Monday, June 10, 2013

XM Principle 6: Agile Hardware Design Patterns

A pattern is an old idea. A pattern is simple way to represent implicit knowledge about well-known solutions to well-known problems. Patterns were pioneered in architecture by Christopher Alexander to facilitate the understanding of good solutions to common challenges in building houses and other structures. Software developers picked up on the idea to communicate solutions to typical challenges in computer systems. WIKISPEED has identified a number of patterns to help design good hardware. For example:

  1. Wrapper – Use a wrapper to adapt a third party part to your contract. If you use the supplier's interface as your contractual interface, any change in either product or supplier will probably cause you to redesign the interface, a potentially expensive undertaking.
  2. Facade – Use a façade, a connector of connectors with a simple interface, whenever multiple wires (like data & power) need to go to the same place.
  3. Singleton – Every component needs power, data and ground. The first thing every engineer wants to create when designing a new component is the power, data and ground bus. The singleton pattern says for each basis component, there is just one in use. So if you need a power-data-ground bus - use ours!

Sometimes the patterns have a cost. The wrapper pattern added 8 kg to the weight of a WIKISPEED car, for example by adding an extra slab of aluminum between the chassis and the suspension.

Was the design pattern worth the extra weight? Yes, because that pattern allowed Team WIKISPEED to a) reduce several hundred pounds from the weight of the car by steady optimization, and b) react easily and cheaply to the changing suspension requirements. Had they not been able to do that, they would not have been able to participate in the final selection round.

Next: Continuous Integration Development

3 comments:

Erland Lewin said...

I really appreciate your posts on Extreme Manufacturing, please don't stop here!

Peter said...

Erland,

Thanks for the encourgement! I will try to get some texts onlune this weekend...

It's coming, honest!

Peter said...
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