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6.2.2 | CHARACTERISTICS OF A ROBOT
01 | THE THREE SYLLABUS CHARACTERISTICS
The specification identifies three characteristics of a robot:
- A mechanical structure or framework.
- Electrical components, such as sensors, microprocessors and actuators.
- It is programmable.
These parts must work together. A bare frame cannot follow instructions; a program on its own cannot physically move an object.
Robots can look very different. A fixed factory arm, a robot vacuum and a drone can all bring these characteristics together.
02 | MECHANICAL STRUCTURE OR FRAMEWORK
The mechanical structure is the physical framework and arrangement of parts that supports the robot’s action.
It can include a body, chassis, joints, wheels, arms, mounts or a gripper mechanism, depending on the task.
| Robot | Possible structure | Why it suits the task |
|---|---|---|
| Factory arm | A fixed base with linked joints and a tool mount | Reach and position the tool or object |
| Robot vacuum | A body with wheels and cleaning mechanisms | Move across a floor and carry the equipment |
| Drone | A frame supporting motors and propellers | Support the equipment needed for flight |
Strength, size, reach and stability affect what the robot can do. A programmed movement is useful only if the structure can perform it within its physical limits.
03 | THE FRAME IS NOT THE MOTOR
The framework supports and constrains movement. An actuator provides the action that moves or operates part of that framework.
For a robot arm, the links and joints define its movement arrangement. Motors or other actuators drive the joints.
Useful distinction: the arm’s structure determines where it can reach; the actuator supplies movement; the program determines the commanded action.
A robot need not move its whole body. A fixed base can support joints that perform the task.
04 | SENSORS: PROVIDE INPUT
Sensors detect or measure information that the robot can use. Examples include proximity, light, temperature or position-related readings.
| Input information | Possible use |
|---|---|
| Object presence or nearness | Respond to an obstacle or locate an item |
| Joint or wheel movement | Check a movement or position |
| Light or image information | Follow a visual feature or identify a scene feature |
A sensor supplies information; it does not automatically interpret every situation correctly. The program must use the reading appropriately.
Some robots follow a predefined sequence with limited sensing. Do not assume every robot needs the same sensor types or a camera.
05 | MICROPROCESSOR: EXECUTE THE CONTROL PROGRAM
A microprocessor executes instructions and processes input information. In a robot, it can determine output commands according to the program.
For example, it can compare a proximity reading with a threshold and request the drive motors to stop.
The controller may also manage timing and coordinate several mechanisms. Its instructions are not the same as the physical force produced by a motor.
Real robot controllers can use microcontrollers or more complex computing arrangements. For the syllabus, recognise the processing role among the electrical components.
06 | ACTUATORS: MAKE THE PHYSICAL ACTION
An actuator converts a control input into a physical action.
| Actuator / arrangement | Action |
|---|---|
| Motor driving a wheel | Move the mobile robot |
| Motor driving an arm joint | Change the arm’s position |
| Gripper actuator | Open or close the gripping mechanism |
| Motor and propeller | Produce thrust in a drone |
Actuators need suitable power and control circuitry. The processor’s command is not necessarily enough to drive the equipment directly.
A speaker or screen can provide information, but a robot’s task may also need physical actuation beyond displaying a message.
07 | PROGRAMMABLE: BEHAVIOUR DEFINED BY INSTRUCTIONS
Programmable means that instructions can be specified to determine the robot’s behaviour. A program can define a sequence, respond to inputs or combine both.
Sequence example: move the arm, close the gripper, move to another position and release.
Input-based example: read an obstacle sensor and stop movement when the defined condition is met.
Changing the program can change behaviour without rebuilding every mechanical part. However, it cannot make the hardware perform actions outside its capabilities.
Programmable does not mean the robot learns by itself. A robot can follow fixed instructions without AI.
08 | SEE THE PARTS COOPERATE
STRUCTURE
Chassis, wheels and mounts support movement and sensing.
ELECTRICAL COMPONENTS
Sensor supplies input; processor determines commands; motors provide movement.
PROGRAM
Read the input and apply a defined movement or stopping rule.
For a mobile robot, all three are needed for the intended physical behaviour. The program does not replace the chassis, and the motor does not replace the decision-making instructions.
09 | WORKED EXAMPLE: ROBOT ARM
A robot arm transfers small items between two positions.
| Characteristic | Example | Contribution |
|---|---|---|
| Mechanical framework | Base, linked arm sections and gripper | Support reach and handling |
| Electrical components | Controller, joint sensors and motors | Obtain information, process instructions and drive movement |
| Programmable | A defined pick-and-place sequence | Specify the order and conditions of actions |
Joint sensing can help the controller check movement. The program commands the next stage; the actuator moves the structure.
Do not simply write “it has parts”. Identify the characteristic and explain how it contributes to the task.
10 | APPLY THE CHARACTERISTICS TO A DRONE
Structure: the frame holds the components in their required arrangement.
Electrical components: sensors provide relevant information, the controller processes instructions and motors turn propellers.
Programmability: control software determines how inputs and commands affect motor outputs.
A person can supply commands while automatic stabilisation runs onboard. Being programmable does not require the complete task to be fully autonomous.
11 | WHAT THE CHARACTERISTICS DO NOT REQUIRE
| Claim | Correction |
|---|---|
| A robot must look human | Its framework can be designed for the task |
| A robot must have wheels | Fixed arms and flying systems use other structures |
| A robot must use machine learning | Fixed instructions can define behaviour |
| A robot must connect to the internet | A controller can operate locally |
| A robot must have no human operator | Remote commands and programmed control can coexist |
A software-only chatbot does not have the physical framework and actuators of a robot. A humanoid appearance is also not proof of intelligence.
12 | COMMON MISTAKES
- Structure, motor and program are interchangeable: explain their different roles.
- The sensor performs the physical action: it supplies input.
- The processor generates the motor’s force: it issues commands through suitable control hardware.
- Programmable means self-learning: learning is not required.
- A fixed base means not a robot: its mechanism can still act physically.
- Every robot has identical sensors: components depend on the task.
- Code can remove all mechanical limits: hardware capabilities still constrain behaviour.