Know and understand computer controlled systems including robotics in manufacture, production line control, autonomous vehicles

6 ICT Applications – Computer‑Controlled Systems

Learning Objective

Know and understand computer‑controlled systems, including:

• Robotics in manufacturing
• Production‑line control
• Autonomous vehicles

1. Computer‑Controlled Systems and the Systems Life‑Cycle

A computer‑controlled system is an ICT application that combines hardware (sensors, actuators, controllers) and software to monitor and direct machines or processes with little or no continuous human intervention.

In the Cambridge IGCSE ICT syllabus these systems must be examined through the Systems Life‑Cycle (AO3). The stages are:

1. Analysis – Identify the problem, required functions and constraints.
2. Design – Produce a specification sheet (inputs, outputs, performance criteria), select sensors/actuators, choose a controller type and design the control algorithm (e.g., ladder‑logic flow).
3. Development & Testing – Write / simulate the programme, test with prototype hardware and refine.
4. Implementation – Install hardware, upload the final programme, connect the HMI.
5. Evaluation – Verify that the system meets the specification, assess reliability, safety and cost, and recommend improvements.

2. Key Components

3. Robotics in Manufacturing

3.1 How Robots Are Programmed

• Teach‑pendant programming – Operator moves the robot through the required path; the controller records the positions.
• Offline programming – A computer‑based simulation creates the programme before it is transferred to the robot.
• Programming languages / logic – Ladder logic, block‑diagram language or specialised robot languages (e.g., RAPID, KRL) are used, similar to PLC programming.

3.2 Typical Applications

• Welding and joining
• Pick‑and‑place operations
• Material handling and palletising
• Inspection and quality control

3.3 Advantages

• Higher speed and consistency → increased productivity
• Improved accuracy → lower defect rate
• Capability to work in hazardous environments → enhanced safety
• Flexibility – software changes can re‑configure tasks quickly

3.4 Disadvantages / Limitations

• High initial capital cost for hardware, sensors and programming tools
• Requirement for skilled personnel to program, maintain and troubleshoot
• Limited ability to handle unexpected variations without re‑programming
• Ongoing maintenance and calibration costs

4. Production‑Line Control

4.1 Control Strategies

4.2 Simple Closed‑Loop Example (PID)

For a conveyor belt that must run at 0.5 m s⁻¹:

1. Sensor measures actual belt speed.
2. Controller calculates error = set‑point – actual speed.
3. PID algorithm (Proportional + Integral + Derivative) determines the motor voltage required to minimise the error.
4. Actuator (motor driver) adjusts the voltage, closing the loop.

5. Autonomous Vehicles (AVs)

5.1 System Layers – Hardware, Software & Communication

• Perception (Hardware) – Lidar, radar, cameras and ultrasonic sensors create a real‑time model of the environment.
• Decision‑making (Software) – AI‑based algorithms interpret the model, plan routes and decide how to react to obstacles.
• Control (Hardware + Communication) – Actuators manage steering, acceleration and braking; CAN‑bus or Ethernet communicates commands from the software to the actuators.

5.2 Safety & e‑Safety

• Redundancy – Multiple sensors and backup processors ensure a single failure does not cause loss of control.
• Fail‑safe mode – The vehicle brings itself to a safe stop if a critical fault is detected.
• Continuous health monitoring – Diagnostic software runs in real time and alerts the system to degraded components.
• e‑Safety – Encrypted firmware updates, secure V2X communication and protection against cyber‑attacks.

5.3 Ethical & Legal Issues (Limitations)

• Liability – who is responsible in the event of an accident (manufacturer, software developer, owner)?
• Data privacy – AVs collect large amounts of location and sensor data that must comply with data‑protection legislation.
• Regulatory compliance – vehicles must meet national and international safety standards before deployment.

6. Benefits and Limitations of Computer‑Controlled Systems

7. Impact of ICT on Methods of Working

• Shift from manual, repetitive tasks to supervisory and analytical roles.
• Greater need for technical skills – programming, troubleshooting and data interpretation.
• Remote monitoring and control allow operators to manage production from a central control room.
• Enhanced data collection supports continuous improvement and predictive maintenance.

8. Additional Considerations

• Regular maintenance and calibration of sensors and actuators to prevent drift.
• Backup and recovery plans – e.g., UPS power supplies, redundant controllers and version‑controlled software.
• Training for operators and technicians on HMI use, troubleshooting, safety procedures and e‑safety.
• Compliance with health & safety legislation and, where applicable, data‑protection regulations.

9. Sample Exam Questions

9.1 Question 1 (AO1‑AO3)

Question: Explain how a PLC can be used to control a conveyor belt that stops automatically when a product reaches the end of the line. Include the role of sensors, the control logic and the actuator.

Answer outline (mark‑scheme style)

1. AO1 – Knowledge (2 marks) – Identify the components: photo‑electric sensor, PLC, motor‑controller (actuator) and HMI.
2. AO2 – Understanding (2 marks) – Describe how the sensor detects the product, converts the presence into an electrical signal and sends it to the PLC.
3. AO3 – Application/Analysis (2 marks) – Explain the PLC programme: IF sensor = ON THEN output = STOP. Mention that the PLC output drives the motor controller which cuts power to the conveyor motor, causing the belt to stop.
4. AO3 – Evaluation (1 mark) – Comment on safety (e.g., use of a second sensor as redundancy) or suggest an improvement (e.g., feedback loop to control belt speed).

9.2 Question 2 (AO3 – Evaluation)

Question: Discuss one limitation of using PLCs in a small workshop that produces custom furniture.

Suggested points (any 4 marks)

• High upfront cost for a PLC, I/O modules and programming software may be prohibitive for a small business.
• PLC programming typically uses ladder logic, which requires specialised training; the workshop may not have staff with the required skills.
• Flexibility is limited if the product range changes frequently – each new product may need a new programme and re‑wiring of I/O.
• Maintenance and spare‑part availability can be an issue; a fault may halt production for longer than a manual system would.

10. Quick Revision Checklist

• Define a computer‑controlled system and link it to the Systems Life‑Cycle.
• List the four key components and give a real‑world example of each.
• Name the three main robot programming methods and at least two robot‑control languages.
• Distinguish between sequential, parallel and feedback (closed‑loop) control strategies.
• Explain the three layers of an autonomous vehicle and give one safety/e‑safety measure for each layer.
• Be able to discuss at least three advantages and three disadvantages of computer‑controlled systems.
• Recall how ICT changes the way people work in manufacturing environments.