Now that we’ve 1) interviewed our customers, 2) reviewed basic literature on the topic, 3) divided the project into sub-assemblies, and 4) began specifying desired traits and characteristic functions of the sub-assemblies, it’s time we merge everything together via tools called Design Structure Matrix (DSM) Methods. Professor Steven Eppinger has published a companion to your textbook on the topic. DSM’s are useful for spotting the connections and relationships in complex systems. Take for example the problem of assessing the Technology Readiness Level (TRL) for the Mars Curiosity Rover:

Architecture DSM Example

We used our intuition, post-its, and considerable time planning over the summer to accomplish this at the system level. As our design develops we will likely come back to these for system flow diagrams.

The most popular DSM is known as the House of Quality (HOQ). The seminal article in Western culture on the HOQ was written by John Hauser and Don Clausing in 1988. It’s worth the read. The HOQ is the centerpiece of Quality Function Deployment (QFD) that originated in a shipyard division of Mitsubishi in 1978. A handy flash tool explaining the HOQ is here. In essence, phase 1 of the HOQ is a neat design heuristic to ensure your method for assessing design performance matches the customer/client needs. Phase 2 then maps the engineering characteristics to use for assessing your specific sub-assembly alternatives, shown in the Figure below. Phases 3-4 then map the best sub-assembly to production process capabilities, which is beyond the scope of our class.

HOQ mapping to subs

Extensive use in industry and studies on the effectiveness of the HOQ over the years have shown that the method significantly improves inter-team communication, speed to delivery, and number of required design iterations. It’s safe to say that the HOQ is the leading design structure matrix method for engineers.

Based on this, consider the HOQ your team started to draft over the weekend. Does the global HOQ we drafted over the summer have adequate quality characteristics? Are you sure you can measure/quantify how effectively your potential designs will perform relative to the global system characteristics and customer requirements? Take 5 minutes to review and discuss the HOQ for your team’s sub-assembly, including changes that must be made and questions you need answered.

We’re approaching the time to develop a preliminary design specification. This design specification lays out the template that we’ll measure our overall design performance with and will guide us the rest of the semester. On Friday you’ll need to practice a 20 minute presentation discussing: 1) the client/customer need/background, 2) separate sub-functions/systems, 3) the needs, performance measures, and how you will assess them for your specific sub-assembly (overview of HOQ), and 4) how these connect to the global-system (overview of global HOQ). You will present a final version of this initial design specification for team-level grades and feedback in class on Monday. On Wednesday, you will post a web version of this presentation to the H2-Refuel team website. A Draft Presentation Grading Rubric for the presentation and post is here.

In order to prepare for this class-level activity, we need to break into our role-teams: 1) Builders, 2) Theorists, 3) Compliance, 4) Reporters, and 5) Liaisons. Take a moment to introduce yourselves and your sub-assemblies. Here are suggested problems for your role teams to address:

  1. Liaisons– You need to facilitate the presentations i.e. come up with a plan to practice and then deliver the presentations. Begin in a neat way. Setup each of the sub-assemblies to efficiently deliver their content, and wrap everything up leaving us feeling good and confident. Practice like you play. This should be clean, crisp, high-scoring, and professional.
  2. Reporters– You need to come up with a standard template for each of the teams to communicate their content with. If done well, this template will allow you to easily transfer the content to the H2-Refuel website. HINT: Customers tend not to understand the HOQ. So you need to consider your audience and what you need to communicate.
  3. Compliance– Addressing the design standards and competition requirements is essential to developing a complete HOQ. Make sure all of the sub-assemblies have identified and appropriately applied design standards.
  4. Theorists– Discuss how to link your sub-assembly HOQs to the global-system assembly HOQ so that we can efficiently track the influence of sub-assembly alterations to overall system-level performance. You can probably link separate spreadsheets within an Excel file. Also assess the adequacy of the current engineering characteristics in the global HOQ and make revisions.
  5. Builders– You pragmatic practitioners. Make sure we have a plan and can actually measure the metrics in the HOQs. We also need to connect all of you to Brian Karlberg and the TFRB build space. The shipping container is coming soon.