robot classification

robot classification

1. PARTS OF ROBOT

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

3. Manipulator Base Appendages Shoulder Arm Grippers

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

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

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

7. Power Source (The food) Electric Pneumatic Hydraulic

8. Robot Joints Prismatic Joint : Linear, No rotation involved. (Hydraulic or pneumatic cylinder) Revolute Joint : Rotary, (electrically driven with stepper motor, servo motor)

9. Robot Coordinates Cartesian/rectangular/gantry (3P) : 3 cylinders joint Cylindrical (R2P) : 2 Prismatic joint and 1 revolute joint Spherical (2RP) : 1 Prismatic joint and 2 revolute joint Articulated/anthropomorphic (3R) : All revolute(Human arm) Selective Compliance Assembly Robot Arm (SCARA): 2 paralleled revolute joint and 1 additional prismatic joint Delta :   These spider like robots are built from jointed parallelograms connected to a common base.

10. Cartesian Coordinate System

11. Cartesian Coordinate System X- Axis

12. Cartesian Coordinate System Y- Axis

13. Cartesian Coordinate System Z- Axis

14. Cartesian Coordinate System

15. Cylindrical Coordinate System

16. Cylindrical Coordinate System Y - Axis

17. Cylindrical Coordinate System Z - Axis

18. Cylindrical Coordinate System q - Axis

19. Cylindrical Coordinate System

20. Polar (Spherical) Coordinate System

21. Polar (Spherical) Coordinate System  - Axis

22. Polar (Spherical) Coordinate System q - Axis

23. Polar (Spherical) Coordinate System g - Axis

24. Polar (Spherical) Coordinate System

25. Revolute (Joined-Arm) Coordinate System

26. Revolute (Joined-Arm) Coordinate System a - Axis

27. Revolute (Joined-Arm) Coordinate System  - Axis

28. Revolute (Joined-Arm) Coordinate System q - Axis

29. Revolute (Joined-Arm) Coordinate System

30. Robotics Joints

31. Robots degrees of freedom Degrees of Freedom: Number of independent position variables which would has to be specified to locate all parts of a mechanism. In most manipulators this is usually the number of joints.

32. Fig. 1.3 A Fanuc P-15 robot. Reprinted with permission from Fanuc Robotics, North America, Inc. Consider what is the degree of Fig. 3 1 D.O.F. 2 D.O.F. 3 D.O.F. Robots degrees of freedom

33. Degrees of Freedom VS Degrees of freedom (DOF) is a term used to describe a robot’s freedom of motion in three dimensional space— specifically, the ability to move forward and backward, up and down, and to the left and to the right. For each degree of freedom, a joint is required. A robot requires six degrees of freedom to be completely versatile.

34. Degrees of Freedom Rotating the base .

35. Degrees of Freedom Pivot the base of the arm.

36. Degrees of Freedom Bending the elbow.

37. Degrees of Freedom Wrist up and down.

38. Degrees of Freedom Wrist left and right.

39. Degrees of Freedom Rotating the wrist .

40. Robot Workspace Fig. 1.7 Typical workspaces for common robot configurations

41. Cartesian Cylindrical Polar Revolute SCARA

42. Joint symbol

43. Function block diagram

44. Reach and Stroke Performance parameters

45. Performance parameters :ACCURACY & Repeatability Repeatability - is how well the robot will return to a programmed position. This is not the same as accuracy. It may be that when told to go to a certain X-Y-Z position that it gets only to within 1 mm of that position. This would be its accuracy which may be improved by calibration. But if that position is taught into controller memory and each time it is sent there it returns to within 0.1mm of the taught position then the repeatability will be within 0.1mm. Accuracy – is how closely a robot can reach a commanded position. When the absolute position of the robot is measured and compared to the commanded position the error is a measure of accuracy. Accuracy can be improved with external sensing for example a vision system or Infra-Red. See robot calibration. Accuracy can vary with speed and position within the working envelope and with payload (see compliance).

46. Resolution Resolution The resolution of a robot is a feature determined by the design of the control unit and is mainly dependent on the position feedback sensor . It is important to distinguish the programming resolution from the control resolution . The programming resolution is the smallest allowable position increment in robot programs and is referred to as the basic resolution unit (BRU). For IRB2000 ABB robot it is approximately 0,125 mm on linear axis. The control resolution is the smallest change in position that the feedback device can sense . For example, assume that an optical encoder which emits 1000 pulses per revolution of the shaft is directly attached to a rotary axis. This encoder will emit one pulse for each of 0,36° of angular displacement of the shaft. The unit 0,36° is the control resolution of this axis of motion.

47. Figure: Error affecting control resolution

48. Robot drive system

49. Hydraulic system Power Packs Reservoir Hydraulic pump Electric motor Valves Hoses and pipes

50. Robot Reference Frames Fig. 1.6 A robot ’ s World, Joint, and Tool reference frames. Most robots may be programmed to move relative to either of these reference frames.