Many people, upon hearing the word “robot,” might think of terms like “cool appearance,” “powerful functions,” and “high-end,” associating robots with the advanced and flashy machines seen in sci-fi films like the “Terminator.” However, this is not the case. In this article, we will explore the basic concepts of robotics and how robots accomplish their tasks.
1. Components of a Robot
At the most basic level, the human body comprises five main components:
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Body structure
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Muscle system, used to move the body structure
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Sensory system, used to receive information about the body and the surrounding environment
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Energy source, used to power the muscles and senses
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Brain system, used to process sensory information and direct muscle movement
Of course, humans also possess some intangible traits, such as intelligence and morality, but on a purely physical level, this list is quite comprehensive.
The components of a robot are very similar to those of a human. A typical robot has a movable body structure, a motor-like device, a set of sensors, a power source, and a computer “brain” that controls all these elements. Essentially, robots are “animals” created by humans, machines that mimic human and animal behaviors.
Bionic Kangaroo Robot
The definition of a robot is broad, ranging from industrial robots serving factories to home cleaning robots. According to the broadest current definition, if something is widely considered a robot, then it is a robot. Many robotics experts (those who create robots) use a more precise definition. They stipulate that a robot must have a reprogrammable brain (a computer) used to move its body.
According to this definition, the difference between robots and other movable machines (like cars) lies in their computer components. Many new cars have an onboard computer, but it is only used for minor adjustments. The driver directly controls most parts of the vehicle through various mechanical devices. In contrast, robots differ from ordinary computers in their physical characteristics; each robot is connected to a body, while ordinary computers are not.
Most robots do share some common characteristics.
First, almost all robots have a movable body. Some have only motorized wheels, while others have numerous movable parts, generally made of metal or plastic. Similar to human skeletal systems, these independent parts are connected by joints.
Robots’ wheels and axles are connected by some sort of drive mechanism. Some robots use motors and solenoids as drive mechanisms; others use hydraulic systems; still others use pneumatic systems (systems powered by compressed gas). Robots can use any of these types of drive mechanisms.
Second, robots require an energy source to power these drive mechanisms. Most robots use batteries or wall power outlets for electricity. Additionally, hydraulic robots require a pump to pressurize the liquid, while pneumatic robots need a gas compressor or gas tank.
All drive mechanisms are connected to a circuit via wires. This circuit directly powers electric motors and solenoids and manipulates electronic valves to activate the hydraulic system. The valves can control the path of pressurized fluid flowing within the machine. For instance, if a robot needs to move a hydraulically driven leg, its controller will open a valve connected to the hydraulic pump and the piston on the leg. The pressurized fluid will push the piston, causing the leg to rotate forward. Typically, robots use pistons that can provide bidirectional thrust, allowing components to move in both directions.
The robot’s computer can control all components connected to the circuit. To make the robot move, the computer will activate all the necessary motors and valves. Most robots are reprogrammable. If you want to change the behavior of a robot, you simply need to write a new program into its computer.
Not all robots have a sensory system. Very few robots possess vision, hearing, smell, or taste. The most common sense that robots have is a sense of motion, which is their ability to monitor their own movements. In standard designs, grooved wheels are installed at the joints of the robot. On one side of the wheel is a light-emitting diode (LED) that emits a beam of light through the grooves, hitting a light sensor located on the other side of the wheel. When the robot moves a specific joint, the grooved wheel rotates. During this process, the grooves block the light beam. The optical sensor reads the pattern of light flashes and sends the data to the computer. The computer can accurately calculate the distance the joint has rotated based on this pattern. The basic system used in computer mice is similar to this.
These are the basic components of robots. Robotics experts have countless ways to combine these elements to create infinitely complex robots. Robotic arms are one of the most common designs.
2. How Robots Work
The term “robot” in English comes from the Czech word “robota,” usually translated as “forced laborer.” This description is quite fitting for most robots. Most robots in the world are used for heavy, repetitive manufacturing tasks. They are responsible for tasks that are very difficult, dangerous, or monotonous for humans.
The most common type of manufacturing robot is the robotic arm. A typical robotic arm consists of seven metal parts, connected by six joints. The computer connects stepper motors to each joint to control the robot (some large robotic arms use hydraulic or pneumatic systems). Unlike ordinary motors, stepper motors move precisely in increments. This allows the computer to move the robotic arm accurately, enabling it to repeat the same action continuously. Robots utilize motion sensors to ensure they move the correct amount.
This six-joint industrial robot is remarkably similar to the human arm, having parts equivalent to the shoulder, elbow, and wrist. Its “shoulder” is typically mounted on a fixed base structure (rather than a moving body). This type of robot has six degrees of freedom, meaning it can rotate in six different directions. In comparison, a human arm has seven degrees of freedom.
A six-axis industrial robot joint
The function of the human arm is to move the hand to different positions. Similarly, the role of a robotic arm is to move an end effector. You can install various end effectors on a robotic arm for specific applications. One common end effector can grasp and move different objects; it is a simplified version of a human hand. Robotic hands often have built-in pressure sensors to inform the computer of the force being applied when the robot grasps a specific object. This prevents objects from slipping or being crushed. Other end effectors include spray guns, drills, and paint sprayers.
Industrial robots are specifically designed to repetitively perform the same task in controlled environments. For example, a robot may be responsible for screwing the lids onto jars of peanut butter as they are conveyed along an assembly line. To teach the robot how to perform this task, a programmer will guide the robotic arm through the entire sequence of actions using a handheld controller. The robot accurately stores this sequence of actions in memory, and whenever a new jar comes down the assembly line, it will repeat this sequence.
Robotic arms are one of the basic components used in automobile manufacturing
Most industrial robots work on automobile assembly lines, responsible for assembling cars. In performing large volumes of such work, robots are significantly more efficient than humans, as they are extremely precise. Regardless of how many hours they have worked, they can still drill holes in the same position and screw in bolts with the same force. Manufacturing robots also play a crucial role in the computer industry, as their incredibly precise hands can assemble tiny microchips.
The manufacturing and programming of robotic arms are relatively low in difficulty because they only work within a limited area. However, sending a robot out into the vast outside world complicates matters.
The primary challenge is providing the robot with a viable movement system. If a robot only needs to move on flat ground, wheels or tracks are often the best choice. If the wheels and tracks are wide enough, they can also be used on more rugged terrain. However, robot designers often prefer to use leg-like structures for greater adaptability. Creating legged robots also helps researchers understand natural kinematics, which is beneficial in biological research.
The legs of robots typically move back and forth under the drive of hydraulic or pneumatic pistons. Each piston is connected to different leg components, much like muscles attached to different bones. Coordinating the operation of all these pistons in the correct manner is undoubtedly a challenge. In infancy, the human brain must figure out which muscles need to contract simultaneously to avoid falling while walking upright. Similarly, robot designers must determine the correct combination of piston movements related to walking and program this information into the robot’s computer. Many mobile robots have a built-in balancing system (such as a set of gyroscopes) that informs the computer when adjustments to the robot’s movements are necessary.
The bipedal walking motion itself is inherently unstable, making it extremely challenging to implement in robot manufacturing. To design a more stable walking robot, designers often look to the animal kingdom, particularly insects. Insects have six legs and often exhibit extraordinary balance, adapting easily to various terrains.
Some mobile robots are remotely controlled, allowing humans to command them to perform specific tasks at designated times. Remote control devices can communicate with robots using wired connections, radio signals, or infrared signals. Remote-controlled robots are often referred to as puppet robots and are very useful in exploring dangerous environments or areas inaccessible to humans, such as the deep sea or inside volcanoes. Some robots are only partially remote-controlled. For example, the operator may instruct the robot to reach a specific location without guiding its path, allowing it to find its way on its own.
NASA-developed remotely controlled space robot R2
Autonomous robots can act independently without relying on any control personnel. Their basic principle is to program the robot to respond to external stimuli in a certain way. Extremely simple collision response robots can exemplify this principle.
This type of robot has a collision sensor to check for obstacles. When you turn on the robot, it generally moves along a winding path. When it encounters an obstacle, the impact force acts on its collision sensor. Each time a collision occurs, the robot’s program instructs it to back up, turn right, and then continue forward. In this manner, the robot changes its direction whenever it encounters an obstacle.
Advanced robots apply this principle in more sophisticated ways. Robotics experts develop new programs and sensor systems to create smarter robots with enhanced perception capabilities. Today’s robots can showcase their abilities in various environments.
Relatively simple mobile robots use infrared or ultrasonic sensors to detect obstacles. These sensors operate similarly to the echo-location system of animals: the robot emits a sound signal (or a beam of infrared light) and detects the reflection of the signal. The robot calculates the distance to the obstacle based on the time taken for the signal to reflect.
More advanced robots utilize stereovision to observe their surroundings. Two cameras can provide depth perception, while image recognition software enables the robot to identify the location of objects and distinguish various items. Robots can also use microphones and smell sensors to analyze their environment.
Some autonomous robots can only operate within familiar, limited environments. For instance, lawn-mowing robots rely on buried markers to determine the boundaries of the grass area. Similarly, robots designed for office cleaning require a map of the building to navigate between different locations.
More advanced robots can analyze and adapt to unfamiliar environments, even navigating rugged terrain. These robots can associate specific terrain patterns with specific actions. For example, a rover robot can use its visual sensors to create a map of the ground ahead. If the map indicates a rugged terrain pattern, the robot will know to take a different path. This system is extremely useful for exploratory robots working on other planets.
A set of alternative robot designs employs a looser structure, introducing randomization factors. When such a robot gets stuck, it will move its limbs in various directions until its actions yield results. It collaborates closely with force sensors and drive mechanisms to complete tasks rather than being entirely guided by a computer program. This is similar to how ants attempt to navigate around obstacles: ants seem to try various approaches until they successfully bypass the obstacle.
3. Homemade Robots
In the final sections of this article, let’s explore one of the most intriguing areas in the world of robotics: artificial intelligence and research robots. Over the years, experts in these fields have made significant advancements in robotics, but they are not the only creators of robots. For decades, passionate hobbyists, though few in number, have been building robots in garages and basements around the world.
Homemade robots represent a rapidly growing subculture with substantial influence on the internet. Amateur robotics enthusiasts assemble their creations using various commercial robotic tools, mail-order parts, toys, and even old video recorders.
Like professional robots, the types of homemade robots are diverse. Some weekend robotics hobbyists have created remarkably intricate walking machines, while others design domestic robots for personal use, and some enthusiasts focus on building competitive robots. Among competitive robots, the most familiar are remote-controlled robot warriors, like those seen in the “BattleBots” show. These machines are not considered “true robots” as they lack a reprogrammable computer brain; they are merely enhanced remote-controlled cars.
More advanced competitive robots are controlled by computers. For example, soccer robots can participate in small soccer matches without any human input. A standard robot soccer team consists of several individual robots that communicate with a central computer. This computer “watches” the entire field through a camera and distinguishes between the ball, goals, and players from both teams based on color. The computer constantly processes this information and decides how to direct its team.
Adaptability and Versatility
The personal computer revolution is characterized by its remarkable adaptability. Standardized hardware and programming languages allow computer engineers and amateur programmers to create computers tailored to specific purposes. Computer parts share similarities with craft supplies, with countless applications.
So far, most robots resemble kitchen utensils. Robotics experts have created them for specific uses. However, their adaptability to entirely different applications is not very strong.
This situation is changing. A company called Evolution Robotics has pioneered the field of adaptive robotic software and hardware. The company aims to carve out its niche market with an easy-to-use “robot developer toolkit.”
This toolkit includes an open-source software platform that provides various common robotic functions. For example, roboticists can easily endow their creations with the ability to track targets, follow voice commands, and navigate around obstacles. From a technical perspective, these features are not revolutionary, but what is unusual is that they are integrated into a simple software package.
The toolkit also comes with some common robotic hardware that can be easily combined with the software. The standard toolkit provides infrared sensors, motors, a microphone, and a camera. Robotics experts can utilize a set of enhanced mounting components to assemble all these parts, including aluminum body parts and sturdy wheels.
Of course, this toolkit is not meant for creating mediocre creations. Priced at over $700, it is certainly not a cheap toy. However, it represents a significant step towards new robotic science. In the near future, if you want to create a new robot that can clean a room or take care of pets while you are away, you may only need to write a BASIC program to do so, saving you a significant amount of money.
4. Artificial Intelligence
Artificial intelligence (AI) is undoubtedly the most exciting field in robotics and also the most controversial: while everyone agrees that robots can work on assembly lines, there is disagreement about whether they can possess intelligence.
Just like the term “robot,” defining “artificial intelligence” is equally challenging. The ultimate artificial intelligence is a reproduction of human thought processes, essentially a machine with human-like intelligence. Artificial intelligence encompasses the ability to learn any knowledge, reasoning ability, language capability, and the ability to form its own opinions. Currently, robotics experts are far from achieving this level of artificial intelligence, but they have made significant progress in limited areas of artificial intelligence.
Computers now possess the ability to solve problems within limited domains. The process of executing problem-solving using artificial intelligence is quite complex, but the basic principle is very simple. First, an AI robot or computer collects facts about a situation through sensors (or human input). The computer compares this information with stored information to determine its meaning. It calculates various possible actions based on the collected information and predicts which action will yield the best results. Of course, the computer can only solve problems that its programming allows it to address; it does not possess general analytical capabilities. Chess computers are an example of such machines.
Some modern robots also possess limited learning abilities. Learning robots can recognize whether a certain action (like moving a leg in a specific way) achieved the desired result (like bypassing an obstacle). The robot stores this information, and when it encounters the same situation again, it will attempt to execute the action that successfully addressed the issue. Similarly, modern computers can only do this in very limited scenarios. They cannot collect all types of information like humans. Some robots can learn by mimicking human actions. In Japan, robotics experts demonstrated dance moves to a robot, teaching it how to dance.
Some robots possess interpersonal communication capabilities. Kismet is a robot created by the MIT Artificial Intelligence Laboratory that can recognize human body language and vocal tones, responding accordingly. The authors of Kismet are interested in the interactions between adults and infants, which can be completed solely through tone and visual information. This low-level interaction can serve as the foundation for humanoid learning systems.
Kismet Robot
Kismet and other robots created by the MIT Artificial Intelligence Laboratory employ an unconventional control structure. These robots are not controlled by a central computer managing all actions; instead, their low-level actions are governed by lower-level computers. Project leader Rodney Brooks believes this is a more accurate model of human intelligence. Most human actions are performed automatically rather than being determined by higher-level consciousness.
The real challenge of artificial intelligence lies in understanding how natural intelligence works. Developing artificial intelligence is not like creating an artificial heart; scientists do not have a simple and concrete model to refer to. We know that the brain contains billions of neurons, and our thinking and learning occur through the establishment of electronic connections between different neurons. However, we do not understand how these connections enable advanced reasoning capabilities, and we are even unaware of how lower-level operations are achieved. The neural networks in the brain seem to be complex beyond comprehension.
Therefore, artificial intelligence remains largely theoretical. Scientists propose hypotheses regarding the principles of human learning and thinking, then use robots to experiment with their ideas.
Just as the physical design of robots serves as a convenient tool for understanding animal and human anatomy, research into artificial intelligence also aids in understanding how natural intelligence works. For some robotics experts, this insight is the ultimate goal of designing robots. Others fantasize about a world where humans coexist with intelligent machines, using various small robots to perform manual labor, healthcare, and communication. Many robotics experts predict that the evolution of robots will ultimately lead us to become cyborgs, humans fused with machines. There is reason to believe that future humans will implant their thoughts into robust robots, living for thousands of years!
Regardless, robots will play an important role in our future daily lives. In the coming decades, robots will gradually expand beyond industrial and scientific fields into everyday life, similar to how computers began to permeate households in the 1980s.
Image and text sourced from Sensor Technology
Initial review: Tang Cuimei
Secondary review: Huo Xiaoyin
Final review: Wang Xianfang
