Introduction to robotics

Md. Ferdous Alam, Lecturer, MEE, SUST

Hello class!

Let’s watch a video!

So, what do you think?

• It’s cool, isn’t it?

• The dedication is not!

A brief history

• The first digital and programmable robot was invented by George Devol in 1954 and was named the Unimate. It was sold to General Motors in 1961 where it was used to lift pieces of hot metal

What is a robot?

• “A robot is re-programmable, multi-functional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks.”

(Robotics Institute of America)

Classification

• Variable-Sequence Robot: A device that performs the successive stages of a task according to a predetermined method easy to modify

• Playback Robot: A human operator performs the task manually by leading the Robot

• Numerical Control Robot: The operator supplies the movement program rather than teaching it the task manually

• Intelligent Robot: A robot with the means to understand its environment and the ability to successfully complete a task despite changes to the environment.

Degrees of freedom (DOF)• Degrees of freedom, in a mechanics context, are specific,

defined modes in which a mechanical device or system can move. The number of degrees of freedom is equal to the total number of independent displacements or aspects of motion.

• Six degrees of freedom (6DoF) refers to the freedom of movement of a rigid body in three-dimensional space. Specifically, the body is free to change position as forward/backward (surge), up/down (heave), left/right (sway) translation in three perpendicular axes, combined with changes in orientation through rotation about three perpendicular axes, often termed pitch, yaw, and roll.

• The human body has 244 degrees of freedom.

Let’s watch it

Robot Accessories

• Manipulator / Rover: This is the main body of the Robot and consists of links, joints and structural elements of the Robot.

• End Effector: This is the part that generally handles objects, makes connection to other machines, or performs the required tasks. It can vary in size and complexity from a endeffector on the space shuttle to a small gripper.

• Actuators : Actuators are the muscles of the manipulators. Common types of actuators are servomotors, stepper motors, pneumatic cylinders etc

• Sensors: Sensors are used to collect information about the internal state of the robot or to communicate with the outside environment. Robots are often equipped with external sensory devices such as a vision system, touch and tactile sensors etc which help to communicate with the environment

• Controller: The controller receives data from the computer, controls the motions of the actuator and coordinates these motions with the sensory feedback information.

Robot Configurations

• Cartesian/Rectangular Gantry(3P): These Robots are made of 3 Linear joints that orient the end effector, which are usually followed by additional revolute joints.

• Cylindrical (R2P): Cylindrical coordinate Robots have 2 prismatic joints and one revolute joint.

• Spherical joint (2RP): They follow a spherical coordinate system.

• Articulated/anthropomorphic(3R): An articulated

robot’s joints are all revolute, similar to a human’s arm.

• Selective Compliance Assembly Robot Arm (SCARA) (2R1P): They have two revolute joints that are parallel and allow the Robot to move in a horizontal plane, plus an additional prismatic joint that moves vertically.

Wrist motions

How to make a robot?

• Typical knowledgebase for the design and operation of robotics systems

–Dynamic system modeling and analysis

–Feedback control

–Sensors and signal conditioning

–Actuators (muscles) and power electronics

–Hardware/computer interfacing

–Computer programming

• Sensors: Piezoelectric sensors

• Controller: Provide necessary intelligence to control the manipulator/mobile robot process the sensory information and compute the control commands for the actuators to carry out specified tasks.

• Storage Hardware: Storage devices: e.g., memory to store the control program and the state of the robot system obtained from the sensors.

• Computation Hardware: Computational engine that computes the control commands.

• Interface Hardware: Hardware to interface digital controller with the external world (sensors and actuators)

Analog to digital converter

LM 358 OP amp

LM 1458 dual operational OP amp

Industrial Applications of Robots

Robots in Space

Humanoid

• Advanced Step in Innovative Mobility

Robots in Hazardous Environments

TROV in Antarcticaoperating under water

HAZBOT operating inatmospheres containingcombustible gases

Medical Robots

Robotic assistant formicro surgery

Robots in Military

Thank you!

See you in the next termfor any query reach me @217