The document describes a project to build a 6 degree of freedom (DOF) robotic arm. A group of 3 students are building the robotic arm under the supervision of Engr. Hamza Shahid. The project aims to accurately control the movement of the robotic arm using servo motors on all six axes. The objectives are to study object picking and placing, build the mechanical structure, develop a functional gripper, and accurately control motion. An Arduino microcontroller will initially be used to control axis movement with the potential for an FPGA to incorporate more sensors later. Progress so far includes literature review, acquiring the mechanical structure, selecting servo motors, and achieving single axis movement with Arduino code. Future work includes completing the arm, coding

1. Department of Electrical Engineering
Controller of 6 DOF Robotic Arm
Group Members:
Muhammad Shahram Arshad (400541)
Muhammad Nabeel(400406)
Aitazaz Ahsan(400405)
Supervisor:
Engr. Hamza Shahid

2. Department of Electrical Engineering
Problem Statement
 The foremost task of the project is to accurately control the movement of the robotic
arm using servo motors on all six axis.
 Low cost and light weight robot capable of executing many industrial and personal
applications and having many numerous possibilities.
 Construction of small scaled 6 DOF robotic.

3. Aims & Objectives
Objectives of the Project are as follows
 Study the concept of picking and placing of an object utilizing 6 axis robotic arm.
 Procurement the mechanical structure of the robot.
 Achieve a functional gripper.
 Accurately control the motion of the robotic arm.
 Make an interface between the programming of robotic arm and the sensors.
 Make the robot capable of stopping at the desired location.
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4. Literature Study / Data
Collection
 We read paper regarding the feedback mechanism of servo control using open loop system and
closed loop system.
 Advantages of closed loop are that angular position can be controlled precisely, but the feedback
of actual position can also be obtained during the system operation. The voltage feedback which
comes from the built-in potentiometer is accurate enough to represent the actual angular position
of the motor.
 We also came across a project of 6 DOF robotic arm that was implemented on FPGA
 Project focused on the build of a multipurpose robotic arm which can perform operations with
higher accuracy with 6 degrees of freedom.
 Arm exhibited higher speed of operation and lower delay in processing due to the use of FPGA for
processing and control.
 Improved the speed of operation and reduced the latency of response when used for applications
such as bionic arm when compared to present methods.
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5. Methodology
 Understanding mechanical design of the robotic arm.
 Accruing the mechanical structure.
 Suitable controller for the control of servo motors.
 Selection of the right servo motors.
 Development of end effector.
 Axis movement utilizing Arduino (current objectives are achievable by Arduino)
 Use of FPGA for incorporation of more sensors.
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6. Proposed Design Block Diagram
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7. Mechanical Structure
Types of mechanical structures that are available today are as follows
1. Joint arm
 Resembles human arm
 Very Flexible and accurate
 Ability to reach over obstructions and achieve and positon
 Applications include paint spraying, arc and spot welding, machine tending etc
2. SCARA (Selective Compliance Articulated Robot Arm)
 Designed for peg board type of assembly
 heavily used in the electronics industry.
 Stiff in the vertical direction
 Fairly small in size and capable of operating at high speeds.
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8. Mechanical Structure
3. Cartesian co-ordinate robotic arm
 High Rigidity
 Less flexible
 Very Accurate and Flexible
 Often seen in machine tools and measuring machines
4. Cylindrical co-ordinate robotic arm
 Very similar to the Cartesian co-ordinate robots
 Robots have good rigidity
 Good for jobs requiring straight line moves
 Disadvantage of these robots is their inability to reach around objects.
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9. Mechanical Structure
 Joint arm was selected for our robotic arm because
( Resembles human arm, highly flexible and has ability to reach over objects)
 Problems faced in designing and constructing such mechanical structure were
 High cost, less accuracy due to play in the structure.
 Mechanical structure was ordered by a third party having similar design as required.
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10. Servo Motors
 Servo motors are generally an assembly of four things: a DC motor, a gearing set, a
control circuit and a position-sensor (usually a potentiometer).
 They usually have three wires (power, ground & control).
 Servo motor works on PWM (Pulse width modulation) principle, means its angle of
rotation is controlled by the duration of applied pulse to its Control PIN.
 Some servos have an additional wire which for analog feedback.
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11. Servo Motors
Servo motors used in our robotic arm are (KS3620)
KS-3620 digital servo parameters are:
 Torque (4.8V) 12.0kg/cm
 Torque (6.6V) 15.0kg/cm
 Speed: 0.07 seconds (4.8V) ¦ 0.06 seconds (6.0V)
 Operating voltage: 4.8v 6.6v DC voltage
 Weight: 55g
 Bearing Type: Ball Bearing × 2
 Motor type: strong magnetic high speed motor
 Gear type: copper and aluminum
 Working temperature: -20°C-60°C
 Working frequency: 500µs/2500hz
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12. Controller
 Various controllers have been implemented to control 6 DOF robotic arm
 Our objectives can be achieved using Arduino microcontroller.
 FPGA can be incorporated to add more sensors to the robotic arm.
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13. Controllers
Hardware Features of the Arduino:
 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 of which 0.5 KB used by bootloader
 SRAM: 2 KB (ATmega328)
 EEPROM: 1 KB (ATmega328)
 Clock Speed: 16 MHz
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14. Controller
Key Features of FPGA Mojo V3:
 Spartan 6 XC6SLX9 FPGA
 84 digital IO pins
 8 analog inputs
 8 general purpose LEDs
 1 reset button
 1 LED to show when the FPGA is correctly configured
 On board voltage regulation that can handle 4.8V - 12V
 A microcontroller (ATmega32U4) used for configuring the FPGA, USB
communications, and reading the analog pins
 On board flash memory to store the FPGA configuration file
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15. Open Loop System
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 Servo motor has a control unit inside the servo motor casing.
 It works on closed loop feedback mechanism inside servo.
 Over all system with servo motors and controller is open loop system.
 Feedback is in the form of a potentiometer (pot) connected to the output shaft of the
motor which is fed to the control unit of servo. The output of the pot is proportional to
the position of the servo shaft.
 Controller with the servo motors forms the open loop system.

16. Object Gripper
For the gripping of an object we using the claw gripper.
 Problem faced by the gripper are
 Feedback of servo its self.
 Inability to achieve angle while holding the object.
 Negative feedback causes servo to achieve the angle.
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17. Limiting Switch on Gripper
 Limiting on the gripper can solve the problem
 When the grippers hold an object and the limiting switch is closed
 It will provide an electrical signal to the controller.
 Which will tell controller to stop sending PWM signal to servo motor.
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18. Progress of Project
 Literature Review of the project.
 Accruing the mechanical structure and problems faced.
 Working of servo motors.
 Achieved the movement of axis using Arduino.
 Coding using Arduino.
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19. Future Work
 Complete working of the robotic arm.
 Coding algorithms for the simultaneous movement of axis.
 Achieve the accurate picking and placing of the object.
 Development of the accurate end effector.
 Incorporation of sensors for pick and place detection.
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20. Cost
Equipment Price
1. Mechanical Structure Rs.15320
2. Servo Motors Rs.16680
3. Arduino UNO Rs.550
4. Arduino Sensor Shield v5.0 Rs.300
5.MOJO V3 (FPGA) Rs.5500
Total Rs.38350
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21. Gantt Chart
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22. References
 [1] A S Sadun, J Jalani, J A Sukor "ARPN: A comparative study on the position control method of dc servo motor
with position feedback by using Arduino,” (ARPN), vol. 11, no. 18, pp. 10955, September 2016.

 [2] D Shri Lakshmi Pravalika and Dr. Alex Noel Joseph Raj " IJIET: FPGA based robotic arm with six degree of
freedon” International Journal of Innovations in Engineering and Technology, vol. 2, no. 1, pp. 2319-1058,
February 2013.
 [4] Agus Bejo, Wanchalerm Pora and Hiroaki Kunieda, “Development of a 6-axis robotic arm controller
implemented on a low-cost microcontroller,” in 2009 6th International Conference on Electrical
Engineering/Electronics, Computer, Telecommunications and Information Technology, Pattaya, Chonburi,
Thailand, 2009, pp. 772-776.
 [5] Electronics Hub available at https://www.electronicshub.org/raspberry-pi-vs-arduino
 [6] Adafruit (analog feedback) available at https://learn.adafruit.com/analog-feedback-servos/about-servos-and-
feedback
 [7] FPGA vs Microcontrollers available at https://electronics.stackexchange.com/questions/4382/fpgas-vs-
microcontrollers
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23. Thank you
Any Questions ?
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