Health aware fault-tolerant forklift design and control in industry 4.0

The central objectives of the presented research work are the development of design methods and a control system which allow to incorporate knowledge concerning the health of system elements in industrial applications. The paper presents a framework combining fault-tolerant design, useful lifetime aware design, fault-tolerant control and planned condition dependent maintenance. These elements of the framework are explained and detailed investigations of some of these elements are presented. Fault-tolerant design is explained on the example of the drive modules of an industrial forklift. For useful lifetime aware design a detailed investigation concerning the health (respectively the remaining useful life (RUL)) of certain machine elements in forklifts in high storage warehouses is explained. The chosen machine elements are ball bearings due to their frequent application and enormous significance in industrial systems. For these elements, a multiple model-based Takagi-Sugeno scheme is presented that is capable to follow and predict the degradation of a technical system. Fault-tolerant control in this framework is explained through the application of a virtual fuzzy actuator for the drive system of the forklift.