Designing cable harness assemblies in virtual environments

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Abstract

Cable harness assemblies are amongst the most costly items in any electro-mechanical product. The domain is not widely recognised as an area for academic research. Internationally, some efforts have been made to automate or semi-automate the choice of cable harness path through the use of artificial intelligence (AI) via CAD systems, but with little success. Common themes voiced are that the problem is too open-ended and it is very difficult to capture the design intent of the activity. Human input is still very much required to guide the computer systems to reach an ‘optimum’ solution. Case study investigations were carried out at five advanced manufacturing organisations to determine the current industrial practice. The investigations revealed that the cable harness design and planning (CHDP) process is essentially sequential in nature and consists of lengthy activities carried out late in the overall product development cycle. It was also found that there has been little attempt to integrate any of the core activities involved. This paper describes work undertaken at Heriot-Watt University to research the effectiveness of immersive virtual reality for designing and routing cable harnesses by enhancing the expertise of the cable harness designer rather than by replacing the individual via an automated system. The new virtual cable design system developed in the course of this work has now undergone some pilot trials to test its usability. The system will subsequently be used to carry out full industrial trials in conjunction with a number of high technology equipment manufacturers. These pilot trials, combined with the case studies of current practice carried out at the companies, have highlighted a number of issues regarding cable design, particularly that immersive VR has a potentially unique role to play in the integration of cable harness electrical and mechanical design activities.

Introduction

Cable harnesses are a vital part of all electro-mechanical systems from aircraft and automobiles to personal computers and domestic appliances. In many instances the cable harness is one of the most costly items in the overall engineered system. In spite of this the detail design and planning of cable harnesses are often only addressed almost as afterthoughts at the end of the product design process. Cable harness design and planning (CHDP) in fact cover a set of manually intensive, time-consuming and costly activities. There is the obvious problem of determining satisfactory routes for bundles of cables in crowded spaces. The wires themselves will vary in size depending on their duties. The stiffness and mass distribution of the bundle is determined by the size and type of cables involved. Acceptable bend radii must be defined as well as the position and distribution of the fasteners used to constrain the harness.

One important concern for harness designers is that of voltage drop. Voltage drop is directly proportional to cable length and inversely proportional to cable cross-sectional area. Ideally, the designer must find a routing configuration that maintains a suitable voltage drop for all cables in the bundled harness. Fig. 1 shows an example of a completed cable harness ready for assembly into a final product. Current industrial practice, confirmed in case study investigations at five leading UK companies, often requires the building of a physical prototype of a new design before engineers are able to manually determine the correct cable lengths and routes, as well as the numbers and positions of fasteners. Once a set of suitable cable paths have been chosen and the associated components selected, the results are entered into a database that allows the production of two-dimensional drawings and parts lists together with assembly instructions. It is vital that this information is accurate and well-proven since the actual manufacture of the harness assembly is often carried out by an external specialist supplier.

The routing problem is further complicated by the vulnerability of the cable harness to decisions made upstream. The cable harness may have to be reconfigured after only minor changes that affect, say, the chassis and the individual modules within a prototype product. The routing process can even result in the late and expensive re-design of the machine chassis to allow the cables to reach their terminal points.

Section snippets

Background

In spite of its industrial importance, cable harness design is not widely recognised as an area for academic research. Most investigators who have explored the subject have attempted to semi-automate or automate the choice of harness path through the use of artificial intelligence (AI) in conjunction with CAD systems. Such systems are used as a review tool for use after the equipment has been designed.

Park et al. [1] recognised that cable harness design requires in depth three-dimensional

Industrial case studies

As part of the present research, case study investigations were carried out carried out at five UK advanced electro-mechanical technology businesses. These were carried through extensive visits, discussions and meetings with practitioners and managers. The results were documented and returned to the companies involved for their verification.

Taken together, the five case studies show that the CHDP process is essentially sequential in nature and consists of lengthy activities carried out late in

Cable layout using immersive virtual reality

The virtual design and planning cable routing system at Heriot-Watt University is implemented on a Hewlett-Packard workstation with additional VR hardware and software from Division Ltd. CAD models of a prototype assembly can be imported directly into the system which negates the need for any extra component modelling. As illustrated in Fig. 3, the user interacts with the system by means of a head mounted display (HMD). This provides a stereo image of the virtual environment. A

System architecture

The set of nodes and cable sections created by the user are stored in a multi-linked graph structure containing a linked list of nodes and a further linked list of joins for each node [9] (Fig. 8).

At the end of the routing session, the system generates a text file by traversing the graph structure and extracting useful information which details the bills-of-materials and process planning information associated with the physical cable harness. These outputs include the types of end connectors

Pilot study

A pilot study was carried out to evaluate:

  • 1.

    the usability and robustness of the VR routing tools developed;

  • 2.

    the effects of learning by comparing repetitions for each methods and the key differences between the two cable creation methods.

Six participants took part in the pilot study, aged between 23 and 30, all were male post-graduate students from the Department of Mechanical and Chemical Engineering at Heriot-Watt University. None of them had used an immersive virtual reality system before. A

Conclusion

This paper has described a novel software tool to assist users to perform cable routing in a virtual environment. The system here has been successfully tested in pilot trials. The recommendations made by the participants during the pilot study were noted and changes had been incorporated into virtual cable routing system. Firstly to enable easier user selection of the cabling tools, the dimension of the virtual toolbox for choosing cable routing methods has been enlarged to the size of a

Acknowledgements

The authors are grateful to the five companies that collaborated in this research, for their support of this work and for access to their expertise and knowledge. The support of the EPSRC, through access to the equipment provided under grant GR/K41823, is also very gratefully acknowledged.

References (9)

  • H. Park, H. Lee, M.R. Cutkosky, Computational support for concurrent engineering of cable harnesses, in: Computers in...
  • A.B. Conru, M.R. Cutkosky, Computational support for interactive cable harness routing and design, in: Proceedings of...
  • A.B. Conru, A genetic approach to the cable harness routing problem, in: Proceedings of the IEEE Conference on...
  • C.J Petrie et al.

    Using Pareto optimality to coordinate distributed agents

    Artificial Intell. Eng. Des. Anal. Manuf.

    (1995)
There are more references available in the full text version of this article.

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