ENGR 107: Engineering Fundamentals Lecture 4: The Engineering Design Process: The Engineering Method and Problem Solving Process C. Schaefer September 15, 2003

Egnineering Fundamentals 1072 Assignment Read Chapter 2 of the textbook. Group Cost ROM’s, Bills of Material, and list of required tools are due today to the Systems Engineering Group. Systems Engineering group: preliminary schedule and budget due on Wednesday. Groups: review hull and keel construction.

September 15, 2003Egnineering Fundamentals 1073 The Engineering Method A process within a process. – Systems engineering process. Engineering method. The engineering method is the formal approach an engineer takes to solve a particular problem. The engineering method is a “thought process” or approach similar to, though not identical to, the scientific method.

September 15, 2003Egnineering Fundamentals 1074 The Engineering Method 1 1. Identification of problem. 2. Analysis. 3. Transformation. 4. Alternative solutions. 5. Modeling. 6. Information gathering. 7. Experimentation. 8. Synthesis. 9. Evaluation and testing. 10. Presentation of solution. 1 Engineering: An Introduction to a Creative Profession, G.C. Beakley, D.L. Evans, J.B. Keats

September 15, 2003Egnineering Fundamentals 1075 The Engineering Method 2 Recognize and Understand the Problem. Accumulate Data and Verify Accuracy. Select the Appropriate Theory or Principle. Make Necessary Assumptions. Solve the Problem. Verify and Check Results. 2 Engineering Fundamentals and Problem Solving, A.R. Eide, R.D. Jenison, L.H. Mashaw, L.L. Northrup

September 15, 2003Egnineering Fundamentals 1076 The Engineering Method 3 Identify and define the problem. Research the problem – Accumulate data. – Relevant theory. – Previous solutions and approaches. Solve the problem – Develop alternatives. – Modeling/simulation. – Experimentation – Synthesis Testing and verification. Presentation. 3 My general method of solving engineering problems. The “Schaefer Method”. The engineering method is a continuous feedback loop.

September 15, 2003Egnineering Fundamentals 1077 The Problem With These Approaches? They are predominantly analytical with no explicit creative process. Problem solving consists of two elements; – Creative – Analytic Much emphasis in academia and industry on analytical methods almost at the exclusion of creative processes.

September 15, 2003Egnineering Fundamentals 1078 Analytic and Creative Problem Solving 1 Identify the problem. Define the working criteria or goals. Research and gather data. Brainstorm for creative ideas. Analyze. Develop models and test. Make the decision. Communicate and specify. Implement and commercialize. Prepare post-implementation review and assessment. 1 Oakes, et al

September 15, 2003Egnineering Fundamentals 1079 Contrast with Scientific Method Define the problem. Gather the facts. Develop a hypothesis. Perform a test. Evaluate the results. Notice that science is not overly concerned with implementation, only knowledge gathering.

September 15, 2003Egnineering Fundamentals Let’s Look at an Example Simplified “real world” example; SUV anti- lock braking system (ABS).

Sport Utility Vehicle (SUV) Anti-Lock Braking System (ABS)

September 15, 2003Egnineering Fundamentals Identification of Problem What is required? What must be done and why? Scope of problem – define problem boundaries. Example – Anti-lock Braking System – Is it possible to successfully retrofit an ABS developed for compact cars to heavier, sports utility vehicles?

September 15, 2003Egnineering Fundamentals Research the Problem Can we decompose the problem into easily managed subproblems? This step defines, for example; – Literature review for similar problems and solutions to those problems. – Relevant analytical and modeling techniques. – Testing requirements. – Design constraints. – Resource requirements and allocation. – Project schedule.

September 15, 2003Egnineering Fundamentals Research – ABS Example Literature search; Internet search on ABS. Constraints (example); – Retain compact car ABS system architecture. – SUV ABS costs cannot exceed 110% of current compact car ABS system cost. – Time to market – 3 months. – Performance criteria; SUV Total Time to Stop  15% increase over compact car. SUV Wheel Lock Skid Time  10% increase over compact car. Approach: – Develop MATLAB model of ABS system. – Parametric analysis using model. – Modify system constants.

September 15, 2003Egnineering Fundamentals Solve the Problem Develop alternatives. For example; – Hardware and software design alternatives. – List of independent variables to vary in modeling or simulation. Modeling – Conceptual models. – Physical models and engineering mockups. – Graphical models. – Mathematical models. – Computer models.

September 15, 2003Egnineering Fundamentals Solve the Problem Experimentation – Computer simulation. – Testing, for example; Ground tests. Flight testing. Synthesis – Subproblem solutions are merged. – E.g., manufacturing and engineering resolving issues associated with manufacturability.

September 15, 2003Egnineering Fundamentals Solve Problem – ABS Example ABS hardware and system architecture fixed with exception of interface to SUV. Control software can be modified. Matlab simulation. Skid pad testing to verify simulation results. Presentation of results to Product Development Team.

September 15, 2003Egnineering Fundamentals ABS Braking Simulation Model

September 15, 2003Egnineering Fundamentals Simulation Results Vehicle Weight = 1600lbs Hydraulic Lag – 0.01 sec

September 15, 2003Egnineering Fundamentals Simulation Results Vehicle Weight = 2900 lbs Hydraulic Lag – 0.01 sec

September 15, 2003Egnineering Fundamentals Simulation Results Vehicle speed and wheel speed Speed(rad/sec) Time(secs) Vehicle speed (  v ) Wheel speed (  w ) Vehicle Weight = 2900 lbs Hydraulic Lag – 0.03 sec

September 15, 2003Egnineering Fundamentals Simulation Results Vehicle Weight = 2900 lbs Hydraulic Lag – sec

September 15, 2003Egnineering Fundamentals Presentation Baseline Best Solution

September 15, 2003Egnineering Fundamentals Testing - ABS

September 15, 2003Egnineering Fundamentals Presentation Is this relationship linear or nonlinear? Wt = 2900 lbs

September 15, 2003Egnineering Fundamentals Presentation Wt = 2900 lbs

September 15, 2003Egnineering Fundamentals Results Performance Criteria Satisfied. Total Time to Stop – Required –  15% increase over compact car. – Actual – 12.8% increase. Wheel Skid Lock Time – Required –  10% increase over compact car. – Actual – 0% increase over compact car. Time to market – 1.5 months for S/W revisions. Cost – Less than a 2% increase.