Personal Utility Vehicle Review

PERSONAL UTILITY VEHICLE
Department of Mechanical Engineering, Dr. AIT Page 1
1. INTRODUCTION
The ever-growing travel expenses associated with Single Occupancy Vehicles (SOV), in
terms of time, money, and emotional stress, created a need for better, easier, and
environmental friendly transportation modes. A wide range of responses to such needs have
emerged to the market in recent years such as, smaller and energy efficient cars, community
bound golf carts and electric cars in the motorized category and Inline skates, bicycles, and
scooters considered under the non-motorized category. Technologically advanced Segway
Human Transport is a new addition to the existing transportation modes, unveiled at the end
of year 2001. Since its introduction, Segway HT has caused a good stir in the transportation
community and general public. Therefore a number of transportation professionals and
advocates are carrying out the debate on why it should be treated as non-motorized device
and should it be operated on sidewalks.
As claimed by its developer and manufacturer, Segway HT is a self- balancing, personal
transportation device that’s designed to operate in any pedestrian environment. Segway
derived from the word “Segue” means “to transition smoothly from one state to another”.
Segway HT can travel three times faster than the average walker, empowering the pedestrian
with speed and a comfortable ride. Majority of people who have tried Segway HT, express
that Segway HT was easy to learn and to maneuver in the traffic.
The device is a combination of durable mechanical system controlled by electrical
system. As seen in the figure, the basic structure consists of handle bar, adjustable controlling
shaft and a standing platform. The entire unit balances intuitively on two wheels. The unit
moves forward if the rider leans forward, moves backwards if leaned backwards. Straighten
up to gently stop the device. With the slight twist of handles rider can maneuver to right or
left. The technology behind this is known as “Dynamic stabilization”. Segway HT equipped
with five specially designed gyroscopes and tilt sensors that detects the change in the rider’s
center of gravity one hundred times a second. Ten microprocessors in the controlling board
sends commands to powerful electric motors to keep the Segway HT balanced to provide a
smooth ride. To ensure safety and security of the riders, Segway makes use of redundant
sensors and electrical systems that share the load. If problem arises in any one system the
other maintains the balance and slows down before powering off. As claimed by the Segway
HT developers, the device balances are not affected by the travel velocities or loading factors.
That is, unit remains balanced whether traveling at its top speed, with full loading capacity, or

slowly maneuvering in crowded streets. As the very first Segway accident is reported in
Atlanta, which is discussed later in the paper, raise doubts about limitations to intuitive
balancing of the device. Segway HT operates in a wide range of environmental conditions.
Electronics and other components are sealed and protected and have been tested to with stand
vibrations, temperatures, and exposure to moisture. Segway HT is designed to ride on a
variety of terrains. With proper training and experience, it can be used wherever pedestrian
can walk. It can even maneuver on snow and ice with the addition of snow tires.
i series and e series Segway HT models are designed for commercial
purposes. These models are capable of traveling 11-17 miles on a single charge of Nickel
Metal Hydride (NiMH) battery. The standing platform is 19 x 25 inches with ground
clearance of 8 inches. The turning radius is zero, meaning the device can turn without
impacting the people nearby. Segway HT i series weigh 83 lbs and carry a person weighing
up to 250 lbs. The e series with a self-weight of 95 lbs can carry 75 lbs of cargo, addition to
250 lbs of passenger load. With the cargo carry bags attached, e series is designed to carry
cargo. The e series is equipped with an electronic stand, which keeps the unit balanced while
loading and unloading of cargo. The accessories can be customized to suit the commercial
needs.
Segway HT requires an intelligent key to start and to make mode selection such as- Learning
Mode, Sidewalk Mode, and Free Environment Mode, which will restrict the Segway HT
maximum speed to 6 mph, 9 mph and 12.5 mph respectively. With its unique 64-bit encoded
security ID, the device is protected against theft. Still the company recommends storing it in
a safe place, securing it to an immovable object. Cable and bicycle locks can be used for this
purpose.
Personal utility vehicle is a three wheeled battery powered vehicle. It is designed on
the idea of Segway, a two wheeled self-balancing vehicle. It is one of the low speed
transportation devices, used to travel on sidewalks, roadways etc. It is a clean and green
vehicle. The electric vehicles are a revolution in the field of green transportation. The
personal utility vehicle is both an effective and efficient device allowing the user to travel
further, faster and carry more than would be possible on foot. The device is simple,
technologically sound and easy to use when controlled in the correct manner.
The front wheel is a castor wheel and the rear wheels are driven by 2 DC motors
whose speed is controlled by a DC motor drive controller, an electronic device. The direction

is controlled by the handle attached to the front wheel. The motion is controlled by brake
mechanism.
The vehicle runs on flat surfaces, and the rider has to manage speed, maneuver the
device, pass a variety of objects and stop in response to environmental stimuli like people,
traffic, signals, curbs and obstructions such as poles , park benches etc.

2. LITERARY SURVEY
2.1 Batteries – Lead-acid batteries.
Fig 2.1 – Lead-Acid Battery
Specifications: Voltage - 12V
Current rating – 7.5 ampere hour/20 hour
Type - Lead acid
Dimensions- 5.94 L x 2.56 W x 3.7 H Inches
Lead-acid is the oldest rechargeable battery in existence. Invented by the French physician
Gaston Planté in 1859, lead-acid was the first rechargeable battery for commercial use. 150
years later, we still have no cost-effective alternatives for cars, wheelchairs, scooters, golf
carts and UPS systems. During the mid-1970s, researchers developed a maintenance-free
lead-acid battery that can operate in any position. The liquid electrolyte is gelled into
moistened separators and the enclosure is sealed. Safety valves allow venting during charge,
discharge and atmospheric pressure changes. Driven by different market needs, two lead-acid
systems emerged: The small sealed lead-acid (SLA), also known under the brand name of
Gel cell, and the larger Valve-regulated-lead-acid (VRLA). Both batteries are similar.
Finding the ideal charge voltage limit is critical. A high voltage (above 2.40V/cell) produces
good battery performance but shortens the service life due to grid corrosion on the positive
plate. A low voltage limit is subject to salvation on the negative plate. Leaving the battery on
float charge for a prolonged time does not cause damage.

Table 2.1- Lead-Acid Battery Characteristics
The optimum operating temperature for the lead-acid battery is 25*C (77*F). Elevated
temperature reduces longevity. As a guideline, every 8°C (15°F) rise in temperature cuts the
battery life in half. A VRLA, which would last for 10 years at 25°C (77°F), would only be
good for 5 years if operated at 33°C (92°F). The same battery would desist after 2½ years if
kept at a constant desert temperature of 41°C (106°F). The sealed lead-acid battery is rated at
a 5-hour (0.2) and 20-hour (0.05C) discharge. Longer discharge times produce higher
capacity readings because of lower losses. The lead-acid performs well on high load currents.
Lead-Acid battery is used as the power source for the PUV. Two 12V-DC
batteries are used in PUV. The batteries are connected in series. Battery supplies power to the
motors to drive the wheels. The batteries are rechargeable. Charging a lead acid battery is
simple but the correct voltage limits must be observed.
Overcharging with high charging voltages generates oxygen and hydrogen gas by electrolysis
of water, which is lost to the cell. Periodic maintenance of lead-acid batteries requires
inspection of the electrolyte level and replacement of any water that has been lost. Due to
the freezing-point depression of the electrolyte, as the battery discharges and the
concentration of sulfuric acid decreases, the electrolyte is more likely to freeze during winter
weather when discharged.
The advantages of using Lead-Acid batteries are
 Inexpensive.
 Mature, reliable and well-understood technology - when used correctly, lead-acid
is durable and provides dependable service.
 The self-discharge is among the lowest of rechargeable battery systems.
 Capable of high discharge rates.
Type Voltage Regulation Initial Current
Stand by use 13.5 - 13.8 Less than 2.6A
Cycle use 14.4 - 15 Less than 2.6A

2.2 Motors – 12V DC motors.
Fig 2.2- DC Motor
Specifications: Speed - 1500 RPM
Power - 0.2 HP
Voltage - 12V
A DC motor is any of a class of electrical machines that converts direct current electrical
power into mechanical power. The most common types rely on the forces produced by
magnetic fields.
Nearly all types of DC motors have some internal mechanism, either electromechanical or
electronic; to periodically change the direction of current flow in part of the motor. Most
types produce rotary motion; a linear motor directly produces force and motion in a straight
line. C motors were the first type widely used, since they could be powered from existing
direct-current lighting power distribution systems. A DC motor's speed can be controlled over
a wide range, using either a variable supply voltage or by changing the strength of current in
its field windings. Small DC motors are used in tools, toys, and appliances. Larger DC
motors are used in propulsion of electric vehicles, elevator and hoists, or in drives for steel
rolling mills.

Motors are fixed to the chassis through screwed bolt and it is the main source of
power which is to drive the vehicle. There are two motors, each for one wheel. Each motor is
driven by a separate 12v battery.
2.3Wheels.
Wheels are basic components of Personal Utility Vehicle for the motion of vehicle. Two
types of wheels are used in front end and rear end of PUV.
Quantity - 3
Front wheel - Castor wheel (1)
Rear wheels – Rubber wheels (2)
2.3.1 Rear Wheels.
Fig 2.3.1 - Rear wheel
Wheels are attached to motor spindle through bearings. It is driven by 12V DC motors. Two
Rubber wheels with bearings are used as rear end wheels.

2.3.2 Castor Wheel.
Fig 2.3.2 - Castor Wheel
Castor wheel is the front end wheel that passes through the chassis and is attached to PUV
handle. It is the guiding wheel and is used by rider to control the direction of vehicle.
2.4 Wooden box for assembly and support.
Fig 2.4 – Wooden Box
Wood used - Jungle wood
Capacity - up to 150 kg’s

Dimensions: Length - 425 mm
Width - 575 mm
Height - 275 mm
Chassis is made of wooden block and four wooden blocks are used to make the frame. To
make chassis to be balanced, four wooden blocks of equal weights are used. Jungle Wood is
the material used. It is engaged firmly with the help of stud. Stud is to connect the wooden
block together with the nut. Slots are provided in wooden box for two batteries and at rear
end two motors are fixed. At front end hole is provided for vehicle handle.
2.5 Handle for maneuvering the vehicle.
Fig 2.5 - Handle
PUV handle is made of mild steel of length 120cm and is cut to form a T joint. T joint is
formed by arc welding of two mild steel. Handle passes through the hole provided in front
end of wooden box and is connected to castor wheel. Handle is detachable as it is connected
to castor wheel through threaded nut. Brake for controlling the speed is attached to handle at
top, same as cycle brake.

2.6 Rim Braking System.
Rim brakes are so called because braking force is applied by friction pads to the rim of the
rotating wheel, thus slowing it and the bicycle. Brake pads can be made of leather, rubber or
cork and are mounted in metal "shoes". Rim brakes are typically actuated by the rider
squeezing a lever mounted on the handlebar.
Rim brakes are inexpensive, light, mechanically simple, easy to maintain, and powerful.
However, they perform relatively poorly when the rims are wet. This problem is less serious
with rims made of aluminium than on those with carbon fiber, steel or chromed rims.
Because the rims can carry debris from the ground to the brake pads, rim brakes are more
prone to clogging with mud or snow than disc brakes (where both braking surfaces are high
off the ground), particularly when riding on unpaved surfaces. The low price and ease of
maintenance of rim brakes makes them popular in low- to mid-price commuter bikes, where
the disadvantages are greatly alleviated by the unchallenging conditions. The light weight of
rim brakes also makes them desirable in road racing bicycles.
Rim brakes require regular maintenance. Brake pads wear down and have to be replaced.
Over longer time and use, rims become worn. Rims should be checked for wear periodically
as they can fail catastrophically if the braking surface becomes too worn. Wear is accelerated
by wet and muddy conditions. Some types of rim brake, e.g. dual pivot, require that the rim
be relatively straight; if the rim has a pronounced wobble, then either the brake pads rub
against it when the brakes are released, or apply insufficient or uneven pressure to the rim.
Fig 2.6 - Rim Brake

2.7 ELECTRONIC DC MOTOR SPEED CONTROLLER
Fig 2.7(a) – DC Motor Speed Controller
SPECIFICATIONS:
Power requirement: 10-50VDC
Rated current: 40A（Maximum output current）
Frequency: 12000HZ
Control Motor Power: 0.01-2000W,
12V:480W (max), 24V:960W (max)
36V:1440W (max), 50V:2000W (max)
Regulation range: 5-100%
PCB Size: 90x51mm (inch: 3.5"x2")
Plastic Case size: 105x55x40mm (inch:4"x2.2"x1.6")
Weight: 130g

DC motor speed controller is used to vary the speed of the DC motors by turning the
potentiometer knob. Since gear boxes are costly, the electronic component being less costlier
helps in easy regulation of the speed. The speed is varied by the method of pulse width
modulation (PWM). This type of controllers are used in electric scooters, golf buggies etc.
Fig 2.7(b) - Connection Details
The terminals of the motors and batteries are connected to the DC motor control drive. Just
turning the knob one can control the speed of the motors.
2.7.1 Individual Components of DC Motor Speed Controller
The DC motor speed controller circuit has different components. They are as follows
1)NE555 Timer IC
The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation,
and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and
as a flip-flop element. Derivatives provide up to four timing circuits in one package. The
NE555 is s monolithic timing circuit and is highly stable controller capable of producing
accurate time delays or oscillation. In the time delay mode of operation, the time is precisely
controlled by one external resistor and capacitor. For a stable operation as an oscillator, the
free running frequency and the duty cycle are both accurately controlled with two external
resistors and one capacitor.

Modes-
The IC 555 has three operating modes:
Monostable mode: In this mode, the 555 functions as a"one-shot" pulse generator.
Applications include timers, missing pulse detection, bounce free switches, and touch
switches, frequency divider, capacitance measurement, pulse-width modulation (PWM) and
so on.
Astable (free-running) mode: The 555 can operate as an oscillator. Uses include LED and
lamp flashers, pulse generation, logic clocks, tone generation, security alarms, pulse position
modulation and so on. The 555 can be used as a simple ADC, converting an analog value to
a pulse length.
Bistable mode or Schmitt trigger: The 555 can operate as a flip-flop, if the DIS pin is not
connected and no capacitor is used. Uses include bounce-free latched switches.
Fig 2.7.1(a) – NE555 Timer IC
Key features:
 Low turn-off time
 Maximum operating frequency greater than 500 kHz
 Timing from microseconds to hours
 Operates in both astable and monostable modes
 Output can source or sink up to 200 mA
 Adjustable duty cycle
 TTL compatible
 Temperature stability of 0.005% per °C

The pin diagram and the functions of the pins are as follows:
Fig 2.7.1(b) - Pin diagram NE555
PIN NAME PURPOSE
1 GND Ground reference voltage, low level (0 V)
2 TRIG
The OUT pin goes high and a timing interval starts when this input falls
below 1/2 of CTRL voltage .
3 OUT This output is driven to approximately 1.7 V below +VCC, or to GND.
4 RESET
A timing interval may be reset by driving this input to GND, but the
timing does not begin again until RESET rises above approximately 0.7
volts
5 CTRL
Provides "control" access to the internal voltage divider (by default, 2/3
VCC).
6 THR
The timing (OUT high) interval ends when the voltage at THR
("threshold") is greater than that at CTRL
7 DIS
Open collector output which may discharge a capacitor between
intervals. In phase with output.
8 VCC
Positive supply voltage, which is usually between 3 and 15 V depending
on the variation.
Table 2.7.1(a) - NE555 Pin Details

2)MOSFET
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET)
is a type of transistor used for amplifying or switching electronic signals.
Fig 2.7.1(c)- MOSFET
Although the MOSFET is a four-terminal device with source (S), gate (G), drain (D), and
body (B) terminals, the body (or substrate) of the MOSFET is often connected to the source
terminal, making it a three-terminal device like other field-effect transistors. Because these
two terminals are normally connected to each other (short-circuited) internally, only three
terminals appear in electrical diagrams. The MOSFET is by far the most common transistor
in both digital and analog circuits, though the bipolar junction transistor was at one time
much more common.
The main advantage of a MOSFET over a regular transistor is that it requires very little
current to turn on (less than 1mA), while delivering a much higher current to a load (10 to
50A or more). However, the MOSFET requires a higher gate voltage (3-4V) to turn on.
In enhancement mode MOSFETs, a voltage drop across the oxide induces a
conducting channel between the source and drain contacts via the field effect. The term
"enhancement mode" refers to the increase of conductivity with increase in oxide field that
adds carriers to the channel, also referred to as the inversion layer. The channel can contain
electrons (called an nMOSFET or nMOS), or holes (called a pMOSFET or pMOS ), opposite
in type to the substrate, so nMOS is made with a p-type substrate, and pMOS with an n-type
substrate (see article on semiconductor devices).
In the less common depletion mode MOSFET, detailed later on, the channel consists of
carriers in a surface impurity layer of opposite type to the substrate, and conductivity is
decreased by application of a field that depletes carriers from this surface layer.

The "metal" in the name MOSFET is now often a misnomer because the previously
metal gate material is now often a layer of polysilicon (polycrystalline silicon). Aluminum
had been the gate material until the mid-1970s, when polysilicon became dominant, due to its
capability to form self-aligned gates. Metallic gates are regaining popularity, since it is
difficult to increase the speed of operation of transistors without metal gates.
Likewise, the "oxide" in the name can be a misnomer, as different dielectric
materials are used with the aim of obtaining strong channels with smaller applied voltages.
3) Heat Sink
In electronic systems, a heat sink is a passive heat exchanger that cools a device by
dissipating heat into the surrounding medium. In computers, heat sinks are used to cool
central processing units or graphics processors. Heat sinks are used with high-power
semiconductor devices such as power transistors and optoelectronics such as lasers and light
emitting diodes (LEDs), where the heat dissipation ability of the basic device is insufficient
to moderate its temperature.
Fig 2.7.1(d) - Heat Sink
A heat sink is designed to maximize its surface area in contact with the cooling medium
surrounding it, such as the air. Air velocity, choice of material, protrusion design and surface
treatment are factors that affect the performance of a heat sink. Heat sink attachment methods
and thermal interface materials also affect the die temperature of the integrated circuit.
Thermal adhesive or thermal grease improve the heat sink's performance by filling air gaps
between the heat sink and the heat spreader on the device. The most common heat sink
materials are aluminium alloys. Aluminium alloy 1050A has one of the higher thermal
conductivity values at 229 W/m•K but is mechanically soft. Aluminium alloys 6061 and 6063

are commonly used, with thermal conductivity values of 166 and 201 W/m•K, respectively.
The values depend on the temper of the alloy.
4) Potentiometer
The DC motor speed controller consists of a 50K potentiometer. A potentiometer, informally
a pot, is a three-terminal resistor with a sliding or rotating contact that forms an adjustable
voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable
resistor or rheostat.
Fig 2.7.1(e) – Potentiometer
The measuring instrument called a potentiometer is essentially a voltage divider used for
measuring electric potential (voltage); the component is an implementation of the same
principle, hence its name.
Potentiometers are commonly used to control electrical devices such as volume
controls on audio equipment. Potentiometers operated by a mechanism can be used as
position transducers, for example, in a joystick. Potentiometers are rarely used to directly
control significant power (more than a watt), since the power dissipated in the potentiometer
would be comparable to the power in the controlled load.

3. PROBLEM DEFINITION
Vehicular pollution has grown at an alarming rate due to growing urbanization. The air
pollution from vehicles in urban areas, particularly in big cities, has become a serious
problem. The pollution from vehicles has begun to tell through symptoms like cough,
headache, nausea, irritation of eyes, various bronchial and visibility problems. The other
factors of vehicular pollution in the urban areas are 2-stroke engines, poor fuel quality, old
vehicles, inadequate maintenance, congested traffic, poor road condition and old automotive
technologies and traffic management system.
Not only air pollution, noise pollution is also a major problem. In the city, the main sources
of traffic noise are the motors and exhaust system of autos, smaller trucks, buses, and
motorcycles. This type of noise can be augmented by narrow streets and tall buildings, which
produce a canyon in which traffic noise reverberate.
Fuel prices have risen; there is a greater awareness of the damage caused by carbon
dioxide and other greenhouse gas emissions and environmental and political forces have de-
stabilized the global petroleum supply. The PUV can help reduce dependence on foreign oil,
use the existing energy supply more efficiently, and reduce pollution. The PUV helps to
reduce the pollution by cutting down the oil usage, and by using the existing energy sources
more efficiently. The PUV do not produce any emission during the operation except for the
recharging of the batteries during which heat emission takes place.

4. MODELLING AND IMPLEMENTATION
4.1 Motor Control Using PWM
Pulse Width Modulation (PWM) uses digital signals to control power applications, as well as
being fairly easy to convert back to analog with a minimum of hardware. Analog systems,
such as linear power supplies, tend to generate a lot of heat since they are basically variable
resistors carrying a lot of current. Digital systems don't generally generate as much heat.
Almost all the heat generated by a switching device is during the transition (which is done
quickly), while the device is neither on nor off, but in between. This is because power follows
the following formula:
P = E I, or Watts = Voltage X Current
If either voltage or current is near zero then power will be near zero. PWM takes full
advantage of this fact.
PWM can have many of the characteristics of an analog control system, in that the digital
signal can be freewheeling. PWM does not have to capture data, although there are
exceptions to this with higher end controllers.
There are many different ways to control the speed of motors but one very simple and easy
way is to use Pulse Width Modulation. But before we start looking at the ins and outs of
pulse width modulation we need to understand a about how a DC motor works.
Next to stepper motors, the Permanent Magnet DC Motor (PMDC) is the most commonly
used type of small direct current motor available producing a continuous rotational speed that
can be easily controlled. Small DC motors ideal for use in applications were speed control is
required such as in small toys, models, robots and other such Electronics Circuits.
A DC motor consists basically of two parts, the stationary body of the motor called the
“Stator” and the inner part which rotates producing the movement called the “Rotor”. For
D.C. machines the rotor is commonly termed the “Armature”.
Generally in small light duty DC motors the stator consists of a pair of fixed permanent
magnets producing a uniform and stationary magnetic flux inside the motor giving these
types of motors their name of “permanent-magnet direct-current” (PMDC) motors.
The motors armature consists of individual electrical coils connected together in a circular
configuration around its metallic body producing a North-Pole then a South-Pole then a
North-Pole etc., type of field system configuration.
The current flowing within these rotor coils producing the necessary electromagnetic field.
The circular magnetic field produced by the armatures windings produces both north and

south poles around the armature which are repelled or attracted by the stator’s permanent
magnets producing rotational movement around the motors central axis as shown.
Fig 4.1(a) - DC Motor Working
As the armature rotates electrical current is passed from the motors terminals to the next set
of armature windings via carbon brushes located around the commutator producing another
magnetic field and each time the armature rotates a new set of armature windings are
energized forcing the armature to rotate more and more and so on.
So the rotational speed of a DC motor depends upon the interaction between two magnetic
fields, one set up by the stator’s stationary permanent magnets and the other by the armatures
rotating electromagnets and by controlling this interaction we can control the speed of
rotation.
The magnetic field produced by the stator’s permanent magnets is fixed and therefore cannot
be changed but if we change the strength of the armatures electromagnetic field by
controlling the current flowing through the windings more or less magnetic flux will be
produced resulting in a stronger or weaker interaction and therefore a faster or slower speed.
Then the rotational speed of a DC motor (N) is proportional to the back emf (Vb) of the
motor divided by the magnetic flux (which for a permanent magnet is a constant) times and
electromechanical constant depending upon the nature of the armatures windings (Ke) giving
us the equation of: N ∝ V/Keϕ.
One simple and easy way to control the speed of a motor is to regulate the amount of
voltage across its terminals and this can be achieved using “Pulse Width Modulation” or
PWM.

As its name suggests, pulse width modulation speed control works by driving the motor with
a series of “ON-OFF” pulses and varying the duty cycle, the fraction of time that the output
voltage is “ON” compared to when it is “OFF”, of the pulses while keeping the frequency
constant. The power applied to the motor can be controlled by varying the width of these
applied pulses and thereby varying the average DC voltage applied to the motors terminals.
By changing or modulating the timing of these pulses the speed of the motor can be
controlled, ie, the longer the pulse is “ON”, the faster the motor will rotate and likewise, the
shorter the pulse is “ON” the slower the motor will rotate. In other words, the wider the pulse
width, the more average voltage applied to the motor terminals, the stronger the magnetic
flux inside the armature windings and the faster the motor will rotate and this is shown
below.
Fig 4.1(b) - PWM
The use of pulse width modulation to control a motor has the advantage in that the power loss
in the switching transistor is small because the transistor is either fully “ON” or fully “OFF”.
As a result the switching transistor has a much reduced power dissipation giving it a linear
type of control which results in better speed stability.

4.2 MODELLING
The modelling of the PUV is done using the modelling software CATIA.
Fig 4.2(a) - Wooden box with motors and wheels
Fig 4.2(b) - Model of PUV

5. SYSTEM ASSEMBLY AND TESTING
5.1 System Assembly
1. The motors are fixed at the back end of the chassis facing opposite.
2. Motor shaft is fitted to the wheel for free rotation of wheels.
3. Castor wheel is fixed at the front end of the wooden chassis.
4. Batteries are connected in series and then are connected to the motors.
5. Handle is fitted in the front side of the chassis.
6. Mechanical brakes are attached to handle at top.
Fig 5.1(a) – CATIA Model of System Assembly

Fig 5.1(b) - PUV Assembly
5.2 Testing
After the system assembly, the system is tested for various properties.
1. Speed - The speed of the vehicle is found to be varying from 6-10 kmph. It is also
found that the speed of the vehicle depends on the weight of the rider.
2. Torque - Initially the vehicle requires some external torque, later the vehicle runs
smoothly.
3. Load - The vehicle carries an average load of 60kgs and on increasing the load the
speed of the vehicle may vary and higher torque is expected to be given at the
beginning.
4. Battery life - The vehicle runs with greater speeds when the battery is in fully charged
state. As the battery drains the speed of the vehicle decreases. And the battery life is
about 30 minutes.

5.3 Advantages
 A clean, green, eco-friendly machine (zero emission).
 Low operating costs: no need for gas and inexpensive battery charging (A complete
cycle charge will take eight to ten hours)
 More work can be done by using the product VS walking.
 Reduces fatigue caused by walking.
 Can be developed further for higher end applications.
 Simplicity in building.
5.4 Disadvantages
 The distance travelled by the vehicle and the speeds may vary with weight of the
rider.
 Slow, having a max speed varying between 6 to 10 kmph.
 Ground clearance is less.
 Does not exactly say how far the Segway will go with riders of different masses.
 Unlike bicycles, a drained Segway cannot be pedaled home or a charge.

6. OPPORTUNITIES FOR TRANSPORTATION
IMPROVEMENT
People from rural surroundings are drawn to urban developments for better social and
economic opportunities. However when population density increases, the urban problems
associated with higher population densities are multifold. A few easily identifiable examples
include congested roads and sidewalks, increased pollution, and reduced open spaces. A Part
of these problems can be explained by the massive pavement and vast size of parking lots and
garages in the urban areas. SOVs certainly created large expenses for urban dwellers along
with the comfort and convenience it brought to its users. Therefore, this section will address
the potential opportunities created by introduction of Personal Utility Vehicle as a potential
transportation mode to improve efficiency of transportation systems.
6.1 Relieve Congestion
Cities and traffic have developed hand-in-hand since the earliest large human settlements.
The same forces that draw inhabitants to congregate in large urban areas also lead to
sometimes intolerable levels of traffic congestion on urban streets and thoroughfares.
Effective urban governance requires a careful balancing between the benefits of
agglomeration and the disadvantages of excessive congestion. Road traffic congestion poses a
challenge for all large and growing urban areas. Congestion involves queuing, slower speeds
and increased travel times, which impose costs on the economy and generate multiple
impacts on urban regions and their inhabitants. Congestion also has a range of indirect
impacts including the marginal environmental and resource impacts of congestion, impacts
on quality of life, stress, and safety as well as impacts on non-vehicular road space users such
as the users of sidewalks and road frontage properties.
On the other hand, the Personal Utility Vehicle only needs a lane width of 3
to 4 feet at the most. Taking into consideration of the lower speed of the vehicle, lanes can be
created for PUV’s and PUV’s could be used for short distance travelling which not only
reduces the traffic but also helps in cutting down pollution.

6.2 Reduce Gasoline Consumption and Air Pollution
Emission from the vehicles is the primary cause of air pollution throughout the nation. In
urban streets where vehicles are turned on and off a number of times, the pollution is more
compared to highways with higher speeds. This is because of cold start, a large amount of
pollutants are released when the automobiles are started and traveling at lower speeds than at
higher speeds. Carbon monoxide, hydrocarbons, nitrogen oxides and particulate matters are
major pollutants as a result of, improper fuel combustion and evaporation. Air toxics
produced by mobile sources, are suspected to cause serious health problems. Carbon dioxide,
methane and nitrous oxide are greenhouse gases contributing to global warming. It is
estimated that some 7 million premature deaths may be attributed to air pollution. India has
the highest death rate due to air pollution. India also has more deaths from asthma than any
other nation according to the World Health Organization. In December 2013 air pollution was
estimated to kill 500,000 people in China each year. There is a correlation between
pneumonia-related deaths and air pollution from motor vehicles.
Air pollution is estimated to reduce life expectancy by almost nine months across the
European Union. Causes of deaths include strokes, heart disease, COPD, lung cancer, and
lung infections.
The average trip speed on many Indian city roads is less than 20 kilometers per hour;
a 10 kilometer trip can take 30 minutes, or more. At such speeds, vehicles in India emit air
pollutants 4 to 8 times more than they would with less traffic congestion; Indian vehicles also
consume a lot more carbon footprint fuel per trip, than they would if the traffic congestion
was less. Emissions of particles and heavy metals increase over time because the growth of
the fleet and mileage outpaces the efforts to curb emissions.
Petrol is getting really ridiculously expensive these days and scientists say that if we don't
do something to reduce carbon emissions within 5 years, permanent climatic change would
have taken place. Gasoline is an extinguishable natural resource and its conservation is
essential. From the above paragraph it is clear that vehicles with low speed cause a lot of
emission. Instead of using bikes and cars for short trip purposes PUV can be used.

6.3 Increase Productivity
Personal Utility Vehicles increases the productivity in the sense more work can be done or
more load can be carried using the vehicle than by walk. It also saves a lot of time. PUVs can
be implemented in the fields where walking is mostly involved like
 Postal Service
 National Park Service
 Street Patrolling
 Distribution Centers etc.
Just like the Segway’s are already in use for the above purposes in the US, PUV
being cheaper than a Segway can also be used for the above purposes with some
technological improvisation,
6.4 Create Livable Communities
The planning and design of communities over the past decades precluded other options or
made them so inconvenient that few people walk, ride bike, or take public transportation. The
automobiles have negatively impacted even existing communities and older neighborhood
that had once been walkable and well served by mass transportation. Cars are required rather
than optional. While many people find convenient to drive cars to run mundane errands, but
often find themselves waiting in traffic jam. The automobile has its clear advantages in terms
of flexibility and comfort. In contrast, most transit systems have been operating on rigid
routes and schedules and limited geographic overages. For reasons of economic practicality,
some destinations simply can’t be served or serviced as frequently as others. A small number
of hardcore cyclists or roller-skaters may insist on using non-motorized modes. Limited or
non- existing dedicated non-motorized traffic lanes often make it unsafe for those riders.
If PUV is well accepted and adapted by the urban communities, congestion on
roads can be relieved greatly. Noise and air pollution can be reduced. The boundaries
between residential and commercial districts will fade, as people will start moving to multi-
use neighborhoods, leading to compact urban land use form.
6.5 As a Link in Intermodal Transportation
In the urban and sub urban areas with extensive mass transportation, accessibility from the
neighboring areas to the facility if often neglected. People who have to use transit for long
commute often have to drive from home to the transit station. Therefore the transit provider
usually will have to bear the construction and maintenance of parking lots or decks adjacent
to the stations.

PUV can be a link in intermodal transportation by substituting these auto trips. Trains and
buses should be able to accommodate these units on board for the convenience of the
passengers. Further PUV rental stations can be provided close to the transit so that people can
easily rent and drop off at convenient locations near their destination.

7. CHALLENGES TO TRANSPORTATION SYSTEMS
It is certain numerous opportunities for PUV can be pointed out. However, it is also clear that
a large number of obstacles are lying ahead before PUV gain wide acceptance by general
public and transportation professional. Therefore, it is also imperative to point out a few
challenges created by such a device.
7.1 The Cost
PUV is very cheap when compared to Segway which costs more than a car in India. The cost
involved in fabricating the vehicle and the cost of the components involved in it are as shown
in the table below
COMPONENT QUANTITY COST( in Rupees)
DC Motor 2 5000
Lead-Acid Batteries 2 1500
Braking System 1 220
Wooden Box 1 2500
Wheels 3 1200
DC Motor Speed Controller 1 1000
Handle 1 300
Miscellaneous 600
Total 12,320
Table 7.1 (a) Cost Involved
PUV doesn’t involve the use of gyroscope which helps in reducing the cost to a great extent
compared to that of a Segway. Exclusion of the gyroscopic unit also decreases the effort of
programming. So a common user can also repair or service the vehicle when needed without
the help of a technician.

7.2 Charging the batteries
Anything above 2.15 volts per cell will charge a lead acid battery; this is the voltage of the
basic chemistry. This also means than nothing below 2.15 volts per cell will do any charging
(12.9V for a 12V battery) However, most of the time a higher voltage is used because it
forces the charging reaction at a higher rate. Charging at the minimum voltage will take a
long time. As you increase the voltage to get faster charging, the voltage to avoid is the
gassing voltage, which limits how high the voltage can go before undesirable chemical
reactions take place. The typical charging voltage is between 2.15 volts per cell (12.9 volts
for a 6 cell battery) and 2.35 volts per cell (14.1 volts for a 6 cell battery). These voltages are
appropriate to apply to a fully charged battery without overcharging or damage. If the battery
is not fully charged you can use much higher voltages without damage because the charging
reaction takes precedence over any over-charge chemical reactions until the battery is fully
charged. This is why a battery charger can operate at 14.4 to 15 volts during the bulk-charge
phase of the charge cycle.
Since the batteries are placed inside the wooden box, in order to avoid removing the
batteries again and again for charging, batteries are connected in series and two wires are
extended outside the box to which the connectors of the charger can be connected and the
charged.

8. CONCLUSION
The technology behind PUV operation is new and innovative. The PUV can transport a
person and some cargo with less electricity consumption. The range and speed is appropriate
for a short travel trip. Transportation planners can look at this as a possible link in intermodal
system of transportation to promote mass transportation. Use of such vehicles is viewed as an
opportunity in congestion management of urban roadways. Environmental benefits are
expected to follow, when congested roads are relieved.
Challenges to transportation system by PUV are important, as this involves safety of
PUV users as well as pedestrians sharing the sidewalks. Sidewalks shared by different age
groups with various activity and reaction levels are at a greater risk. Segway, which is three
times faster than a walker, increases the conflicts between pedestrians and Segway users.
Increased number of community advocates and doctors are concerned about the safety issues.
The requirements such as pavement condition, type are not know for smooth operation of
PUV. How PUV technology can negotiate pot- holes and uneven surfaces are causes of
concern.
After examining the PUV technology and related uses of non-motorized transportations, it is
believed that a long term solution is to establish dedicated non-motorized lanes in urban
environment, which will promote more energy efficient and environment friendly travel
means.

9. APPLICATIONS AND FUTURE ENHANCEMENTS
 It is used in industries to move from one place to other.
 It can be used in law enforcement/security purposes.
 Helps military staff in various roles to travel throughout large bases and vast facilities
quickly.
 It can be used for Robotics Mobility Platform.
 It can be used even by consumers for campus use.
 PUV racing can be organized.
 Elevates the visibility, responsiveness and productivity of critical staff.
 By using high capacity motors it can carry more loads.
 By using high capacity batteries large distance can be travelled.
 Attaching a seat, the vehicle can be used by the physically disabled.

10. REFERENCES
1) Reinventing the wheel: A story of genius, innovation and grand ambition by Steven
Kemper.
2) Cervero.R, Walk and ride, factors influencing pedestrian access to transit journal of
public transportation.
3) Segway TM, Potential opportunities and challenges for human transportation systems
by Ron fang Liu, Rohini Parthasarathy.
4) Role of Segway Personal Transporter in emission reduction and energy efficiency by
John David Heinzmann and B. Michael Taylor, Segway Inc.
5) Design and fabrication of failsafe Segway transporter by M Thompson, J.Beula
Juliette Mary.

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