Summary of Simple Examples of PID Control

00:00:00 - 00:10:00

This video discusses the use of PID controllers to stabilize an unstable control system. It gives two examples of how a PID controller can be used to maintain a steady state error. In the first example, a driver is trying to control their position instead of speed when approaching a stoplight. In the second example, a driver is following a friend who is moving at a constant speed. The three pads in a PID controller contribute to the overall control system in different ways, and it is important to understand the dynamics of the system in order to choose the appropriate controller.

• 00:00:00 In this 1-paragraph video, control system lecturer John Peake explains how proportional controllers work to maintain a steady state error in a system. If the gain (a parameter in a proportional controller) is too high, the system can runaway and be dangerous.
• 00:05:00 The video discusses the simple examples of PID control, which are used to stabilize an unstable control system. In the first example, a driver is trying to control their position instead of speed when approaching a stoplight. The control system is unstable, and adding the derivative term to the equation makes it even more unstable. PID control can be used to stabilize the system by adjusting the change in pedal angle based on the rate of change of the error. In the second example, a driver is following a friend who is moving at a constant speed. The reference signal is their friend's position, and the controller output is a pedal angle. If the pedal angle is constant, then there is a steady state error and the driver will always trail behind their friend. If the pedal angle is not constant, then the driver has an error signal that looks like this: The derivative path is zero and the proportional path causes the driver to press the gas pedal down to its current location. In this situation, the pedal will not be moved, and the driver will continue to drive behind their friend.
• 00:10:00 The three pads in a PID controller contribute to the overall control system in different ways, and it is important to understand the dynamics of the system in order to choose the appropriate controller.