Principles of Engineering System Design

1. Principles of Engineering System Design Dr T Asokan asok@iitm.ac.in

2. Dr T Asokan asok@iitm.ac.in 044-2257 4707 Principles of Engineering System Design Lecture 3

3. Modern Product/System development Process • Stage Gate Process/Water Fall Process • Spiral Process • System Vee T Asokan

4. The development process where there are stages or phases or activities in the development work, followed by periodic gates is known as stage-gate development process or water fall development process. A gate is an evaluation by upper management or within the team structure to ensure the next stage is worth carrying forward. Any product development process should pass through each gate to make it to the point of product launch. T Asokan

5. Early gates ensure that there is a market for the product and that it can be developed and manufactured. Later gates ensure detailed integration factors such as ensuring that the software functions with the mechanical hardware. At each gate decision is to be made whether to proceed with the product or Kill the product or some features of it. Typically few projects are killed outright in the later stages, instead specifications are revised in the light of difficulties and budget allocations are typically expanded. T Asokan

6. Testing and Validation: The purpose of this stage is to provide validation of the entire project: the product itself, the production/manufacturing process, customer acceptance, and the economics of the project. Discovery: Activities designed to discover opportunities and to generate new product ideas. Build Business Case: This is the critical homework stage - the one that makes or breaks the project. Technical, marketing and business feasibility are assessed resulting in a business case which has three main components: product and project definition; project justification; and project plan. Launch: Full commercialization of the product - the beginning of full production and commercial launch. Development: Plans are translated into concrete deliverables. The actual design and development of the new product occurs, the manufacturing or operations plan is mapped out, the marketing launch and operating plans are developed, and the test plans for the next stage are defined. A more effective, efficient, faster process that improves your product innovation results. T Asokan

7. Problems/challenges with the stage-gate/waterfall method • Real projects rarely follow the sequential flow • Does not accommodate the natural uncertainty in the design process, especially at the early stages • A working version of the system is available only towards the end of the process T Asokan

8. Spiral Model SPIRAL Model Spiral model product development is practiced in time-compressed industries such as software products. Here one repeats stage-gate process several times before finishing the product to 100% completion, where at the end of any of the stage-gate processes, one has a partial product that works. It may not be fully featured, but it works. Example: A software for word processing T Asokan

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10. System Engineering “ Vee” T Asokan

11. User Requirements & Concept of Operations System Demonstration & Validation Systems Engineering Domain System Requirements & Architecture System Integration & Test Component Design Component Integration & Test Component Engineering Domain Procure, Fabricate, & Assemble Parts The “Vee” Model of System Development T Asokan

12. T Asokan ED309

13. Mission Operation & Continuous Quality Improvement Plan Analysis Retirement S ystem Final Validation Plan Requirements System Test Functional Verify Verification Plan Decomposition Subsystems D e c o m Physical Test p Test Plan n o o Decomposition Components s i t i t a i r o g n e t n I Build Components The design downstroke and the manufacturing upstroke T Asokan

14. Ford Product Development System

15. N- Model • The down stroke of V-model is split into two components to emphasize the difference between functional and physical models T Asokan

16. System Design Activities- Example--SPACECRAFT

17. T Asokan ED309

18. During the space system conceptual design • process, the system engineer will • Gather and allocate requirements • Help the customer define or refine CONOPS* • Coordinate the design team • Define the broad outlines of the spacecraft design • Make top-level design decisions • In consultation with subsystem experts and the customer • Maintain a ”picture of the whole system” • Keep everyone in the team on the same page * CONOPS: Concept of Operations T Asokan

20. Key terms in System Engineering • A SYSTEM is a collection of entities that interact to generate behavior not found in the individual entities • The entities that make up a system are usually referred to as subsystems • Each subsystem may be a system on its own right T Asokan

21. A system takes inputs and generates corresponding outputsInputs and outputs may be Matter (fuel or raw material) Energy (electricity or heat) Information (bit stream or an operator key press) The relationships between the input and output are the system functions T Asokan

22. context external systems system • System • System task or functions • System’s external systems • Systems context External system: A set of entities that interact with system via the system’s external boundaries. Context of a system is a set of entities that can impact the system but cannot be impacted by the system T Asokan

23. Define Requirements Retirement, Disposal & Replacement Investigate Alternatives The system life cycle Operation, Maintenance & Evaluation Full-Scale Design Integration & Test Implementation T Asokan

24. Identification of Need Production/ Manufacturing Concept Definition Retirement Deployment System Integration Preliminary System Design Operation Refinement Detailed Configuration Design Maintenance Development phase, manufacturing phase, deployment phase, training phase, operation/maintenance phase, refinement, retirement phase. T Asokan

25. Cost and Influence of Each Phase of the Life Cycle for a Municipal Transportation System Retirement & Retirement & Retirement & Replacement Replacement Replacement Operation & Operation & Operation & Maintenance Maintenance Maintenance Manufacturing Manufacturing Manufacturing Full Scale Full Scale Full Scale Design Design Design Concept Concept Concept Exploration Exploration Exploration Define Define Requirements Requirements The size of each object is The size of each object is propotional propotional propotional to its cost. to its cost. to its cost. The length of each object ’ s shadow is proportional to its influence. T Asokan

26. Cost evolution for a typical project* T Asokan

27. The System Design Process Redesign Describe Concept - 1 , Write Use Define Subsystems & Evaluate Customer Designs Cases Interfaces , Designs Needs Create Design Discover Describe Concept - 2 , Requirements Define Subsystems & Interfaces , Create Design Define Functions Describe Concept - 3 , Define Subsystems & Develop Interfaces , Architecture Create Design T Asokan

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29. The systems engineering process Stakeholder Requirements Management Element Plan and Organize Plans and Direction Control Analyze Problem Assess and Select Synthesize Solution Outcomes and Decisions Verify Solution Technical Element Physical Solutions T Asokan

30. Summary • Classification of systems • System engineers and their roles • System design processes • Economic impact of design process • System life cycle T Asokan