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The amazing power of closed-loop control: How does it make systems smarter?
With the advancement of technology, smarter systems are constantly appearing in our lives, and one of the secrets behind this is "closed-loop control." This technology not only improves the anti-interference ability, but also greatly increases the automation rate. This approach collects and uses feedback information to form a control loop, thereby adjusting the system to achieve the desired effect.
The basic principle of a closed-loop control system is to continuously adjust the input to achieve a stable state by continuously measuring the output and comparing it with the target input.
Operation principle of closed-loop control system
The concept of closed-loop control derives its name from the path of information in a system: the input to a process (e.g., the voltage applied to an electric motor) has an effect on the output of the process (e.g., the speed or torque of the motor). These outputs are measured by sensors and processed by controllers, the results of which, as control signals, are “fed back” into the process as inputs, thus closing the loop.
In many applications, closed-loop control performs better than open-loop control because it can adapt to changing environments and uncertainties.
Advantages of closed-loop control
Closed-loop control systems have several distinct advantages. They are robust to external perturbations (e.g., hill-climb effects in cruise control) and guarantee performance even when the model is not perfect. In addition, such a system exhibits lower sensitivity to parameter variations, further improving the reference tracking performance.
For example, modern cars' cruise control systems use this technology. When encountering a slope, the car's speed will drop due to gravity, but the system will adjust the throttle in time to restore to the speed set by the driver. This process is driven by a PID (proportional-integral-derivative) control algorithm.
Differences between open-loop and closed-loop control
Open-loop control systems operate in a pre-determined manner, while closed-loop control systems can adapt to current conditions, which makes closed-loop control more flexible and adaptable. For example, in a typical closed-loop control system, the system output is fed back to the controller through a sensor and compared with a reference value to generate a correction signal to adjust the system performance.
Such a process ensures that the system continues to operate efficiently in a changing environment.
Application of PID controller
One of the most common controller forms is the PID controller. It continuously calculates the error between the desired set point and the actual process variable and makes adjustments to the input based on three components: proportional, integral, and derivative. PID controller is considered as the most important feedback control design due to its wide application in various control systems.
When setting PID parameters, iterative adjustments are often required to obtain the best closed-loop dynamics, a process that may not require a clear understanding of the plant model.
Future Potential
With the development of artificial intelligence and automation technology, the potential of closed-loop control systems lies in realizing higher-level intelligent applications. For example, in future smart city settings, traffic lights can be adjusted in a closed loop based on real-time traffic flow to improve road usage efficiency.
Closed-loop control is not just a simple technical issue; its development will affect the operating modes of all industries in the future. Perhaps in the near future, we humans and technology will work together to create new possibilities. How will this affect the way we live?
