International Journal of Advance Foundation And Research In Science & Engineering (IJAFRSE)

Volume 1, Special Issue , Vivruti 2015. Impact Factor: 1.036, Science Central Value: 26.54

Design Of Segway Personal Transporter

Sadhana Pai, Jayesh Yadav, Rupesh Ramane, Pooja Pangare, Aniket Paranjpe
Department of Electronics And Telecommunication
FR.C.Rodrigues Institute Of Technology, Vashi
sadhana_pai@rediffmail.com, jayeshyadav.0123@rediffmail.com, pooja.pangare@gmail.com,
rupesh.r.ramane@gmail.com, aparanjpe93@gmail.com

ABSTRACT

This paper describes the design and fabrication of Segway personal transporter. The Segway is
based on the principle of inverted pendulum that will keep an angle of Zero degrees with vertical
at all times. The Segway is an intelligent vehicle which uses gyroscopic sensors detect the motion
of rider, so that he can accelerate, brake or steer the vehicle. This Segway is absolutely eco-
friendly mode of transport which causes zero pollution.

Index Terms : fabrication, gyroscopic, inverted pendulum, Segway

I. INTRODUCTION

The Segway was introduced in the year 2001 by Dean Kamen. It is commercially manufactured by
Segway Inc. of New Hampshire, USA [1]. This paper describes the design and fabrication of Segway using
gyroscopic sensors, Arduino-UnoR3 development board and battery powered electric motors. The
design which we have come with will cost the Segway around 20,000 as compared to original Segway
which costs around 3 lakhs plus tax, thus making the product cost effective [2].
The Segway PT is a two-wheeled, self-balancing, battery-powered electric vehicle. The self-balancing
Principle of the Segway is as shown in
the Fig.1(a).

The balancing action of segway is as explained below fig. 1(b). in this Diagram A, on the left show that the
rider standing, with gravity and the Segway reaction force in balance. In diagram B the rider has leaned
forward to start moving. The purple arrow is gravity/weight .The magenta arrow is the reaction force of
rider against the Segway. The dashed blue line is the vector sum of the two. If the Segway doesn’t
respond rider will fall forward as the Segway is pushed backward. Diagram C shows the response of the
Segway as it sense the tilt of the Segway platform as rider leaned forward. The computers order the
motors to power the wheels and accelerate the Segway. The force of acceleration is the red arrow, and

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 International Journal of Advance Foundation And Research In Science & Engineering (IJAFRSE)
Volume 1, Special Issue , Vivruti 2015. Impact Factor: 1.036, Science Central Value: 26.54

the reaction force of the Segway to rider is the orange arrow. The dashed yellow line is the vector sum of
the two forces. Diagram D shows that the sum of the forces in diagrams B and C are in balance. The vector
sums run through each other and the rider, so there are no unbalanced forces or torque. The onboard
computers adjust the power to the wheels to keep the forces balanced through the rider. This how the
Segway balances itself out. Fig.1(b) shows balancing of Segway at different conditions that are
accelerating, cruising (constant velocity) and decelerating [3].

II. BLOCK DIAGRAM

Power Arduino GY521

Supply Board Module

Motor
Driver D.C.
Motors

Figure 2. Control System Block Diagram

A. Arduino board
The Arduino Uno is a microcontroller board based on the ATmega328 . It has 14 digital input/output
pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB
connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support
the microcontroller.

B. GY521 module
The triple-axis MEMS gyroscope in the MPU-60X0 includes a wide range of features: Digital-output X , Y
and Z Axis angular rate sensors (gyroscopes) with a user-programmable full scale range of ±250, ±500,
±1000, and ±2000°/sec. this angular rate sensor performs the task for the Segway.

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 International Journal of Advance Foundation And Research In Science & Engineering (IJAFRSE)
Volume 1, Special Issue , Vivruti 2015. Impact Factor: 1.036, Science Central Value: 26.54

C. Motor Driver
The Saber tooth 2X25 is one of the most versatile, efficient and easy to use dual motor drivers on the
market. It is suitable for high powered robots - up to 100lbs in combat or 300lbs for general purpose
robotics. Out of the box, the Saber tooth can supply two DC brushed motors with up to 25A each. Peak
currents of 50A per channel are achievable for a few seconds.
D. DC Motor
Motor is fixed with the chassis through screwed bolts and it is the main source of power to drive the
vehicle. There are two motors, each for one wheel. The motors are driven by two 12 V batteries arranged
in series. The maximum torque provided by the motor is 18kgf-m Approx.

E. Power Supply

The power supply for the Segway is two 12v dc motors connected in series to give 24V dc to source
16.5A current require to drive the motor.

III. DESIGN CONSIDERATION

A. Torque Calculations
Maximum weight of rider = 80 kg
Chassis weight including batteries = 40 kg
Therefore, Total weight=120 kg (approx.)
Coefficient of friction between road and tyre = 0.3
Torque required = Friction Force * Radius Of Wheel
T = 120*0.3*25cm
T = 9 kgf-m (Approx.)
As two motor are used. Therefore torque required by each motor = 4.5 kgf –m(Approx.)

B. 2D Representation Of Segway Chassis

Top view
Side view

C. Circuit Diagram

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 International Journal of Advance Foundation And Research In Science & Engineering (IJAFRSE)
Volume 1, Special Issue , Vivruti 2015. Impact Factor: 1.036, Science Central Value: 26.54

Figure 3(A). Control System Circuit Diagram

The basic circuit diagram is as shown in above fig.3(a). It consists of 2 switches used for controlling the
operation of Segway named as engage switch & kill switch[4]. Series connected 12v batteries provides
24v supply & a constant current source. One of the pot out of these two is used to adjust the gain &
potentiometer is used to control the steer/direction values.

D. Specifications of Components in control system

Table1. Specifications of Arduino Uno R3[5]

Microcontroller ATmega328
Operating Voltage 5V
Input Voltage (recommended) 7-12V
Input Voltage (limits) 6-20V
Digital I/O Pins 14 (of which 6 provide PWM output)
Analog Input Pins 6
DC Current per I/O Pin 40 mA
DC Current for 3.3V Pin 50 Ma
Flash Memory 32 KB (ATmega328) of which 0.5 KB used by bootloader
SRAM 2 KB (ATmega328)
EEPROM 1 KB (ATmega328)
Clock Speed 16 MHz

Table2. Specifications of GY521 MPU6050

VDD = 2.375V-3.46V,
VLOGIC (MPU-6050 only) 1.8V±5%
, TA (Ambient temperature) 25°C
Gyroscope operating current 3.6mA
Standby current 5µA

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 International Journal of Advance Foundation And Research In Science & Engineering (IJAFRSE)
Volume 1, Special Issue , Vivruti 2015. Impact Factor: 1.036, Science Central Value: 26.54

Figure 3(b). Orientation of axis of rotation & polarity of rotation

IV. MECHANICAL SYSTEM

Figure 4(a). Mechanical structure

The mechanical system shown in fig.4(a) comprises of base plate, handle and wheels. The best suitable
material for base plate is iron due to its high strength. As a very high load acting on base plate, we use
angle plates to avoid bending. For handle we use 1 inch diameter steel pipe. The pipe is threaded to form
a ‘T’ joint. When the rider tilts forward the platform along with the handle tilts forward. The motors are
bolted to the base plate from bottom. For transmitting the torque produced by motor to wheels we have
designed coupling. It is made up of MS rod with chain sprockets. This design will help to improve the
torque of the motors. In this we have made cycle like structure by using bearing, Rod & sprockets. The
batteries are mounted on the platform and control circuit below platform and rider is ready to ride.

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 International Journal of Advance Foundation And Research In Science & Engineering (IJAFRSE)
Volume 1, Special Issue , Vivruti 2015. Impact Factor: 1.036, Science Central Value: 26.54

V. LOGICAL PROGRAM FLOW

Figure 5. logical program flow

VI. RESULT

We have completed the fabrication and testing of the gyroscope. The interfacing of gyroscope has been
done to read raw values of various tilt angles & accelerometer values at various positions. Position of the
gyroscope is used to determine speed & direction of the Segway.

VII. CONCLUSION

We will be Programming the arduino board as per the logical flow given above so that at the last we can
see that segway can be manufactured at a very low cost.

VI. REFERENCES

[1] http://en.wikipedia.org/wiki/Segway_PT , December,2014 .

[2] M Thompson, J.Beula Julietta Mary,“Design and fabrication of fail safe segway,” International
Journal of Mechanical and Industrial Technology, vol. 2, no. 1, pp. 767-782,April 2014.

[3] Brian G.R. Hughes, “The Unique Physics of the Segway PT Balanced at All Times”, May 30,2009.

[4] http://www.instructables.com/id/Rideable-Segway-Clone-Low-Cost-and-
EasyBuild/,December,2014

[5] http://arduino.cc/en/Main/arduinoBoardUno
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