The invention relates to a process for actuating the steering cylinders of mobile machines, in particular wheel loaders, graders, mobile excavators or the like.
Wheel loaders, but also other machines starting with a certain size have two separate control systems because of safety requirements as well as legal regulations. In this case, the second system, which is frequently called an emergency control system, becomes operational only if the primary system cannot meet its function as designed due to a defect or interference. Thus, the primary system must be designed such that it meets all legal and technical driving requirements, in particular also for low steering system speeds. The emergency steering system is non-functioning during this operating condition, but requires energy because of the constant transfer by pumping of its feed current. In addition, expensive emergency valves and flow-through indicators are required, which become effective when the primary system fails. Even though the emergency control system as a rule is used rarely or never and thus is not employed frequently, it can occur that this system fails rather than the main system, so that its failure must be indicated as well. Furthermore, the additional components such as emergency valves and flow-through indicator result in pressure losses, which have a negative effect on the energy balance.