CHAPTER 1

INTRODUCTION

1.1 Background Study

Unmanned Helicopter can be determined by the no onboard pilot and it’s

flown by autonomously based on pre-programmed flight plans. Nowadays,

unmanned helicopters are about to become easy to operate and affordable thanks to a

stabilization system developed at the entrepreneurial incubator program at the

Technion-Israel Institute of Technology in Haifa. In UAVs, not only is stability an

issue, but "all the controls are backwards," Kalisch explains. [1] "Right is left, left is

right. Backward is forward and vice versa". The system uses intelligent devices

which control the component such as standard accelerometers, gyroscopes to

maintain proper orientation, motor driver and so on.

Unmanned Helicopter is basically exist base from the conventional helicopter

where helicopter here it means an aircraft which is lifted and propelled by one or

more horizontal rotors each of two or more rotor blades. Helicopters are classified as

rotary-wing aircraft to distinguish them from fixed-wing aircraft. The word

'helicopter' derives from the Greek words helix (spiral) and pteron (wing). The

compensatory, aviational advantage is maneuverability where the helicopters can

hover, reverse, and take off and land vertically. [2] Flying subject only to availability

of re-fueling airport and load and altitude limitations and fly to anywhere and land

any place with enough landing space.

By referring to the previous helicopter usage, we can notice that it have

advantages and disadvantages in their many way. For an example in the military,

there are many type of helicopter is used in war such as attack helicopter, transport

helicopter, observation helicopter, utility helicopter and also maritime helicopter.

Each of helicopters has their own function in order to make sure that the actual

purpose is gained. But as it say before each of them have their own advantages and

disadvantages. There are a lot of people dies and injures at war.[1] So the unmanned

helicopter is design to overcome the problem in term of safety and avoid that

unwanted scenario from happen again and again. With adding some intelligence

technology in this product and it will become more efficient and safe to be used.

Other than that, there are several advantages where we can found in the

Unmanned Helicopter (UH) such as is that it flies by computer and the computer

reacts far faster than a human can. Piloted helicopters that exist today would have

difficulty in getting much above 12,500ft, less than half the height of Everest, and

conventional engine types would be struggling to fly and maintain power in the thin

air. There are many crashed helicopters in the Himalayas that attest to flight

difficulties using conventional rotorcraft. The helicopter’s sophisticated computers

react and fly the helicopter quicker than a pilot could react. [3]

1.2 Problem Statement

Base on the topic given, one of the very first problems helicopter designers

encountered when they tried to create a machine that could hover was the problem of

speed rotation motor. Newton's third law of motion requires that for every action

there is an equal and opposite action. A typical single main rotor helicopter has a

rotor system mounted on a rotor mast. But in this project, we will build the system

which has two different motor with different speed where it’s needed to be stabilize

at the different post of center-of-gravity (CG) according due to the center of

helicopter where so called tandem rotor where the arrangement as a tandem rotor is

mainly used with big helicopters. Because of the opposite rotation of the rotors, the

2

torque of each single rotor will be neutralized. The construction of the control system

is much more complicated, compared to a helicopter with a tail rotor.

The primary advantage of tandem rotor configuration is the ability to lift

heavy loads whose position relative to the helicopter's centre of gravity is less critical

than in the single rotor configuration. Because there is no anti-torque rotor, full

engine power can be applied to lifting the load. By combining the idea between the

Unmanned Helicopter (UH) with the tandem rotor configuration, we can barely have

a batter solution for the nowadays problem in terms to the safety, facilities and

overcome some previous invention yet still dealing with the interface intelligent

which is controlled the devise. [4]

Figure 1.1 Tandem Rotor Helicopter

By focusing on the counteracting rotor torque reaction, the main idea of a tail

rotor to counter torque reaction and provide directional control was not used on most

early designs. Most early machines were built with either coaxial or laterally side-by-

side rotor configurations. Yet, building and controlling two rotors was even more

difficult that for one rotor. Igor Sikorsky was the first to successfully use the tail

rotor in the single rotor helicopter configuration we know today.

So the major problem in this project is how we want to stabilize the speed

rotation of both motors so they can hover statically and after done some researches

and a discussion with the instructor we finally decide to use speed sensor together

3

with the PIC Microcontroller to stabilize the speed rotation of both motor. In

addition, we use height sensor to make sure the unmanned helicopter will hover at

the controlled height.

1.3 Objective

The objective of this project is to:

(i) Design and program an unmanned helicopter.

(ii) Use a microcontroller system by using PIC microcontroller in order to

stabilize the speed of both rotors.

1.4 Scope of Project

This project will design a hovering system for tandem rotor Unmanned

Helicopter (UH). In develop this project the scope to be considered are:

(i) Design and developed circuit for control of Unmanned Helicopter.

(ii) The hovering range of the Unmanned Helicopter is limited to 3 meter.

(iii) The UH will remain hovering for 10 seconds and then will go down to

the ground.

4

CHAPTER 2

LITERATURE REVIEW

2.1 An Overview

A hovering system is a design system that make thing fly at the space.

Devices that can hover in air or water are needed for many military and commercial

applications. Vertical axis propeller systems can normally provide the thrust required

supporting the weight of the device, but many previous designs have proved to be

naturally unstable, and have had to be stabilized by active stability systems. These

usually incorporate motion sensors, such as accelerometers, gyroscopic sensors,

complex electronic processing networks, and mechanical actuators to provide the

action to create the necessary stabilizing moments. [2]

A helicopter is an aircraft which is lifted and propelled by one or more

horizontal rotors each of two or more rotor blades. Helicopters are classified as

rotary-wing aircraft to distinguish them from fixed-wing aircraft. The word

'helicopter' derives from the Greek words helix (spiral) and pteron (wing). The

compensatory, aviational advantage is maneuverability where the helicopters can

hover, reverse, and take off and land vertically. Flying subject only to availability of

re-fueling airport and load and altitude limitations and fly to anywhere and land any

place with enough landing space. [5]

Unmanned Helicopter can be determined by an aircraft with no onboard pilot.

UAVs can be remote controlled aircraft (e.g. flown by a pilot at a ground control

station) or can fly autonomously based on pre-programmed flight plans or more

complex autonomous flight systems and nowadays, unmanned helicopters are about

5

to become easy to operate and affordable thanks to a stabilization system developed

at the entrepreneurial incubator program at the Technion-Israel Institute of

Technology in Haifa. In UAVs, not only is stability an issue, but "all the controls are

backwards," Kalisch explains. "Right is left, left is right. Backward is forward and

vice versa". The system uses intelligent devices which control the component such as

standard accelerometers, gyroscopes to maintain proper orientation, motor driver and

so on. [1]

2.2 Tandem Rotor Helicopters

Tandem rotor helicopters operate a little differently than do the single rotor

variety. In a tandem rotor helicopter, you have no tail rotor, so there is no translating

tendency to deal with, but you still have pedals for directional control at a hover.

Your cyclic control, which is used as it always has been in single rotor helicopters,

has not changed either. The only thing different in terminology for tandem rotor

aircraft is the term "Thrust control", which is used to describe the collective pitch

control lever. It is used in the same way as any other collective, but the tandem guys

use the term thrust control.

Figure 2.1 Tandem rotor helicopters

6

Tandem rotor helicopters operate in forward flight by using "Differential

Collective Pitch" or "DCP". DCP is basically just increasing more pitch in one rotor

system then the other to make the aircrafts attitude change. By increasing the pitch in

the aft system more than the forward system, the aircraft will tilt nose low, and

accelerate forward. To climb without changing airspeed, more pitch is placed in both

systems simultaneously. It is really a matter of aircraft attitude more than anything

else. If the aircraft is in a nose high attitude, it will climb and bleed off airspeed. If it

is too nose low, it will dive and increase airspeed. The amount of pitch put in each

rotor system will dictate airspeed and altitude. The pilot will fly the aircraft just like

any other, but the rotor systems will act in a way peculiar to tandem helicopter flight.

The picture here is of a tandem helicopter in level hovering flight. Notice both rotor

systems are depicted as level. The actual blades will "Cone" a bit. What this means is

they will bend upwards to the tip. The more the weight on the aircraft, the more the

blades will cone.

2.3 PIC Microcontroller Implementation

Regarding this project, several reviews were made. One of the researches

made is about the brain of the tandem rotor Unmanned Helicopter (UH) which is PIC

microcontroller. In 1989, Microchip Technology Corporation introduced an 8-bit

microcontroller called the PIC, which stands for Peripheral Interface Controller. This

microcontroller had small amounts of data RAM, a few hundred bytes of on-chip

ROM for the program, one timer, and a few pins for I/O ports, all on a single chip

with only 8 pins. [17] Microcontroller is general purpose microprocessor which has

additional parts that allow them to control external devices. Basically, a

microcontroller executes a user program which is loaded in its program memory. [6]

The reason for using microcontroller is general purpose microprocessor

which has additional parts that allow them to control external devices. Basically, a

microcontroller executes a user program which is loaded in its program memory.

7

Figure 2.2 PIC microcontrollers in DIP and QFN packages

Instead of using the microcontroller, PIC type of microcontroller architecture

is distinctively minimalist. PIC microcontroller is the name for the microchip

microcontroller (MCU) family, consisting of a microprocessor, I/O ports, timer (s)

and other internal, integrated hardware. [6] It is characterized by the following

features:

(i) Separate code and data spaces.

(ii) A small number of fixed length instructions.

(iii) Most instructions are single cycle execution (4 clock cycles), with

single delay cycles upon branches and skips.

(iv) A single accumulator (W), the use of which (as source operand) is

implied

(v) All RAM locations function as registers as both source and/or

destination of math and other functions.

(vi) A hardware stack for storing return addresses.

(vii) A fairly small amount of addressable data space (typically 256 bytes),

extended through banking.

(viii) Data space mapped CPU, port, and peripheral registers.

(ix) The program counter is also mapped into the data space and writable

(this is used to synthesize indirect jumps).

Unlike most other CPUs, there is no distinction between "memory" and

"register" space because the ram serves the job of both memory and registers, and the

ram is usually just referred to as the register file or simply as the registers. PIC

microcontrollers have a very small set of instructions (only 35 instruction), leading

8

some to consider them as RISC devices, however many salient features of RISC

CPU's are not reflected in the PIC architecture. For examples:

(i) It does not have load-store architecture, as memory is directly

referenced in arithmetic and logic operations.

(ii) It has a singleton working register, whereas most modern

architectures have significantly more.

PICs have a set of register files that function as general purpose RAM;

special purpose control registers for on-chip hardware resources are also mapped into

the data space. The addressability of memory varies depending on device series, and

all PIC devices have some banking mechanism to extend the addressing to additional

memory. Later series of devices feature move instructions which can cover the whole

addressable space, independent of the selected bank. In earlier devices (ie. the

baseline and mid-range cores), any register move had to be through the accumulator.

[7]

All PICs feature Harvard architecture, so the code space and the data space

are separate. PIC code space is generally implemented as EPROM, ROM, or FLASH

ROM. In general, external code memory is not directly addressable due to the lack of

an external memory interface. The exceptions are PIC17 and select high pin count

PIC18 devices. [7]

The word size of PICs can be a source of confusion. All PICs (except dsPICs

and PIC24s) handle (and address) data in 8-bit chunks, so they should be called 8-bit

microcontrollers. However, the unit of addressability of the code space is not

generally the same as the data space. For example, PICs in the baseline and mid-

range families have program memory addressable in the same word size as the

instruction width, example like 12 or 14 bits respectively. In contrast, in the PIC18

series, the program memory is addressed in 8-bit (bytes), which differs from the

instruction width of 16 bits. In order to be clear, the program memory capacity is

usually stated in number of (single word) instructions, rather than in bytes. [7]

9

The PICs architecture has no (or very meager) hardware support for saving

processor state when servicing interrupts. The 18 series improved this situation by

implementing shadow registers which save several important registers during an

interrupt. The PICs architecture may be criticized on a few important points:

(i) The few instructions, limited addressing modes, code obfuscations

due to the "skip" instruction and accumulator register passing makes it

difficult to program in assembly language, and resulting code difficult

to comprehend. This drawback has been alleviated by the increasing

availability of high level language compilers.

(ii) Data stored in program memory is space inefficient and/or time

consuming to access, as it is not directly addressable.

2.4 Feedback Control System

A basic closed-loop control system is shown in Figure 2.3. This figure can

describe a variety of control systems, including those driving elevators, thermostats,

and cruise control. Closed-loop control systems typically operate at a fixed

frequency. The frequency of changes to the drive signal is usually the same as the

sampling rate, and certainly not any faster. After reading each new sample from the

sensor, the software reacts to the plant's changed state by recalculating and adjusting

the drive signal. The plant responds to this change, another sample is taken, and the

cycle repeats. Eventually, the plant should reach the desired state and the software

will cease making changes. [8]

Figure 2.3 A closed-loop control system

10

A standard definition of a feedback control system is a control system which

tends to maintain a prescribed relationship of one system variable to another by

comparing functions of these variables and using the difference as a means of

control. A feedback control system often uses a function of a prescribed relationship

between the output and reference input to control the process. Often, the difference

between the output of the process under control and the reference input is amplified

and used to control the process so that the difference is continually reduced. The

feedback concept has been the foundation for control system analysis and design. [9]

Figure 2.4 Close loop (feedback) control block diagram

Feedback is information in a closed-loop control system about the

condition of a process variable. This variable is compared with a desired condition

to produce the proper control action on the process. Information is continually "fed

back" to the control circuit in response to control action. [10]

One of the most important characteristics of control systems is their transient

response, which often must be adjusted until it is satisfactory. If an open-loop control

system does not provide a satisfactory response, then the process must be replaced or

modified. By contrast, a closed-loop system can often be adjusted to yield the desired

response by adjusting the feedback loop parameters. A second important effect of

feedback in a control system is the control and partial elimination of the effect of

disturbance signals. Many control systems are subject to extraneous disturbance

signals which cause the system to provide an inaccurate output. Feedback systems

have the beneficial aspect that the effect of distortion, noise, and unwanted

disturbances can be effectively reduced.

11

The transient response of a feedback control system is of primary interest and

must be investigated. A very important characteristic of the transient performance of

a system is the stability of the system. A stable system is defined as a system with a

bounded system response. That is, if the system is subjected to a bounded input or

disturbance and the response is bounded in magnitude, the system is said to be stable.

[10]

The concept of stability can be illustrated by considering a right circular cone

placed on a plane horizontal surface. If the cone is resting on its base and is tipped

slightly, it returns to its original equilibrium position. This position and response is

said to be stable. If the cone rests on its side and is displaced slightly, it rolls with no

tendency to leave the position on its side. This position is designated as neutral

stability. On the other hand, if the cone is placed on its tip and released, it falls onto

its side. This position is said to be unstable.

In redesigning a control system in order to alter the system response, an

additional component or device is inserted within the structure of the feedback

system to equalize or compensate for the performance deficiency. The compensating

device may be an electric, mechanical, hydraulic, pneumatic, or other-type device or

network, and is often called a compensator.

2.5 Pulse Width Modulation (PWM)

Pulse-width modulation (PWM) is a device that may be used as an efficient

light dimmer or DC motor speed controller. Pulse-width modulation control works

by switching the power supplied to the motor on and off. The DC voltage is

converted to a square-wave signal, alternating between fully on and zero. If the

switching frequency is high enough, the motor run at the steady speed. [11] By

controlling analog circuits digitally, system costs and power consumption can be

drastically reduced. In nowadays implementation, many microcontrollers and DSPs

already include on-chip PWM controllers, making implementation easy. In a

nutshell, PWM is a way of digitally encoding analog signal levels.

12

Through the use of high-resolution counters, the duty cycle of a square wave

is modulated to encode a specific analog signal level. The PWM signal is still digital

because, at any given instant of time, the full DC supply is either fully on or fully off.

The voltage or current source is supplied to the analog load by means of a repeating

series of on and off pulses. The on-time is the time during which the DC supply is

applied to the load, and the off-time is the periods during which that supply is

switched off. Given a sufficient bandwidth, any analog value can be encoded with

PWM.

Pulse-width modulation uses a square wave whose duty cycle is modulated

resulting in the variation of the average value of the waveform. If we consider a

square waveform f (t) with a low value ymin, a high value ymax and a duty cycle D (see

Figure 2.5), the average value of the waveform is given by:

(2.1)

As f (t) is a square wave, its value is ymax for and ymin for

. The above expression then becomes:

(2.2)

This latter expression can be fairly simplified in many cases where ymin = 0 as

. From this, it is obvious that the average value of the signal ( ) is

directly dependent on the duty cycle D.

13

Figure 2.5 A square wave, showing the definitions of ymin, ymax and D

Figure 2.6 shows three different PWM signals. Figure 2.6 (a) shows a PWM

output at a 10% duty cycle. That is, the signal is on for 10% of the period and off the

other 90% while Figures 2.6 (b) and Figure 2.6 (c) show PWM outputs at 50% and

90% duty cycles, respectively. These three PWM outputs encode three different

analog signal values, at 10%, 50%, and 90% of the full strength. If, for example, the

supply is 9V and the duty cycle is 10%, a 0.9V analog signal results.

Figure 2.6 PWM signals of varying duty cycles

Figure 2.7 shows a simple circuit that could be driven using PWM. In that

figure, a 9 V battery powers an incandescent light bulb. If we closed the switch

connecting the battery and lamp for 50 ms, the bulb would receive 9 V during that

interval. If we then opened the switch for the next 50 ms, the bulb would receive 0 V.

If we repeat this cycle 10 times a second, the bulb will be lit as though it were

connected to a 4.5 V battery (50% of 9 V). We say that the duty cycle is 50% and the

modulating frequency is 10 Hz. [12]

14

Figure 2.7 A simple PWM circuit

Most loads, inductive and capacitative alike, require a much higher

modulating frequency than 10 Hz. Imagine that our lamp was switched on for five

seconds, then off for five seconds, then on again. The duty cycle would still be 50%,

but the bulb would appear brightly lit for the first five seconds and off for the next. In

order for the bulb to see a voltage of 4.5 volts, the cycle period must be short relative

to the load's response time to a change in the switch state. To achieve the desired

effect of a dimmer (but always lit) lamp, it is necessary to increase the modulating

frequency. The same is true in other applications of PWM. Common modulating

frequencies range from 1 kHz to 200 kHz. [12]

Many microcontrollers include on-chip PWM units. For example,

Microchip's PIC16C67 includes two, each of which has a selectable on-time and

period. The duty cycle is the ratio of the on-time to the period; the modulating

frequency is the inverse of the period. To start PWM operation, the data sheet

suggests the software should:

(i) Set the period in the on-chip timer/counter that provides the

modulating square wave.

(ii) Set the on-time in the PWM control register.

(iii) Set the direction of the PWM output, which is one of the general-

purpose I/O pins.

(iv) Start the timer.

(v) Enable the PWM controller.

Although specific PWM controllers do vary in their programmatic details, the

basic idea is generally the same. One of the advantages of PWM is that the signal

remains digital all the way from the processor to the controlled system; no digital-to-

analog conversion is necessary. By keeping the signal digital, noise effects are

15

minimized. Noise can only affect a digital signal if it is strong enough to change a

logic-1 to a logic-0, or vice versa. [11]

2.6 Dc Motor

At the most basic level, electric motors exist to convert electrical energy into

mechanical energy. This is done by way of two interacting magnetic fields - one

stationary, and another attached to a part that can move. A number of types of

electric motors exist, but most BEAM bots use DC motors in some form or another.

DC motors have the potential for very high torque capabilities (although this is

generally a function of the physical size of the motor), are easy to miniaturize, and

can be "throttled" via adjusting their supply voltage. DC motors are also not only the

simplest, but the oldest electric motors. [18]

Figure 2.8 The DC Motor

The basic principles of electromagnetic induction were discovered in the

early 1800's by Oersted, Gauss, and Faraday. By 1820, Hans Christian Oersted and

Andre Marie Ampere had discovered that an electric current produces a magnetic

field. The next 15 years saw a flurry of cross-Atlantic experimentation and

innovation, leading finally to a simple DC rotary motor. A number of men were

involved in the work, so proper credit for the first DC motor is really a function of

just how broadly you choose to define the word "motor".

16

In any electric motor, operation is based on simple electromagnetism. A

current-carrying conductor generates a magnetic field; when this is then placed in an

external magnetic field, it will experience a force proportional to the current in the

conductor, and to the strength of the external magnetic field. As you are well aware

of from playing with magnets as a kid, opposite (North and South) polarities attract,

while like polarities (North and North, South and South) repel. The internal

configuration of a DC motor is designed to harness the magnetic interaction between

a current-carrying conductor and an external magnetic field to generate rotational

motion. [18]

Figure 2.9 The sketch of DC Motor

A DC motor works by converting electric power into mechanical work. This

is accomplished by forcing current through a coil and producing a magnetic field that

spins the motor. The simplest DC motor is a single coil apparatus, used here to

discuss the DC motor theory. The process can be explained in further detail by

observing the diagram below.

The voltage source forces voltage through the coil via sliding contacts or

brushes that are connected to the DC source. These brushes are found on the end of

the coil wires and make a temporary electrical connection with the voltage source. In

this motor, the brushes will make a connection every 180 degrees and current will

then flow through the coil wires. At 0 degrees, the brushes are in contact with the

voltage source and current is flowing. The current that flows through wire segment

C-D interacts with the magnetic field that is present and the result is an upward force

on the segment. The current that flows through segment A-B has the same

17

interaction, but the force is in the downward direction. Both forces are of equal

magnitude, but in opposing directions since the direction of current flow in the

segments are reversed with respect to the magnetic field. At 180 degrees, the same

phenomenon occurs, but segment A-B is forced up and C-D is forced down. At 90

and 270-degrees, the brushes are not in contact with the voltage source and no force

is produced. In these two positions, the rotational kinetic energy of the motor keeps it

spinning until the brushes regain contact.

Figure 2.10 The parts of DC Motor

18

CHAPTER 3

METHODOLOGY

3.1 An Overview of Project Procedure

The methodology explains about the flowing chart in how to develop a

hovering system for a tandem rotor UH where the block diagram will show about the

controller operational of the hovering system.

Figure 3.1 Project procedure

19

Figure 3.1 shows the step of finishing this project. While doing the research

and literature review for this project, the important and relevant information can be

obtained by surfing internet, browsing books and also with the guidance from

supervisor in charge. Basically, the project will start with collecting the information

from internet or others references. With finding the literature review while gathering

more knowledge about the system is al about. Then do the designing circuit together

with the fabrication terms. After that, it goes on to testifying the project and if there

are no other problems occur we can proceed with the report writing.

Within this project, there are two important aspects to be implemented in

order to make sure this project success, theoretical aspect and practical aspect. The

theoretical part gives scientific knowledge as regards electronic-device model and

design-analysis technique. The practical part allows the student to gain more

understanding of the theoretical concept with develop a hardware.

Figure 3.2 Block diagram of Hovering System

In the block diagram in Figure 3.2, the flow of the operational operation for

hovering system will be determined. This system has been divided into three parts

which are input, output and the feedback part.

3.2 Working Environment

20

A hovering system for tandem rotor UH needs a minimum space of 1.5 meter

high and 1.5 meter wide and with no obstacles at the surrounding area. The most

important is the safe from the any electrical devices to prevent from the short circuit

from happen. Besides that, we use the room for the demo. Although there is no

worried about the weather condition unless we need to perform outside the room the

velocity of the wind must be considered because of that will effect the balanced of

the speed for the propeller of the tandem rotor UH.

3.3 Review of Previous Design

It is important to have a review on the past designs so that study can be done

on advantages and disadvantages of the designs and its shortcomings can be

improved. This will prevent the repetition of the same design process, and further

modifications can be made in order to make the new design become more effective

and interactive.

Table 3.1 Main Parts with the specification

Parts Specification

PIC Microcontroller PIC18F4550

Speed Sensor RE08A

DC Motor Driver Cytron MD30A

3.4 Design Characteristics

21

The design characteristic or features are based on rules and regulation that we

had been agreed before. Therefore, best design is necessary to optimize the system of

the hovering system for tandem rotor UH. Some of the designs criteria are show as

follow:

(i) PIC Microcontroller – PIC18F4550

In this system, PIC18F4550 type of microcontroller is use to control

the operation. The control circuit will determine the speed and the

direction of the motor. One of the received signals received from user

inputs will be a control reference. It will be fed into the PWM circuit

to generate an appropriate duty ratio. The control circuit also will

receive a direction/stop command from the user inputs. It will be fed

into the DC motor driver circuit in order to allow the motor to run or

stop.

(ii) 30A Motor Driver – Cytron MD30A

The 30A Motor Driver circuit will enable the motor to choose the

direction that it is supposing to be running and also to come to a

complete stop if that is what the user instructed. This circuit will

receive PWM signals as a input from the control circuit for the user

defined action. Cytron MD30A is designed to drive high current brush

motor or application. It is a full bridge motor driver intended for wide

range of robotics and automotive applications. The board incorporates

most of the components of the typical applications. With minimum

interface, the board is ready to be plugged and play. It even includes

two push buttons for fast test run. Simply add in power, this driver is

ready to drive high current motor.

22

(iii) DC Motor – 12V DC Motor

A 12V brushless dc motor had been used for this system. When the

coil is powered, a magnetic field is generated around the armature.

The left side of the armature is pushed away from the left magnet and

drawn toward the right, causing rotation. The armature continues to

rotate. When the armature becomes horizontally aligned, the

commutate reverses the direction of current through the coil, reversing

the magnetic field and the process then repeats.

(iv) Speed Sensor – RE08A

RE08A is a rotary encoder kit which comes with a slotted disc (8

slots) and a simple interface sensor board. This speed sensor is used to

measure the speed value of both motor and give the feedback to the

microcontroller in order to stabilize both speed values to the same

amount to get the stable hovering.

(v) Rechargeable Battery – LIP-11.1-2000

11.1 V LiPo Rechargeable Battery is a voltage supply to the whole

circuits. It’s provided the 2200mAh and it a high-polymer type of

battery and compare to others it’s come with the solid size and weight.

(vi) Voltage Regulator – L7805

This voltage regulator is regulated the voltage supply to the maximum

of output voltage 5.2V to provide to the sensitive integrate circuit

such as PIC18F4550 in order to make sure that devices is functioning.

23

3.5 Design System

In this design, two systems have been generated for future analysis where

there are programming system for PIC18F4550 Microcontroller and another one is

feedback or closed-loop system for the stabilizing both rotor for tandem rotor UH

where we use speed sensor as a feedback item. Both of the systems need to be

synchronized in order to make an effective hovering design.

3.5.1 PIC18F4550 Microcontroller Structure

To design a speed controller must be using a microcontroller as a brain to that

design. Microcontroller that we used is PIC18F4550. This type of devices offers the

advantages of all PIC18 microcontrollers where they are namely, high computational

performance at an economical price with the addition of high endurance, Enhanced

Flash program memory. In addition to this feature, the PIC18F4550 family

introduces design enhancements that make these microcontrollers a logical choice for

many high-performances, power sensitive applications.

Figure 3.3 Pin diagram of PIC18F4550

24

Other than that, PIC18F4550 have the other feature which a Phase Lock Loop

(PLL) frequency multiplier. It’s available to both the high-speed crystal and external

oscillator modes, which allows a wide range of clock speeds from 4 MHz to 48 MHz.

because of we need to make sure that the speed of rotor is high enough to flied the

UH so the very high frequency is needed for that.

Figure 3.4 Crystal or ceramic resonator operation (HT, HS or HSPLL

configuration)

By referring to Figure 3.4, in HS, HSPLL, XT and XTPLL Oscillator modes,

a crystal or ceramic resonator is connected to the OSC1 and OSC2 pins to establish

oscillation. It shows the pin connections. The oscillator design requires the use of a

parallel cut crystal.

Figure 3.5 PLL block diagram (HS mode)

25

In this project, crystal value of 8.0 MHz is used. Base to the table 2.2 at

Appendix A, it shows that the crystal frequency for 4 MHz, 8 MHz and 20 MHz are

on HS type. Figure 3.5 explain the internal circuit built in the PIC Microcontroller

about PLL for HS mode. The HSPLL, ECPLL and ECPIO modes make use of the

HS mode oscillator for frequencies up to 48 MHz. The prescaler divides the

oscillator input by up to 12 to produce the 4 MHz drive for the PLL. The XTPLL

mode can only use an input frequency if 4 MHz is used which is drives the PLL

directly.

1

PIC18 F4550

8 M H z

C R Y S TA L

14

3132

1211

5 VV C C

13

Figure 3.6 Basic schematic diagram for PIC18F4550

26

3.5.2 PIC18F4550 Microcontroller Programming

This program is used to generate the basic or the original frequency that

used for speed controller design, which also know as carrier frequency. In the other

hands, with this programming the feedback system of the tandem rotor UH is

functioning. The basic programming description for the PIC18F4550 Microcontroller

is used to control the speed rotation for the both rotor. So, if the speed sensors detect

the different value in both rotors then it will give feedback to the microcontroller to

make it stable again. In order to make the speed stable, the duty cycles in PWM is

used as a preference to adjust it.

Figure 3.7 Speed controller block diagram

The programming of the feedback system is referred to the speed

controller block diagram in Figure 3.7. When the speed sensor detect the different

value from both rotors it will give feedback to the microcontroller and the

microcontroller will analyzed the data and give the new output through CCP 1 and

CCP2 direct to the motor driver through to both DC motor.

27

Figure 3.8: Speed controller flow chart

Figure 3.8 Speed controller flow chart

To become more understand about the flow for PIC18F4550

programming, refer to the Figure 3.8. The first, the system will be set to the 65% of

duty cycles for both HPWM and process will continue by determining the speed for

speed at rotor 1 and speed at rotor 2 after that, the microcontroller will analyzed the

data weather speed at rotor 1 is equal with the speed at rotor 2 or not. If not, the

analyzed will continue in order to defined which one of the speed needed to be

increase or decrease by increasing or decreasing the duty cycle of the HPWM. The

full project programming can be seen in Appendix B.

28

3.5.3 Software Development

In order to interface the hardware with the electronic equipment, Melabs

EPICTM Programmer software is required. This programmer is a software program

that runs on a PC to develop applications for Microchip microcontrollers. Before

that we need to change the type of document by compiling it with the MicroCode

Studio. Below are the steps on how to develop the project using this software:

(i) Open the MicroCode Studio program

(ii) Compile the program

Figure 3.9 Programming of the system

Figure 3.9 shows the programming of the system after the

compilation is done. Before we do the compilation, we must save the

document and then we compile. The documentation type will change

to the .HEX after the compiling.

29

(iii) Open the Melabs EPICTM Programmer

Figure 3.10 Select for PIC18F4550

Open Melabs EPICTM Programmer then select for PIC18F4550

as shown as Figure 3.10. The melabs EPIC™ Programmer connects to

a PC compatible parallel printer port. The melabs Serial Programmer

connects to a PC compatible serial port. The melabs USB Programmer

and melabs U2 Programmer connect to a PC USB port or powered

USB hub. Each programmer may be controlled by the melabs

Programmer software.

(iv) Open melabs configuration

Figure 3.11 Setup for PLL

After the selection of the PIC type Figure 3.11 show the step

to setup the melabs configuration for PLL application. Seen the 8

MHz crystal is used and the HS mode oscillator for frequencies is up

to 48 MHz, the configuration must be fill correctly.

30

(v) Open the compile programming

Figure 3.12 Programming selected

Figure 3.12 show the step for selecting the programming that

had been saving in .HEX type documentation. This were done after

the deleting the entire previous program in the PIC.

(vi) Verify the Program

Figure 3.13 Verifying the program

Figure 3.13 shows the complete of verifying program and the

PIC18F4550 is ready to be used.

31

3.5.4 DC Motor Driver Structure

MD30A is designed to drive high current brush motor or application. It is a

full bridge motor driver intended for wide range of robotics and automotive

applications. The board incorporates most of the components of the typical

applications. With minimum interface, the board is ready to be plugged and play. It

even includes two push buttons for fast test run. Simply add in power, this driver is

ready to drive high current motor. It has been designed with capabilities and features

for:

(i) Support up to 30A maximum.

(ii) 5V logic level compatible inputs.

(iii) 5V to 12V compatible for Vcc.

(iv) PWM speed control up to 10 KHz.

(iv) Bi-directional control for 1 motor.

Figure 3.14 Connection to microcontroller and DC motor

The connection of the DC motor driver shows in Figure 3.14 above. For this

project, two DC motor drivers were use seen there are two rotors in this system that

need to be stabilized. It’s used to give the input to the motors. The output from this

DC motor driver is the pulse digital. So, it will act like switching in order to make the

rotor run discontinuously. Therefore, it can prevent the rotors running directly

because if that happen the load burden will increase and the rotors can get hot

speedily. See Appendix C for more information.

32

3.5.5 Speed Sensor Structure

RE08A is a rotary encoder kit which comes with a slotted disc (8 slots) and a

simple interface sensor board. Rotary encoder is a sensor or transducer used to

convert the data of rotary motion into a series of electrical pulses which is readable

by controller. The slotted disc has a 35mm outside diameter with 8 slots that provides

16 transitions. The optical sensor is used to sense the 16 transitions of the slotted

disc. With these transitions, controller is able to recognize the rotary angle of the

disc. With this concept, a rotary encoder can be employed in a DC motor shaft for

the controller to ‘know’ its current position.

Figure 3.15 Connection to microcontroller

By referring to the Figure 3.15 the circuit is simply connect such us the “+5”

and “Gnd” to 5V supply, further connect the “Sig” pin to microcontroller input pin.

Normally, the “Sig” will be connected to Counter/Clock/Encoder input for automatic

counting purpose. Output the speed sensor is in pulse form. For the slot disc

installation, in order to get the rotation output from rotating shaft, the slotted disc

must be placed within the space between optical sensors as shown in Figure 3.16

below.

33

Figure 3.16 Speed sensor and 8 slots disc installation

By follow the installation guide and configure microcontroller to count the

pulses generated when the shaft rotates. Please refer Appendix D for more

information.

3.5.6 Height Sensor Structure

The Honeywell HMC1051 family of magnetoresistive sensors is Wheatstone

bridge devices to measure magnetic fields. They are extremely sensitive, low field,

solid-state magnetic sensors designed to measure direction and magnitude of Earth’s

magnetic fields, from 120 micro-gauss to 6 gauss.

Figure 3.17 Height Sensor (HMC1051)

With power supply applied to a bridge, the sensor converts any incident

magnetic field in the sensitive direction to a differential voltage output. In addition to

34

the bridge circuit, the sensor has two on-chip magnetically coupled straps; the offset

strap and the set/reset strap. These straps are Honeywell patented features for

incident field adjustment and magnetic domain alignment; and eliminate the need for

external coils positioned around the sensors. Please refer Appendix E for more

information.

Figure 3.18 Pin Configuration of HMC1051

Honeywell HMC1051 has been designed with capabilities and features for:

(i) Miniature Surface-Mount Packages.

(ii) Low Voltage Operations (1.8V).

(iii) Low Cost.

(iv) 4-Element Wheatstone Bridge.

(v) Wide Magnetic Field Range (+/- 6 Oe).

35

Figure 3.19 Package Drawing of HMC1051

CHAPTER 4

RESULT AND DISCUSSIONS

36

4.1 PIC18F4550 Microcontroller Programming Analysis

For the PIC18F4550 programming, the PicBasic Pro Compiler (or PBP) it used. It

makes the programming even quicker and easier to program Microchip Technology’s

powerful PICmicro microcontrollers (MCUs). The English-like BASIC language is

much easier to read and write than the quirky Microchip assembly language. PBP has

over 80 commands. Some commands are similar to the PicBasic commands with

minor changes. Decisions were made that we hope improve the language overall.

4.1.1 PicBasic Pro Commands

COUNT command, “COUNT Pin, Period, Var”. This command is used to

count the number of pulses that occur on Pin during the Period and stores the result

in Var. Pin can take values 0 to 15 but the “Portname.number” format is

recommended (e.g. PORTB.0). The highest frequency that can be counted with

4MHz crystal clock is 25 kHz and 125 kHz when a 20 MHz clock is used.

HPWM command, “HPWM Channel, Dutycycle, Frequency”. Some PIC

microcontrollers have one or more built-in circuits to generate pulse width-

modulated square-wave signals (PWM). For example, PIC 16F877 has two PWM

Channels. Channel 1 is known as CCP1 (also PORTC.2) and Channel 2 is known as

CCP2 (also PORTC.1). Dutycycle can vary from 0 to 255 which corresponds to 0%

(low all the time) to 100% (high all the time), respectively. A value of 127 gives 50%

duty cycle. The highest Frequency is 32,767 Hz, and on microcontrollers with two

channels, the Frequency must be the same on both channels. The PWM signal output

from the specified pin continuously in the background while the program executes

other instructions.

IF..THEN..ELSE command, these commands are similar to the PicBasic IF..THEN

command but the PicBasic Pro language provides more flexibility when one or more

comparisons are made. These commands can be used in the following format:

Format 1:

37

IF Comparison [AND/OR Comparison…] THEN Label

Format 2:

IF Comparison [AND/OR Comparison…] THEN Statement….

Format 3:

IF Comparison [AND/OR Comparison…] THEN

Statement….

ELSE

Statement…

ENDIF

Figure 4.1 Output when duty cycle is 50% at CCP1 and CCP2

Figure 4.1 shows the output waveform at CCP1 and CCP2 in 50% of duty

cycles. Channel one is represent of CCP1 and Channel 2 is represent of CCP2.

4.1.2 Calculations

Using the results from the oscilloscope, the value of RPM can be calculated.

38

(4

.1)

(4.2)

From that calculation, the RPM value of 10% till 100% can be calculated and

had been list in the Table 4.1 and Table 4.2 below. When the speed sensor detect the

different value at the rotor, it will give feedback to the PIC18F4550 microcontroller

and the microcontroller will analyzed the data an make the duty cycle of both rotor

changes. This process continued until they get the same value of data. The process

can be fully understood by referring to the flow chart in Figure 3.8.

Table 4.1 RPM calculation value for speed at rotor 1

DUTY CYCLE PRM

0% 0

10% 741

20% 1482

30% 2223

40% 2964

50% 3705

60% 4446

70% 5187

39

80% 5928

90% 6669

100% 7411

Table 4.2 RPM calculation value for speed at rotor 2

DUTY CYCLE PRM

0% 0

10% 698

20% 1327

30% 2565

40% 3012

50% 3705

60% 4900

70% 5025

80% 6124

90% 6578

100% 7501

4.2 Circuitry Development Analysis

During the project, the most problematic part is when done the DC motor

driver circuit. It’s because of the heating problem that needs to be face. Before the

CYTRON MD30A is used there is other type of DC motor driver that already used.

40

Figure 4.2 Circuit of Hovering System for Tandem Rotor UH

4.2.1 DMOS Full Bridge Driver

While using the DMOS full bridge driver, both DC motors still can run but

it’s because without the load. The integrated circuit will get slowly hot and by adding

the propeller the integrated circuit become hot faster. Therefore this driver cannot

perform indepently. The device can be combined with a current regulator like the

L6506 to implement a transconductance amplifier for speed control .For more

information see Appendix E.

The I.C. is a full bridge driver for a motor control applications realized in

Multipower-BCD technology which combines isolated DMOS power transistors with

DMOS and Bipolar circuits on the same chip. Since the I.C. integrates full H-Bridge

in a single package it is ideally suited for DC motors.

41

Figure 4.3 Circuit of DMOS Full Bridge Driver

4.3 Final Result

The final result of this project is that the programming for the hovering

system for tandem rotor UH is functioning. It can be prove by the LED indicator in

the circuit. If the red LED is emitted then it shows that the speed at rotor 1 is higher

then the speed at rotor 2. When the yellow LED is emitted, its shows that the speed at

rotor 2 becomes much higher then speed at rotor 1. But when both rotors have a same

speed then the green LED will be emitting. However the unmanned helicopter still

cannot hover properly like the expected result before. Based on troubleshooting

process it found that there are few parts that make the hovering system for tandem

rotor UH hover stably is fail, there are:

(i) The type of DC motor driver.

Base on this part, the most chance that make the hovering

system fail is when the motor did not get the exact value of voltage

and current to run it. Other consideration is even the rotor cam still

run at no load there is no guarantee that they also can run with load.

By changing the push-pull four channel and MOSPEC TIP35 motor

driver this problem is successfully overcome.

42

(ii) Weight of the unmanned helicopter.

By looking at the model of unmanned helicopter itself, the

weight is also play the important rule. After finished the unmanned

helicopter prototype and done all the connection with the main circuit

nad motor, the overall weight is 830 gram. The component selecting

must be relevant to the system and they must have a light weight in

order to make the load of UH is reduces. Beside that, the usage of

tandem helicopter itself is very helpful in order to solve this problem.

Because one of the advantages of tandem rotor is they can stand more

weight then other type of rotor system.

(iii) Mechanical design.

The one part that cannot be recovered in this project is the

mechanical part of the prototype of UH. It must be considered about

the length, the size of component that has been used. After do the

troubleshooting the base where one side the rotor and the propeller

have been installed is not tough enough. That problem cause the

unmanned helicopter cannot lift properly and that part is also shaking

so the propeller condition is not in the stable and cannot hover.

Figure 4.4 Hovering System for tandem rotor UH

43

CHAPTER 5

CONCLUSION AND RECOMMENDATIONS

5.1 Conclusion

This project provides an automatic operation of stabilizing speed of two

rotors using the PIC18F4550 microcontroller program. In this project, there are two

important systems that must be developed. The first is the tandem rotor system where

the rotors must be rotate in the opposite direction in order to canceling each other

torque. So we must design the circuit that can make the rotors rotate oppositely. The

other system is the PIC18F4550 microcontroller system. The PIC need to be install

with the correct programming to make sure the system function exactly like we need.

The failure of the programming program will make the feedback system of tandem

rotor UH cannot be running. The usage of appropriate sensors is also important to

make sure the process runs smoothly. The more accurate the input signal goes into

the PIC microcontroller, the more efficient the operation will be. Wire tagging is also

important while doing this project. Each wire must be connected correctly since there

are a lot of wires used in this PIC18F4550 connection. The wires must be connected

with careful to prevent the risk of short circuit which can damage the electrical

component.

Finally, Hovering System for Tandem Rotor is not successfully done. All the

circuits, devices functions in a right manner. But, the result is just right side lift about

7 inches and the left side not lifts. So in the end, the unmanned helicopter cannot lift

properly because of the physical condition of the prototype needs to be improving in

the future in order to overcome the problems state before.

44

5.2 Future Recommendation

After we do the project troubleshooting, there are few recommendations that

have been introduced to make this more effective and interactive. In order to make

this system become efficient, height determination can be added on it. This devices

can track the exactly height that used need to hover this UH. This device will interact

with the feedback system in this project and the new PIC184550 programming will

be needed. Besides that, the mechanical part of the prototype of unmanned helicopter

must be change. From using board and polystyrene to plastic or Polyvinyl

chloride(PVC) that will reduce more weight on mechanical part of prototype of

unmanned helicopter.

By adding and manipulated unmanned helicopter, the application of the

tandem rotor also becoming more interesting such as a military survey mission with

addition camera on it or the UH can become a rescue helicopter at the very high

altitude. As the information, the human brain cannot functional at 100% at very high

altitude and high pressure. So the UH will become the effective solution to that

problem.

5.3 Costing and Commercialization

5.3.1 Costing

This part explains about the costing of this project. The total project cost for

all components is estimated to be RM 312.40. The highest cost is reflected in the

price of helicopter blade component and DC motor, this part actually cannot buy

separately because it’s come with a package. Even though the price of these

components is expensive, it is still a necessary item and the less expensive substitutes

are nonexistent. The component chosen based on the performance of the component,

45

means that the chosen component rating is above designed value. The table of

component cost is on Table 5.1.

Table 5.1: The cost of component

Device Manufacture Qty UnitUnit Cost(RM)

Extended Cost(RM)

Capacitor 50V 2 1uF 0.20 0.40Capacitor 50V 1 100uF 0.40 0.40Resistor 2 220Ω 0.20 0.40Resistor 2 4.7kΩ 0.30 0.60Led 1 0.50 0.50LM7805 Bay Linear 1 1.50 1.50Crystal 1 20MHz 5.00 5.00Toggle switch 1 1.50 1.50Strip board 2 2.00 4.00Heat sink (small) 1 1.50 1.50Connector 10 0.50 5.00jumper wire 2 1m 0.30 0.60PIC 18F4550 1 40.00 40.00DC motor (12V) 2

130.00 130.00Helicopter blade 2Driver motor (MD30A) 2 30.00 60.00Speed sensorLiPo battery 1 60.00 60.00IC Base 1 40 pin 1.00 1.00

TOTAL RM 312.40

5.3.1 Commercialization

The total project cost is RM 312.40. Even though the price is quite expensive

and it does not function very well, the price is still considered reasonable because of

we are using the dc motor 12V. Usually in the market, they are using dc motor up to

5V. Because of that the overall component need to change to the suitable component

in order to use dc motor 12V. The important components that need to change are

battery and driver motor.

46

So this project is not suitable to be commercialization, because of the price.

In order to reduce the price, we need to change the dc motor. After that we can use

the component in the market.

47

REFERENCE

[1] Article (26 July 2001) “Unmanned Helicopter Breakthrough”, Citing internet

sources URL http://www.scienceagogo.com/news/about.shtml

[2] Wikipedia “Unmanned Helicopter”,

http://www.answers.com/main/=unmanned+helicopter,

Accessed on 12th February 2008

[3] Helicopter Rescue. Citing internet source URL

http://www.gizmg.com/g/6793/

[4] Global security “Advanced Tandem Rotor Helicopter (ATRH)”, Citing

internet sources URL http://www.globalsecurity.org/military/

[5] Glen S. Bloom. The Helicopter Page. Citing internet sources URL

http://www.helicopterpage.com

[6] Dogan Ibrahim (2001). PIC Basic:Programming and Projects. Oxford, UK.

[7] Wikipedia “PIC Microcontroller”

http://en.wikipedia/wiki/PIC_Microcontroller,

Accessed on 25th March 2008

[8] Barr Michael “Closed-loop control Embedded system programming”, Citing

internet source URL http://netrino.com

48

[9] Mc Graw Hill Professional “Control System”,

http://www.answers.com/main/=control+system,

Accessed on 9th March 2008

[10] Pulse-width modulation (PWM). Citing internet source URL

http://www.tpub.com

[11] Pulse-width modulation (PWM) controller. Citing internet sources URL

http://www.cpemma.co.uk/pwm

[12] “Introduction to Pulse Width Modulation (PWM)”, Citing internet source

URL http://netrino.com

[13] Wikipedia “TandemRotor”,

http://www.answers.com/main/=tandem+rotor,

Accessed on 9th February 2008

[14] ELH Communications Ltd. (2004). Motor controlling. Citing internet sources

URL http://www.epanorama.net

[15] Wikipedia “DC Motor”, Citing internet sources URL

http://en.wikipedia.org/wiki/DC_motor

Accessed on 20th August 2008

[16] Theodore Wildi (sixth edition), Electrical Machines, Drives and Power

System, Pearson Prentice Hall.

[17] Tim Wilmshurst. “Designing Embedded Systems with PIC Microcontrollers

Principles and Applications” Newnes.

[18] DC motor. Citing internet sources URL

http://www.solarbotics.net/starting/200111_dcmotor/200111_dcmotor.html

Accessed on 20th August 2008

49

REFERENCE

[1] Article (26 July 2001) “Unmanned Helicopter Breakthrough”, Citing internet

sources URL http://www.scienceagogo.com/news/about.shtml

[2] Wikipedia “Unmanned Helicopter”,

http://www.answers.com/main/=unmanned+helicopter,

Accessed on 12th February 2008

[3] Helicopter Rescue. Citing internet source URL

http://www.gizmg.com/g/6793/

[4] Global security “Advanced Tandem Rotor Helicopter (ATRH)”, Citing

internet sources URL http://www.globalsecurity.org/military/

[5] Glen S. Bloom. The Helicopter Page. Citing internet sources URL

http://www.helicopterpage.com

[6] Dogan Ibrahim (2001). PIC Basic:Programming and Projects. Oxford, UK.

[7] Wikipedia “PIC Microcontroller”

http://en.wikipedia/wiki/PIC_Microcontroller,

Accessed on 25th March 2008

[8] Barr Michael “Closed-loop control Embedded system programming”, Citing

internet source URL http://netrino.com

50

[9] Mc Graw Hill Professional “Control System”,

http://www.answers.com/main/=control+system,

Accessed on 9th March 2008

[10] Pulse-width modulation (PWM). Citing internet source URL

http://www.tpub.com

[11] Pulse-width modulation (PWM) controller. Citing internet sources URL

http://www.cpemma.co.uk/pwm

[12] “Introduction to Pulse Width Modulation (PWM)”, Citing internet source

URL http://netrino.com

[13] Wikipedia “TandemRotor”,

http://www.answers.com/main/=tandem+rotor,

Accessed on 9th February 2008

[14] ELH Communications Ltd. (2004). Motor controlling. Citing internet sources

URL http://www.epanorama.net

[15] Wikipedia “DC Motor”, Citing internet sources URL

http://en.wikipedia.org/wiki/DC_motor

Accessed on 20th August 2008

[16] Theodore Wildi (sixth edition), Electrical Machines, Drives and Power

System, Pearson Prentice Hall.

[17] Tim Wilmshurst. “Designing Embedded Systems with PIC Microcontrollers

Principles and Applications” Newnes.

[18] DC motor. Citing internet sources URL

http://www.solarbotics.net/starting/200111_dcmotor/200111_dcmotor.html

Accessed on 20th August 2008

51

Appendix A

PIC18F4550 Datasheet

52

53

54

55

56

Appendix B

PIC18F4550 Project Programming

define osc 20 'Oscilator Speed in MHz

define ccp1_reg portc 'Motor HPWM Config

57

define ccp1_bit 2 'for right motordefine ccp2_reg portcdefine ccp2_bit 1 'for left motor

D1 var byteD2 var byteSPEED1 var byteSPEED2 var byteD1=166D2=166

HPWM 1, D1, 1000 '65% Duty CycleHPWM 2, D2, 1000 '65% Duty Cycle

trisb = %11111111

right_sensor var portb.0 'Speed Sensor Configleft_sensor var portb.1

MAIN:count portb.0,1000,SPEED1 'count Speed for Right Sensorcount portb.1,1000,SPEED2 'count Speed for Left Sensor

if SPEED1<SPEED2 thenD2=D2-1

ENDIF

IF SPEED1>SPEED2 thenD2=D2+1

endifgoto main

58

Appendix C

MD30A Motor Driver Datasheet

59

60

61

62

63

64

Appendix D

Speed Sensor Datasheet

65

66

67

68

Appendix E

Height Sensor Datasheet

69

70

71

72

73

Appendix F

DMOS Full Bridge Driver Datasheet

74

75

76

77

78