Week 1 Flashcards
(13 cards)
What is control?
Designing an algorithm to generate inputs for a plant (e.g., car, motor) so that it produces desired outputs.
What are the key components of a control system?
Plant (G): The system being controlled.
Controller (C): Generates inputs to achieve the desired output.
Instrument (H): Measures system output.
Feedback: Compares actual output with the desired output.
What is a block diagram?
A visual representation of a control system showing the flow of signals.
What are key block diagram rules?
Series Combination (Cascaded Blocks): Multiply transfer functions.
Parallel Combination: Add transfer functions.
Feedback Loop: G equiv = G / (1 + GH) (Negative feedback system).
How to simplify a block diagram?
Use block diagram rules to combine elements into an equivalent single block.
Open vs Closed Loop Control
Open-loop control:
No feedback. Controller acts based on input only.
Pros: Simple, low-cost.
Cons: Cannot correct errors or respond to disturbances.
Closed-loop control:
Uses feedback to adjust input and correct errors.
Pros: More accurate, adapts to disturbances.
Cons: More complex and costly
Example of Open vs Closed Loop
Open Loop: washing machine running a fixed cycle, timer on microwave
Closed Loop: thermostat, water level control (reservoir)
How to find the overall gain of a system?
Gev = output / input = KG / 1+ KGH
find the system input (u)
= output - feedback
= yo - y
output (yo)
= G u
feedback (y)
= H yo
= G H u
General Approach for Solving Closed-Loop Control System Questions
- Determine if the system is open-loop or closed-loop.
- If closed-loop, use the control law, u = Kp( yd - y)
- Define the Input-Output Relationship, yo = Gu
- If feedback is present, express y in terms of yo, y = H yo
(removing all unknowns y, u, etc)
General Approach for Solving Open-Loop Control System Questions
- Determine if the system is open-loop or closed-loop.
- If no feedback is present, the system is open-loop, yo = G u
- substitute out knowns and rearrange
