Real-time Load Determination of Wheel Loader Components

The lifecycle costs of systems are moving more and more into the focus of machine manufacturers to ensure competitive edges and strengthen customer relations. This results in development goals such as higher avail-ability, maintenance intervals according to requirements, and minimized outages and downtime costs.
Mobile machines are subjected to loads which, occasionally, are characterized by the working task, the environmental boundary conditions and the operator. In practical use of mobile machines, some operators are not very experienced in handling a machine, for instance when using machines in the construction industry. In these cases, performing the job enjoys priority over the state of a machine and its service life. The situation is aggravated by the fact that entrepreneurs, especially in the fields of add-on and special machines, prefer to use leased vehicles, thus the operators are confronted with new machines all the time. Because of the individual control characteristics of operators, this results in permanently changing sequences of motions and load situations for the machine. The high loads occur frequently in operation and can lead to premature failure of a machine. ... mehrAs a result, it will be impossible to continue the activities needed to fulfil the working task and, on the other hand, it may be necessary to repair or even scrap a machine and buy a new one. Both consequences result in economic harm for the machine owner.
In the many cases it is difficult to influence the working task and the environmental conditions established by the environment in the light of the objective, e.g. to achieve the required result while simultaneously minimizing component load. On the other hand, operation of a vehicle offers a more evident degree of freedom in minimizing damage. Vehicle control systems adapted to external conditions and the working task, which make operators and vehicles perform under operating conditions less prone to result in damage, thus can reduce loads and defects and, consequently, also reduce operating and maintenance costs. The final conse-quence is a higher availability of the machines.
A control system of this kind requires knowledge of current loads and load-bearing capabilities of components of a mobile machine. Developing a method of real-time load determination as shown for the boom of a wheel loader therefore is the content of this article.