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How Robots Work

By:Tom Harris&Chris Pollette|

Mobile Robots

Boston Dynamics Hyundai robot dog
Boston Dynamics' robot dog Spot is displayed at CES 2022, the world's largest annual consumer technology trade show, held in Las Vegas.Tayfun Coskun/Anadolu Agency via Getty Images

Robotic arms are relatively easy to build and program because they only operate within a confined area. Things get a bit trickier when you send a robot out into the world.

First, the robot needs a working locomotion system. If the robot only needs to move over smooth ground, wheels are often the best option. Wheels and tracks can also work on rougher terrain. But robot designers often look to legs instead, because they are more adaptable. Building legged robots also helps researchers understand natural locomotion — it's a useful exercisein biological research.

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Typically, hydraulic or pneumatic pistons move robot legs. The pistons attach to different leg segments just likemusclesattach to different bones. It's a real trick getting all these pistons to work together properly. As a baby, your brain had to figure out exactly the right combination of muscle contractions to walk upright without falling over. Similarly, a robot designer has to figure out the right combination of piston movements involved in walking and program this information into the robot's computer. Many mobile robots have a built-inbalance system(a collection ofgyroscopes, for example) that tells the computer when it needs to correct its movements.

Designers commonly look to the animal world for robotic locomotion ideas. Six-legged insects have exceptionally good balance, andthey adapt wellto a wide variety of terrain. Four-legged robots such as Boston Dynamics' Spotlook like dogs, and the similaritybreeds comparisonsas they take on dangerous jobssuch as construction inspection. Two-legged robots are challenging to balance properly, but humans have gotten better with practice. Boston Dynamics' Atlas甚至可以做跑酷.

Aerial robots are also inspired by real-world examples. Although many use wings like we see on airplanes, researchers have also developed techniques usingfly-wing-like soft actuators. Most people now are familiar with the propeller-powered drones that provide amazing camera shots for entertainment, sporting events and surveillance. Some of these hovering bots can also be networked together to create swarms of robots such as those seen at theTokyo Summer Olympic Gamesin 2021.

Underwater, robots may walk across the sea floor. One example is Silver 2,a crab-like robotdesigned to find and clean up plastic waste. TheBenthic Rover II使用踏板本月ead. Snake robots, which of course take their name from the animals whose locomotion they copy,can operate underwaterand on land. They even work well in the human body, where they canperform surgical repairs.

Some mobile robots are controlled by remote — a human tells them what to do and when to do it. The remote control might communicate with the robot through an attached wire, or usingradioorinfrared signals. Remote robots are useful for exploring dangerous or inaccessible environments, such as the deep sea or inside avolcano. Some robots are only partially controlled by remote. For example, the operator might direct the robot to go to a certain spot, but instead of steering it there, the robot finds its own way.