forward design example rev ii - philadelphia university. fwd design...forward design example rev ii...
TRANSCRIPT
DR. TAREK A. TUTUNJI
REVERSE ENGINEERING
PHILADELPHIA UNIVERSITY, JORDAN
2015
Forward Design Example Rev II
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Introduction
Examples for forward design will be presented and discussed
The objective is to let students think of the seven-steps
and how they are applied to several systems This will allow the students to review their design skills
and later compare the forward design steps with the reverse engineering steps
First, the students are asked to work on two simple
designs. Then, the design for more complex systems are provided.
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Example: Pen
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Pen Design
What is the need?
What are the specifications?
What options are available?
Design a pen in class with your group!
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Example: AC-DC Converter
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
AC-DC Converter Design
What is the need?
What are the specifications?
What options are available?
Design an AC-DC converter in class with your group!
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Case Study: Crane Design
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
1. Define the Problem
The objective is to build a small prototype crane that can translate a weight in three dimensions by manual joystick.
Specifications:
Load = 5 kg
Speed = 0.11 m/s
Constraints
Time 8 months
Budget: $800
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
2. Gather Information
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
2. Gather information
An overhead crane is a crane where the hook-and-line mechanism runs along a horizontal beam that itself runs along two widely separated rails.
Also a hoist is used to lift the items, the bridge, which spans the area covered by the crane, and a trolley to move along the bridge.
Its purpose is to move objects automatically between two locations in a factory
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
2. Gather Information
Main Components
Bridge
Rail
Trolley
Beam
Hook
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
2. Gather Information
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
2. Gather Information
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
2. Gather Information
Electrical components Motors
Electronics
Controller
Sensor
Mechanical components Shafts
Gears
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
3. Propose Solutions
Type of crane
Tower
Overhead
Type of actuators
Electric: DC, AC, or Stepper
Pneumatic
Type of sensors
Optical
Limit Switches
Type of controller
PC
Microcontroller
Analog
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
4. Study the Solutions
Overhead crane works better than Tower for our purpose
Microcontroller
Cheaper than PC
More accurate than analog
DC Motor
Cheaper than AC and easier to control
Easier than pneumatic
Sensors
Limit switch for linear end position
Optical encoder for motor position
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
4. Study the Solutions: Choose
Single girder overhead crane with dimensions: 2 m length, 1.2 m width, and 1 m height
Three DC motors for xyz-directions
PIC microcontroller
Limit switches, three positioning sensors, control and drive circuits
Keypad. The user can specify the desired position by entering the coordinates on the keypad
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
5. Analyze & Design: Block Diagram
Controller Power
Electronics Interface
Limit Switch Sensors
Crane Plant Electrical Motors
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Analysis: Weight Calculations
Motors weight = 1.5kg ×2 = 3kg
• Shaft and bearing =4kg
• U- Shape steel bar and steel sheet = 2kg
• Screws and roundels = 0.25kg
• Teflon wheels = 0.25 kg
• Other parts = 0.5 kg
Total weight of Trolley = 10 kg
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Analysis: Power Calculations
F = M × g F = 5 kg × 9.81 m/s² = 49.05 N
T = F × R T = 49.05 N × 0.025 m = 1.23 N.m
Pm = T × ω Pm = 1.23 N.m × 4.7 rad/s = 5.8 watt.
P actual = 5.8 watt × 1.6 = 9.6 watt
Pe = 9.6Watt /0.8 = 12 Watt
Pe = I × V
We chose DC motor with V = 12 V, I = 3 A.
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Analysis and Design: Simulation
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Design: Mechanical Drawings
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Design: Flow Chart
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Final Design
The mechanical components were composed of the frame, the girder, and the trolley.
The frame used bars of hot roll steel AISI 1020: two parallel tracks of 2m length, six vertical columns of 1m length, and sixteen side holding bars.
The girder consisted of two parallel girder tracks of 1.2 m length mounted to side rolling bases.
The trolley part had two 36 watt DC motors with internal worm gear assembly mounted to side rolling bases.
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Final Design
Actuators:
Three DC motors as: Hook motor to lift the load, trolley motor to move the trolley above the girder, and girder motor to move the girder above the bridges. Each dc motor (3 A, 12V) had internal gears in order to reduce the speed and increase the torque with a gear ratio 1/140.
Sensors:
Two linear optical encoders were used as displacement sensors for the x-y positioning with a resolution 1pulse/cm. The tracks were made from plastic and fixed to the frame. For the z-direction, rotational optical encoders were placed on the shaft of the pulley with a resolution of 20pulse/revolution.
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
6. Implement: PCB
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Implementation: Mechanical
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
7. Evaluate
The crane was tested in the labs
Equipment used: Scopes and multi-meters
Different loads (up to 5 Kg) were used
Speed of movement was measured using stopwatch
Microcontroller was damaged during testing.
Limit switches were calibrated.
The load cable was re-packaged
Added support to the skeleton frame
Insulated the controller using the opto-coupler.
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Final Prototype
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Acknowledgement
The crane project work was the effort of two student design teams:
Team 1:
Abd Al-hafez Suleiman
Yosef Abo Hurira
Team 2:
Hassan Abu Zahra
Moafeq Alkhateeb
Fadi Darweesh
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Aircraft Elevator Design
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Aircraft Elevator Design
Dr. Tarek A. Tutunji Engineering Skills, Philadelphia University
Conclusion
Design examples were provided to show the 7-design steps
The examples included Pen
Electrical Converter
Overhead Crane
Aircraft Elevator