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Prepared by Q. C. Nguyen (PhD) & C.B. Pham (PhD)

Mechatronics Dept., Dynamics & Control Group, 207701‐Industrial Robot

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Overview of Robots



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Outline‐ What are robots?‐ Brief history of robot‐ What is a industrial robot‐ Industrial robot configuration‐ Industrial robot classification‐ Robot programming ‐ Industrial robot applications



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What are robots?‐ Definition (Robotics Association of America): "A

reprogrammable, multifunctional manipulatordesigned to move material, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks" . Complicated definition!

‐ A simpler version: “An automatic device that performs functions normally ascribed to humans or a machine in the form of a human.”



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‐What are Robots? Ans: Machines with sensing, intelligence and mobility

‐Why use Robots? Ans: Perform 4A tasks in 4D environments

Industrial robots Mobile robots

Kinematics DynamicsControl

Kinematics/Control Sensing and SensorsMotion planning Mapping/Localization

AutomationAugmentationAssistanceAutonomous

Dangerous, Dirty, Dull, Difficult

Another point of view….



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‐ Many devices with varying degrees of autonomy are called robots.

‐ Many different definitions for robots exist. ‐ Some consider machines wholly controlled by an operator to be robots.

‐ Others require a machine be easily reprogrammable.

Who’s to say?



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What is a industrial robot?‐ A manipulator (or an industrial robot) is composed of a series of links connected to each other via joints. Each joint usually has an actuator (a motor for e.g.) connected to it.‐ These actuators are used to cause relative motion between successive links. One end of the manipulator is usually connected to a stable base and the other end is used to deploy a tool.



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Robots in Early History‐ Ancient Greek poet Homer described maidens of gold, mechanical helpers built by Hephaistos, the Greek god of metalsmiths.‐ In 1495, Leonardo da Vinci drew plans for a mechanical man.‐ Real robots were only possible in the 1950s and 1960s with the introduction of transistors and integrated circuits.



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Robots in Early History

‐ 1948, A teleoperator‐equipped articulated arm is designed by Raymond Goertz for the Atomic Energy Commission.‐ 1961, The first industrial robot was online in a General Motors automobile factory in New Jersey. It was Devol and Engelberger's UNIMATE. It performed spot welding and extracted die castings..‐ 1980, The robot industry starts its rapid growth, with a new robot or company entering the market every month.



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First Commercial Robot‐ After the 1950’s the first commercial robot nicknamed the “Unimate”, was created.‐ The first Unimate was installed at a General Motors plant to work with heated die‐casting machines.



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- Following the early instances of robots in plays and science fiction stories , robots then started to appear on television shows, like Lost in Space (1965) and then in Hollywood movies.‐ Scientists today are still a long way off from programming robots which can think and act like humans.



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Industrial Robot DefinedA general‐purpose, programmable machine possessing certain anthropomorphic characteristics

‐ Hazardous work environments‐ Repetitive work cycle‐ Consistency and accuracy‐ Difficult handling task for humans‐Multishift operations‐ Reprogrammable, flexible‐ Interfaced to other computer systems



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What will we focus on? Robots in industries

Robots are used in a vast range of industries.

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Robot components



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Structures of Robot• Manipulator consists of joints and links

– Joints provide relative motion– Links are rigid members between joints– Various joint types: linear and rotary– Each joint provides a “degree‐of‐

freedom”– Most robots possess five or six

degrees‐of‐freedom• Robot manipulator consists of two

sections:– Body‐and‐arm – for positioning of

objects in the robot's work volume– Wrist assembly – for orientation of

objects



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Manipulator Joints

• Translational motion– Linear joint (type L)– Orthogonal joint (type O)

• Rotary motion– Rotational joint (type R) – Twisting joint (type T)– Revolving joint (type V)



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Joint Notation Scheme‐ Uses the joint symbols (L, O, R, T, V) to designate joint types used to construct robot manipulatorSeparates body‐and‐arm assembly from wrist assembly using a colon (:)

‐ Example: TLR: TR

‐ Common body‐and‐arm configurations …



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Polar Coordinate Body‐and‐Arm Assembly

‐ Notation TRL:

‐ Consists of a sliding arm (L joint) actuated relative to the body, which can rotate about both a vertical axis (T joint) and horizontal axis (R joint)



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Cylindrical Body‐and‐Arm Assembly

‐ Notation TLO:

‐ Consists of a vertical column, relative to which an arm assembly is moved up or down‐ The arm can be moved in or out relative to the column



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Cartesian Coordinate Body‐and‐Arm Assembly

‐ Notation LOO:

‐ Consists of three sliding joints, two of which are orthogonalOther names include rectilinear robot and x‐y‐z robot



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Jointed‐Arm Robot

Notation TRR



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SCARA Robot

‐ Notation VRO‐ SCARA stands for Selectively ‐Compliant Assembly Robot Arm‐ Similar to jointed‐arm robot except that vertical axes are used for shoulder and elbow joints to be compliant in horizontal direction for vertical insertion tasks



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Robot Classification

There are four main aspects to classifyrobots:

‐ Types of workspace

‐ Robot generation

‐ Types of control

‐ Drive system



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Cartesian Configuration

Classification based on type of workspace



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• Cylindrical Configuration




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• Spherical Configuration




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• Revolute/Jointed Configuration




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Classification based on robot generationsSeveral organizations have defined classification systems fordifferent types of robots. One such organization is JARA, theJapan Robot Association (previously JIRA, the Japan IndustrialRobot Association). They define six different classes of robot:

1. Manual handling device: This type of robot has multipledegrees of freedom, but all of its actions are performed underthe direct control of an operator. Certain devices in this class maybe referred to as co‐bots (cooperative robots).

2. Fixed sequence robot: This type of robot repeats a fixedsequence of actions without needing to be controlled by anoperator. However, the sequence of actions it performs cannotbe modified (i.e. it is not programmable).



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Classification based on robot generations

3.Variable sequence robot: This type of robot is similar to class 2,except that the sequence of actions can be reprogrammed easilyallowing it to be quickly adapted to perform new tasks.

4.Playback robot: This type of robot is first guided through a sequenceof actions by an operator, then repeats the same actions automatically.

5.Numerical control robot: This type of robot moves through asequence of actions, which it receives in the form of numerical data.

6.Intelligent robot: A robot that senses its environment and responds tochanges in it in order to continue performing its function.



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Classification based on types of control

Pick-and-Place Robot Continuous Path Robot



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• Electric Drives

Classification based on drive systemCommon drive systems used in robotics are electric drive,hydraulic drive, and pneumatic drive.

Electric drive robots are relativelyaccurate compared to hydraulicallypowered robots.

Types: AC/DC servomotors, stepper motors.

Advantages: quiet, less floor space,electric power readily available, clean‐air environments, precision.



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• Pneumatic DrivesPneumatic drives: air‐driven actuators.

Advantages: economical, easy installation, less costly than hydraulic drives, good speed and accuracy.

Disadvantages: precision is less than electric drives (air is compressible), air needs conditioning, noisy, vibration.

Classification based on drive system



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Classification based on drive system

• Hydraulic Drives

Advantages: precise motion control over a wide range of speedsand loads, robust, and greater strength.

Disadvantages: expensive, high maintenance, not energyefficient, noisy, not suited for clean‐air environments.

Hydraulic drives are electric pump connected to a reservoir tank and a hydraulic actuator.



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Robot Programming• Leadthrough programming

– Work cycle is taught to robot by moving the manipulator through the required motion cycle and simultaneously entering the program into controller memory for later playback

• Robot programming languages– Textual programming language to enter commands into robot controller

• Simulation and off‐line programming– Program is prepared at a remote computer terminal and downloaded to robot controller for execution without need for leadthrough methods



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Leadthrough Programming

1. Powered leadthrough – Common for point‐to‐

point robots– Uses teach pendant

2. Manual leadthrough – Convenient for

continuous path control robots

– Human programmer physical moves manipulator



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Leadthrough Programming Advantages• Advantages:

– Easily learned by shop personnel– Logical way to teach a robot– No computer programming

• Disadvantages:– Downtime during programming– Limited programming logic capability – Not compatible with supervisory control



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• Textural programming languages• Enhanced sensor capabilities• Improved output capabilities to control external equipment• Program logic• Computations and data processing• Communications with supervisory computers

Robot Programming



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Simulation and Off‐Line Programming



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Robot ApplicationMachine loadingPick and place operationsWeldingPaintingSamplingAssembly operationManufacturingSurveillanceMedical applications Assisting disabled individuals Hazardous environmentsUnderwater, space, and remote locations

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Industrial Robot Applications1. Material handling applications

– Material transfer – pick‐and‐place, palletizing– Machine loading and/or unloading

2. Processing operations– Welding– Spray coating– Cutting and grinding

3. Assembly and inspection



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Robotic Arc‐Welding Cell• Robot performs flux‐cored arc welding (FCAW) operation at one workstation while fitter changes parts at the other workstation



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Will we become robots?

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