Modularisation of the wire harness to reduce complexity
DST Dräxlmaier Systemtechnik GmbH
Mr. Wortberg is Systems and Projects Engineer, Innovation Management
Wire harness concepts
Development of a modularisation concept
In order to be able to produce wire harnesses automatically, a profound structural change must be made to the wire harness.
Sub-project 3 aims to provide approaches to solutions for the structurally systematised vehicle electrical systems of tomorrow. During the first phase of the sub-project, a proposal for reducing the variety of parts in the wire harness was developed. Phase 2 addresses the topic of the “standardised system connector” that is needed to make modularisation possible: if the wire harness is divided into smaller, automated sub-ranges (production modules), these require clearly defined and standardised plug connectors as interfaces, so-called system connectors.
Starting point and motivation
Producing a main wire harness automatically in its current form would not be economical at all. The main reasons for this are as follows:
- There is too much variety in the components
- Too much intermeshing/interweaving in large wire harnesses
- Lack of a pinning convention
- The cables are too long
The excessively long cables could be prevented by adjustments to the production machines. On the other hand, the large variety of parts, the extensive intermeshing and the lack of a pinning convention are obstacles to automation that need to be reduced or eliminated.
The fact that the number of different components is continuously increasing inevitably leads to an increase in the variety of parts. One reason for this is the significant increase in functions without any convention regarding the use of standardised, modular connectors by the function providers.
Any additional or new function (e.g. ADAS) triggers a chain reaction of further process steps. At least one additional control unit, several sensors with new digital interfaces and various actuators are needed to control and network the components. All components require fail-safe connections to each other and must guarantee a constant power supply. At the moment,
“Just connect it the way it comes”
is the credo that manufacturers follow today. This results in an extremely intertwined set of lines with an unmanageable variety of parts and processes that stifles any attempt at automation at the outset.
What is needed now are approaches and concepts that lead to a reduction in the variety of parts and processes (focus of phase 1), enable/promote automated production by removing the intermeshing (focus of phase 2) and thus provide an innovative solution for the on-board electrical system of tomorrow.
Current working focuses
One current focus of the work being carried out is the analysis of the causes of intermeshing in the electrical system. Starting with a variety of hypotheses concerning the causes, these causes will be examined in greater detail after an evaluation of the possible ways forward. One likely way forward will be to draw up a standard interface to modularise the on-board electrical system and the resulting energy and data interfaces to be standardised. >
In the future, interface concepts for a sensible division of the wire harness into production modules will be developed. This division into sub-scopes reduces the complexity of the individual, much smaller wire harness modules. However, the possibility of reproducing today’s level of variance should not be disregarded. The complexity is shifted from a single-piece wiring harness into a) smaller partial scopes and b) their combinatorics with each other. The solution approaches developed for division into partial scopes are to be evaluated on the basis of their feasibility with all parties involved and then combined into a uniform concept.
The next step is to compare the underlying interconnection paradigm of automotive wire harnesses with that of IT and consumer electronics. The extent to which paradigms and technologies that may deviate from the current automotive state of the art can be borrowed from the IT and consumer product environment needs to be assessed.