Posted: September 13th, 2017

Embedded Systems Design and Development

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5ET003 Assignment 2

Department of Engineering

Module Title: Professional Engineering and the Micro-electronics

Module Code: 5ET003

Component Number:   2 of 2 Element Number: 1 of 1

Element Title

Embedded Systems Design and Development:

Design and development of an embedded control

system for a 4-axis CNC Drillingmachine.

Weighting: 50%

Learning Outcomes to be assessed:

Marking Criteria:

Written reports produced using IT skills.

In order to achieve a D5 (minimum pass grade) students are expected to

produce an individual report of approximately 1500 words, showing a basic

understanding of the subject area using standard available material. The

reports are to be produced electronically using relevant illustrations, where

applicable.

In order to achieve A16 (highest pass grade) students must produce an

individual report that demonstrates extensive well researched knowledge of

the subject area, expressing competent personal opinions and arguments.

The report must be electronically produced, well-illustrated, adequately

referenced and set out with good use of relevant illustrations.

The minimum pass mark for this component is D5.

Assignment Issued: 24

th

November 2014

Latest date for submission: 12

th

January 2015

Assignments submitted after the deadline, and without an authorised extension, will be

graded F0.

Please mark your assignment for the attention of: Dr A Zakeri

You should make it very clear what sources of information have been used; where material/information from these

sources is quoted, it must be clearly referenced using the Harvard Referencing System. (Details can be obtained from

Learning Centre pages on the University website).

The assignment must be handed in at the Telford student access point.

A signed receipt must be obtained when the assignment is submitted. You should keep your receipt in a safe place.

You are required to keep your own electronic and/or hard-copy of any work submitted.

5ET003 Assignment 2

Department of Engineering

Module: 5ET003 Professional Engineering and the Microelectronics

Assignment 2: Microelectronics

Assignment brief:

Embedded Systems Design and Development:- Design and development of an

embedded control system for a 4-axis CNC Drilling machine.

Introduction

Use PIC16f88 microcontroller to develop an embedded control system for a 4-axis CNC

machine carrying out drilling operations on aerospace parts. The manufacture of military

aircraft entails rigid demands on the dimensional accuracy of the component parts. One of the

demands is a complete inter-changeability of parts without any modification of the pattern of

drilled holes. This demand is met by the use of programmable machines. In most cases where a

robot is used within aircraft manufacturing it is programmed to handle and position sheet metal

parts to make possible further operations using another machine. In this case the CNC machine

will be used for performing the machining (drilling) operation. The concept of a CNC drilling

machine is to be realised by development of an embedded 4-axis motion control system for this

machine that makes use of PIC16F88 microcontroller. The structure of the propose CNC drilling

machine control system is shown in Figure1.The work to be drilled and its drill template is

shown in Figure 2

Figure1 Proposed CNC drilling machine control system.

Stepper motor 3

5ET003 Assignment 2

Figure2. Drill template with sheet metal panel

The embedded system shown in Figure1 uses four stepper motors as actuation

devices. Two Stepper motors are used for positioning of the worktable, one stepper

motor will be used for position of workhead (drilling tool) and one stepper

motor will be used for the process of drilling.

Figure 3 shows worktable movement achieve through rotation of Leadscrew by

stepper motor. Worktable bring the work under the drill head through moving in

X-axis and Y-axis or simultaneously in both X and Y directions.

Figure 3 Worktable movement achieve through rotation of Leadscrew by

stepper motor

5ET003 Assignment 2

Figure 4- Mechanism for movement of workhead

Figure 4 Stepper motor 3 will move the workhead to up and down in Z direction

Stepper motor 4 rotates the drill for carrying out the drilling operation

Figure 5 below shows overall structure of 4-axis CNC control system (schematic of

the movement of workhead by Stepper motor 3 is presented for visualisation of

mechanism as well as stepper motor interfacing)

Figure 5 overall structure of embedded 4-axis CNC control system

Stepper motor 3

Stepper motor 4

rotating the drill

5ET003 Assignment 2

Requirement

Students are required to elaborate on the concept of CNC control of drilling operation

and discuss the design and development of hardware and software required for the

realisation of a 4-axis motion control system for the proposed CNC machine. A written

report of 3000 (fully referenced) required, the report should include in the following:

1- Design outline- More elaborate description of the embedded system to be developed

and the purpose of its design and literature review. This section should in particular

describe the

– Hardware and software requirement for position and speed control of worktable

– Hardware and software requirement for position and speed control of workhead

– Hardware and software requirement for control of workhead (drill) operation.

2- Detailed analysis of the proposed system illustrating a generalised blockdiagram of the system and highlighting important features /considerations

3- The interfacing of the hardware components to microcontroller (interfaces).

4- Software design:- Flowchart and list of the codes being developed

5- Potential implementation issues (any consideration that would affect development and

operation of the system

6- Summary and Discussion.

Solution instruction (Guidelines)

Stepping motors are normally used for small robots with low speed and torque

requirements. When used for such applications, they have the advantage that they can

be operated in open loop mode thereby eliminating the need for interfacing rather

expensive feedback transducers.

D.C. motors and stepping motors are used for providing rotary motion in robots. Both of

these motors are however, unsuitable for directly producing a linear motion. Rotary

motion can be translated into linear motion using rack and pinion drives. An alternative

possibility involves the use of a lead screw type device whose speed is rather limited.

The prospective embedded system will position the worktable under the workhead and

moves the workhead in Z direction by first approaching the work in high speed and then

moving the workhead (dril) slowly into the work to create holes, and then retrieve the

work upward and moving the worktable to a length that allows next hole to be produced

in the work. Through consideration of lead-screw’s pitch students should calculate the

number of pulses required sending to stepper motors for achieving a particular distance

travel, and through the change in frequency of pulse train students should be able to

achieve various travel speeds. The use of sensors for any end- stop location detection

and for stroke length determination can also be considered.

This assignment requires students to interface a keypad and four stepper motors to a

PIC16f88-based microcontroller board and develop appropriate programs (codes) for

5ET003 Assignment 2

the microcontroller so that it can scan the keypad and actuate (run) particular stepper

motor when particular key on the keypad is pressed. LCDs can also be Interfaced to the

microcontroller to display sensory information and or number of holes produced.

Marking criteria:

You are required to investigate and design all the interfacing and the codes required for

the development of the proposed embedded system for control of the CNC drilling

machine. You should submit an individual report of 3000 words length (fully

referenced), including in your report the following:

Headings (Tasks / Requirements) Marks

1 Description of the proposed embedded system and the purpose of its

design and literature review.

20%

2 Detailed analysis of the proposed embedded system illustrating a generalised

block diagram of the system and highlighting important features /considerations

including the sensors and actuators required for effective monitoring and

supervisory control of CNC drilling operation.

10%

3 Hardware specification (how the hardware components connect together and to

the microcontroller ( interface). This in particular requires discussion and

explanation of

3.1 interfacing of sensors and actuators (motors) to the microcontroller- how

many sensors and actuators used

3.2- interfacing of the microcontroller to LCD for the display of

sensory data/information/feedback.

3.3- interfacing of microcontroller to a Keypad for the issuing of the command

signals to the microcontroller to maintain optimum position for worktable and

workhead etc,

include in this section the code required for the acquisition of data from sensors

and their storage into the outstation microcontroller

20%

4 Software design:- Flowchart and list of the code

This should include Flowchart and list of codes for individual tasks as well as code

for overall continuous operation of the embedded system using sensory feedback

and actuation signals. Include in this section the following particular codes:

4.1- the code required for the positioning of woktable

4.2- code for receiving keypad command signals into the microcontroller to

maintain an optimum position of workhead and worktable and the actual

drilling operation.

4.3 Code for transmission of sensory data to an LCD display.

4.4 overall code continuous operation of the embedded system illustrating

Use of appropriate LOOPS for the effective execution of the overall tasks of a

CNC drilling machine 40%

5 Summary and Discussion including recommendation of potential improvement of

the system.