Chapter End Effectors 9 Objectives Discuss the types

Chapter End Effectors 9

Objectives • Discuss the types of movements an end effector can perform. • Describe the types of end effector grippers and effector tools. • Identify the benefits of changeable end effectors. • List important factors and desirable characteristics to be considered in the design of end effectors. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

End Effector Movement • Prehensile movements use thumb and fingers • Nonprehensile movements do not require dexterity or use of thumb Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Prehensile Movements • Five basic prehensile, or gripping, movements Goodheart-Willcox Publisher Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Nonprehensile Movements • Do not require finger dexterity or use of opposable thumb Goodheart-Willcox Publisher Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Types of End Effectors • Grippers – Prehensile; grasp and move objects • Tools – Nonprehensile Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers • Mechanical finger grippers – Move in parallel or angular motion Goodheart-Willcox Publisher Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers • Two-finger grippers – Human thumb and index finger SCHUNK Intec Inc. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers • Two-finger with rotating joint Goodheart-Willcox Publisher Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers • V-shaped fingers with two points of contact on each finger Schunk-USA Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers • Three-finger grippers – Human thumb, index finger, and third finger SCHUNK Gmb. H & Co. KG Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers • Four-finger grippers – Square and rectangular parts • Collet grippers – Pick and place uniform cylindrical parts – 360° of clamping contact – Round, square, or hexagonal shapes Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers • Vacuum grippers – Use suction – One or more suction cups – Exact positioning not as critical Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Grippers • Multi-cup vacuum grippers increase contact surface area Pacific Robotics, Inc. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

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 Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Tools • Various types perform specific tasks – Welding – Material application – Machining and assembly • Automatic tool changer – More than one end effector – Change when needed Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Tools • Typical automatic tool changer applications Schunk-USA Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

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 Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

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 Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

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 Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

End Effector Design • Evaluate operation, workpiece(s), and environment – Inertia – Gripping force – Part orientation – Gripper sensing capabilities Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

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 Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Desirable Characteristics • Compliance is ability to tolerate misalignment of parts • Remote center compliance (RCC) device – Compensates for workpiece misalignment or irregularities Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

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 Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Custom-Designed End Effectors • Dual end effector has internal and external gripping capabilities Schunk-USA Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Custom-Designed End Effectors • Vision guidance system allows robot to find objects not placed symmetrically De-STA-Co Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

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 Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.