SOFTWARE IN PRACTICE
Fleshing Out WBS Level 3
Now let's move ahead in time to the point where the Electric Vehicle concept is in place and the Preliminary Design is complete.
We now know much more about the makeup of our vehicle so we can flesh out level 3 of our product WBS.
The engineers have chosen a serial drive train so let's take this branch of the WBS and elaborate down to level 4 and beyond.
Notice that, in practice, we make the WBS a product oriented family tree by nominating system components as WBS elements. The outcome should look like a bill of materials breakdown.
Elaborating the the Electronic Control Unit
The Electronic Control Unit (or ECU) is an important drive train component. According to the design this is the device that controls the flow of power between the battery, generator and electric motor in the various vehicle operating modes.
It's currently a black box. We know roughly what it does but we don't know how. So we're going to develop a System Requirements Specification to describe its functions in detail. When we've firmed up our requirements we can go ahead and do some design.
The deliverable from the design effort will be a System Architecture Specification that allocates all the required ECU functions to either hardware or embedded software.
Following that we'll need hardware and software design descriptions.
Our ultimate deliverables are the hardware platform and the embedded software.
These components will be individually tested before they're integrated and tested as a unit.
The integrated ECU will then be tested in a purpose-built test bed. To achieve this we'll need the test bed, a Test Plan, a Test Design and testing services.
Developing Work Packages
At this point we've pretty much identified all the deliverables and services required to create the ECU.
We can now define the work in detail with a set of work packages. And finally, to get the work done, we'll allocate the packages to our design, construction and testing teams.
Completing the WBS
To complete the project WBS we'll go through this process with all the level 3 elements.
Progressively elaborating the deliverable until we've identified all the activities directly applied to building our concept car.
About this talk
When you've completed your work breakdown structure (WBS) for the planning phase of your project, the job is done, right? Wrong! The WBS evolves over time as you discover more about your end product. Les Chambers illustrates this process of WBS evolution down to the development of work packages with the case study he introduced in the video: The WBS Development Process.