ICT 0417 – 6 ICT Applications: Computer Controlled Systems
6 ICT Applications – Computer Controlled Systems
Learning Objective
Know and understand computer‑controlled systems, including:
Robotics in manufacturing
Production line control
Autonomous vehicles
1. What is a Computer‑Controlled System?
A computer‑controlled system uses hardware (sensors, actuators, controllers) and software to monitor and direct the operation of machines or processes without continuous human intervention.
2. Key Components
Component
Function
Typical Example
Sensor
Detects physical variables (temperature, position, light, etc.) and converts them into electrical signals.
Proximity sensor on a robotic arm
Controller (PLC / Microcontroller)
Processes sensor data using programmed logic and sends commands to actuators.
Programmable Logic Controller in a conveyor system
Actuator
Converts electrical signals into mechanical motion.
Electric motor driving a conveyor belt
Human‑Machine Interface (HMI)
Allows operators to monitor status and input commands.
Touchscreen panel on a production line
3. Robotics in Manufacture
Industrial robots perform repetitive, precise, or hazardous tasks. They are programmed using:
Teach‑pendant programming – operator moves the robot through desired motions, which are recorded.
Offline programming – software simulation creates the program before deployment.
Typical applications include:
Welding and joining
Pick‑and‑place operations
Material handling and palletising
Inspection and quality control
Suggested diagram: A robotic arm on an assembly line with labelled sensor, controller, actuator, and HMI.
4. Production Line Control
Production lines are often controlled by a network of PLCs that coordinate the flow of products.
Control Strategy
Description
Advantages
Sequential Control
Operations occur in a fixed order, one after another.
Simple to design; predictable output.
Parallel Control
Multiple stations operate simultaneously, synchronised by a master controller.
Higher throughput; efficient use of equipment.
Feedback Control (Closed‑loop)
Sensor data is continuously compared with desired values; controller adjusts actuators to correct errors.
Improved accuracy; ability to adapt to variations.
5. Autonomous \cdot ehicles (A \cdot s)
A \cdot s integrate a range of computer‑controlled technologies to navigate without driver input.
Perception: Lidar, radar, cameras, and ultrasonic sensors create a real‑time model of the environment.
Decision‑Making: Algorithms (often based on AI) interpret data, plan routes, and handle obstacles.
Control: Actuators manage steering, acceleration, and braking according to the planned path.
Key safety concepts:
Redundancy – multiple sensors and backup systems.
Fail‑safe mode – vehicle stops safely if a critical fault is detected.
Continuous monitoring – health‑check software runs in real time.
Suggested diagram: Layers of an autonomous vehicle – perception, decision‑making, and control.
6. Benefits of Computer‑Controlled Systems
Increased productivity – machines operate faster and continuously.
Improved quality – precise control reduces defects.
Enhanced safety – hazardous tasks are performed by machines.
Flexibility – software changes can re‑configure processes quickly.
7. Limitations and Considerations
High initial cost for hardware and programming.
Need for skilled personnel to design, program, and maintain systems.
Potential for system failures – importance of regular maintenance and backup plans.
Ethical and legal issues, especially for autonomous vehicles (e.g., liability).
8. Sample Exam Question
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:
Sensor detects product at the end of the belt (e.g., photo‑electric sensor).
Sensor signal is sent to the PLC.
PLC program contains a conditional statement: IF sensor = ON THEN output = STOP.
PLC output drives a motor controller (actuator) that cuts power to the conveyor motor, stopping the belt.