INTRODUCTION TO ROBOTICS AND AUTOMATION.pptx

Robotics and Automation

1. Chap 7: Introduction to Robotics Prepared by : 1.Mahesh Padsala (100210125032) 2.Abhay Harshora (100210125012) 3.Punit Bhalgamiya (100210125021) 4.Dharmesh Jasoliya (100210125055) 5.Jatin Lathiya (100210125033) PRODUCTION ENGINEERING, GEC Bhavnagar. GUIDED BY : Prof D.K.DAVE

2. Introduction Basic elements of a robot Classification of robot Physical configuration of robot Basic robot motion Technical features Actuators Sensors Robot applications C ontent

3. What is an Industrial Robot? An industrial robot is a reprogrammable, multi-functional manipulator designed to move materials, parts, tools, or special devices through variable programmed motions for the performance of a variety of tasks. An industrial robot c onsists of a number of rigid links connected by joints of different types, controlled and monitored by a computer.

4. CRITERIA FOR ROBOT SELECTION TYPE: Non-servo, servo, servo-controlled. WORK ENVELOPE: Rectangular, cylindrical, spherical, jointed arm. SCARA PAYLOAD CYCLE TIME REPEATABILITY DRIVE: Electric, pneumatic, hydraulic, any combination. UNIQUE CAPABILITIES

5. Basic Elements Of A Robot End Effector Manipulator Actuator Controller Sensors Processor Software

6. End Effector The end effector is part that is connected to the last joint of a manipulator, which generally performs the required tasks or handles the objects. The hand of a robot has a provisions for connecting the end effector that is specially designed for a purpose. The end effector is either controlled by the robot’s controller or the controller communicates with the end effector’s controlling device such as PLC.

7. Manipulator Manipulator is the combination of mechanical linkages, connected by joints to form an open-loop kinematic chain. The Manipulator is capable of movements in various directions. The joints of the Manipulator produce the motion which is either rotary or linear. The Manipulator gets the tasks performed through the end effector, which is connected to the Manipulator. Some manipulators are :

8. Mechanical Grippers

9. Vacuum Grippers

10. The wrist and gripper subassemblies

11. Actuators The actuators are the drivers used to actuate the joints of the manipulators. They produce relative rotary or linear motion between the two links of the joints. In short, they are the ‘Muscles’ of the manipulator. The common types of actuator are : servomotors, stepper motors , pneumatic cylinders, and hydraulic cylinders. The actuators are controlled by controller.

12. Controller The controller receives the instructions from the processor of a computer and controls the motions of the actuators. It takes feedback from the sensors. Functions of the controllers: It stores the positions and sequence date of the manipulator. It initiates and terminates the motion of the individual components(links) of the manipulator in a desired sequence and at the specified point. It permits the robot to be interfaced to the outside world via sensors.

13. Sensors The sensors are used to collect the information about the status of the manipulator and the end effector. This can be done continuously or at the end of a desired motions. The sensors collects the information like: instantaneous position, velocity and acceleration, of various links and joints of the manipulator. The information is sent to the controller. Using this information, the controller determines the configuration of the robots and controls the movement of the manipulator. The information sent by the sensors can be the analog, digital or combinations of two.

14. The sensors used in robots can be divided into two classes: Non visual sensors Visual sensors Non visual sensors: The non visual sensors include: limit switches, position sensors, velocity sensors, or force and tactile sensors. Visual sensors: The visual sensors include: TV cameras, vision system, charge-coupled device(CCD), or charge injected device(CID).

15. Processor: The processor is the brain of the robot, which calculate the motion of the joints so as to achieve the desired action of the robot. It sends signals to the controller and receives the feedback from the controller. The processor is a computer which is dedicated to a single purpose.

16. Software There are generally three groups of software that are used in robot: Operating system: for operating the computer. Robotic software: for operation of the robot. Application programmes : for operation of peripheral devices.

17. What are the parts of a robot? Manipulator Pedestal Controller End Effectors Power Source

18. Manipulator Base Appendages Shoulder Arm Grippers

19. Pedestal (Human waist) Supports the manipulator. Acts as a counterbalance.

20. Controller (The brain) Issues instructions to the robot. Controls peripheral devices. Interfaces with robot. Interfaces with humans.

21. End Effectors (The hand) Spray paint attachments Welding attachments Vacuum heads Hands Grippers

22. Power Source (The food) Electric Pneumatic Hydraulic

23. TYPES OF ROBOTS An industrial is an all- purpose machine equipped with computer memory capable of replacing human labor by automatic performance of movements. Some typical types of robots are: Manual manipulator : This type of a robot is worked by an operator and is used in applications, where working conditions are hostile for humans. For Example, in a molten metal pouring application, the worker can safely handle the material from a distance, with the help of a robot. Fixed sequence robot: This robot performs repetitive operations according to a predetermined sequence.

24. 3) Variable Sequence robot: This robot performs repetitive operation according to well defined set of instructions, which can be easily changed. 4) Playback Robot : In many cases, a teach pendent is provided for online non-textual commands. This method where the robot is programmed with the help of a teach pendent is known as lead-through programming. The various sequence of the operation can be signaled through the teach pendent , which would be recorded. The robot is thus taught the various motions, which it duly records and performs them independently at a later stage. Such robot having the ability to store the arm position are called as playback robot or teachable robot.

25. 5) NC robot : These robots are a part of CIM and are controlled by a central computer. They can perform a given task according to the sequence, conditions and position as commanded by the numerical dada from the computer. 6) Intelligent robot: The third generation of robots use sensors to detect the changes in the work environment. The sensors could be touch or vision based. With this capability, the robot has a decision ability to control the operations.

26. ROBOT GEOMERTICAL CLASSIFICATION Cartesian or Rectangular robots Cylindrical robots Spherical or polar robots Revolute or articulated robots Snakelike or tensor-arm robots

27. Cartesian work space configuration: Robots with Cartesian configurations consists of links connected by linear joints (L). Gantry robots are Cartesian robots (LLL). Type of configuration ADVATEGES: High resolution and high accuracy. Good obstacle avoidance and collision prevention. Independency of gravity loading, that is, ease of joint motion control. DISADVANTAGES: Large structural framework. Confinement of the workspace. More complex mechanical design for linear sliding.

28. Cylindrical work space configuration: A robot with 2 prismatic joints and a rotary joint – the axes consistent with a cylindrical coordinate system. ADVANTAGES: Almost independent of gravity loadings. Collision-free movement. Two linear axes make mechanical design less complex. DISADVANTAGES: Large amount of structures. Restriction on compatibility with Other manipulators in a common workspace. Less accuracy and resolution. Type of configuration

29. Polar (spherical) configuration robots: Type of robot Polar robots have a work space of spherical shape . Generally, the arm is connected to the base with a twisting (T) joint and rotatory (R) and linear (L) joints follow. ADVANTAGES: Low weight low complexity. Short joint travel for many motions. Good resolution. DISADVANTAGES: High variable torques on second & third joint of arm, Creating a counterbalance problem. Position error is large.

30. Joined-arm (articulated) configuration robot : The robot which contains arms like human which can rotates much like the human waist is know as revolute robot. ADVANTAGES: Flexibility to reach over or under an object. DISADVANTAGES: Poor accuracy, resolution High variable torque on joints. Limited ability to avoid obstacles, high moment of inertia, gravity effects, dynamic instability. Type of configuration

31. Snakelike or Tensor-Arm robot: These robot arms can take any shape in the three –dimensional space. Thus they necessarily consist of many element that can move with respect to there adjacent element.

32. BASIC ROBOT MOTIONS The degree of freedom or grip of a robotic system can be compared to the way in which the human body moves. For each degree of freedom a joint is required. The degrees of freedom located in the arm define the configuration. Each of the five basic motion configurations discuss previously utilizes three degrees of freedom in the arm. Three degrees of freedom located in the wrist give the end effector all the flexibility.

33. A total of six degrees of freedom is needed to locate a robot’s hand at any point in its work space. Although six degrees of freedom are needed for maximum flexibility, most robot employee only three to five degrees of freedom. The three degrees of freedom located in the arm of a robotic system are: The rotational reverse: is the movement of the arm assembly about a rotary axis, such as left-and-right swivel of the robot’s arm about a base.

34. The radial traverse : is the extension and retraction of the arm or the in-and-out motion relative to the base. The vertical traverse : provides the up-and-down motion of the arm of the robotic system. The three degrees of freedom located in the wrist, which bear the names of aeronautical terms, are: Pitch or bend : is the up-and-down movement of the wrist. Yaw : is the right-and-left movement of the wrist. Roll or swivel : is the rotation of the hand.

35. Robot programming and interfaces The setup or programming of motions and sequences for an industrial robot is typically taught by linking the robot controller to a laptop , desktop computer or (internal or Internet) network . A robot and a collection of machines or peripherals is referred to as a work cell , or cell. A typical cell might contain a parts feeder, a molding machine and a robot. The various machines are 'integrated' and controlled by a single computer . How the robot interacts with other machines in the cell must be programmed, both with regard to their positions in the cell and synchronizing with them.

36. Robot programming: Manual method or Show and teach method Walk through method Lead through method Or Guiding Off-line programming Or programming languages Manual method: The manual method is more like setting up a machine rather than programming this involutes setting mechanical stops, cams, switches, or relays in the robot’s control units( RCU ). This method is suitable for pick and place type of robot .

37. 2. Walk through method : I n the walk through method the programmer manually moves the robots arm and hand through the motion sequence of the work cycle. This method is appropriate for spraying painting and the arc welding. 3. Lead method : The lead through method make use of teaching pendant to power drive the robot through its motion sequence. This method is very popular, being easy and convenient. 4. Off-line method : OFF-line robot programming is accomplished on a computer terminals. After preparing the program, it is entered into the robot memory for use during the work cycle. This method had the advantage of saving the production time otherwise lost in teaching the robot a new task.

38. Robot programming languages: Join control languages - LEVEL 1 Primitive motion languages - LEVEL 2 Structured languages - LEVEL 3 Task-oriented languages - LEVEL 4

39. Some of the robot languages are: VAL - versatile algorithmic language AML - A manufacturing language MCL - Manufacturing control language RAIL - Robotic automatic incorporated language VML - Virtual machine language SRL - Structured robot language ROBEX - Robot Exapt AUTOPASS - Automatic parts assembly systems RAPT - Robot Automatic programmed tools LAMA - language for automatic mechanical assembly

40. Actuators Actuators control each of the axes and maintain the direction of moving. Since robots need to handle weights from various components, it has a larger change in motion. Therefore, the motion of actuators is very important. Commands about the direction of movement are sent from the computer of the robots and feedbacks are checked at the same time to ensure the moving parts follow the correct path. This process requires a high-speed computer to send out commands, and reading the machine’s motion at reasonable speed.

41. Based on the type of actuating elements, the actuators are classified into four types: Mechanical actuators Hydraulic actuators 3) Pneumatic actuators 4) Electric actuators

42. Mechanical actuators The mechanical actuator use the elements like : rack and pinion, gears, power screw, belt, etc., for providing the motive force/ torque for the manipulator joints of the robots. Based on the type of movements : Linear mechanical actuators Rotary mechanical actuators

43. 1) Linear mechanical actuators: The following linear mechanical actuators are used to actuate the linear manipulator joints the robots: Rack and pinion Reciprocating ball screws

44. 2) Rotary mechanical actuators The following rotary actuators are used to actuate the rotary joints of robot: Timing belts Gear pairs Harmonic drives

45. 3) Hydraulic actuators The hydraulic actuators use the pressurized fluid for providing motive force for the manipulator joints of the robots. Two types of hydraulic actuators: Linear hydraulic actuators Rotary hydraulic actuators

46. Single acting hydraulic cylinder Double acting hydraulic cylinder 1) Linear hydraulic actuators

47. 2) Rotary hydraulic actuators Three types of rotary hydraulic actuators: Gear motors Vane motors Piston motors

48. 4) Pneumatic actuators The pneumatic actuators use the compressed air for providing motive force for the manipulator joints of the robots. Linear pneumatic actuators Rotary pneumatic actuators Linear pneumatic actuators: it may be the single acting or may be double acting pneumatic cylinders used to actuate the linear joints of the robots. Rotary pneumatic actuators: 1) vane motors 2) piston motors

49. 5 ) Electric actuators Types of electric motors used as rotary actuators in robots. D.C motors Reversible A.C motors Brushless D.C motors A.C servo motors Reversible A.C motors D.C servo motors Stepper motors

50. Robot sensors Transducer is a device that converts one type of physical variable (e.g. force, pressure, velocity) into another form, commonly electrical voltage. Sensor is a transducer used to make a measurement of physical variable. The sensor are used to collect the information about the status of the manipulator and end effector with respect to object position. This can be done continuously or the at the end of a desired motion. The information sent to the controller. Using this information, the controller determines the configuration of the robot at the given instant and controls the movement of the manipulator. The information sent by the sensors can be either analog, digital, or combination of two.

51. Types of sensors Classification based on contact: Tactile or contact sensors: It can be further divided into three categories. Touch sensors (binary): Used to indicate whether the contact has been made with object or not, without regard t the contacting force. exe: limit switches, microcontroller. Force sensors: Force sensors are type sensors in which the output signal is proportional to a local force. Magnitude of the magnitude of the contact force between the object and the sensors. exe :: piezoelectric sensors, force-sensing resistors, strain gauges.

52. Tactile or contact sensors:

53. 2. Non contact sensors

54. C . Position and displacement sensors: The position and displacement sensors are used to measure the displacement , both rotary and linear. Exe:: piezoelectric meters, encoders, linear variable differential transformers(LVDT). 2. Non contact sensors: Non contact sensors measure the parameter without contacting the object. Proximity and range sensors: Proximity sensors give an indication, when object is close to the sensors. Range sensors are used to measure the distance between the object and the sensors.

55. (2) Robot (or machine) vision system: It is concerned with the visual image taken by camera is typically digitized and stored in the computer memory. (3) Voice synthesizers: It includes voice sensing and voice programming. Voice programming is used for oral communication of instructions to the robot. When the spoken word matches the stored word, robot performs the particular action which corresponds to the word.

56. Classification based in reference position Based on the reference position with respect to which the parameters are measured by sensors, the sensors are classified into two types: 1.Internal sensors : these are used for measurement of parameter with respect to some reference position on robot itself. 2.External sensors : these are for measurement of parameter with respect to some reference position outside the robot structure.

57. 64 COMPARISON OF THE TWO TYPES EXTRINSIC INTRINSIC APPLICATIONS- TEMPERATURE, PRESSURE,LIQUID LEVEL AND FLOW. LESS SENSITIVE EASILY MULTIPLEXED INGRESS/ EGRESS CONNECTION PROBLEMS EASIER TO USE LESS EXPENSIVE APPLICATIONS- ROTATION, ACCELERATION, STRAIN, ACOUSTIC PRESSURE AND VIBRATION. MORE SENSITIVE TOUGHER TO MULTIPLEX REDUCES CONNECTION PROBLEMS MORE ELABORATE SIGNAL DEMODULATION MORE EXPENSIVE

58. ADVANTAGES OF ROBOTS: REVOLUTION IN MEDICAL SCIENCE AND HEALTH CARE SYSTEMS. NEW & WIDE SCOPE IN EDUCATION & TRAINING. A GOOD HELP IN NUCLEAR INDUSTRY. USED TREMENDOUSLY IN SPORTS ACTIVITIES. PLAY THE ROLE OF AN EFFICIENT ASSISTANCE. IN RESEARCH AND DEVELOPMENT SCIENCES. CAN VERY WELL HANDLE HOUSEHOLD BUSINESS.

59. ADVANTAGES OF INDUSTRIAL ROBOT: DIE CASTING SPOT WELDING ARC WELDING INVESTMENT WELDING FORGING & PRESS WORK PLASTIC MOULDING SPRAY PAINTING & SURFACE TREATMENT FOUNDRY APPLICATIONS MACHINE TOOL LOADING PALLETIZATION INSPECTION & TESTING

60. DISADVANTAGES:  Robots lack capability to respond in emergencies.  Robots, although superior in certain senses, have limited capabilities in Degree of freedom, Dexterity, Sensors, Vision system, real time response.  Robots are costly, due to Initial cost of equipment, Installation costs, Need for Peripherals, Need for training, Need for programming .

61. APPLICATIONS OF ROBOT: 1. Parts handling to perform the following tasks: (a) Recognizing, sorting of parts. (b) Picking and placing the parts at desired locations. (c) Loading and unloading the parts on machines. (d) Palletizing and depalletizing. 2. Parts processing to perform the following operations: (a) Routing (b) Drilling (c) Riveting (d) Arc welding (e) Grinding (f) Flame cutting (g) Debarring (h) Spray painting ( i ) Coating (j) Sandblasting (k) Gluing (l) Polishing (m) Heat treatment

62. 3. Product fabrication involving assembly of various products: (a) Electric motors (b) Car bodies 4. Handling hot or heavy work piece, 5. Repetitive operations, 6. Part geometry must permit mechanical handling.

63. THANK YOU ANY QUESTIONS???