2. Chapter
End Effectors 9

3. Objectives Discuss the types of movements an end effector can perform.
Describe the types of end effector grippers and end effector tools.
Identify the benefits of changeable end effectors.
List important factors and desirable characteristics to be considered in the design of end effectors.

4. End Effector Movement Prehensile movements use thumb and fingers
Nonprehensile movements do not require dexterity or use of thumb

5. Prehensile Movements Five basic prehensile, or gripping, movements
Goodheart-Willcox Publisher

6. Nonprehensile Movements
Do not require finger dexterity or use of opposable thumb
Goodheart-Willcox Publisher

7. Types of End Effectors Grippers Tools
Prehensile; grasp and move objects
Tools
Nonprehensile

8. Grippers

9. Grippers Mechanical finger grippers Move in parallel or angular motion
Goodheart-Willcox Publisher

10. Grippers Two-finger grippers Human thumb and index finger
SCHUNK Intec Inc.

11. Grippers
Two-finger with rotating joint
Goodheart-Willcox Publisher

12. Grippers V-shaped fingers with two points of contact on each finger
Schunk-USA

13. Grippers Three-finger grippers
Human thumb, index finger, and third finger
SCHUNK GmbH & Co. KG

14. Grippers Four-finger grippers Collet grippers
Square and rectangular parts
Collet grippers
Pick and place uniform cylindrical parts
360° of clamping contact
Round, square, or hexagonal shapes

15. Grippers Vacuum grippers Use suction One or more suction cups
Exact positioning not as critical

16. Grippers Multi-cup vacuum grippers increase contact surface area
Pacific Robotics, Inc.

17. Grippers Electromechanical grippers
Magnetic field created by permanent magnet or electromagnet
Electromagnetic gripper uses dc power source
Only handle materials containing iron
Custom designed for specific applications

18. Tools Various types perform specific tasks Automatic tool changer
Welding
Material application
Machining and assembly
Automatic tool changer
More than one end effector
Change when needed

19. Tools
Typical automatic tool changer applications
Schunk-USA

20. Tools Welding tools vary according to operation
Arc welding torch attached to robot arm
Tool changers attach spot weld device to arm
Laser and gun welding systems with proper tool changers

21. Tools
Material application for palletizing, packaging, and handling operations
Rapid tool changing automates and improves process
Robots for machining and assembly require different tools
Rapid tool changing critical to productivity

22. Changeable End Effectors
Required by manufacturing robots
Increases effectiveness and flexibility
Quick-change tooling
Interface adapters must be standardized
Change end effectors with minimum downtime

23. End Effector Design Evaluate operation, workpiece(s), and environment
Inertia
Gripping force
Part orientation
Gripper sensing capabilities

24. Desirable Characteristics
Strength to carry out tasks
Withstand rigorous use
Guard against strain damage
Breakaway devices
Overload sensor detects obstructions or overload conditions
Signals controller to shut down

25. Desirable Characteristics
Compliance is ability to tolerate misalignment of parts
Remote center compliance (RCC) device
Compensates for workpiece misalignment or irregularities

26. Custom-Designed End Effectors
Can be designed for a particular application
Broaden range of tasks that can be performed
Can be designed to handle fragile or oddly shaped parts

27. Custom-Designed End Effectors
Dual end effector has internal and external gripping capabilities
Schunk-USA

28. Custom-Designed End Effectors
Vision guidance system allows robot to find objects not placed symmetrically
De-STA-Co

29. Custom-Designed End Effectors
Expandable grippers clamp irregularly shaped workpieces
Hollow rubber envelopes enlarge when pressurized
Even distribution of surface pressure
Grip outside or inside surface