Library Management Robot

Library Management Robot

Design and Fabrication

Mayank Pathak

Mechanical Department

Medicap Institute of Technology and Management, Indore, India

Surbhi Kanthed Computer Science Department Ujjain Engineering College,

Ujjain, India

Manish Pandit Mechanical Department

Medicaps Institute of Technology and Management, Indore, India

Rohit Sanvaliya

Mechanical Department

Medicaps Institute of Technology and Management, Indore, India

Abstract Robots are used for various purposes in day-to- day life. With ever growing technology and competition there is a desire for doing work in less time, also considering economy in the equation. Keeping this into consideration this project aims at minimizing the efforts required to arrange books in a library. A library generally consists of thousands of books and there are two or three employees to arrange them. The Library Management Robot (LMR) will mitigate the problems by collecting the books from library counter and then arranging the books, one by one, into shelves.

The LMR works on general principle of RFID, Line following and kinematics of robotic arm. The LMR will initially scan the RFID tag of a book and then find its shelf according to the data previously fed into it. Then it will travel to the shelf according to the path following the lines made on the floor of library. After reaching the shelf, LMR will pick the book and place it in the respective rack in the shelf. The same procedure will be repeated for every book.

The robot consists of a microprocessor (ATmega328), two motors for locomotion, four different motors for arm, RFID reader and proximity sensors for gathering surrounding information.

This project will definitely prove helpful for library enabling them to work efficiently and eliminating problem like misplacing of books.

Keywords RFID; library management; robotic arm.

1. INTRODUCTION

   1. Introdution to Problem

      • Difficult to search record when there is no computerized system, or if the records are large in number.[1]

      • Placing books from the counter or reading table to the respective shelf.

      • Due to increase in the number of shelves in the library it is difficult for a single person to remember such a large records.

      • The cost reduction in the management of the library.

      • Assisting the librarian to decrease efforts in managing the books in the library.

        TABLE I. SPECIFICATIONS OF ROBOT

        Parameter	Specifications
        Model name of robot unit	Library Management Robot [L.M.R.]
        Claw arm movement(*a)	(*a=) 125mm
        Horizontal arm movement(*b)	(*b=) 100mm
        Vertical arm movement(*c)	(*c=) 1200mm
        Wrist rotating angle	±270°
        Axis combination	X(1st axis)+Y(2nd axis)+Z(3rd axis)+T(4th axis)
        Maximum payload	2kg
        Composite speed	X(1st axis), Y(2nd axis) : 1000mm/s Z(3rd axis):2000mm/s T(4th axis):1500/s
        Position repeatability	X(1st axis), Y(2nd axis), Z(3rd axis):±0.25cm T(4th axis):±0.18cm
        Maximum allowable inertia moment around T-axis	0.078 kgm2
        Position detection	Position encoder
        Drive motor	DC servomotor for one joint + Johnson motors for two joints + Rectangular gearbox side shaft motors
        Weight	Approx. 9.5 Kg

   2. Description of Robot

   The Library Management Robot helps to minimize the problem of library management by accurately identifying the place of the book according to the Dewey classification and placing the book in the right shelf. It identifies the unique identity of each book and searches for the place for that identity in the database feed to the robot [2].

   The LMR has two main parts; base which has two motors, two degree of freedom, and column which has four motors, four degree of freedom. These motors are controlled by ATmega8 micro controller. This micro controller is programmed in such a way so that the whole functioning of the robot can be done by pressing a single button.

2. COMPONENTS OF ROBOT

   Chemistry Information: 304 Stainless Steel
   Element	Percentage
   C	0.08 max
   Cr	18 20
   Fe	66.345 74
   Mn	2 max
   Ni	8 – 10.5
   P	0.045 max
   S	0.03 max
   Si	1 max

   Chemistry Information: 304 Stainless Steel
   Element	Percentage
   C	0.08 max
   Cr	18 20
   Fe	66.345 74
   Mn	2 max
   Ni	8 – 10.5
   P	0.045 max
   S	0.03 max
   Si	1 max

   To achieve the objectives set, LMR is designed to have 4 + 2 that is 6 Degree of freedom. The arm consists of four degree of freedoms viz.

   1. For translating the X arm.

   2. For translating the Y arm.

   3. For lifting up the Cartesian box.

   4. For rotating the Cartesian box along vertical axis.

   1. Body Components

      1. Chasis

         The chassis for this robot is made up of mild steel sheet of

         2 mm thickness. The sheet is bent into angles to provide strength. The chassis is of dimensions 18X12X5 (L X B X H). A step is provided on one side of chassis to allow more travel for the vertical arm.

         TABLE II. SQUARE PIPE SPECIFICATIONS

      2. Castor Wheel

   Fig 1. Chassis

   A caster (or castor) is a free to rotate, single, double, or compound wheel that is designed to be mounted to the bottom of a larger object (the "vehicle") so as to enable that object to be easily moved. They are available in various sizes, and are commonly made of rubber, plastic, nylon, aluminum, or stainless steel. The caster wheels used in this robot are made aluminum with a total height of 15mm.

   4) Battery

   Fig 3. Pipe Dimensions

   Fig 4. Square Pipe

   Fig 2. Castor Wheel

   3) Vertical Support Square Shaft

   The vertical rod is made up of square section pipe of length 48. Weight/ Linear foot: 0.27750781 Kg. This material meets the following specs: ASTM A554 [3].

   The battery used here is a 12V and 7mAH dry lead-acid Battery. It find its application in UPS systems.

   Fig 5. Battery used

   1. Control Box

      The control box is the heart and brain of an actuator solution. It translates the signals from the control unit into perfectly controlled movement and adjustment of the actuators. The control box also links the various accessories connected to the system. It controls all theelectrical components fitted in the robot. It encapsulates microcontroller as well as all the connections to each component.

   2. Rectangular Gearbox Side shaft motor

      It is a high torque DC motor that works on 12V. It runs at 200 rpm and torque provided by this motor is 35 kg-cm. The gear ratio employed by this motor is 350:1.

      Fig 6. Side shaft DC Motor

      1. Bevel Gears

         (a)

         (b)

         Fig 8. (a) Bevel Gear Dimensions. (b) Bevel Gears Used.

      2. Cartesian Box

         1. Mechanical Components

            1. X-Rod

               It is used to provide a linear motion to the gripper. It provides a travel of 6cm which will enable the gripper to carry and place two books in one cycle.

            2. Y-Rod

               It is used to provide a linear travel of 15cm to the gripper. It will allow the gripper to go inside the shelf and come back.

            3. Gripper

               It consists of two moving members which come in contact with the book to pick it. It consists of a worm and two pinions to tighten and loosen the grip. When the motor turns clockwise, the gripper opens and vise-versa.

   3. Plastic Rack

   The plastic rack used in this robot is of dimensions 22.86 cm X 1cm X 1cm (L X B X H). The module of the rack being 0.8.

   1. Servo Motors

      Fig 9. Worm and Worm gripper

      Fig 7. Plastic Rack

      The servo circuitry is built right inside the motor unit and has a position able shaft, which usually is fitted with a gear (as shown below). The motor is controlled with an electric signal which determines the amount of movement of the shaft.

3. SENSORS

   1. White line sensor

      1. Rollers

      Fig 10. MG946R Servo Motor

      As you can see in below figure, a line sensor is composed of a number cells and each cell is composed of a sender and a receiver. The particularity of this sender/receiver pair, is that it sends light that shall be reflected by the line to be detected but not by the eventually opaque background surrounding this line. Any sender/receiver pair that is able to make a difference between a line and the rest of ground (of a different color) can be used in a line sensor.

      So the first aspect that affects the precision and the quality of a line sensor, is the number of cells. The second aspect to be considered when building a line sensor, is the cell spacing (or the distance between a cell and the other.)

      Plastic rollers with metal base are used to support various links and arms which move from one place to another.

   2. DC Motors

   Fig 11. Plastic Rollers

   Two high torque DC motors of 150 rpm has been used in this robot.

   Fig 12. DC Motor (High Torque)

   Fig. 13. Working of IR line follower

   Fig 14. Digital white line sensor

   TABLE III. PIN CONFIGURATION OF WHITE LINE SENSOR

   Pin No.	Connection
   1	GND
   2	VCC
   3	Sensor1
   4	Sensor2
   5	Sensor3
   6	Sensor4
   7	Sensor5
   8	NC
   9	VCC
   10	GND

   1. RFID scanner

      Fig15. Working of RFID Sensor

      RFID is an acronym for radio-frequency identification and refers to a technology whereby digital data encoded in RFID tags or smart labels (defined below) are captured by a reader via radio waves. RFID is similar to barcoding in that data from a tag or label are captured by a device that stores the data in a database. RFID, however, has several advantages over systems that use barcode asset tracking software. The most notable is that RFID tag data can be read outside the line- of-sight, whereas barcodes must be aligned with an optical scanner.

      Fig 16. RFID scanner

      RFID technology is employed in many industries to perform such tasks as:

      • Inventory management

      • Asset tracking

      • Personnel tracking

      • Controlling access to restricted areas

      • ID badging

      • Supply chain management

      • Counterfeit prevention (e.g., in the pharmaceutical industry)

   2. Position encoder

   Fig 17. Position encoder

   Position Encoder Kit used to measure speed of motor, find out distance travelled by robot etc.

   In this assembly you will get Position Encoder with RA Mount with three pin Relimate connector, One Universal Wheel. This Wheel is made up of high strength nylon. Wheel has thickness of 10mm and diameter of 51.5mm.

   TABLE IV. SPECIFICATIONS OF POSITION ENCODER

   S. No.	Part	Specifications
   1.	Position Encoder	Position Encoder with RA Mount Encoder resolution: 5.44mm / pulse.
   2.	Encoder Metal Disk	Material: 1mm thick MS Disc Size: 39mm Diameter Mounting Hole Size: 3mm Diameter
   3.	Universal Wheel	Diameter: 50mm Wheel thickness: 10mm. Hole: 6mm.
   4.	Motor Mount	Material: 2mm thick MS steel. Size: Motor mounting side: Height 41mm, Width 38mm; Bracket mounting side: Height 21.5mm, Width 38mm. Hole for Motor mounting: 14mm diameter.

   Fig 18. Schematic diagram of position encoder

4. CHIP CIRCUIT

   1. Motor driver L298N

      TABLE V. ARDUNIO UNO SPECIFICATIONS

      Name	Specifications
      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
      EEPROM	1 KB
      Clock Speed	16 MHz

      Name	Specifications
      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
      EEPROM	1 KB
      Clock Speed	16 MHz

      Fig. 19. L298N Motor Driver

      Motor channels: 2

      Maximum operating voltage: 46 V Peak output current per channel: 2 A Minimum logic voltage: 4.5 V Maximum logic voltage: 7 V

   2. Motor driver L293D

5. DESIGN ANALYSIS WITH SPECIFICATION

   1. Requirements

      • To cover each of the six shelves of all the racks.

      • To travel from the counter to the last rack following th white line attached close to the shelf for large free floor space.

      • To fetch the shelf number of the book for placement.

      • To not have any human interfere while in operation.

      • To set an initialization button and kill switch for ease of operation.

   Fig. 20. L293D Motor Driver

   Input Voltage: 4.5V 36V

   Max. Current: 600 mA for each motor Can drive DC and Stepper Motors

   C. Arduino UNO ATmega328

   Fig. 21. Arduino UNO layout

   1. Limitations And Considerations

      • Minimum five DOF required to pick and place the book.

      • Space limitation in making chassis of the robot.

      • Two book carrying capacity which increases the gross weight.

      • Power limitations due to unaffordable cost.

      • Speed limitations due to unaffordable cost.

        Fig.4.1 Library Shelves

        Fig.4.1 Library Shelves

      • Height limitation due to increase in height of center of gravity thus more power or more support hence increase in cost.

        Fig. 22. Library for which designing of Robot is done.

   2. Design Of Different Parts

      1) Design Of Chassis

      The distance between the two consecutive racks is 4ft. Thus the dimensions of the chassis is set to be 1 X 1.5 X 0 .5 cubic feet.

      A step is provided at one side of the box of 1 X .5 square feet so that the Cartesian box can be travelled up to the last shelf.

      The ground clearance is set to be 1.5cm to have low center of gravity and also to cover the bottom most shelf.

      1. Design Of Vertical Rod

         The height of the rod is calculated on the basis of the height of the top most shelf and the distance between two consecutive shelves, base height, cell height and base thickness.

         h = b + 4 * c + 3* t

         Where,

         h: Total height of vertical rod.

         b: Height of base from the ground. c: Height of each shelf.

         t: Thickness of base of each shelf.

      2. Design Of X-Rod

         The length of the connecting rod between the vertical rod and the rod containing the claw (Y rod) is calculated according to the placement of the books in the temporary book kept on the robot.

         The distance between the placements of the two books is found to be 6 cm for a general thickness of the book. Hence after the addition of the spaces used by roller supports, Y rod and Cartesian box, the length of X rod is set as 8.

      3. Design of Y-Rod

         The length of the Y rod is calculated based on the shelf depth, distance of the robot from the shelf and the position of the vertical rod.

         column with bearing housing on the top is 4ft.On the chassis end of the rod it is housed with the bevel gears with splined coupling of internal square section.

   3. Cartesian Box

   The Cartesian box is made of cuboidal shape, using mild steel sheet of 2mm thickness, of dimension 230mm X 80mm and thickness of 1mm. These four panels are bolstered to form a box by using 8 L-clamp. It encapsulates 3 motors for providing various motions to the arm. The Cartesian box is supported to the vertical column with the help of rollers from 3 sides and from pinion attached to remaining one side. X-rod is supported with 3 rollers at the base and 2 rollers from either sides. Also it supports a motor to drive Y-rod. The Y-rod is also supported with rollers for providing 2 D.O.F. to it.

   VII. CALCULATIONS

   A. Center Of Gravity Of The Robot

   l = .5 * sd + c

   Where,

   l: Length of Y rod sd: Depth of one shelf.

   c: Clearance between the robot and shelf

   1. Design Of Cartesian Box

   The main and most complicated component of the robot is the Cartesian box. Its design is based on the dimensions of the roller support, design of X and Y rods, motor placements according to the rods[4].

6. FABRICATION OF PARTS

1. 3D Printing

   Some of the parts in the robot is manufactured using 3D printing technology such as jaws, spline hub and motor hub. The technology uses material known as ABS.

2. Chassis

   The chassis with dimensions 1 X 1.5 X .5 ft3 is made up of mild steel sheet of 2mm thickness. A step is also provided on one side which is by omitting the height of the front part of the robot of dimensions 0.5ftX 0.5 ft.

3. Vertical Column

   A vertical column made of stainless steel square section rod of 26mm X 26mm and thickness 2mm. The height of the

   x- axis

   Fig. 23. Top View of Robot

   Formula for calculation of C.G. is

   ( )

   . . =

   Now, the mass of the components on robot are:

   1. Battery : 1.5 Kg.

   2. Drive motor : 1.1 Kg.

   3. Wheels : 100 grams.

   4. Bevel gear set : 1.25

      Kg.

   5. Johnson motors : 280 grams.

   6. Servo motor : 55 grams.

   7. Rack : 48 grams.

      w us relat tained

      w us relat tained

   8. Steel pipe : 600 grams/feet

y-axis

y-axis

No ing the weights of each component and measuring the ive distances, the center of gravity of the robot is ob by putting these values into the formula:

x = 22.42 cm

y = 15.06 cm z = 53.15 cm

1. Bending Moment Calculation

   1. Bending Moment Without Book

      1. Moment at claw (when claw is inside) Mclaw = 0.5×0.06×9.81

         = 0.2943 N-m

      2. Moment at claw (when claw is outside) Mclaw= 0.5×0.19×9.81

         = 0.931 N-m

      3. Moment of X-rod about point E

         Mxc(e)= 0.66×9.81×0.21 + 0.221×9.81×0.105

         = 3.636 N-m

         Mxd(e)= 1.85 N-m

      4. Moment at Vertical Rod

         Mvr=2.5×9.81×0.12 = 2.943 N-m

   2. Bending Moment With Book

      1. Moment at claw (when claw is inside) Mclaw = 2.5×0.06×9.81

         = 1.4715 N-m

      2. Moment at claw (when claw is outside) Mclaw= 2.5×0.19×9.81

         = 4.65 N-m

      3. Moment of X-rod about point E Mxc(e)= 2.5×9.81×0.21

         = 5.150 N-m

         Mxd(e)= 4.1516 N-m

      4. Twisting Moment about point E when claw is at A T.M.e(A) = 2.5×9.81×0.06

         = 1.4715 N-m T.M.e(B) =2.5×9.81×0.19

         = 4.65 N-m

      5. Moment at Vertical Rod

         Mvr=2×9.81×0.24 + 2.5×9.81×0.12

         = 7.6518 N-m

      6. Twisting moment at vertical rod T.M.e(A) = 2×9.81×0.24 N-m

VIII. WORKING & PERFORMANCE EVALUATION OF ROBOT

searching this tag ID in the database feed to the robot, it gets the shelf number and the path which the robot should travel in order to get to the destination shelf.

STEP 4: Traversing to the shelf

The robot then travels to the shelf where the book is to be kept. It does this by simply following the line on the floor and making decisions of turns by using the data in microcontroller.

STEP 5: Placement of Cartesian box

The height of the Cartesian box is adjusted by the vertical linear motion on the rack with the help of pinion, as shown in Fig. 24. After reaching the defined height, the gripper hand is moved forward and the book is inserted in the shelf.

STEP 6: Placing book

The book is then released from the gripper and the gripper hand is moved back and then lowered.

STEP 7: Scanning next book

The robot then scans next book by bringing the gripper near the book. The RFID of that book is then sent to the database to retrieve the shelf number and the path to travel to that shelf. Process shown in Fig. 25.

STEP 8: Placing second book

After successfully identifying the book shelf, the robot travels to the shelf and then places the book to the respective cell.

STEP 9: Returning to counter

After placing both the books in their shelves, the robot returns to the counter for beginning next Pick and Place Cycle.

1. Working Of Robot

   The robot is preprogrammed to do a defined task. It does every task in a predefined sequence, which is as follows:

   STEP 1: Switching ON/OFF

   The robot starts to work after being switched ON by the operator. This switch also acts as kill switch to stop the robot in case of malfunctioning.

   STEP 2: Placing books on platform on robot

   The operator can place upto two books on the platform of robot. The robot will successfully place these books to their shelves. The books should be placed such that the binded side of the book should face the claw of robot.

   STEP 3: Scanning of book for shelf position

   The robot then bring the claw to the leftmost book on the platform and then read the RFID tag of that book. Then by

   Fig. 24. Manufactured Robot

2. Performance Evaluation

The robot has been made as per designed to fulfill a particular need. Many problems have been faced in fabrication as well as implementation of the various motions. Thereafter the chassis and base has been prepared for properly balancing

Fig. 25. Picking up book from platform

the weight of Cartesian box and traversing masses. Stability of the robot was a huge task. The overall center of gravity was much above the base.

The robot is capable of picking two books from the counter and placing them to the required shelves. The gripper can lift one book precisely to its position. Also the robot could navigate itself towards the destination shelf and thus automatically places the book by reading its radio frequency identity. It can carry two books at a time and can place one book at a time. Such robots in sufficient numbers can alleviate the work of placing books in robots.

ACKNOWLEDGMENT

We would like to thank Professor Sanjay Jathar and Professor Rajguru, who had guided us throughout the work. They had motivated us to complete the work successfully.

REFERENCES

1. McClure, C. R. (1980). "LIBRARY MANAGERS: Can They Manage? Will They Lead?" Library Journal: 2391.

2. Dewey, Melvil (1876), Classification and Subject Index for Cataloguing and Arranging the Books and Pamphlets of a Library (Project Gutenberg eBook), retrieved 31 July 2012

3. http://www.steel-pipes.net/hollow-sections.html

4. Robot Arm Configurations