Raspberry Pi Hexapod Wooden Robot.

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Introduction: Raspberry Pi Hexapod Wooden Robot.

About: I am interested in the development of Monozukuri-Based Educational Robotics that encourage students to imagine, design and manufacture mechanisms and robots from scratch.


It was a dream then a challenge, then it became a reality. The motivation was to teach to the young generations in preparatory, secondry and technical secondry schools in my country Egypt how to manufacture a walking Robot from simple and low-cost materials. Actually، I proposed this work to you because your opinions, comments and your evaluations will give me the power to continue moving forward in this educational field by supporting our students not just in Egypt but in other African countries.
Robots in education have became important tools to enhance students skills in mathematics, computing, imagination, thinking, creativity and productivity. The education systems in Egypt and African countries in general suffers from some chronic problems, including the lack of practical educational methods, the lack of continuous modernization, and the lack of financial resources to activate these practical curricula. Where the process of education is limited to the theoritical way and this does not achieve the required development needed to these countries.

Five years ago, I was in Japan ( The beautiful country and the exhibition of sciences) for a short training course in Mechatronics and Robotics field. One of my dreams was to find the way to renew the education system in my country Egypt and to help other African countries, to help the young generations to achieve their contries aspirations and to end poverty, frustration, hunger and the war.
Of course, I can not do it alone, but together and with your support we can line up to confront poverty, hunger, frustration, and despair to achieve the integrated development in a framework of cooperation. I hope that all of you can support the development efforts in Egypt & Africa. Let's start ------->

Definition of the hexapod robot:
A hexapod robot is a mecchanical vehicle platform that walks on six legs, each leg have three servomotors 3DOF three degree of freedom, the purpose is to build the robot from scratch by imagining the designing structure of the hexapod and manufacturing the body structure using very simple tools and low cost materials.

Supplies:

Basic components:
1- Servomotors SG92R (18 units).
2- Raspberry pi 2 model B.(1 unit).
3- Sheet of wood MDF 4mm. (1 unit).
4- Wires (male-female, male-male).
5- Metal wires diameter 7mm. (2 Meter).
6- Adapter 5V. (1 unit).

Teacher Notes

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Step 1: Introduction.

Servo Motor: A servomotor is a rotary actuator or linear actuator
that allows for precise control of angular or linear position, velocity
and acceleration. It consists of a suitable motor coupled to a sensor
for position feedback. It also requires a relatively sophisticated con-
troller, often a dedicated module designed specifically for use with
servomotors.

2- Raspberry Pi: is a small PC integrated in the palm size of the
hand low-cost and less energy consumption, "less than 3 watts."
It was designed at Cambridge University to help teach computer
science students and capable to integrates between Linux systems and
knowledge of programming and electronics systems, smart control
at the same time, making this small computer achieves a stunning
success in both educational and practical projects. The Raspberry Pi
is contained on a single circuit board and features ports for (HDMI -
USB 2.0 - Composite video - Analog audio - Power - Internet - SD
Card)

3- Wires: are made from metal, it using to flow the electricity. Please
Take care when you connect wires in circuit to avoid the short circuits
maybe happen. In this circuit we need to use two type of wires
(male-male wires and male-female wires).

4- Sheet of MDF: are made from wood, In the start to achieve the
structure of robot I preferred to choose this soft kind of wood to be
easy to cutting and forming it, The kind of MDF thickness 4mm is
good to start this project by using very simple tools.

5- Metal wire: are made from metal with thickens 0.7mm, the wire
using for link between the servo and the joint made from MDF, after
calculating the distance between the servo and the joint you should
cut and folding from the parties as shown in the picture.







Step 2: Basic Tools.

You need to use some basic tools to cutting and folding the MDF sheet. Some tools to connect the electrical connections and some measurements tools.

Step 3: The Structure of Hexapod Robot.

The hexapod robot is based on mobile (walking) robots principles. The structure is divided for two parts: Mechanical design and electrical design.

♧ The mechanical design is divided in two stages:
• The mechanical structure of the robot body includes the base parts of the hexapod and the six legs , each leg have 3 servo motors to facilitate the movement,
• The six legs are moving by 18 servo motors the controller of the robot is Raspberry Pi 2 Model B (the brain).

■ The first try to make a hexapod robot as shown above.

Step 4: Design the Structure Body.

Start to design the structure body of the hexapod by imagining how is the robot shape should be, in this project I started to design by own self as shown in the above pictures.

Step 5: Cutting the MDF Sheet

Start to cutting the MDF sheet depend on the dimensions you designed for the body and the legs using the soft cutting tool.

Step 6: Installation: Fix the Servos

Start to fixing the 18 servo motors and link them with the joints by using the metal wire after measuring the actual distance between both.

Step 7: Kaizen Concept.

♧ Definition: Kaizen Japanese concept is the practice of continuous improvement, that mean taking small actions for the continue development to achieve big achievments. One of the most notable features of kaizen is that big results come from many small changes accumulated over time. This concept has been misunderstood to mean that kaizen equals just small changes.

♧ Question: What is the importance of Kaizen in our work?
To build your robot system, the results come after you start to divide your actions with continuous improvement, that mean everyday with modifying small things new to the system the achievements will be big. Let's continue ------->

Step 8: The Electronic Circuit.

♧ To build the electronic circuit, we should prepare the following:
1- 18 Servo Motors + Raspberry Pi2 Model B + Source power 5 V. + PC or Laptop + HDMI cable + Display + USB
cable + Wires (male-male, male-female)
2- Connect the Servo motor as follows:
• GND from the servo with GND (Pin 6) in Raspberry Pi2 Model B.
• Pulse from the servo with GPIO 14 (Pin 8) in Raspberry Pi2 Model B.
• Power from the servo with +5V (Pin 4) in Raspberry Pi2 Model B.
■ The Electrical design is the connection between servos, Raspberry Pi2 Model B and the power source, it uses to moving the hexapod robot system depend on the programming codes you make.

Step 9: First Time Using Raspberry PI.

♢ For the first time using the Raspberry Pi, please following the next
steps:
1- Start to download NOOBS offline and network install software from
Raspberry Pi website.
2- Format the SD micro memory card (Should be not less than 4 GB) by
using SDFormatter V4.0 and change the settings as follows:
• Change the volume label to FAT.
• Change the option of the FORMAT SIZE ADJUSTMENT to ON for making better formatting to the SD card.
3- Upload the NOOBS installer on SD micro memory and connect the
Raspberry Pi as follows:
• Connect the mouse and the keyboard to USB port in Raspberry Pi.
• Connect the network cable in router to the LAN port in Raspberry Pi.
• Connect the HDMI cable from HDMI port in Raspberry Pi to the display.
• Connect the Raspberry Pi with micro USB power supply +5.1V (RPI doesn’t have an "On/Off" switch).
4- Start to setup NOOBS by selecting Raspian, the setup will take several
hours.

Step 10: The Pins Ordering in Rasspberry PI 2 B+

● The above photo, the student should learn about the Pins ordering
in Rasspberry Pi2 B+.
● Students should know about the difference between the numbers of
GPIO and the Pins ordering on Raspberry Pi board when starting to connect it with servos.

Step 11: Exercise: Motion Primitives - Starting LXTerminal

□ The terminal or command line on a computer allows a user a great deal of control over their system (or in this case, Pi!). Users of Windows may already know it by several names (Command Prompt or Powershell), users of Mac OS may be familiar with Terminal. These tools allow a students to directly manipulate their systems through the use of commands. These commands can be chained together and/or combined together into complex scripts.

□ On the Raspberry Pi (running Raspbian), the default termina application is LXTerminal. This is known as a ’terminal emulator’,
The application can be found on the Raspberry Pi desktop and when started will look something like the above photo.

Step 12: Exercise: Control Servomotor by Using Raspberry PI

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BOARD)
GPIO.setup(14, GPIO.OUT)
pwm= GPIO.PWM(14,50)
pwm.start(5)
pwm.ChangeDutycycle(2) % the servo is moving now
pwm.ChangeDutycycle(4) % Now change the value and the
servo continue to move.
pwm.ChangeDutycycle(7) % another value

Step 13: Exercise: Moving the Servomotor by Change the Value of Angel Positions

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BOARD)
servoPin=14
GPIO.setup(14, GPIO.OUT)
pwm= GPIO.PWM(servoPin,50)
pwm.start(7)
for i in range(0,20):
desiredPosition=input("where do you want the servo? 0-180 "
DC=1/18.*(desiredPosition)+2
pwm.ChangeDutyCycle(DC)
pwm.stop()
GPIO.cleanup()

Step 14: A Quick Overview of the Training Course in Japan.

The training course (Practical Technology for Mechatronics and Robotics) was held in cooperation between JICA Kyushu (KIC) and Kitakyushu International Techno-Cooperative Association (KITA). The Training program helped me to better understand Mechatronics systems.
In particular, the most beneficial lesson I learned are as follows:
1- The Fundamental lectures in Control Engineering, Information Technology, Electronics, Electrical Engineering, and Mechanical Engineering.
2- The Practices and experiments to build circuits using PIC, simulation technology, computer control, AC variable speed motor control in JICA laboratories and in Japanese companies and laboratories.
3- To understand Japanese practices and industries in real situations by visiting technical high schools and factories (for example Yaskawa – Daifuku – Nissan – Mitsubishi Electric co. – Shinnippon Non Destructive Inspection co. – SMC Co. - Tokyo Denki University – Kyushu Institute of Technology) to learn more about industrial robot control, injection modeling machines and machine tools.
By participating in this training course in Japan, I reinforced a number of important skills needed for good management of work, such as organization skills, planning skills, technical skills and communication skills. Also, I reinforced self-improvement skills to develop new educational robots and to interact with the surrounding community (schools, universities).
I would thank the Japanese professors and coordinators of this course for the big effort and support to teach and care about me when I were in Japan.
I was thrilled of having this unique opportunity and honor to be a participant of this course.
Also I would like to express my sincere gratitude to JICA, KITA, Japanese Government and Japanese People to provide this important training course. I deeply appreciate all the support I have got throughout the three month training time.

Raspberry Pi Contest 2020

This is an entry in the
Raspberry Pi Contest 2020

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