Development of automatic lift axle system for trucks with mechanical suspensions

In 2014, the automatic lift axle dropping system is expected to be a legal obligation for trucks in Turkey. The aim of an automatic lift axle auto-drop system is to drop the appropriate live axle of a truck automatically based on the loading condition, instead of being manually controlled by the driver. In this paper, an algorithm providing the rules defined in the mass and dimensions regulation and a simulator that can be used to test this algorithm are developed for a truck with a mechanical suspension. During the simulations, the condition of the truck's load is used as an input and the automatic lift axle system algorithm decides on the axle(s) that canot be lifted by the driver. The determination of the vertical load shared by each axle is a statically indeterminate problem and the Direct Stiffness Method is used to obtain the solution in the simulator. Simulations are used to illustrate the use of the simulator and the developed algorithm. Extensive experimental work on testing the algorithm has been conducted on a truck with a prototype automatic lift axle system.