Automated systems

Q1. 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 a microprocessor or computer.

✬  If the input data from sensors is analogue, then it is first converted into digital signal by 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 to be taken, then the microprocessor sends 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 measure the physical quantities from its surroundings (like, temperature, sound, light, pressure, etc.) and send it to the micro-controller / microprocessor of the automated system.

✬  Sensor is an analogue device which needs 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 reads the physical quantities of the environment, so we need it in all automated systems.
2. It could be used in dangerous environment where human can not reach like chemical or nuclear reactor, etc.
3. It is used to measure the quantities very quickly, very accurately without errors.
4. It helps to avoid human error.

Q2. a)  Describe how sensors, microprocessors and actuators can be used in collaboration to create automated systems.

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

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

⇒  Microprocessor compares the input data with the stored values and take 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 station.
2. Transport - such as autonomous cars/buses, trains, unpiloted aircraft, automated signal control system.
3. Agriculture - such as green house 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 light ON and OFF at home/office.
7. Science - automatic control of laboratory experiment which requires 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 environment.
3. Avoids the possibility of human errors.
4. Cost effective, as it replaces human work force and operate 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.

Q3.  An example of an automated system is the control of the entry and exit to a private car park. Cameras takes a photograph of a car's number plate on entry which is then checked before the barrier is raised. At the exit, another camera captures the car's number plate, which is again checked before raising the barrier.

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 recognizes 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. Your answer should 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 presence of a vehicle and send data to the computer which then sends a signal to operate the camera.

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

⇒  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 is allowed to move towards the barrier.

⇒  When the car approaches the barrier, then the infrared or ultrasonic sensor captures the data and send 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 the input signal is beyond the stored limit to identify the presence of car, then the microprocessor sends signal to the actuator to open the barrier to park the car.

⇒  On car's exit, the driver has to scan his driving license again; take the car and move towards the camera, where his car number and license number is compared with data stored in database.

⇒  If the data matches, then the parking charge is calculated, collected and is allowed to move towards the barrier, which opens for exit in the same way as it did during entry.

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 paper work of recording vehice details on entry and exit.
3. Cost effective, as it 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 the possible to illegal 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 smart card (RC smart card) could be included into the system, which need to be verified on entry.

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

Q4.  A car is equipped with  self-parking technology. 

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 changes in real-time, which gives the immediate details about its surrounding to the automated system.

(ii)  Sensors :

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

(iii) Actuators :

⇒  Microprocessor handle 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 are both transmitters and receivers.

⇒  The sensors transmit signals that bounce of 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 monitors all objects; avoid dents and scratches.
3. Avoids traffic disruption in cities as it takes very less time to stack car 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.

Q5.  Describe  how embedded systems in a car prevent the driver exceeding a set speed  and also prevent the car getting too close to the vehicle in front of it. Include the role of the microprocessor and any named sensors in your answer.

⇒  Speed sensors (like Speedometer, rotating Shaft Speed sensor or Magnetic sensor on wheels) reads the speed of the car, while Proximity sensor (like infrared, ultrasonic or radar) reads the distance of vehicle in front or car and sends its data 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 set maximum speed of the car and minimum allowed distance between the vehicles.

⇒  If the speed of the car is more than the set limit, or if distance between the vehicles is less than the set limit, then the microprocessor send signal to the actuator to apply brakes / reduce throttle (reduce speed) and alert the driver by sounding alarm.

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

Q6. a)  Describe how  automated weather station  can be used in the fight against climate change.

✬  Automated weather station require a microprocessor, storage device to store database, battery (usually with solar-powered charging) and range of sensors like -

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

✬  The data from sensors are sent to a 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.

✬  Accurate metrological data can then be used by microprocessor to identify hotspots where extreme weather events are likely to occur.

✬  Microprocessor then sends alert message to the concern authorities and general public to take approximate measures to tackle the situation and get prepared for it.

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

⇒  Automatic weater station only needs to use actuators to keep a bucket (rain guage) for collecting rain water for a pre-defined interval of time.

⇒  If the microprocessor gets signal of rain-fall, then it will send signal to the actuator to operate a piston to keep a 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 automated weather station.

1. Provides accurate measurements of weather data.
2. Collect data from dangerous remote places where human can't work.
3. Have 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 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.

Q7.  A large  greenhouse  is being used to grow tomatoes under controlled conditions. For optimum growth, the tomatoes require the right lighting levels, correct temperature and regular watering.

Describe how automated systems could be used to ensure the correct growing conditions are maintained. The only human involvement would be as a remote supervisor.

✬  Automated Green house make use of sensors like - light sensor to measure light intensity, temperature sensor to measure the temperature, and ultrasonic water level sensor to measure the amount of water in the irrigation channels.

✬  These sensors send their data through wireless transmission to the controller (computer system) every ten minutes.

✬  The controller compares the input water level data with the stored limit, if it is beyond the stored limit, then it sends signal to actuator to switch ON/OFF the valve to pump water.

✬  The controller compares the input temperature and light intensity with the stored limit, if temperature is beyond the stored limit, then it sends signal to the actuator to switch ON/OFF the heating/cooling system, and if light intensity is beyond the stored limit, then it sends signal to the actuator to switch ON/OFF the lighting/shading system.

✬  Using a schematic of a number of processes on a computer screen and via internet links to the controllers, the supervisor can oversee the controlled conditions of green house from one central point.

✬  If the supervisor wishes to further increase or reduce the temperature/light/water supply systems, he can override the controller if necessary.

Q8. a)  Name suitable sensor for each of the following automated systems.

Describe the function of your named sensor in each case.

(i)   Manufacture of a new vaccine that requires the mixing of four liquids in the ration 1:2:3:4 as a single batch. The four liquids must be totally mixed and the temperature must be maintained at 35⁰C (+/- 1⁰C) which is a critical temperature.

⇒  Level sensors in four different burette (liquid container) is 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 send it to the microprocessor. The microprocessor compares the input temperature with stored value. If it is below 34⁰C or above 36⁰C, then it sends signal to the actuator to switch ON/OFF the cooling 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 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 in infrared beams to avoid any person 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.