Design and operation of synchronized robotic arm

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 02 Issue: 08 | Aug-2013, Available @ http://www.ijret.org 297
DESIGN AND OPERATION OF SYNCHRONIZED ROBOTIC ARM
Goldy Katal1
, Saahil Gupta2
, Shitij Kakkar3
1
Student, Electrical and Electronics Department, Maharaja Agrasen Institute of Technology, Delhi, India,
2, 3
Student, Electrical and Electronics Department, HMR Institute of Technology, Delhi, India,
katal.goldy@gmail.com, saahilgpt005@gmail.com, shitijkakkar91@gmail.com
Abstract
The paper manuscript deals with the designing and implementation of Synchronized Robotic Arm, which is used to perform all the
basic activities like picking up objects and placing them. In this paper, a robotic arm is designed, synchronized with the working arm
and would perform the task as the working arm does. The work done by the robotic arm would be highly precise, as a digital servo
motor is used. A servo motor of 230 oz-inch is used in the project, but motors with more capacity can also be used as according to the
desired work. This robotic arm can also be used for precision works. For instance some work has to be done very precisely but the
conditions do not suit human beings. In such conditions, this robotic arm can be used remotely and the task can be accomplished. The
programming is done on ATMEGA-8 Microcontroller using Arduino programming. The potentiometers are also used to detect the
angle of rotation and the signals are then sent to the microcontroller. In today’s world, this Robotic arm has turned out very
benevolent. Besides Robotics and Automation, these kinds of arms have applications in other fields also.
Keywords –Arduino, ATMEGA-8, IC, Potentiometers, Servo Motors
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1. INTRODUCTION
A Robot is a virtually intelligent agent capable of carrying out
tasks robotically with the help of some supervision.
Practically, a robot is basically an electro-mechanical machine
that is guided by means of computer and electronic
programming. Robots can be classified as autonomous, semi-
autonomous and remotely controlled[6].Robots are widely
used for variety of tasks such as service stations, cleaning
drains ,and in tasks that are considered too dangerous to be
performed by humans. A robotic arm is a robotic manipulator,
usually programmable, with similar functions to a human arm
.This Robotic arm is programmable in nature and it can be
manipulated. The robotic arm is also sometimes referred to as
anthropomorphic as it is very similar to that of a human hand.
Humans today do all the tasks involved in the manufacturing
industry by themselves. However, a Robotic arm can be used
for various tasks such as welding, drilling, spraying and many
more[1].A self sufficient robotic arm is fabricated by using
components like micro-controllers and motors. This increases
their speed of operation and reduces the complexity. It also
brings about an increase in productivity which makes it easy
to shift to hazardous materials. In the implementation process,
the necessary components of structure ICs, blocks and power
supply are all assembled on the PCB[9].The main part of the
design is ATMEGA-8 micro-controller which coordinates and
controls the product’s action. This specific micro controller is
used in various types of embedded applications. Robotics
involves elements of mechanical and electrical engineering, as
well as control theory, computing and now artificial
intelligence. According to the Robot Institute of America, “A
robot is a reprogrammable, multifunctional manipulator
designed to move materials, parts, tools or specialized devices
through variable programmed motions for the performance of
a variety of tasks [9].The robots interact with their
environment, which is an important objective in the
development of robots[8]. This interaction is commonly
established by means of some sort of arm and gripping device
or end effectors. In the robotic arm, the arm has a few joints,
similar to a human arm, in addition to shoulder, elbow, and
wrist, coupled with the finger joints; there are many joints [7].
The design process is clearly explained in the next section
with detailed information regarding the components which are
used, followed by the implementation leading to results and
finally ends with conclusion.
2. DESIGN OF ROBOTIC ARM
The Robotic Arm is designed using the Microcontroller i.e.
ATMEGA8 Micro-controller using Arduino programming.
This process works on the principle of interfacing servos and
potentiometers. This task is achieved by using Arduino board.
Potentiometers play an important role The remote is fitted
with potentiometers and the servos are attached to the body of
the robotic arm. The potentiometer converts the mechanical
motion into electrical motion. Hence, on the motion of the
remote the potentiometers produce the electrical pulses, which
are en route for the arduino board. The board then processes
the signals received from the potentiometers and finally,
converts them into requisite digital pulses that are then sent to
the servomotors. This servo will respond with regards to the
pulses which results in the moment of the arm [5].

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Figure 1 shows the image of a servo motor. It consists of a
motor which is coupled to a sensor, used for position
feedback, through a reduction gearbox. It also accompanies
a relatively sophisticated controller, usually a dedicated
module designed specifically for use with servomotors In
short, the micro controller interfaces all these components
specified below. A short list of components include
1. Servo motors
2. Potentiometers
3. ATMEGA 8
4. Figure 1 shows the image of a servo motor. It consists of a
motor which is coupled to a sensor, used for position
feedback, through a reduction gearbox. It also accompanies
a relatively sophisticated controller, usually a dedicated
module designed specifically for use with servomotors
In short, the micro controller interfaces all these components
specified below. A short list of components include
1. Servo motors
2. Potentiometers
3. ATMEGA 8
4. Arduino Deumilanove
2.1 Circuit Diagram
Fig 1: Circuit Diagram of a Robotic Arm
2.2 Servo motors
Servo refers to an error sensing feedback control which is used
to correct the performance of a system. Servo or RC Servo
Motors are DC motors equipped with a servo mechanism for
precise control of angular position. The RC servo motors
usually have a rotation limit from 90° to 180°. But servos do
not rotate continually. Their rotation is restricted in between
the fixed angles. A servomotor is a motor, which forms part of
a servomechanism.[12]
Fig 2: A Servo Motor
The Servos are used for precision positioning. They are used
in robotic arms and legs, sensor scanners and in RC toys like
RC helicopter, airplanes and cars. The specifications for
Servomotor used are as follows:
 Weight- 55g
 Dimension- 40.7*19.7*42.9mm
 Stall torque- 10kg/cm
 Operating speed- 0.20sec/60degree(4.8v)
 Operating voltage 4.8-7.2V.
 Temperature range 0-55 degrees.
Fig 3: Block diagram of a Servo Motor
2.3 Potentiometers
A Potentiometer (pot for shot) is a variable resistor. The two
output terminals act as a fixed resistor. A movable contact
called a wiper (or a slider) moves across the resistor,
producing a variable resistance between the centre terminals
and the two sides[12].A potentiometer is basically a voltage
divider which is used for the measurement of electric
potential. Potentiometers are commonly used to control
electrical devices such as volume controls on audio
equipment. Potentiometers which are operated by a
mechanism can also be used as position transducer.

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Fig 3: A Potentiometer
A potentiometer is a manually adjustable electrical resistor
that uses three terminals. In many electrical devices,
potentiometers are establishes the levels of output. For
example, in case of a loudspeaker, a potentiometer is used to
adjust the volume or taken the case of a television set,
computer monitor or light dimmer; it can be used to control
the brightness of the screen or light bulb.
Fig 5: Circuit Diagram of a Potentiometer
2.4 Arduino Deumilanove
Arduino is a single-board microcontroller (accepted open
source), successor of the open-source wiring platform which is
designed to devise the process of using electronics in
multidisciplinary functions [10].
Fig 6: An Arduino Deumilanove
Arduino board consists of the following parts :
 USB connector
 Power connector
 Automatic power switch
 Digital pins
 Analog pins
 Power pins
 Reset switch
3. OPERATION PROCESS
3.1 Working Principle
The working principle can be understood from the figure 7.If
we want the robotic device to undertake a given task, then it is
important to control it and it should also possess the capability
of sending specific orders to the manipulator which has to be
carried out in terms of positions or velocities of its final
effectors [2]. Secondly, it should be able to sense the real
obtained position or velocity. There are many other sensing
capabilities that may be pivotal depending on the application.
Therefore, in order to implement a control algorithm for the
manipulator to solve a particular task, it is mandatory to
control its basic functions which include moving and sensing,
which further leads to the development of a software platform
[3]. Basically, a robotic manipulator and sensors
manufacturers provides a set of functions to interface with the
low level features of robots and sensors. Now these functions
are needed to be integrated within the full software
applications which are then used to solve a particular task.

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Fig 7: Complete Circuit Block Diagram
3.2 ATMEGA8 Micro-controller
ATmega8 is a AVR 8-BIT Microcontroller featuring In-
system Programmable capability along with Flash code
storage. This micro-controller is re-programmable up to 1000
times. It also features 32 working registers, single clock cycle
execution giving up to 1MIPs/MHz
Fig 8: ATMEGA 8
The key features of ATMEGA8 are :
 8K BYTES of In-System Programmable Flash
 512 Bytes EEPROM, Endurance: 100,000
Write/Erase Cycles
 Two 8-bit Timer/Counters with Separate Prescaler,
one Compare Mode
 Analog Comparator
 One 16-bit Timer/Counter with Separate Prescaler,
Compare Mode, and Capture Mode
 Real Time Counter with Separate Oscillator
 6-channel ADC -Four Channels 10-bit Accuracy and
Two Channels 8-bit Accuracy
 Programmable Serial USART
 External and Internal Interrupt Sources
 23 Programmable I/O Lines
 4.5 to 5.5V operation
The low-power Atmel 8-bit AVR RISC-based microcontroller
consists of 8KB of programmable flash memory, 1KB of
SRAM, 512K EEPROM, and a 6 or 8 channel 10-bit A/D
converter. The device supports throughput of 16 MIPS at 16
MHz and operates between 2.7-5.5volts.
Fig 9: Schematic view of Atmel AVR
4. APPLICATIONS OF ROBOTIC ARM
 The robotic arm can be designed to perform any desired
task such as welding, gripping, spinning etc., depending
on the application. For example robot arms in
automotive assembly line perform a variety of tasks
such as wielding and parts rotation and placement
during assembly.
 In space the space shuttle Remote Manipulator System
have multi degree of freedom robotic arms that have
been used to perform a variety of tasks such as
inspections of the Space Shuttle using a specially
deployed boom with cameras and sensors attached at
the end effectors.
 The robot arms can be autonomous or controlled
manually and can be used to perform a variety of tasks
with great accuracy. The robotic arm can be fixed or
mobile (i.e. wheeled) and can be designed for industrial
or home applications. Robotic hands often have built-in
pressure sensors that tell the computer how hard the
robot is gripping a particular object. This keeps the
robot from dropping or breaking whatever it's carrying.

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Other end effectors include blowtorches, drills and
spray painters. this improves their performance.
 In medical science: "Neuroarm" uses miniaturized tools
such as laser scalpels with pinpoint accuracy and it can
also perform soft tissue manipulation, needle insertion,
suturing, and cauterization.
Fig 10: A Robotic Arm
5. FUTURE WORK
The future scope of Robotic Arm is commendable. It will
involve patients who are paralyzed from down the neck can
manipulate robotic arms with their thoughts. It will be able to
direct a mechanical arm to pick up a bottle of coffee and bring
it to her lips. It was the first time she'd been able to drink
without assistance in nearly 15 years. There will be a thriving
need for the Robotic arm in military, industrial and many
more.
REFERENCES
[1] C. F. Olson, Lab. JP, Technol. CIo, Pasadena,
“Probabilistic self localization for mobile robots”; IEEE
Transactions on Robotics and Automation 16,1, 55-66, 2000.
[2] R.B. Gillespie, J. E. Colgate, M. A. Peshkin, “A general
framework for robot control”; IEEE Transactions on Robotics
and Automation, 17,4, 391-401, 2001.
[3] Devendra P. Garg and Manish Kumar, “Optimization
Techniques applied to multiple manipulators for path planning
and torque minimization”; Engineering Applications of
Artificial Intelligence 15, 3-4, 241-252, 2002.
[4] J. C. Trinkle and R. James Milgram, “Complete Path
Planning for Closed Kinematics Chains with Spherical Joints”;
SAGE International Journal of Robotic Research 21, 9, 773-
789, 2002.
[5] M. Gemeinder and M. Gerke, “GA-based Path Planning
for Mobile Robot Systems employing an active Search
Algorithm”; Journal of Applied Soft Computing 3, 2, 149-158,
2003. [2]. “Six-servo Robot Arm” from www.arexx.com.cn on
13-11-2011 pg: 1-18
[6]. Jegede Olawale, Awodele Oludele, Ajayi Ayodele,
“Development of a Microcontroller Based Robotic Arm”, in
Proceedings of the 2007 Computer Science and IT Education
Conference pg: 549-557.
[7]. “Six-servo Robot Arm” from www.arexx.com.cn on 13-
11-2011.
[8]. “Robotic Arm” - www. NASA explores. com
[9]. “Robot software” from Wikipedia, the free encyclopedia
on 04-3-2012
[10]. “ATMEL – short notes”, www.atmel.com
[11]. “Arduino MCU”, - www.arduino.com
[12]. “Servomotors & system design components”, -
www.bhashaelectronics. Com

Design and operation of synchronized robotic arm

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Design and operation of synchronized robotic arm