1. What a robot is
A robot is a programmable mechanical machine that senses its environment, processes that information and performs physical actions to carry out a task.
Robotics is the branch of engineering and computer science that designs, builds and programs robots. A robot is really a particular kind of automated system (topic 15): it has the same sensor-microprocessor-actuator pipeline, but with an added physical body that can move or manipulate things in the real world.
Dumb robots vs smart robots
One way to group robots is into two broad categories:
| Dumb robots | Smart robots | |
|---|---|---|
| How they behave | Repeat a fixed sequence of programmed instructions over and over | Adapt to changing conditions and learn from data |
| Use AI? | No | Yes |
| Flexibility | Low: cannot handle anything outside the programmed routine | High: cope with novelty and respond to feedback |
| Example | A robotic arm that welds the same point on every chassis on a car assembly line | A surgical robot that adjusts its movements based on live imaging during an operation |
As AI and machine learning improve, the boundary between dumb and smart robots is blurring; many modern industrial robots now have learning features that older generations lacked.
2. The three characteristics every robot shares
The syllabus expects you to remember three characteristics that every robot has:
| Characteristic | What it means |
|---|---|
| Mechanical structure | A physical body built from parts (arms, joints, wheels, tracks, grippers) that can move and interact with the environment |
| Electrical components | The internal sensors, microprocessors and actuators that read the world and drive the body |
| Programmable | Designed to follow a precise set of instructions (a program); the same hardware can usually be reprogrammed to do different tasks |
A device that has only one or two of these is not a robot:
- A computer has electrical components and is programmable, but no mechanical structure that moves, so it is not a robot.
- A toy car has a mechanical structure but is not programmable, so it is not a robot.
- A robotic vacuum cleaner has all three: a mechanical body, sensors and motors inside, and a program that decides how to clean. It therefore counts as a robot.
Exam tip
Giving the reason a machine counts as a robot
When a question names a machine and asks why it is a robot, the credited answers are the three characteristics: it has a mechanical structure or framework, it has electrical components (sensors, a microprocessor, actuators) and it is programmable. Naming one electrical component is enough, so "it has sensors" earns that point. Read the stem first: it may state one characteristic itself and ask for one other, and then only the remaining two are credited. Describe what the machine is, not what it does: sowing seeds or driving itself is a task, not a characteristic.
3. Inside a robot
A robot is built from the same components covered in topic 15 (automated systems), with one extra category specific to robotics: the .
Sensors
Sensors are the robot's input devices, measuring the environment so the robot knows what is around it.
Typical sensors on a robot:
- Cameras and vision sensors: let the robot see objects, read text, recognise shapes.
- Proximity / distance sensors: detect how far away nearby objects are (ultrasonic, infrared, LIDAR).
- Touch / pressure sensors: tell the robot when it has gripped or bumped into something.
- Position / encoder sensors: report the angle of each joint or the distance each wheel has rotated.
- Temperature, light, gas, humidity sensors: depending on the task.
Microprocessor
The microprocessor is the robot's brain. It reads the sensor inputs, runs the program, and decides what each actuator should do next.
Modern robots may use a single microcontroller for simple tasks or a network of processors with onboard AI accelerators for complex perception and decision-making.
Actuators
turn the microprocessor's electrical signals into physical motion.
Common actuators in robots:
- Electric motors for wheels, joints and rotating tools.
- Servos for precise angular position (e.g. controlling each finger of a gripper).
- Hydraulic or pneumatic cylinders for heavy lifting in industrial robots.
- Solenoids for snap-action switching of small mechanisms.
End-effectors
An end-effector is the tool or hand at the end of a robot arm: the part that actually interacts with the world.
Examples of end-effectors:
- A gripper or claw to pick things up.
- A suction cup for handling flat or fragile objects.
- A welding torch, paint sprayer or drill for industrial tasks.
- A scalpel or laser scalpel on a surgical robot.
- A screwdriver on an assembly robot.
The same robot arm can often swap between different end-effectors to do different jobs, which is part of why a single industrial robot can be reprogrammed for many tasks.
Putting the components together
The data flow inside a robot is the same closed-loop pattern as any automated system:
sensors → microprocessor → actuators (turning end-) → environment changes → sensors read again
The environment changes because the end-effector did something; the sensor picks up that change on the next reading; the microprocessor decides what to do next. The cycle repeats many times a second.
4. Examples and applications
The syllabus lists six application areas of robotics. For each you should know the typical role and the trade-offs.
Industry
Robots are widely used on factory floors for tasks that are repetitive, dangerous, or require very precise motion.
- Roles: welding car bodies, painting, assembling electronics, quality inspection with vision systems, packaging finished goods.
- Advantages: faster than humans, consistent quality, work 24/7, do not get tired, can handle heavy parts.
- Disadvantages: very high upfront cost, can miss subtle defects that need human judgement, replaces manual jobs.
Transport
Logistics and warehousing now use robots extensively.
- Roles: warehouse that find, move and pack goods (e.g. in Amazon fulfilment centres); autonomous trucks; self-driving cars; automated trains.
- Advantages: efficient picking and packing, less reliance on manual labour, work in 24/7 shifts.
- Disadvantages: high infrastructure cost, safety concerns when robots and humans share the same space, dependence on reliable software.
Agriculture
Modern farms increasingly use robots for precision agriculture.
- Roles: planting and seeding machines that place seeds at exact depths and spacings; harvesting robots; robotic weed sprayers; automated milking.
- Advantages: precise planting and chemical use, less labour, larger yields, work overnight.
- Disadvantages: very expensive to buy, may struggle with uneven terrain or unpredictable weather, smaller farms cannot afford them.
Medicine
Robots are used in hospitals for surgery, rehabilitation and laboratory work.
- Roles: surgical robots that assist surgeons with delicate procedures (e.g. da Vinci); rehabilitation robots that guide patients through repetitive physical-therapy movements; lab robots handling samples.
- Advantages: extreme precision, less invasive surgery (smaller incisions, shorter recovery), tireless repetition during therapy.
- Disadvantages: very high cost, requires specialist training, cannot provide emotional support the way a human therapist can.
Domestic
Robots in the home are still mostly limited but growing.
- Roles: robotic vacuum cleaners, lawn mowers, window cleaners; smart kitchen helpers that chop, measure and stir; companion robots for the elderly.
- Advantages: free up the user's time, help people with limited mobility, work consistently.
- Disadvantages: limited capabilities (cannot handle every situation), can be expensive, may struggle in cluttered or unusual environments.
Entertainment
Robots appear in education, theme parks and animatronic shows.
- Roles: educational robots that teach programming, animatronic figures in theme parks, performance robots, interactive museum exhibits.
- Advantages: engaging and interactive for children, can be reprogrammed for new lessons, available 24/7 in attractions.
- Disadvantages: high cost, cannot replace the guidance of a human teacher, may break and need expensive repair.
5. Advantages and disadvantages of using robots
Many of these have appeared in the application-specific tables above; here is the general view.
Advantages
| Advantage | Why it matters |
|---|---|
| Safety | Robots can do dangerous jobs (bomb disposal, deep-sea inspection, radioactive cleanup, factory welding) that would put humans at serious risk |
| Repeatability and precision | A robot performs the same action with the same accuracy every time; ideal for assembly, surgery and laboratory tasks |
| 24/7 operation | Robots do not need breaks, sleep, food, holidays or pay |
| Productivity | Tasks are completed faster, with less rework and fewer mistakes |
| Strength | Robots can lift heavy loads humans could not safely handle |
| Working in extreme environments | Robots can operate at very high or low temperatures, in vacuum, underwater, or in space |
| Frees humans for higher-value work | Routine tasks are automated; humans can focus on tasks needing creativity or judgement |
Disadvantages
| Disadvantage | Why it matters |
|---|---|
| High upfront cost | Designing, buying and installing robots is expensive; ROI may take years |
| Ongoing maintenance | Robots need regular service, software updates and occasional repair |
| Job displacement | Roles disappear when their tasks are automated; workers may need re-training |
| Inflexibility | Most robots only handle the situations they have been programmed for; novel scenarios may baffle them |
| Cyber-security risk | Networked robots can be hacked; consequences range from production downtime to physical harm |
| Lack of human judgement | Robots cannot weigh ethical considerations or react to unusual situations the way a person can |
| Safety risks to humans nearby | Industrial robots are powerful; collisions with workers can cause injury, so they often need cages or careful safety zones |
| De-skilling of the workforce | If a robot does the skilled work, fewer humans learn the trade; the skills may be lost over generations |
Exam tip
Explaining the drawbacks of using a robot
Tie each drawback to the scenario. For a self-driving tractor the credited points were high set-up and maintenance costs (skilled experts needed to fix it), the farmer needing costly reskilling, deskilling of workers, fewer employees and so unemployment, a malfunction (failing to stop for a person) and the expense of changing what it does. Each drawback is a point and a linked reason or consequence is another, so three marks can come from three drawbacks or from fewer, each developed. Buying, maintaining and changing its function are separate cost points, so name the cost rather than writing "it is expensive".
Ethical and legal questions
Robotics, combined with artificial intelligence (topic 17), raises a set of harder questions that go beyond simple pros and cons:
- Accountability: if a robot makes a decision that injures someone, who is responsible: the manufacturer, the programmer, the operator, or the owner?
- Safety: how do we test a robot's behaviour exhaustively to prove it is safe before deploying it?
- Algorithmic bias: if a smart robot was trained on data that contained bias, it can repeat or amplify that bias in its decisions.
- Legal liability: existing laws were written for human actors; rules for autonomous machines are still being developed.
- Employment: as more jobs are automated, society has to decide how to support workers whose roles disappear.
These are open questions, not questions with one right answer.