Motorless robots
Published on 02 Jun 2021

A team of mechanical engineers has developed a new class of actuating material that may help the development of motorless robots in future.

The system developed by Professor Alfonso Ngan Hing Wan (Croucher Senior Research Fellowship 2009, Croucher Fellowship 1992, Croucher Scholarship 1991) of the University of Hong Kong uses nickel hydroxide-oxyhydroxide and can be actuated directly by visible light or electricity.

When integrated into a well-designed structure, a “mini arm” made by two hinges of actuating materials can easily lift an object 50 times of its weight

The actuation can be instantly triggered to produce a fast deformation and exert a force equivalent to 3,000 times its own weight. As opposed to other light driven materials, nickel hydroxide-oxyhydroxide produces a strong, quick and stable actuation. The level of stress and speed produced is comparable to mammalian skeletal muscles.

Light-induced materials are desirable because they enable wireless operation of robots, which is ideal for the development of micro biomimetic robots, artificial muscles and medical devices. However, high material and production costs have limited their use in robotics.

The material developed by Ngan is inexpensive and can be easily fabricated within three hours. The material can also be actuated by electricity and can be integrated into the existing robotics system.

Professor Norman Tien of the University of Hong Kong commented, ”This discovery of light-stimulated actuators by Professor Ngan is exciting and groundbreaking. Materials like these will make possible future robots that are very different from what we have today.”

Ngan believes that by scaling up the fabrication, artificial muscles comparable to that of mammalian skeletal muscles could be produced.

“It will take an additional five to ten years to study how the material can be applied before products are launched on the market,” said Ngan.

The research was published in Science Robotics[3].

Professor Alfonso Ngan Hing Wan is a leading authority on deformation mechanisms of materials. He has performed pioneer work on viscoelastic effects in nanoindentation, and statistical theories for deformation of micro-crystals and materials with random microstructures. He is the only Chinese so far to have received the prestigious Rosenhain Medal of the Institute of Materials , Minerals and Mining, and he holds a Higher Doctorate (DSc) from the University of Birmingham.

Extended Reading:

  1. Prof Ngan’s personal page (The Croucher Foundation): https://scholars.croucher.org.hk/scholars/alfonso-ngan-hing-wan
  2. Prof Ngan’s personal page (The University of Hong Kong): https://www.mech.hku.hk/academic-staff/Ngan-A.H.W.
  3. Science Robotics in 2018: http://robotics.sciencemag.org/content/3/18/eaat4051.full