Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
3.4 Analysis and Design I
Dr. Tarek A. Tutunji
Philadelphia University
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Preview The 2nd and 3rd steps in the design process, Gathering
Information and Proposing Solutions , was presented in the previous sequence.
In this sequence, the 4th step in the design process, Study Solutions will be presented.
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Seven Design Steps1. Define the Problem2. Gather Information3. Propose Solutions
4. Study the Solutions
5. Analyze and Design the chosen solution6. Implement the Design7. Evaluate Performance
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Study the Solutions Evaluate all the proposed designs detailing the strengths
and weaknesses
The study/analysis is composed of Feasibility Study Eliminate ideas without consuming time
Preliminary Design General design
Choose a Solution (Design) Might need to re-visit the design objective
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Feasibility Study Analyze each potential solution
Use simple calculations and heuristics
Choose the best solution (s) Not possible to investigate all initial solutions in details
Consider Cost, Time, and Difficulty
Eliminate some solutions
Develop a rating scheme
Select a few of the initial solutions
Document the solutions
Communicate solutions with management
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Example: Problem Statement A company product is packaged into two different size
boxes. It already has an automated packaging system, but is running into delays during the manual sorting of the boxes. Therefore, it is required to sort the boxes according to their sizes automatically.
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Example: Sketch Problem
Box ABox B
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Example: Proposed Solutions Add another production line
Sort the boxes on another station
Add two sub-belts
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Feasibility
Solution Quick Analysis
Add another production line Too expensive
Sort on another station Time consuming
Add sub-belts Works well
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Example: Sketch
Box
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Proposed Sensors / Feasibility Weight
Image
Light
Sensor Type Quick Analysis
Weight Works, but might need more circuit functions
Image Too expensive
Light Works well
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Light Sensors to measure size
Box ABox B
Transmitters Receivers
If only one signals is OFF Box A
If both signals are OFF Box is B
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Actuator Mechanism / Feasibility Vertical arm (from the top)
Sliding Door (from the bottom)
Push arm
Swing arm
Mechanism Quick Analysis
Vertical Arm Complicated
Up-sliding Door Complicated and Expensive
Push arm Might cause damage
Swing Arm Works Well
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Example: Sketch
Box
Sensor
Actuator 1 Actuator 2
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Preliminary Design Analyze each potential solution Use calculations
Choose the best solution List advantages and disadvantages of each solution
Use evaluation matrix
A single solution will emerge here
Document the solutions Write report
Communicate solutions with management Give oral presentation
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Type of Actuators Pneumatic
Hydraulic
Electrical
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Pneumatic Actuators Low cost
High reliability
Need piping and installation
Compressibility of air
Poor performance at low speed
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Hydraulic Actuators Large Force
High Power applications
Maintenance is needed (such as oil filteration)
Hazard if leaks occur
Need
Flow and Pressure valves
Pump and Tank
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Electric Motors Accurate control
Reliable
Widely used
Easy to maintain
Variable cost depending on the application
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Actuator TypeType Grade Pneumatic Hydraulic Electric
Cost 30 Good (25) Fair (20) Very Good (27)
Reliability 30 Good (25) Fair (20) Good (25)
Complexity 20 Good (16) Fair (14) Very Good (18)
Safety 20 Very Good (18) Fair (14) Very Good (18)
Total Score 100 84 68 88
Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University
Conclusion Design can be divided into seven-steps
The 4th step, study solutions, was described in this sequence
This includes Feasibility Study and Preliminary Design