Views
4 years ago

FALL 2019

  • Text
  • Association
  • Bolts
  • Engineering
  • Distributors
  • Screws
  • Manufacturing
  • Products
  • Industrial
  • Fasteners
  • Fastener
Distributor's Link Magazine Fall 2019 / Vol 42 No4

54 THE DISTRIBUTOR’S

54 THE DISTRIBUTOR’S LINK GLOBALFASTENERNEWS.COM by JOHN WOLZ EDITOR editor@globalfastenernews.com TEACHING ROBOTS TO INSTALL SCREWS FIN MEDIA SPOTLIGHT So far, humans outperform machines in tightening and loosening screws, but an MIT Technology Review article declares the “future of manufacturing and recycling may depend on changing that.” “In the pantheon of technologies that make our modern society possible, one of the most under-appreciated and neglected is the threaded fastener, more commonly known as the screw,” the article by Emerging Technology from the arXiv declared. “This technology emerged at the dawn of the industrial era, when it became possible to make metal gadgets like these on a large scale.” “The process of screwing and unscrewing is still one in which humans outperform machines,” the “How to Teach a Robot to Screw” article notes. “Robotic devices have difficulty locating screws and their sockets and then manipulating screws and screwdrivers effectively.” So Dima Mironov and a team at the Skolkovo Institute of Science & Technology in Moscow sought to use haptics – the study of the sense of touch – to understand how humans install screws and then build robots that use the same technique. The SIST work has “uncovered a fundamental law of screwing (and unscrewing) that is beginning to make this possible.” Humans use two types of force to drive a screw or release it. “They first apply a pressure or axial force to push the screw into its socket,” the article explained. “They also apply a turning force, or torque, to turn the screw. The required torque depends on friction between the screw and the socket material, and this also depends on the state of the thread.” A key problem in installing screws is avoiding camouts, in which the screwdriver loses its grip on the screw head and slips. So SIST built a device to measure both the axial force and the torque to resolutions of less than 0.1 newtons in the axial direction and 0.003 newton-meters of torque. SIST then had 10 people repeatedly drive a small BUSINESS FOCUS ARTICLE screw—the kind used in smartphone assembly—into a three-millimeter socket and then measured the forces involved. “It turns out that for successful screwing and unscrewing, humans apply an axial force that is proportional to the torque,” the MIT article reported. “During screwing, this force reaches a maximum at the end of the drive; this pattern reverses during unscrewing.” “There is also a periodicity to these forces that comes from humans changing their grip as they turn their hands and re-engage with the screw.” So the SIST team looked at the maximum force exerted during each turn. “This is how they found the universal pattern of screwing and unscrewing forces that can successfully drive home a screw or remove it,” the MIT article reported. The team also found that the required force depends on the type of screw head: screws with a Phillips head require significantly more axial force to avoid cam-outs than screws with a hex head. So given the same axial force, hex heads are less likely to slip than Phillips heads. SIST programmed a robot to recreate the same pattern of forces and measured the forces as the robot worked. When the robot detected a cam-out, it increased the axial force and continued. Mironov declared the robot performed well. “The results of the robotic unscrewing agree with the results of the human experiments and demonstrate the universality of the conditions of the successful unscrewing.” The SIST researchers are part of a team building robots that can take apart electronic items such as smartphones for recycling. The project is called “RecyBot” and the goal is “to create a high-speed intelligent robotic system for dismantling electronics.” GFN Note: Articles in FIN’s Media Spotlight are excerpts from publications or broadcasts that show the fastener industry what the public is reading or hearing about fasteners or fastener companies. GLOBALFASTENERNEWS.COM

THE DISTRIBUTOR’S LINK 55

SHARE A PAGE FROM THIS MAGAZINE

OPTION 1: Click on the share tab above, or OPTION 2: Click on the icon (far right of toolbar) and then click on the icon (top right of the page).

Copyright © Distributor's Link, Inc. All Rights Reserved | Privacy Policy