MATLABTECH

PID Control Implementation of Cruise Control System

1. Controller Settings & Real-Time Data

Measurement (PV):50.0 m
Set Point (SP):50.0 m
Error (e = SP – PV):0.0 m
System Response: Calculating…
P Output:0.00
I Output:0.00
D Output:0.00
Total Output (u):0.00

2. Highway Simulation & Block Diagram

50m
Reference 50.0 + e(t): 0.0 PID Controller 0.0 u(t) Plant (Vehicle) 50.0 Dist Output

3. Live Analysis Graphs

Ziegler-Nichols PID Tuning

The Closed-Loop (Ultimate Gain) Method: A systematic sequence to calculate optimal PID parameters by driving the system to sustained oscillation.

1

Initialize P-Only Control

Set the Integral (I) and Derivative (D) gains to zero. Ensure your controller is operating entirely in Proportional mode. This isolates the system’s reaction to proportional gain.

2

Determine the Ultimate Gain (Ku)

Gradually increase the proportional gain (Kp) from zero. Watch the system’s output response. Stop increasing the gain exactly when the system reaches sustained, stable oscillations (constant amplitude). Record this specific gain value as the Ultimate Gain (Ku).

3

Measure the Ultimate Period (Tu)

While the system is oscillating at the Ultimate Gain (Ku), measure the time it takes to complete one full oscillation cycle (peak-to-peak). Record this time as the Ultimate Period (Tu).

4

Calculate PID Parameters

Using the recorded Ku and Tu values, apply the Ziegler-Nichols tuning formulas to compute the final controller parameters based on your desired control type.

Controller Kp (Proportional) Ti (Integral Time) Td (Derivative Time)
P 0.50 × Ku 0
PI 0.45 × Ku Tu / 1.2 0
PID 0.60 × Ku Tu / 2.0 Tu / 8.0
5

Implement and Fine-Tune

Input the calculated parameters into your control algorithm. The Ziegler-Nichols method generally provides an aggressive, fast-responding starting point (typically resulting in a quarter-wave decay). You may need to manually fine-tune the parameters to reduce overshoot based on the specific safety and performance requirements of your system.