Grasping everything

  • View
    1.243

  • Download
    8

Embed Size (px)

DESCRIPTION

In automated production processes grasping devices play a crucial role in the handling of many parts, components and products. The presentation starts with a grasping framework: a classification of grasping phases, describes how different principles are adopted at different scales in different applications and continues explaining different releasing strategies and principles. Then the presentation illustrates the numerous sensors used to monitor the effectiveness of grasping (part presence, exchanged force, stick-slip transitions, etc.). Later the grasping and releasing problems in different fields (from mechanical assembly to disassembly, from aerospace to food industry, from textile to logistics) are discussed. Finally, the most recent research is reviewed in order to show the new trends in grasping that provide an outlook on the future of both industrial grippers and robotic hands in automated production processes.

Text of Grasping everything

  • 1. Gripping technologies 11 on the basis of the paper Grasping devices and methods inautomated production processes , CIRP Annals - ManufacturingTechnology, Volume 63, Issue 2, 2014,G. FantoniDepartment of Civil and Industrial EngineeringUniversity of Pisa (Italy)NEWTECH 2013STC-A 2011 Fantoni G.- Active surfaces, materials and tools for assembly - 1

2. Remarks The presentation has been prepared for NewTech Conference 2013 and it istitled Gripping Technology. However it is based on the CIRP Keynotepaper titled Grasping devices and methods in automated productionprocesses. Please refer to this presentation by citing the paper as:Fantoni, G., Santochi, M., Dini, G., Tracht, K., Scholz-Reiter, B., Fleischer, J.,Lien, T.K., Seliger, G., Reinhart, G.,Franke, J., Hansen, H.N., Verl, A.,2014,Grasping devices and methods in automated production processes, CIRPAnnals - Manufacturing Technology, Volume 63, Issue 2, 2014, Pages 679-701, ISSN 0007-8506, http://dx.doi.org/10.1016/j.cirp.2014.05.006. The final version of the present paper can be found athttp://www.sciencedirect.com/science/article/pii/S0007850614001887STNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 2 3. Outline Standard definition and abstract definition Grasping process Grasping principles Releasing principles Monitoring principles Trends Why not? Conclusions AcknowledgementsSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 3 4. Outline Standard definition and abstract definition Grasping process Grasping principles Releasing principles Monitoring principles Trends Why not? Conclusions AcknowledgementsSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 4 5. Gripper: definitiona subsystems of handling mechanisms which providetemporary contact with the object to be grasped [..] and ensurethe position and orientation when carrying and mating the objectto the handling equipment [..]; the term gripper is also used incases where no actual grasping, but rather holding of the objectwhere the retention force can act on a point, line or surface [..]Monkman et al. Robot grippersIn abstract terms:h. mechanisms + Block/Hold + object + temporaryThat means that after graspingsome of the DOF of G. and O. are the sameSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 5 6. Cases of not standard grippersSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 6 7. Outline Standard definition and abstract definition Grasping process Grasping principles Releasing principles Monitoring principles Trends Why not? Conclusions AcknowledgementsSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 7 8. The grasping process1. Approaching the object: the gripper is positioned nearby the object.2. Coming into contact with the object surface3. Increasing the grasping force: the grasping force is increased, within certain limits.4. Securing the object. The force stops increasing. The dof of the object are removed5. Lifting the object;6. Releasing the object. Issue at the microscale;Monitoring the grasp: direct or indirect control of force, torque, stick slip sensors, contact.STNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 8 9. But is it true?FEEDING GRASPING HANDLING PLACINGSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 9 10. But is it true?FEEDING GRASPING HANDLING PLACINGSNPorous plies Steel sheetsSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 10 11. But is it true?FEEDING GRASPING HANDLING PLACINGSNPorous plies Steel sheetsSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 11 12. But is it true?FEEDING GRASPING HANDLING PLACINGHigh accelerationsSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 12 13. Adhesion problems in microassemblyForce between a silicon sphere and plane (by Fearing)10010-5force [N]10-1010-6 10-5 10-4 10-3 10-15radius of the sphere [m]STC-A 2011 Fantoni G.- Active surfaces, materials and tools for assembly - 13NEWTECH 2013 G. Fantoni - Gripping technology 14. Releasing??Releasing problems only at microscale? FALSEpermanent magnets onrotors of electric drives Sol-Gel dough products Frozen productsAn for sure at micro and nano scaleSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 14 15. Outline Standard definition and abstract definition Grasping process Grasping principles Releasing principles Monitoring principles Trends Why not? Conclusions AcknowledgementsSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 15 16. Grasping principlesSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 16 17. Standard Friction and Jaw grippersFriction-jaw mechanical gripperssx) two fingers;centre) single moving finger;dx) microgripper piezoelectricallyactuated.2090 9020b)STNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 17a)c) d)See FestoSee Monkman 18. Friction and Jaw grippers: standard?STNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 18 19. Vacuum grippersSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 19 20. Vacuum: the key tech in SMDs assemblySTC-A 2011 Fantoni G.- Active surfaces, materials and tools for assembly - 20NEWTECH 2013 G. Fantoni - Gripping technology 21. Needle gripperSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 21 22. Bernoulli grippersSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 22 23. Capillary grippersAt microscale capillary grippers have been used owing to their flexibilityand reliability; have a compliant behaviour and a self-centring effect;capability of grasping small and light components in a wide range ofmaterials and shapes; capability of handling delicate components as themeniscus between the gripper and the object has a bumper effect.To release parts grasped bycapillary grippers:- Scratching agaist anedge,- Two different fluids,- Changing the grippercurvature,- Electrowetting.STNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 23 24. Capillary principle1 2 Fc=FL+FT (1)GripperT TT TmgSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 24paplFL= 2 HRa2 (2)FT= 2Rasin(+) (3)In the previous equations isthe surface tension (for water~7210-3Nm-1) andH=2(1/r0-1/r1). 25. Capillary grippers Reliable Self centering Compliant It can work without refilling for more than1000 times (grasping-releasing cycles) It leaves traces and can stain lenses orsurface finished parts (mirrors, optics) Particular care in its use with SMDs andother electronic components Often the process need for a followingphase of heating in order to remove (byevaporation) the liquidSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 25 26. Capillary grippers: grasping and releasingSTC-A 2011 Fantoni G.- Active surfaces, materials and tools for assembly - 26 27. Capillary grippers: grasping and releasingGraspingMoving ReleasingWorking principle of theadhesion gripper able tograsp and release micropartsby a curvature change.STC-A 2011 Fantoni G.- Active surfaces, materials and tools for assembly - 27NEWTECH 2013 G. Fantoni - Gripping technology 28. Grasping and releasing microparts exploitingliquids with different surface tensionsA novel grasping and releasing strategy for microparts exploiting liquids with different surface tensions[Fantoni, Porta, Santochi]Releasing Forceh [mm]Vol [mm3]Fc [mN]STNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 28 29. ResultsHigh reliability Centring effectMany tests,all succeeded100% reliabilityAlso for very small releasing volumeSTC-A 2011 Fantoni G.- Active surfaces, materials and tools for assembly - 29NEWTECH 2013 G. Fantoni - Gripping technology 30. Capillary grippersMultiple grasping[Lambert,2005]Extensions to macroscale?STNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 30 31. ice gripperMore in general we can define them as phase transitiongrippers, they exploit the transition of a material fromliquid to solid.Ultrasonic-assisted adhesive forlimp and air-permeable textilesIce gripperfor limp and air-permeable textilesIce gripperformicrolensesSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 31 32. Electrostatic principleConductiveDielectricConductive or dielectric+ + + + + + + + + +- - - - - - - - -+ + + + + + + ++- -+- +- -+- +-V- - - - - -+ + + + + + + + + ++- -+- +- -+- +-- - - - - - - - - - - - - - -STNCE-WA T2E0C11H 2013 Fantoni G.- Active surfaGce.s ,F maantteorinalis -anGdr tiopoplsi nfogr atsescehmnbolylo-gy 32V(a)+ + + +- - - -- - -+ + +++ + ++(d)V(c)V- - - - - - - - - - - - - - -(b) 33. Electrostatic grippersElectrostatic forces:experimental evidencesSTNCE-WA T2E0C11H 2013 Fantoni G.- Active surfa