Robotics

Emam Fathy

Department of Electrical and Control Engineering

email: emfmz@aast.edu

http://www.aast.edu/cv.php?disp_unit=346&ser=68525

Lecture 1

Introduction to Robotics

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Introduction

Robotics is a relatively young field of moderntechnology that crosses traditional engineeringboundaries.

Understanding the complexity of robots and theirapplications requires knowledge of:

– Electrical engineering.

– Mechanical engineering.

– Industrial engineering.

– Computer science.

– Mathematics. 2

Introduction

The science of robotics has grown tremendouslyover the past twenty years, fueled by rapidadvances in computer and sensor technology aswell as theoretical advances in control andcomputer vision.

This course is concerned with fundamentals ofrobotics, including kinematics, dynamics, andcontrol.

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Introduction

A robot is a mechanical or virtual artificial system, usuallyan electro-mechanical machine that is guided by acomputer program or electronic circuit.

Robotics is the branch of mechanical engineering, electricalengineering and computer science that deals with the design,construction, operation, and application of robots.

Robots can be autonomous or semi-autonomous such as:

– Humanoids such as ASIMO (Honda's Advanced Step in

Innovative Mobility).

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• Humanoids such as ASIMO (Honda's Advanced Step in Innovative Mobility).

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Introduction

Robots can be autonomous or semi-autonomous such as:

– Industrial robots.

– Medical robots.

– Patient assist robots.

– Therapy robots.

– Collectively programmed (swarm robots).

– UAV drones.

– Microscopic Nano robots.

– Etc.6

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Modern robots (examples)

Mobile robot

They have the capability to move around in theirenvironment and are not fixed to one physicallocation.

Mobile robots are also found in industry, militaryand security environments or to perform certaintasks like vacuum cleaning.

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Modern robots (examples)

Industrial robots (manipulators) Industrial robots usually consist of a jointed

arm (multi-linked manipulator) and an endeffector that is attached to a fixed surface. One ofthe most common type of end effector isa gripper assembly.

An automatically controlled, reprogrammable,multipurpose, manipulator programmable in threeor more axes, which may be either fixed in placeor mobile for use in industrial automationapplications.

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Industrial Robots

An industrial robot is defined as an automatically controlled,reprogrammable, multipurpose manipulator programmablein three or more axes.

Typical applications of robots include

– Welding.

– Painting.

– Assembly.

– pick and place (such as packaging),

– Product inspection.

– Testing. 17

Types and features

The most commonly used robot configurations are:

1. Articulated robots ( a robot with rotary joints).

2. SCARA robots.

3. Delta Robots ( is a type of parallel robots).

4. Cartesian coordinate robots.

5. Gantry robots (x-y-z robots).

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Technical description

An axis – (degree of freedom “DOF”).

– Two axes are required to reach any point in a plane.

– Three axes are required to reach any point in space.

– If a robot has 3 degrees of freedom it can maneuver the

X-Y-Z axes, It cannot tilt or turn.

– Increasing the number of axes, we can access

more space.24

Technical description

Degrees of freedom (Number of axes) –

– The number of joints.

Or

– Number of DOF of a robot is the number of its motors.

Or

– The number of parameters of the system that may

vary independently.

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2 axes

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3 axes

5 axes4 axes

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Technical description

Working envelope (workspace)– the region of spacea robot can reach.

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Technical description

Kinematics – the actual arrangement of rigidmembers and joints in the robot, which determinesthe robot's possible motions.

Classes of robot kinematics include:

– Articulated.

– Cartesian

– parallel

– SCARA.29

Symbolic Representation of Robots

Robot Manipulators are composed of linksconnected by joints into a kinematic chain.

Joints are:

– Rotary (revolute) - allows relative rotation

between two links.

– Linear (prismatic) - allows a linear relative motion

between two links.

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Common Kinematic Arrangements

• Articulated Configuration (RRR)

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Common Kinematic Arrangements

Spherical Configuration (RRP)

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Common Kinematic Arrangements

SCARA Configuration (RRP)

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Common Kinematic Arrangements

Cylindrical Configuration (RPP)

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Common Kinematic Arrangements

Cartesian configuration (PPP)

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Components

Actuators are the "muscles" of a robot. The most popular actuators are:

– Electric motors

– Linear actuators

– Series elastic actuators (i.e.: spring ).

– Pneumatic artificial muscles.

– Electroactive polymers

– Elastic nanotubes37

Components

• Sensors allow robots to receive information about acertain measurement of the environment, orinternal components. The most popular topics are:

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Components

• Manipulation

– Robots need to manipulate objects; pick up, modify, destroy,or otherwise have an effect.

– The "hands" of a robot are often referred to as endeffectors, while the "arm" is referred to as a manipulator.

Mechanical grippers

– One of the most common effectors is the gripper. In itssimplest form it consists of two fingers which can open andclose to pick up and let go of a range of small objects.

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End of Lec

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