary encoders, 16 bit up-down pulse counter and interrupt controller which maintain a constant control cycle. These devices allow a great load reduction of the onboard navigation computer. Test runs in the laboratory building prove applicability of the method to navigation of the vehicle.