Science & Technology, Singapore (Commonwealth Union) – A team of researchers from the National University of Singapore (NUS) and the Northeast Forest University has developed a groundbreaking wooden robotic gripper that addresses the limitations of traditional gripper materials. Unlike soft plastics that melt at high temperatures or expensive metals that are rigid, this innovative wooden gripper offers both heat resistance and a gentle touch.
Traditionally, robotic grippers have been made from soft plastics to ensure they can handle objects without causing damage. However, these materials are susceptible to melting under high temperatures, limiting their applications in hot environments. On the other hand, grippers made from metals are stiff and expensive, which can restrict their flexibility and practicality.
The collaborative research team from NUS and the Northeast Forest University has introduced a solution in the form of a wooden robotic gripper. This unique gripper is capable of operating effectively in hot environments while maintaining a delicate touch. By utilizing wood as the primary material, the gripper offers heat resistance without compromising its ability to handle objects gently.
Moreover, the wooden gripper boasts an additional advantage: it is driven by changes in moisture, temperature, and lighting in the surrounding environment. This feature significantly reduces energy consumption, making it an energy-efficient alternative to traditional grippers. By leveraging natural environmental factors, the gripper operates in a more sustainable and cost-effective manner.
Assistant Professor Tan Swee Ching, the lead of the research team from the Department of Materials Science and Engineering under the NUS College of Design and Engineering indicated that Wood has great mechanical properties, natural deformation, present in bigger reserves, and is quite economical. In their most recent work, they have demonstrated that wood-based robotic grippers can get the better of the restrictions of traditional actuators as well as manipulators.
Assistant Professor Ching, also said “Our wooden robotic gripper can spontaneously stretch and bend itself in response to moisture, thermal and light stimulation. It also has good mechanical properties, able to perform complex deformation, wide working temperature range, low manufacturing cost, and is biocompatible. These unique features set it apart from conventional alternatives.”
Researchers indicated that that wooden gripper expands when exposed to increased humidity going over 95% RH, closing tightly as the temperature of the area is elevated beyond 70 deg C or when they encounter solar radiation.
The scientists had their work of the invention appear in the online version of scientific journal Advanced Materials in February this year.
Utilizing 0.5 mm-thin pieces of Canadian maple wood, the researchers successfully constructed the wooden robotic gripper. To prepare the wood, they employed a sodium chloride treatment to eliminate lignin, a plant cell wall component. By filling the wood’s large pores with a polymer known as polypyrrole, the material became more adept at absorbing heat and light, enhancing its thermal and light-responsive properties.
In addition, the team devised a novel moisture absorption solution in the form of a nickel-based hygroscopic gel. They coated one side of the modified wood pieces with this gel, while the other side received a hydrophobic film. This deliberate wet-dry contrast enabled the wood to rapidly absorb water vapors when exposed to high humidity, thus facilitating swift changes in the shape of the wooden gripper.
Assistant Professor Tan together with his team are presently seeking to enhance the performance of the wooden gripper, like shortening the bending period from around two minutes at the present, elevating the weight load its able to carry, and gripping objects having various shapes as well as sizes. They are finding techniques to lower the cost and to increase the fabrication of the wooden gripper as well.
With more structural design and performance enhancement, the researchers plan to produce an enhanced version of the wooden gripper to assist fire fighters conduct rescue operations.
