In 1878, Eadweard Muybridge took the photo series The Horse in Motion. People were very interested in the running horse captured in the series. Recently, this interest has come back again. Weeks ago, during the Paris Olympics opening ceremony, Floriane Issert, a horsewoman, rode a metal horse down the river Seine and impressed everyone.
As players in robotics, we at WhalesBot find this cyborg-like design very impressive. We are also curious about how this mechanical horse lifts its legs gently and gracefully. To learn more, we visited the official website of Sanofi, the company that designed and made this horse. We watched a video that showed how they did it, and saw that the team uses several gears in the horse's joints to make careful movements.
What are gears?
Gears are connectors commonly found in machines and engineering. They help move motion and force between different parts. Gears are often wheel shapes with teeth. They fit together to create a system with specific jobs. We can classify gear systems based on their appearance and how they function:
Spur gears
Spur gears are among the most common gears used in robots and other machines. These gears have straight teeth and are placed next to each other on shafts. When two spur gears fit together, they can change the speed or direction of the shafts’ rotation.
Helical gears
Different from spur gears, the teeth of helical gears are cut at an angle. This helps the helical gears mesh smoothly and quietly, making them ideal for applications where reducing noise is important. Additionally, the angled teeth allow for the input and output shafts to be misaligned, making them versatile for use in various machines and systems. Helical gears are often used in car transmissions and high-performance robots, converting rotational motion into linear motion with precision and efficiency.
Bevel gears
Bevel gears have a unique conical shape. These gears are typically fitted on shafts that meet at any angle, often 90 degrees. They are commonly used in robotic arms and other systems that need exact direction changes. The shape of the teeth on bevel gears can vary. Most are straight, but some are spiral or zerol. Bevel gears find uses in several industries, such as automation, machinery, aerospace, and robots.
Worm gears
Worm gears have a screw-like part called the worm that fits together with a gear known as the worm wheel. This special design makes worm gears great for situations that need high power and slow speed, like lifting objects or careful movement control. Worm gears can lock by themselves. This means the gear cannot push the worm backward. This feature is useful in situations where you need to prevent backward movement, such as safety reasons.
Planetary gears
Planetary gears have three main parts: a central gear (called the sun), several smaller gears (the planets), and a round outer gear (the ring gear). The way the planet gears share the load helps provide greater torque and better strength. This is why planetary gears are commonly used in robots, especially when there isn't much space but high performance is needed. They can create different gear ratios in one setup, which adds to their ability and allows for advanced robotic movements. Planetary gears are often used in conjunction with other gear-like components such as sprockets and timing pulleys to create complex and efficient mechanical systems.
What’s the history of gears?
The history of gears goes back to the 4th century BC in China. The oldest examples are on display at the Luoyang Museum in Henan Province. In 330 BC, Aristotle talked about gears. He explained that the direction of rotation changes when one gear turns another. Around 150 to 100 BCE, people built the Antikythera mechanism. This device helped to figure out where the sun and moon were and to understand when eclipses would happen.
In the following centuries, inventors created different geared devices. This includes a south-pointing chariot mentioned by Ma Jun around 200-265 AD in China. There was also a geared astrolabe invented in Isfahan about 1221 AD and some sketches of gears in Leonardo da Vinci's notebooks from 1452-1519. However, it was not until the 17th century that big changes happened. Inventors began to explore new ideas, like gears with steady speed ratios, form cutters, and rotating cutters. The number of patents about gears also began to increase.
Gears are now used widely in many industries. They are also found in daily gadgets like bikes, watches, and even toys.
Why are gears important in robots?
Gears are very important for robots, whether they work in factories or as advanced humanoid machines. First, they help make movements smooth and sharp. In many robotic jobs, being right is key. For example, think of a robot arm that puts small electronic pieces together or a surgical robot that performs careful tasks. You need the movement to be right down to a millimeter. Gears allow you to adjust how fast something turns and how much power it uses. This turns motor strength into exact motions when needed.
Gears help robots work smarter, not harder. By changing gear ratios, engineers can create robots that do their best work in many tasks and situations. This is very helpful when a robot needs to change from fast, light tasks to slower, heavy jobs. By adjusting speed and power with gears, robots can meet different needs without needing several special motors or drive systems. This allows them to operate in high gear, achieving maximum efficiency and performance. This makes it easier and cheaper.
Gear systems are key to making robots strong. In factories where robots work all the time, having strong gears is important. Good gears can handle long use, leading to less downtime and fewer repairs. This reliability helps keep production going, and it is also important for safety where a robot breaking down could be risky.
How are gears used in robots?
How can we use gears in robots? Our team has created several projects for the AI Module 5s robot kit. They show many ways to use gears.
Tower Bridge model
The first model is the Tower Bridge model. How can we lift and drop the sections of our bridge? We use worm gears. These gears slow down movement, boost power, and can lock by themselves. This way, the sections can rise or lower slowly and steadily. The self-locking feature also helps keep the sections in place when not in use, preventing the bridge from falling.
Chainsaw model
Then there is this chainsaw model. The chain of a chainsaw usually spins fast. We use a two-stage gear system to make it go even faster. The first gear system sends power to the second gear system. The second system has a large output gear. Because of this, the cutting chain moves a lot each time the final output shaft spins.
Boom lift model
We have this boom lift model. Boom lifts move people and materials to high places. When the curved arm fully extends, the platform at the end moves up to high areas. In this model, we use a gear reduction. A smaller gear drives a larger gear. This makes speeds lower and torques higher. As a result, the platform goes up and down more easily and steadily.
Logger model
We also have a way to change how things move. In this logger model, we want to show kids what happens to a tree after someone cuts it with an ax. We need a system to show the tree leaning. We use a rack and pinion system. This system has two parts: a pinion, which is a round gear, and a rack, which is a straight gear. The pinion is the input, and the rack is the output. When the motor that is connected to the pinion turns, the tree falls down in a straight line.
How can gears help with STEM learning?
We design gear systems in our courses because we believe they matter for machines and STEM learning. When kids touch gear systems, they learn about engineering and science. They often don't even know they're learning. Here’s what they might discover:
Math and physics
Math becomes much more fun when you use gears. Kids can figure out gear ratios and see how gear sizes change speed and force. Physics is also more exciting. Seeing energy move through gears helps kids understand some big ideas about energy in a way that can be tough to grasp otherwise.
Computer science
kids use robot kits with gears and motors, they practice programming how the gears move. This is a clever way to show them how coding and machines work together.
Soft skills
These activities grab a kid's interest in being an engineer or designer. When they work on difficult gear setups, they learn problem-solving skills that real engineers use daily. By using gears in STEM classes, teachers help kids understand how what they read in their books works in real life. Whether it’s a short demo or a big project, gears make learning more active and enjoyable. This prepares kids to handle challenges in science, tech, engineering, and math.
What are some robot kits that use gears?
If you want to learn or teach about gears in STEM, we have some kits for you:
AI Module 5s
Remember the models we talked about before? They come from the projects in AI Module 5s. This kit offers several types of gears with different numbers of teeth, like spur gears, racks, and worms. If you don’t know how to use them, that’s okay. Projects about gears explain the gear setups in detail. The project-based courses also show you how to build these models and provide sample programs to make them work.
AI Module 1s
We also have different types of gears for AI Module 1s, including spur gears, con gears, bevel gears, worms, and racks. With all these gears, you can surely build complex models like a T-Rex waving its claws, a giggling penguin, or an armored warrior.
EnginBot series
This series helps you see what's happening in the manufacturing industry. In factories and robotic systems, many parts arrive as complete units. This kit includes gearboxes to put gear pieces into tidy boxes. For instance, EnginBot 1s offers a gearbox to slow down speed and others to change the direction of shafts.
Conclusion: continuing evolution of gears
Gears have changed a lot since ancient times. Today, they are very important for making things move smoothly and reliably. As more kids and adults become interested in science and tech, gears will remain important. The next big invention might come from someone playing with gears in a robot kit, and we are looking forward to it.
