Table of Content

1. Project abstract

2. Table of content

3. Project motivation

4. Functionality

5. State of the Art and Patent Analysis

6. High-level Design

7. Design of the subsystem

i. Mechanical Systems

ii. Circuitry & Sensors

iii. Software

8. Integration guide

9. Demo project show

10. Project Review

11. Sustainability

12. Bill of materials

13. Present your team

14. Project Report

The Draw Robot is an ultimate multi-purpose machine that is designed to meet a wide range of expert calligraphic writings as well as general drawings on a flat surface. One can use their computer to produce beautiful handwriting using a real pen that appears handcrafted, which has no mistakes. The main objective of this project is to apply pressure on the pen in order to have varied thicknesses. The result shows that the robot is capable of drawing a line with varied thicknesses with a step size of 0.0316mm. Therefore, depending on the calligraphy pen the robot can draw a line with different thicknesses.

Perhaps one loves calligraphic writing and they cannot write with the same accuracy and precision, here is the solution – Draw Robot. The Draw Robot is a device that can write and draw figures with utmost accuracy and precision. This figure seen below is the handwriting of our colleague’s brother. Isn’t it beautiful? Me and my colleagues, when we try to write in this same fashion, fail to do so. It’s not everyone’s cup of tea, so we decided to design and manufacture a drawing robot that can fulfil our needs.

After our decision, we found out that there are many draw robots available in the market but are expensive and they do not completely fulfil our needs. So, we decided to uplift our task by one step more and make it affordable with some really good extra features for the users to experience a quality product.

The main aim of this project is to design and manufacture a drawing robot that can draw complex figures, calligraphic writings with accuracy and precision. In order to achieve our goals, it is important to know the functions.

Functions of a Draw Robot can be categorized into external functions and internal functions. The external functions are the ones that are directly useful to the customer and they can be divided into two categories: Principal functions and complementary functions whereas the internal functions depend already on the design choices. The external functions include the principal and complementary functions and the internal functions represent the limitations and considerations that should be considered when making design choices.

These functions have been categorized in a table and are shown in the given pictures.

The next step is to make a function chart that exhibits some characteristics of the Draw Robot according to their nature. In the table given below, the co-efficient K refers to the level of importance of a function that is functions with co-efficient K=1 is more important than K=2. The flexibility level is described using the co-efficient F where F1 represents small flexibility, F2 represents moderate flexibility, and F3 represents large flexibility

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1. Robotic Drawing

Publication Number: WO2020072785A1

Publication Date: 2020-04-09

Website: https://worldwide.espacenet.com/patent/search?q=p...

Conclusion: The manufacturing cost and maintenance of this robot is very expensive.

2. Drawing Robot System

Publication Number: WO2021103417A1

Publication Date: 2021-06-03

Website: https://worldwide.espacenet.com/patent/search/fam...

Conclusion: The working area is limited and it does not meet our objective, applying pressure.

The design of the draw robot is very simple with minimum number of components. This helps the user to assemble/dissemble it easily and if there is any problem in the functioning of any electronic or mechanical component, it is easily maintainable.

1. Cart: The cart consists of four shafts, both for X & Y axis. These shafts are connected to the stepper motor mounting on which the motors have been fixed that enables the movement of the cart in linear direction with the help of a continuous belt. The idler pulleys as seen in the figure below establish a frictionless movement and helps to maintain tension in the belt. When pressure is applied, there might be a negligible bending which is overcome by the wheel supports.

2. Z-Axis housing: As our main aim of our project is to write with varied thickness, this can be achieved with a simple yet important mechanism of converting the rotational to linear motion with the help of flexible coupling and lead screw. The stepper motor is connected with flexible coupling which moves in up and down direction with the help of lead screw, thereby creating variable thickness. This complete setup is enclosed in a special house, named as Z-Axis housing.

3. Electronic Setup: The electronic and electrical setup is enclosed in a special box to avoid accidents. The Arduino is connected with the CNC shield and drivers to drive the three stepper motors is powered electrically with 12V DC current and is connected to a laptop. In order to avoid overheating, a cooling fan is attached to the box which is shown in figure below. This casing if fixed in the corner of the board so that it does not interrupt the robot.

Components list:

1. Arduino Uno - 1 piece

2. Stepper Motor Drivers A4988 - 3 pieces

3. Push Buttons - 2 pieces

4. Stepper Motors - 3 pieces

5. CNC Shield

6. Power Switch

7. Cooling Fan

1. Mechanical Systems: In this project, the CAD design has been made using SolidWorks software. The most basic principle such as statics, dynamics, vibration, and reliability have been considered in the design process.

Before diving into fabricating the robot, stress analysis had been done using the software Autodesk Inventor to see whether or not it satisfies the needs. Since the most concern of the system was bending, the structure should have minimum bending at the end of Y-axis. The stress analysis, shows that the static bending is negligible.

a) Requirements: A requirement list is a nested list which contains adequate quantitative and qualitative information. Determining the requirements of a Draw Robot, helps us to focus on the appropriate design criteria and implement appropriate design decisions. The crucial values of the project will be analyzed by prioritizing and categorizing techniques.

b) Conceptual Design: The next step after the requirement list is to find concepts to reach the design criteria. The conceptual design is the initial level of the design process where different concepts are considered and analyzed. Several parameters should be considered and discussed in order to select the best one and to improve the final design.

The main challenge in our project is to guide the pen to the correct vector lines so that it creates a picture with utmost accuracy and precision. In the table below, the essential problems and respective solutions have been discussed.

As all of our team mates are from engineering background, each of them has proposed their own ideas and thoughts about the different types of concepts which can be adopted for this project. Out of concept 1,2,3, we choose the one which satisfied all the conditions which is discussed in the table above.

c) Embodiment Design: The embodiment design is the step of the design process where the design of the product is developed with consideration of both technical and economic criteria. The three basic rules for this step are clarity, simplicity and safety.

2. Circuitry & Sensors: The electrical schematic of the system containing Arduino, the heart of the system, DMOS Micro steeping Motor Driver, three stepper motors, three capacitors, and two switches are depicted in the figure above.

The direct current (DC) voltage needed for the Arduino is between 9 and 12. However, the microcontroller Atmega8 embedded on the Arduino board needs 5 volts to run. To convert this voltage, an integrated circuit (IC) MC33269 - Voltage Regulator Adjustable Output – is already provided to make the voltage needed for it.

Arduino, which is already programmed, sends two commands to each driver namely direction- and step-pin. The direction-pin, indeed, controls the direction of the stepper motor to turn clockwise (CW) or counterclockwise (CCW), and the step pins control the speed of the motor by providing different time duration.

The Arduino Microcontroller controls the position of the stepper motors using software instructions. A brushless DC electric motor that divides a whole rotation into a number of equal steps is known as a stepper motor. Three stepper motors for the X, Y, and Z axes are used to provide precise control over the drawing pen for object sketching. Stepper motor drivers are used to drive stepper motors that can rotate continuously while maintaining precise position control without the need for a feedback system.

3. Software: The software's which are used for this project is explained in detail below:

a). Arduino IDE: It is an open-source, makes it simple to create code and upload it to the board.

b).Inkscape: Inkscape is a free-to-download open-source software that may be customized for specific applications by adding extensions.

c) Candle: The software that connects your CNC machine to your PC is known as control software that is Candle.

The Draw Robot is a simple, modern and precise pen plotter capable of writing or drawing on any flat surface. This guide will allow you to use your computer to produce writing that appears to be handmade.

a) Pen, paper and the clip easel: You will need a pen & a paper to get started. There is a simple arrangement on the board where the paper can be fixed easily. To fix a pen, there is a simple screw mechanism to hold the pen firmly. The vertical position of them pen should be approximately 0.20 to 0.30 mm just above the paper. Any basic pen can be used but for calligraphic artist, a calligraphic pen is advised.

b) Connect Power & USB: The next step is to connect power and USB cables. Connect the USB cable to USB port on your computer. The plug-in power adapter is 12V DC, regulated, centre positive which works with worldwide mains power. Do not use an adapter that changes the voltage. There is a special arrangement made on the electronic casing to switch on & off the device. Once your cables are connected, make sure that the robot has room to move, both in front and behind the machine. To make sure that cables doesn’t get caught, they are properly fixed.

c) Move to home: Prior to drawing, it is necessary to move the pen to the Home. This is exactly the centre of the machine.

d) Calibrate the pen position: It is very important to calibrate the positioning of the pen. Candle software allows us to toggle pen up and down. If there is no movement, double check that you have power and USB connected properly.

Note: The calibration of draw robot has been done. Also, the robot is able to find its “home” using the X- and Y-limits switches.

e) Software implementation: As Candle software is an open-source software, it can be downloaded from internet.

f) Document Orientation: Different types of documents can be used to write or draw. The following are the list of examples: i) Letter Size, ii) A4 size sheet, iii) A formal invitation.

The demo of the project has been made and uploaded on YouTube website to be used for engineers who are interested in building the draw robot.

First of all, we have to admit that the first concept shown in the conceptual design, is the best fit to fulfill our desire to adjust the pressure since the bending of the y-axis of this concept in comparison to the fabricated one is nothing. However, changing the details of the design and modifying the software reasonably solve the bending problem.

It is very important to create a sustainable design and the draw robot has met all the three key areas where engineers are pivotal to create a sustainable design.

a) Material Selection: The design and manufacturing of the draw robot is done in such a way that all the parts can be recycled and reused. All the mechanical parts are used of standard size which is easily available in the market and all the 3D printed parts, which are made up of PLC can be recycled easily.

b) Energy Resource: Energy plays an important role in the manufacturing process. During the designing, all the assumptions and testing were made in software to analyze the defects in the design. The mechanical parts including nuts and bolts were utilized in the best way. The 3D printed parts were perfectly design and verified using SolidWorks software, so that there is no mistake in printing.

Improvements: As far as the design is considered, it was made sure that we utilise the resources in the best manner. The design of cart was improved to reduce the number of shafts, nuts & bolts and 3D printed parts.

The cost of the Draw Robot has been categorized into two parts.

a. Manufacturing cost of 3D printed parts &

b. Components cost.

Reference Website: 3D Printing Price Calculator - Prusa Printers

a) Mohammadjavad Rahimi Dolatabad – He has received B.Sc. Degree in Electronic Engineering program in 2010, Tehran. He obtained his first master's in Mechatronics Engineering in 2020 at Sharif University of Technology, International Campus, Kish Island, Iran—ranked first among Iranian universities.

Please visit his website for more info http://mj-rahimi.com

b) Aiman Quraishi – He has received Bachelor’s in Technology in Mechanical Engineering from JNTU – Hyderabad in the year 2021.

c) Mayur Ashok Sonawane – He has received Bachelor’s in Technology in Mechanical Engineering from Savitribai Phule Pune University, Pune, Maharashtra, India.

In this project, a control unit Arduino Uno which was programmed with GRBL V1.1 accepting G-codes to command the motor has been used. The minimum step size found for the Z-axis was 0.03mm which is enough for drawing calligraphy words. To apply the pressure on the pen for drawing varied thicknesses, the G-codes of the picture have been modified and the error of bending is also has been considered.