6.1 Automated Systems

a) Define what is meant by an Automated system.

★ An automated system is a combination of software and hardware that is designed and programmed to work automatically without human intervention.

★ Sensors are used to take readings from their surroundings and send this data to the microprocessor or computer.

★ If the input data from sensors is analogue, then it is first converted into a digital signal by an Analogue-to-Digital Converter (ADC).

★ The microprocessor will process the input data and take the necessary action based on the program of the automated system.

★ It produces some form of output. If a physical action is to be taken, then the microprocessor sends a signal to the actuator to control motors, wheels, solenoids and so on.

b) The automated system involves the use of sensors and actuator. Describe the function of Sensor and Actuator.

Sensor:

★ A sensor is an input device that continuously reads or measures the physical quantities from its surroundings (like temperature, sound, light, pressure, etc.) and sends it to the micro-controller / microprocessor of the automated system.

★ Sensor is an analogue device which needs an Analogue-to-Digital Converter (ADC) to convert analogue signals to digital, which a microprocessor or microcontroller can understand and process.

Actuator:

★ Actuator is an output device that converts electrical energy into mechanical movement.

★ It is controlled by microprocessor, which gives the ability to computers and other electronic devices to do some physical work.

c) Why do we need sensors? What are the benefits of using sensors?

1. Sensors automatically and continuously read the physical quantities of the environment, so we need it in all automated systems.

2. It could be used in dangerous environments where humans cannot reach like chemical or nuclear reactors, etc.

3. It is used to measure the quantities very quickly, very accurately without errors.

4. It helps to avoid human error.

a) Describe how sensors, microprocessors and actuators can be used in collaboration to create automated systems.

⇒ Sensors continuously read the changes in the environment and send the data to the microprocessor.

⇒ Sensor's analogue signal is converted into digital using ADC for the microprocessor.

⇒ Microprocessor compares the input data with the stored values and takes decisions based on the pre-programmed algorithms.

⇒ Microprocessor sends signal to the actuator to perform the physical task needed to be done by the automated system.

⇒ DAC is used to convert digital signal to analogue for the actuator.

⇒ By working together, these components can create efficient and effective automated systems for a wide range of applications.

b) Name three areas where automated systems are used.

1. Industrial applications — such as automobile manufacturing, control and monitoring of nuclear power stations.

2. Transport — such as autonomous cars/buses, trains, unpiloted aircraft, automated signal control systems.

3. Agriculture — such as greenhouse temperature control system, automated irrigation system.

4. Weather — such as automated weather stations.

5. Gaming — sensors like accelerometers, proximity sensors are embedded in games consoles.

6. Lighting — such as street light control system, automatically turn lights ON and OFF at home/office.

7. Science — automatic control of laboratory experiments which require accuracy and repeatability.

c) Give three general advantages of using automated systems.

1. Much faster than a human operator to take any necessary action.

2. Keep humans away from dangerous environments.

3. Avoids the possibility of human errors.

4. Cost effective, as it replaces human work force and operates 24/7 tirelessly.

d) Give three general disadvantages of using automated systems.

1. Expensive to set up and needs considerable testing.

2. Always possible for a set of conditions to occur that were never considered during testing which could have safety implications.

3. Any computerised system is subjected to cyber-attacks no matter how good the system is.

4. Automated systems always need enhanced maintenance which can be expensive.

a) Name the software that is needed to convert the camera image of the car's number plate into an electronic format that can be used in, for example, a database.

☆ Optical Character Recognition (OCR) software that recognises text and numbers within a digital image.

b) Describe how sensors, cameras, actuators and a computer system can be used to control entry to and exit from the car park. Include how a car number plate meets the criteria for entry and any other security or safety aspects.

⇒ On car's entry to the car park, a Pressure sensor on the ground recognises the presence of a vehicle and sends data to the computer which then sends a signal to operate the camera.

⇒ The camera takes the photograph of the number plate and sends it to the Automatic Number Plate Recognition (ANPR) software equipped with OCR which extracts the text and numbers from the image.

⇒ The unique car number is compared against database records, to check if the vehicle registration number is valid or not, and if the vehicle is reported as stolen or wanted for having committed traffic offences.

⇒ If it is valid without any record of offence, then the car driver is allowed to scan his driving license.

⇒ The car number, driving license number, date and time of entry is stored in a database and the car is allowed to move towards the barrier.

⇒ When the car approaches the barrier, then the infrared or ultrasonic sensor captures the data and sends it to the microprocessor.

⇒ ADC is used to convert the sensor's analogue signal to digital.

⇒ Microprocessor compares the sensor's input signal with the stored data; if it indicates the presence of a car, the microprocessor sends a signal to the actuator to open the barrier.

⇒ At the exit, the driver scans his driving license again; the camera captures the number plate, the car number and license number is compared with data stored in the database.

⇒ Parking charge is calculated, collected, and the car is allowed to move towards the barrier.

c) (i) Describe the advantages of using an automated system to control entry and exit to the car park.

1. Quick and accurate vehicle identification and verification process.

2. Eliminates the manual paperwork of recording vehicle details on entry and exit.

3. Cost effective, as the gates for entry and exit are automated.

4. The system works 24/7 and cars can be parked at any time.

(ii) State the disadvantages of using an automated system to control entry and exit to the car park.

1. Expensive installation and setup cost.

2. Faulty / dirty sensors or cameras can send false data / image to the computer which could lead to a malfunction.

3. Regular maintenance is required to ensure the system works correctly all the time.

(iii) It is possible to illegally copy the number plates to 'fool' the system and allow unauthorised access to the car park. Discuss how you might think this problem could be overcome.

⇒ Vehicle Registration Certificate (RC) smart card could be included into the system, which needs to be verified on entry.

⇒ RC smart card contains a chip which stores all the details of the car like owner's name, car number, its model, address, etc., which is difficult to copy.

a) Explain the role of the following devices in the self-parking technology.

(i) Cameras:

⇒ The cameras feed individual images of all 4 sides of the car to imaging software, which stitches these images together to generate a virtual aerial view, taking into account all the obstacles around the car.

⇒ As the car moves, the images also change in real-time, which gives immediate details about its surroundings to the automated system.

(ii) Sensors:

⇒ Proximity sensors (like infrared, ultrasonic and radar) are located on the bumpers of the vehicle that measure the proximity of an approaching object, either in-front or behind, and alert the automated system if they get too close.

(iii) Actuators:

⇒ Microprocessor handles data received from sensors fixed in the car and directs the actuator to perform physical actions such as control speed by throttle actuation, change direction by steering actuation and stop / move the car by brake actuation.

b) Describe how a self-parking car automatically steers and parks itself in the available parallel or perpendicular parking spot.

⇒ The driver goes along the row of parked cars.

⇒ On-board sensors and cameras gauge the size of any parking spaces, and the on-board computer warns the driver if a suitable space has been found.

⇒ The driver then selects auto-parking and the on-board computer takes over.

⇒ Actuators are used to operate the steering rack, brakes and throttle under the full control of the computer.

⇒ This allows the car to be stacked automatically by performing the parking maneuver with no driver intervention.

⇒ Sensors in the bumpers of the car act as both transmitters and receivers; they transmit signals that bounce off objects and are reflected back.

⇒ The car's on-board computer uses the amount of time it takes for the signal to return to the sensor to calculate the position of any objects.

⇒ The sensors give the computer a 3D image of its surroundings, which allows the car to fit into its parking space; automatically throttle the car by controlling the steering and brakes without driver's intervention.

c) (i) Give two advantages of using automatic self-parking system of a car.

1. Cars can fit into smaller spaces.

2. Safer system since sensors monitor all objects; avoids dents and scratches.

3. Avoids traffic disruption in cities as it takes very less time to stack the car into the parking space.

(ii) Give two disadvantages of using automatic self-parking system of a car.

1. Curbing of wheels is a common problem since the sensors may not pick up low curbs.

2. Faulty / dirty sensors can send false data to the on-board computer which could lead to a malfunction.

3. Over-reliance on automated systems by the driver may lead to the loss of skills.

a) Describe how an automated weather station can be used in the fight against climate change.

★ An automated weather station requires a microprocessor, a storage device to store the database, a battery (usually with solar-powered charging) and a range of sensors like:

• Temperature sensor (thermometer)
• Wind speed sensor (anemometer)
• Humidity sensor (hygrometer)
• Pressure sensor (barometer)
• Level sensor (to measure rainfall)
• Light sensor (to measure hours of daylight)

★ The data from sensors are sent to the microprocessor; any calculations are then done, like calculating hours of daylight, actual rainfall and wind direction.

★ The calculated values are then stored on a central database (via a wireless transmitter).

★ Accurate meteorological data can then be used by the microprocessor to identify hotspots where extreme weather events are likely to occur.

★ Microprocessor then sends alert messages to the concerned authorities and the general public to take appropriate measures to tackle the situation and get prepared for it.

b) Describe when an automatic weather station could need to use actuators.

⇒ An automatic weather station only needs to use actuators to keep a bucket (rain gauge) for collecting rain water for a pre-defined interval of time.

⇒ If the microprocessor gets a signal of rainfall, then it sends a signal to the actuator to operate a piston to keep the bucket for collecting rain water for a fixed time.

⇒ Level sensors are then used to measure the amount of rainfall that fell during that time interval.

c) Give two advantages of using an automated weather station.

1. Provides accurate measurements of weather data.

2. Collects data from dangerous remote places where humans can't work.

3. Has low power consumption (operates using solar panels or wind turbines).

4. Multiple types of data can be collected at the same time.

d) Give two disadvantages of using an automated weather station.

1. May require a large capital investment.

2. Faulty / dirty sensors can send inaccurate or false data.

3. Regular maintenance is difficult if they are in remote locations.

a) (i) Manufacture of a new vaccine that requires the mixing of four liquids in the ratio 1:2:3:4 as a single batch. The four liquids must be totally mixed and the temperature must be maintained at 35 °C (± 1 °C) which is a critical temperature.

⇒ Level sensors in four different burettes (liquid containers) are used to measure the volume of liquid being transferred to a flask (reaction vessel). The tap of each burette is operated by the actuator for the control flow of liquid. The actuator gets signal from microprocessor for the amount of liquid to be released.

⇒ Temperature sensor is used to measure the temperature of the mixture and sends it to the microprocessor. The microprocessor compares the input temperature with stored value. If it is below 34 °C or above 36 °C, then it sends signal to the actuator to switch ON/OFF the cooling / heating system.

(ii) A lighting display has been set up in one room of an art gallery (as part of the exhibition). A random sequence of different coloured LED lights is under microprocessor control. The display only switches on when visitors walk into the room; at the same time, the room lights are dimmed to give the lighting display its most dramatic effect.

⇒ Infrared motion sensors are used to automatically turn ON the lights when visitors walk into the room; and dim the room lights to give the lighting display its most dramatic effect.

(iii) A train uses automatic twin-doors. Both doors open automatically when the train stops. Both doors close again when no-one is still boarding or leaving the train. The doors have a safety mechanism so that a passenger cannot become trapped between the two closing doors. The train can only move off when every door on the train has been safely closed.

⇒ After opening the doors automatically when the train stops, the proximity sensors are used to close the doors if no person is approaching near the gates.

⇒ Infrared sensors are used to detect the presence of a person at the door by breaking the infrared beams, to avoid any person being trapped between the two closing doors.

⇒ Contact sensors are used to detect whether the doors are closed or not, to move the train safely. One part of the sensor is installed on the door while the other piece is fixed on the frame; it completes the circuit only if the door is closed.