Train Zero Model Based Design Facility
Train production has come a long way since what was formerly the Derby Carriage and Wagon Works, now Bombardier’s rail vehicle manufacturing site in Derby, was founded in 1876 by the Midland Railway. Trains today are an integral part in our ever more complex infrastructure, transporting people over 2000 billion kilometres in total around the world. In a metropolis like London, millions of people rely on their train to get them to where they want to go reliably, comfortably and on time.
When Bombardier, the global leader in the rail industry with over 100,000 rail vehicles deployed around the world, won the contract to supply the trains to Crossrail, a new 118 km railway line creating a direct east-west connection straight through greater London (at the time of writing the largest infrastructure project in Europe) they looked to optimise their processes in order to develop a modern train fit for this purpose whilst shortening the time taken in design, verification and validation.
The trains for Crossrail will be over 200m in length and will be able to carry up to 1,500 passengers. They will be state-of-the-art, with features including air-conditioning and on-train passenger information systems with real-time travel information to allow passengers to plan their onward journeys; designed with an emphasis on energy-efficiency and the use of intelligent on-train energy management systems. The trains will also incorporate advanced systems for condition-based maintenance and automated vehicle inspection system.
Inspired by the aerospace industry’s use of “Iron Birds” to incorporate, optimize and validate vital systems at the earliest opportunity in the development cycle, Bombardier wanted to adopt a similar approach for future rolling stock. Bombardier turned to Fraser-Nash Consultancy to help develop a strategy to realize and maximise the potential of the Iron Bird concept. Frazer-Nash is a multidisciplinary engineering consultancy that excels at solving some of today's most complex challenges in engineering. Our experience of working in diverse industries enables us to transfer unique skills across different markets to benefit our clients. Using experience gained across a diverse range of industries (including automotive, renewable energy and aerospace). Frazer-Nash worked with Bombardier to develop a strategy which would not only utilise the iron bird concept, but also provide a facility which would add value throughout the full product development cycle by incorporating Model Based Design techniques.
Train Zero, as Bombardier chose to name their facility, would be the predecessor of the first train in every new series. The Train Zero strategy leverages Model Based Design techniques to optimise everything from requirements capture and validation, through design and on to validation & verification testing at a sub-system and system level. The benefits of this strategy may be summarised as:
- Providing early confidence in vehicle development to customers;
- Promoting commonality of systems;
- Engagement with key suppliers;
- More efficient type testing,
- Support to projects throughout their warranty period;
- Availability to support subsequent projects as a “donor platform”
- Bridging the ‘innovation gap’
- A streamlined verification and validation leg of the Systems Engineering Development V-lifecycle resulting in a shorter overall development cycle.
The strategy affects all parts of the systems engineering development cycle (as shown in the V Life Cycle figure below). Initially taking traditional text based requirements and turning them into models, to be run as a Model-in-the-Loop alongside a plant model allows requirements to be validated more easily by stakeholders and provides a basis for the use of modelling techniques throughout the life cycle. As the process is followed, the models are refined and run on increasingly representative platforms. This follows through the stages of Rapid Controller Prototyping, Software-In-The-Loop, Processor-In-The-Loop to final testing of the integrated sub-systems using Hardware-in-the-Loop. This strategy allows Bombardier to more closely cooperate with their suppliers, potentially even incorporating their existing models, or by jointly creating models for components and systems.
Using this approach, Hardware-in-the-Loop and integration testing may be carried out far earlier in the product development cycle than had ever been possible before in the design of rolling stock.
To make this a reality, Frazer-Nash worked with Bombardier to develop the requirements for a facility capable of implementing their strategy. The chosen solution incorporates both a full scale representation of two carriages (so that all electronic control units could be installed at the proper relative distance from each other to accurately represent the timing characteristics of the communication signals sent between them) as well as additional smaller simulation based rigs to represent the remaining carriages. To meet the requirements, a toolset was needed to provide:
- Hardware IO capable of simulating all of the interfaces found on a train;
- A cost effective and expandable architecture;
- Distributed IO to replicate the physical layout of the train;
- Real time operating system;
- Versatility and ease of reconfiguration;
- The ability to bring together simulation models from a variety of industry standard modelling tools and environments.
Frazer-Nash carried out a study of the commercially available tools on the market which could allow Bombardier to meet these requirements. From a hardware perspective, an essential requirement was the ability to simulate the controller’s I/O and provide stimuli for testing using a versatile control and data acquisition system with a high channel count, low latency throughput and fault insertion capability. At the stage of specifying the application, it was still not possible to have a full visibility of the exact range of I/O that was needed, only that the number of channels would be in the order of 1000s. This meant that the data acquisition hardware must be expandable to be able to cover all possible signals. It also had to be possible to distribute the control and measurement hardware around the Train Zero facility to avoid introducing measurement noise and signal delays that would skew the timing characteristics due to long cabling, as well as unnecessary cabling expenses and labour cost in case rewiring was needed.
The software toolset needed provide a real-time operating system which would be able to execute models in a deterministic manner. The end application needed to have an easily customizable user interface that would allow direct control to the operator, but also able to execute test sequences automatically. Much of the supply chain was already using Mathworks’ Matlab/Simulink or LabVIEW models, but many were also using other modelling tools, so it was essential the software should be able to interact with industry standard tools to maximize the potential for reuse by both Bombardier and their suppliers.
The conclusion of the study carried out by Frazer-Nash was that the ideal toolset to meet Bombardier’s requirements was National Instrument’s development platform. This provides the versatility of data acquisition hardware which Bombardier required, as well as a software development environment capable of executing the variety of models they were working with in real-time. PXI in combination with their EtherCAT expansion chassis provides the necessary channel count, measurement diversity, low latency data transfer and distributed I/O.
Being familiar with the benefits of LabVIEW and Test Stand to develop a user interface and sequencing engine, Frazer-Nash and Bombardier were pleased to learn about VeriStand, NI’s tool for real-time testing. Not only is VeriStand capable of executing all the different types of models required, it also has a significant built in functionality that previously would have been built from scratch in LabVIEW or Test Stand. This includes features such as standardized reporting and a straightforward way of creating test sequences using the Stimulus Profile Editor. This feature provides a sequencing engine which is used for both integration testing of the train systems and validation of the models; any changes made to models may easily be revalidated in the same environment they would be running in later.
With the help of NI’s field engineers, Frazer-Nash assisted Bombardier to select the test system hardware. The first version of the test facility incorporates a VeriStand application providing the user interface and controlling the models deployed on three PXIe-8840 controllers in PXIe-1085 chassis distributed in the driver vehicles and mid-train. The physical signals are read and written through PXI-6289 Multifunction I/O cards, PXI-6515 Industrial DIO cards, PXI-6704 DC Analog Output cards and PXI-2569 Relay Modules in the PXI chassis. NI 9144 EtherCAT slave chassis will be used for further distributing the I/O as requirements develop further. The systems remains expandable, so for future revisions more channels or new types of signals can be easily added, thanks to the modularity of the platform.
Train Zero was officially opened in December 2014 by the Mayor of London, Boris Johnson, and British Secretary of State for Transport, Patrick McLoughlin. In February 2015 it was awarded the Technological Innovation Award at the Rail Business Awards. The new test facility has cemented Bombardier’s position as the leader in the rail industry by adopting a Model Based Design approach, and given them an opportunity to de-risk new technologies and opportunities in the future.
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