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Control system
A control system is a system that manages, commands, directs or regulates the behavior of other devices or systems to achieve a desired output.
How does a control system work?
Takes digital input from sensors. Sensors feed data into a microprocessor based on environment around it. Microprocessor processes data. Sends a digital output used to control the device.
Advantages of a control system
A computer can respond much more quickly than humans
Can run without a break/24hrs
Less error-prone than humans
Consistent, unambiguous
Can be placed in environments hazardous to humans
Disadvantages of a control system
Technical malfunction can occur
Cannot react to unexpected events
Relies on a consistent supply of electricity
Microprocessor
Performs Arithmetic and logical control operations
Accepts electrical signal
Performs calculations and data processing
Collection of logic gates
Microcontroller
Used where task is fixed and predefined (embedded systems)
CPU, RAM, Interface all integrated into one chip
Transducers
Converts one form of energy into another
Sensors and actuators
converts variations in a physical quantity, such as pressure or brightness, into an electrical signal, or vice versa.
Converts electrical energy to physical motion
Senors
Convert one form of energy into another
Sensors: Variations in a physical quantity into an electrical signal.
Convert physical measurements, such as temperature, pressure, or light, into electrical signals that can be processed and analyzed by a control system.
Actuator
Converts inputted electrical energy to physical motion
Turns control signal into mechanical action
Requires control device and source of energy
Active sensors
Has to use electricity in order to produce the output signal
Passive sensors
Does not require its own electricity, and gains from the outside world. Generates an output signal in response to some external stimulus
Analogue sensors
Produce a voltage or signal output response which is proportional to the change in the quantity that they are measuring (the stimulus).
Can take any value within a certain range and has infinte readings.
Digital sensors
Convert physical measurements into a sequence of binary digits (zeros and ones). Discrete ouput
Examples of Analogue sensors
Temperature sensors, light sensors, sound sensors, pressure sensor
Examples of Digital sensors
Proximity sensors, PIR sensors
Converting from Analog to Digital
Convert analog data from sensor into digital data, read by computers.
Analog signal is sampled at regular intervals, the digital values obtained are then encoded into a binary code that can be processed by a microcontroller
Feedback
Signal sent back to system. Based on result or environmental action send signal back to microprocessor to receive optimal results.
Open Loop System
Doesnt take feedback, and repeats the same action based on input.
Input is not adjusted based on output.
Closed Loop System
Takes feedback into account. Corrects Errors in output by using Feedback Loop.
Continuously monitors its output and adjusts its input to maintain stability.
Autonomous Agents
Intelligent agent operating on owners behalf without any interference. Software entities that carry out some set of operations independent from direct instruction by user/owner.
Characteristics of Autonomous Agents
Operates without interference.
Autonomy: Can independently select tasks in order to achieve a goal
Reactive: Senses environments and reacts based on this input in pursuit of its own agenda.
Concurrency/sociality: Can interact with other agents
Persistence: Consistently works in pursuit of its goal
Centralized control system
All components are controlled by a centralized processing unit
Located in a single location
Direct control of the operation of individual nodes and flow information from a single server
Distributed control system
Different components are controlled by a number of different processing units
All work towards a common goal
Spread across multiple locations, interconnected through a network
Distrubuited process and control across multiple locations and interconnected nodes
Advantages of a Centralized control system
Easier to maintain and troubleshoot
only one processor
More control + security
Disadvantages of a Centralized control system
If the sensor/controller/actuator fails, whole system fails
Less power
Less flexibility
Advantages of a Distributed control system
Good performance, shared processing load
Reliability: If one or more computers go offline it is not going to have a huge effect on the overall processing
Scalability: easy to increase the amount of processing power
Flexibility: More/diff types of tasks can be completed
Disadvantages of a Distributed control system
Harder to maintain
More complex software
Cost: The additional hardware required to facilitate communication between nodes can increase the cost of the system.
Security: With multiple nodes in the system, there are more potential points of attack for security breaches.
Embedded system
Dedicated function within a larger mechanical or electrical system
small, low-power, and low-cost
Social and ethical issues with Embedded systems
Security: Embedded systems that are connected to the internet or other networks are vulnerable to cyber attacks, which can compromise the security and integrity of the system
Privacy concerns
They are typically designed for a specific task or application and are not easily reprogrammed for new or different tasks.
They can be difficult to troubleshoot and debug because they are highly integrated and often operate without human intervention.
Advantages of Embedded system
They are compact, low-cost, and consume less power.
They are customizable, allowing the designer to choose the components and software that best meet the system's requirements.
They can be easily integrated into larger systems and networks
Proximity sensor
A proximity sensor is a sensor that detects the presence or absence of an object without physical contact.
These sensors emit an electromagnetic field or beam of radiation, and when an object enters the field or interrupts the beam, the sensor detects the change and provides an electrical signal output.
Humidity Sensor
Measures the amount of moisture in the air and provides an electrical signal output proportional to the humidity
Pressure Sensor
Measures the pressure of gas or liquid and provides an electrical signal output proportional to the pressure
Accelerometer sensor
Measures acceleration and provides an electrical signal output proportional to the acceleration.
Infrared Sensor
Detects infrared radiation and provides an electrical signal output proportional to the detected radiation
Force Sensor
A sensor that measures the force applied to it, such as a strain gauge or a load cell
Ultrasonic Sensor
A sensor that uses sound waves to measure distance, commonly used in robotics and industrial applications
Optical Sensor
A sensor that measures changes in light intensity, commonly used in photometry, colorimetry, and motion detection applications
Examples of Actuators
Electric Motor: An actuator that converts electrical energy into mechanical energy, commonly used in robotics, industrial automation, and automotive applications.
Hydraulic Cylinder: An actuator that uses pressurized hydraulic fluid to create linear motion, commonly used in heavy machinery and industrial automation.
Piezoelectric Actuator: An actuator that uses piezoelectric materials to create precise and rapid motion, commonly used in semiconductor manufacturing and microelectromechanical systems (MEMS)
Lightbulbs
Examples of Transducers
Microphone - a device that converts sound waves into electrical signals.
Thermocouple - a device that converts temperature differences into electrical voltage.
Pressure sensor - a device that measures pressure and converts it into an electrical signal.
Accelerometer - a device that measures acceleration and converts it into an electrical signal.
Analogue data
Any continuous signal or information that varies in a smooth and continuous manner over time. Analog data can be represented by a physical quantity, such as voltage, current, or pressure, and can take on an infinite number of values within a defined range.
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