Notes by a friend for Systems - 5ESB0, kept with the 5ESC0 friend notes

Laplace Transform (friend) - 5ESC0

Differential Equations

Topic: Differential Equations

2nd order DE:

Homogeneous solution:

  • 2 roots:
  • 1 root:

signal_block.png (not included in the repository)

Block signal: : step function

: step response
: impulse response
u(t): input

Relationship between unit impulse and unit step

Partial fraction expansion

feedback_loop.png (not included in the repository)

Dynamic Response

Step response:

undamped natural frequency
damping

Poles:
Typical 2nd order transfer function:


time-scaling effect:

Properties:

Rise time :
Peak time :
Overshoot :
Settling time :

Theorem

Final value:
Initial value:

Zeroes:


Step response of is derivative of of

Feedback Control

Topic: Feedback and Stability
Transfer function shortcuts:


Open:
Closed:

d: load disturbance
n: measurement noise
u: controlled variable
x: physical output
y: measured output (with noise)
F: feed forward
C=D: controller
P=G: plant (controllee)



Stability

Change root of denominator

Sensitivity

Open:
Closed:

System Type & Steady State Error


System type k:

PID

Topic: Controller Design
Second-order:

P

faster response, less damping

PI

  • : zero steady state error for step input
  • 1st-order
  • Disturbance rejection: reject constant disturbance

PD


2nd-order increase damping