Functional Decomposition!

Transcription

1 Functional Decomposition! Design Project Management Rochester Institute of Technology Department Rochester, NY USA Purpose of the functional decomposition:! a small number of functions (the WHAT) that your product must deliver to the customer to satisfy their need (the WHY)" Prepare to map those functions back to customer needs." As long as you provide the correct WHAT to your customer, they will often not care HOW you deliver the functions. " Modularize the product" Provide a structure around which to specify the problem" Provide a structure around which to brainstorm" We will try two different approaches today both may have value for your team!! 1

2 What is the core function?! What is the one core function that the device/product/process needs to accomplish? " What subfunctions need to be performed in order to achieve that function?" This allows you to begin distinguishing your problem/ solution from others." Navigate an individual from Point A to Point B, given A and B (start and end points) and information about the surrounding environment 2

3 Inputs and Outputs?! Flow through the system that is performing this function" Information" Matter" Energy" Region Map Nearest Tag ID(s) Destination Navigate an individual from Point A to Point B, given A and B (start and end points) and information about the surrounding environment On Map? Hardware Health Movement Instructions Heat 3

4 How are you going to perform that function?! Verb-Noun" Examples:" current location/state" destination" route" How is that information, matter, or energy being transformed or moved through the system?" Navigate an individual from Point A to Point B, given A and B (start and end points) and information about the surrounding environment current state target state Route Transmit information to user Support internal components 4

5 Region Map Nearest Tag ID(s) Destination current state target state Route Battery, MCU Transmit information to user On Map? Movement Instructions Hardware Health Heat How are you going to do THAT?! How are you going to identify current state?" current location" current orientation" 5

6 Navigate an individual from Point A to Point B, given A and B (start and end points) and information about the surrounding environment Current State Target State Route Transmit Info to User Support & Manage Internal Components Store Current Location Current Orientation Import Map Accept User Input path next instruction Convert instruction to tactile feedback Support components Maintain Temperature Protect Components Accept Charging Regulate Or: Brainstorm a list of tasks, then sort! Sort tasks into hierarchical order" Ask how you will complete each task" Ask why you must complete each task" Navigate an individual from Point A to Point B, given A and B (start and end points) and information about the surrounding environment Ask how Current State Target State Route Transmit Info to User Support & Manage Internal Components Store Ask why Current Location Current Orientation Import Map Accept User Input path next instruction Convert instruction to tactile feedback Support components Maintain Temperatur e Protect Component s Accept Charging Regulate 6

7 Region Map Receive Map Info Compare current to map On Map? Nearest Tag ID(s) Destination ID current location (RFID) Navigation Loop Receive User Input Record location history path Velocity next instruction Monitor Hardware Health Deliver Information to User Movement Instructions Hardware Health Magnetic Field Charging Orientation (Compass) Store onboard Regulate (MCU: Define Interfaces with, User Input, Map Input, RFID Reader, Compass, Output Drive Circuitry) Heat Enclosure: Support & Manage Internal Components Region Map Receive Map Info Compare current to map On Map? Information Nearest Tag ID(s) Destination ID current location (RFID) Navigation Loop Receive User Input Record location history path Velocity next instruction Monitor Hardware Health Deliver Information to User Movement Instructions Hardware Health Magnetic Field Charging Energy Orientation (Compass) Store onboard Regulate (MCU: Define Interfaces with, User Input, Map Input, RFID Reader, Compass, Output Drive Circuitry) Heat Enclosure: Support & Manage Internal Components 7

8 Consider last week s example! I said, We need a better ladder." " What if I had said, We need a device that provides access to objects above human reach?" Core fuction: Provide access to objects above human reach." Define problem further in the subfunctions" Point of Confusion #1! Functions Constraints" Constraints are system-wide parameters, like cost, weight, overall footprint" Functions are actions, what your device/system will do (verb-noun)" 8

9 Point of Confusion #2! Engineering Metrics and Target Specifications define how well you need to perform these functions/subfunctions, or what constraints you must meet" Metrics = what to measure, units" Specifications = magnitude" Consider specifications for minimally acceptable, target, and ideal conditions" Examples of Functions! Some functions that your product may perform (from Otto & Wood Product Design):" Import, export, transfer, transmit, guide, translate, rotate, allow degrees of freedom" Stop, stabilize, secure, position" Couple, mix, separate, remove, refine, distribute, dissipate" Store, supply, extract" Actuate, regulate, change, form, condition" Sense, indicate, display, measure" 9

10 In-Class Example! Develop a functional decomposition for a device that will enable a person with one hand to secure their hair in a ponytail." R13002, R13201, and R13301 use function tree/fast diagram" R13401, R13701, and R13904 use flow diagram " Regroup! Two teams share function trees" Discussion:" How are these different from yours?" Is one right or wrong? Better or worse?" Are you (or they) missing functions?" Are you (or they) prescribing solutions?" Other questions?" 10

11 Rest of Today! Refine VOC, problem background" Feedback from guide" Follow-up with stakeholders" Prepare for next week s presentation" What information do you want to convey?" What information are you still missing?" Begin considering core function(s) for your project(s)" Next Steps! Assign metrics and specifications" Metrics = what to measure, units" Specifications = magnitude" Consider specifications for minimally acceptable, target, and ideal conditions" Performance Specifications: what the customer sees" Design Specifications: define interfaces" 11