Application of system dynamics for holistic product-service system development

Abstract

In order to develop Product Service Systems (PSS), a holistic view on the system and a coequal development of service and product parts is necessary. Particularly for the beginning of the development of PSS, existing approaches show lacks and start with vague defined initial phases. This leads to inadequate methodological support for the consistent design of the overall system and simultaneous elaboration of the requirements down to the parameters of individual components. Therefore, a procedure is required that completely maps the PSS and enables detailed development for relevant individual areas, taking into account existing constraints. At the beginning of the development a model is necessary, which first defines the system boundaries of the PSS and maps the performance and control flows of the system. In addition, the integration of further actors into the PSS must be made possible. This paper presents an approach that uses System Dynamics (SD) to design a PSS. With this approach, the representation of the system is initially possible at a high level of abstraction, whereby the representation can be further refined and detailed. Parallel to this, a preliminary design for planning and controlling media flows can be carried out from the first system representation and further detailed parallel to the system representation. An essential advantage is that the detailing can also only be carried out for individual areas, which can be displayed in sub-models, but can also be reintegrated into the overall representation. The sub-models can be implemented function-specifically on the basis of resources and competencies of individual actors. For system-relevant areas, planning and design can be concretized in the sub-models (which can be realized by products as well as services) down to the lowest hierarchy level. This can take place up to the definition of individual physical component parameters and has thus up to the phase of the elaboration effects on the development of the parts. In return, the effects of changes in system-relevant parameters on the overall system can also be examined. For the PSS, a model is built in which system-determining functions and principles are represented and developed. The model is constructed in such a way that non-system-determining functions and principles are defined as variables or black boxes. Requirements and parameters are derived from this system development. These are used for the further development steps in the development process. Depending on whether it concerns system-relevant areas or not, the entry into the development process takes place later in the elaboration phase (e.g. in the area of detailed design) or partly earlier in the concept phase (e.g. function development). It is also possible to enter an early phase in the development process of the individual parts, accompanied by already defined functions, sub-functions or parameters that must not be changed in the course of development. With this approach a holistic development of the system with all product and service parts as well as their connections and dependencies is possible.