Posted: February 3rd, 2015

Embedded Systems Design and Development

Paper, Order, or Assignment Requirements

1) I will attach a file in word shows the instruction of the assignment and what requirements should include.
2) I will attach a file in PowerPoint shows how to start MP Lap and Some definitions of the codes. the file name(how to start MP Lap).
3) I will attach also file in PowerPoint for Running StepperMotor and the code required to run a steppermotor. the file name is ( running steppermotor).

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

Stepper motor 3

Figure1 Proposed CNC drilling machine control system.

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

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

Requirement

It requires 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. (fully referenced) required, the report should include in the following:

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.

Detailed analysis of the proposed system illustrating a generalised block-

diagram of the system and highlighting important features /considerations

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

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

Potential implementation issues (any consideration that would affect development and operation of the system

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 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.