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The Evolution of Gear Designs: From Ancient Machinery to Robotics
- Jihyuk Jung
- 7 days ago
- 3 min read
Gears are one of the most important inventions in mechanical engineering. They are essential parts for motion transfer and force between parts of a machine. The unique design of gears, where it has teeth around its circular shape, allows one part to spin another, changing their speed and directions.
Initially, gears were built to make work easier. In ancient China, wooden gears were used to lift water for farming; and in ancient Greece, gears helped track the movement of stars in the Antikythera mechanism. Despite their fragile material such as wood or bronze, these early designs of gears acted as the foundation for the mechanical systems we rely on today.
Innovation of Gear Designs
The design of gears has evolved since the hand carved wooden wheel. Gears evolved from large, heavy, machine produced metal parts (such as clockwork mechanisms, water pumps and windmills) to smaller, smoother and more accurate products.
Gears are no longer large, cumbersome mechanical elements, instead, we see them in small, high strength steel products, such as internal combustion engine components, and in complex configurations. What was once a simple circular motion is today a complex coordinated motion of multiple components. Micro-gear technology allows us to create watches and medical devices with high accuracy, while flexible gears allow robotic systems to mimic human motion.
The advancements in gear design enabled machines to operate faster, more quietly and more efficiently. Therefore, these advancements opened the doors to compact machines, such as drones, smart phones and robots that require extremely precise gear control.
Challenges in Gear Engineering
Throughout the development of gear, engineers have faced numerous challenges on its design. One of the major problems they faced was the problem of inaccuracies as imprecision of teeth designs led to frequent slipping which damaged the overall system. Hence, to resolve this problem, gear designers improved the quality of the materials of the gear, and utilised equipment that could produce gear teeth with greater strength and precision. This development of gear tooth, further enhanced the operation of gears, ensuring that the teeth remained in contact at all times and rotated without interruption from high friction.
Additionally, gear designers struggled with the problem of gears wearing out over time. Metal gears sliding against one another caused deterioration. Therefore, to mitigate this problem, engineers added lubrication systems and utilised harder metals to the gears to reduce friction.
Furthermore, backlash (the small gap that exists between the teeth of two meshed gears), was a significant problem for gear designers who were working to develop machines requiring precise motion. By establishing tighter manufacturing tolerances and by developing gear systems, such as harmonic drive systems, backlash was reduced.
Gears in Modern Robotics: Bringing Robots to Life
In the development of robots, gears are one of the most crucial parts of humanoid robots that are built to move like people. In those machines, gears allow joints to bend and turn and support weight in the way our muscles and bones do. For instance, in the motion of a robot arm, using a small gear attached with a bigger gear, more torque is created, hence moving the large machine with minimal force. This allows the arm to move along smoothly and carry some weight without shaking or dropping. Harmonic drives and cycloidal gears are special gears that are used in humanoid robots. These allow the robots to execute delicate tasks, such as picking up fragile items, drawing, or even medical surgery.Â
References
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Prats, M., Azpiazu, J., GarcÃa, J. et al. (2009) ‘Control of Robotic Systems Using Harmonic Drives’, IEEE Transactions on Industrial Electronics, 56(10), pp. 3895–3902.
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Smithsonian Institution (n.d.) Antikythera Mechanism Exhibit. National Museum of American History. Available at: https://americanhistory.si.edu/collections/search/object/nmah_1817090Â
https://www.piceamotiondrive.com/harmonic-gear-drive-used-in-humanoid-robots.html