Peter the hexapod - Tesina per tecnico industriale

FIRST STEP:

1. Assemble the body of

the robot;

2. Solder the wires to the

microcontroller;

3.Attach the sensors, the

battery and the microcontroller

to the body of the robot.

SECOND STEP:

1. PROGRAMMING THE

MICROCONTROLLER;

2. TESTING THE

FUNCTIONING OF THE

ROBOT. 1/3

HOW DOES A ROBOT WORK?

Human beings are made up of five major components: a body

structure, a muscle system, a sensory system, a power

source and a brain system.

A robot is made up of the

same components:

1- A movable physical

structure;

2- A motor;

3- A sensory system;

4- A power supply;

5- A computer that

controls all of these elements. 2/3

HOW DOES A ROBOT WORK?

Robots need an actuator to operate. For example in our

project the three servos are our actuators that allow the robot

to move.

These actuators need a power source to operate and they are

also wired to an electrical circuit. Robots can be

reprogrammed by rewriting the program for the controller

3/3

HOW DOES A ROBOT WORK?

Not all robots have a sensory system, and few

have the ability to see, hear, smell or taste.

The most common robotic sense is the sense

of movement.

In our project the robot is able to see

the obstacles and avoid them.

Computer languages and programs

Preparing a program is structured following six different steps:

1- Interview the professional responsible for the job to be done;

2- Write a complete detailed description of the job;

3- Analyse the job in order to break it down into steps;

4- Construct a diagram showing the sequence of the most

important steps in the job;

5- write the pogram;

6- test the program on the computer to detect mistakes, known as

"bugs". The testing of programs is called "debugging".

ARTIFICIAL INTELLIGENCE

Artificial intelligence is a controversial field.

Computers can already solve problems but

they can only solve problem for which they

are programmed because they don’t have

any generalized analytical abilities.

Some robots are able to learn but the problem

is that robots can only do this in very limited

situations.

Some robot can interact socially because they

recognize human body languages and voice

inflection and respond correctly.

The real challenge of A.I. Is to understand

how natural intelligence works

Isaac Asimov

BORN IN 1920 IN RUSSIA

HE BECAME FAMOUS AS

SCIENCE-FICTION

WRITER

ACCORDING TO ASIMOV

ROBOTS ARE MERE

MACHINES AND THEY

CANNOT FEEL

EMOTIONS ISAAC ASIMOV

THE THREE LAWS OF ROBOTICS

1- A robot may not injure a human

being, or allow a human being to

come to harm.

2- A robot must obey the orders given it by

human beings except when such orders

would conflict with the first law.

3- A robot must protect its own existence

as long as such protection does not conflict

with the first and second law

.

ROBOTS: PAST AND PRESENT 1/2

Some years ago the

Philadelphia Museum in the

United States acquired what

seemed to be a mechanical

doll.

This robot and others made by

Henri Maillardet in the early

19th century were by no means

the first mechanical devices

designed to imitate the actions

of living creatures.

ROBOTS: PAST AND PRESENT 2/2

In fact we remember Leonardo da

Vinci’s inventions.

“robot”

The word first appeared in

1921 in a Czech play about

rebellious humanoid machines.

It derives from the Czech word for

"forced labour".

After some initial problems they are

now widely used for jobs such as

welding, machining and assembling

electronic parts. Gallery

THANKS TO ALL TEACHERS THAT

HAVE

CONTRIBUTED TO THE SUCCESS

OF THIS PROJECT

ITIS G. MARCONI

Dalmine (-BG-)

Study course: Electrical engineering

and automation

Project work

“PETER THE HEXAPOD”

Candidates: Bresciani Jacopo

Rosa Davide

Tadini Matteo

1

Index:

1. Project charter……………………………………………….pag 3

2. WBS (Work breakdown Structure)……………………..pag 6

3. Gantt Diagram………………………………………………….pag 6

4. Introduction to the project……………………………..pag 7

5. Materials and Tools………………………………………..pag 8

6. Construction ………………………………………………….pag 15

7. Sequencing the Hexapod Gait…………………………….pag 23

8. Using a Script for Obstacle Avoidance………………pag 29

9. Conclusion………………………………………………………pag 31

10. Sources and credits……………………………………...pag 31

2

1. Project charter

Purpose of the document:



The purpose of this document is to clear the basis the project is based on, to make known

the resources that involved Necessary information for analysis and sharing of project

objectives.

Project name:



Peter the hexapod

Motivations behind the project:



Develop a project to be presented to the examination commission in order to demonstrate

the concepts we learned in the school career

Expected benefits:



1- Try to independently develop a design that is able to function properly;

2- Submit a complete project that meets the goals set at the start of work;

3- Present a project work that is able to exemplify in the best way the skills learned during

the study course;

4- Develop a project that allows us to get a high score on examination.

Purposes of the project:



Develop a robot with microcontroller-based technology that is able to walk through the use

of three servos and to avoid the objects thanks to two proximity sensors. The whole is

powered by a battery of 4.8 V and 200mAh which will be charged by a charger suitably

constructed by us. The movement of the robot will be controlled by a program that we have

written on a PC using a special software and then have inserted into our microcontroller

connected via a USB port. The development of the project must be able to satisfy correctly

the objectives set at the beginning of the work and expected benefits.

Macro activities and organization:



The macro activities into which our project can be divided are the following:

1- Design;

2- Assembly; 3

3- Programming;

4- Test;

5- Project definition.

The choice of developing this project was made taking into account our technical skills. The

probabilities of success of this project are therefore very high and on a careful pre-analysis

we have reached the conclusion to conduct all activities independently, without delegating

anything outsi

Main actors and their roles:



ROLE: NAME:

Coordinator of the project work Antonio Izzo

Team member Davide Rosa

Team member Jacopo Bresciani

Team member Matteo Tadini

Provider Pololu robotics and electronics

Time and costs:



Project duration:

Project start 02/04/2012 Project end date 06/06/2012

date

Cost:

Part Quantity Cost (for a single

part)

Pololu micro maestro partial 1 18.95 US$

kit

Sub-micro servo 3,7g Generic 3 8.95 US$

Pololu Carrier with Sharp 2 6.95 US$

GP2Y0D810Z0F Digital

Distance Sensor 10cm

Battery Pack: 4.8 V, 200 mAh 1 5.39 US$

Total expenditure 65.09 US$

4

Risk analysis:



In project management methodologies, an important space is devoted to the techniques of

risk analysis (risk analysis).

The risk associated with an event (or threat) is the product of the probability of occurrence

for the scale of the impact caused

RISK = Probability * Damage

The damage caused by a threat can be economic, temporal, social, or all possible combinations

between the three.

Regarding to the damage it has the impact that the damage can lead to the project

(sometimes the risk analysis is evaluated directly by calculating the economic impact).

The head of Project management must carefully include the issues associated with evaluating

risk in context.

In our project we may run into some risks related to:

Timing;

– Delivery units ordered;

– Damage to mechanical parts;

– Malfunctioning of the project

– 5

2. WBS (Work breakdown structure)

The first essential step of a project is to divide the project into tasks to be assigned to specific

responsible. This breakdown is made by defining the work breakdown structure (WBS). It is a tool

that, through a logical hierarchical, decomposes in a systematic way the project in aggregate

activity progressively smaller, until you get to identify the elementary activities and work

packages. The aim of WBS is to support the definition of the work needed to achieve a desired

result.

3. Gantt Diagram

The Gantt diagram is surely the most used tool for describing the temporal planning of a project.

Its simplicity, readability and the possibility of integrate it with the structure of the WBS makes

it the most used in project planning. The Gantt diagram is based on two orthogonal axes: the

vertical axis lists all the activities in which the project is broken down, while the horizontal axis

shows the time variable. Each activity is represented by a horizontal bar whose placement is

determined by the planned start date and whose length is the estimated lifetime in the forecast.

Is important to emphasize the presence of milestones, that are significant events in the life of a

project. 6

4. Introduction to the project

Six-legged locomotion is a simple, robust system of walking that is very popular both in the animal

kingdom and among robotics hobbyists. Robot hexapods range from simple one-motor toys to advanced

platforms with 18 or more servos. This tutorial shows you how to build an autonomous hexapod robot

using three servos. “Peter the hexapod” is capable of walking forward and backward, and can turn left

and right.

Two forward-looking distance sensors provide obstacle avoidance. The brain of the hexapod is the

Pololu Micro Maestro, a 6-servo controller that can read inputs and play motion sequences in a stored

script. 7

5. Materials and Tools

Parts list:

Quantity Part # Part Notes

Get the kit version so

that you can solder in

Pololu Micro-Maestro

1 1351 your own wires

Partial Kit for the most compact

possible robot.

These generic servos

Sub-Micro Servo provide the lowest

3 1053 3.7g possible cost and

Generic Weight.

Pololu Carrier with This is a tiny

Sharp distance sensor with

GP2Y0D810Z0F a long enough range

2 1134 Digital Distance to keep

Sensor your hexapod out of

10cm trouble.

8 This battery pack will

provide enough power

Battery Pack: 4.8 V, at about 5 V to

1 2251 200 power the hexapod

mAh for five or ten

minutes.

Used to form the

legs of the hexapod.

3 - “Jumbo” paper clip These should be 6"

long

when unfolded.

Tools required:

• Soldering iron and solder

• Hot glue gun

• Wire stripper

• Long-nose pliers

• Diagonal cutter

• Some wire for connecting the parts

5.1. Micro Maestro 6-Channel USB Servo Controller (Partial

Kit)

The six-channel Micro Maestro raises the performance bar for serial servo controllers with

features such as a native USB interface and internal scripting control. Whether you want high-

performance servo control (0.25μs resolution with built-in speed and acceleration control) or a

general I/O controller (e.g. to interface with a sensor or ESC via your USB port), this tiny,

versatile device will deliver. Header pins are included but not soldered into this partial kit

version (all surface-mount components are soldered).

9

The Micro Maestro is the smallest of Pololu’s second-generation USB servo controllers. The

Maestros are available in four sizes and can be purchased fully assembled or as partial kits:

Micro Maestro — partial kit

 Mini Maestro 12 — fully assembled

 Mini Maestro 12 — partial kit

 Mini Maestro 18 — fully assembled

 Mini Maestro 18 — partial kit

 Mini Maestro 24 — fully assembled

 Mini Maestro 24 — partial kit

 The Mini Maestros offer higher channel counts and some additional features.

Micro Maestro 6-channel USB

servo controller bottom view

with quarter for size reference.

The Micro Maestro is a highly versatile servo controller and general-purpose I/O board in a highly

compact (0.85"×1.20") package. It supports three control methods: USB for direct connection to a

computer, TTL serial for use with embedded systems, and internal scripting for self-contained, host

controller-free applications. The channels can be configured as servo outputs for use with radio

control (RC) servos or electronic speed controls (ESCs), as digital outputs, or as analog inputs. The