PID tuning is the process of finding the values of proportional, integral, and derivative gains of a PID controller to achieve desired performance and meet design requirements.
If you use the Closed-Loop PID Autotuner block, the plant remains under control of the PID controller with its current gains during the experiment. Closed-loop tuning uses sinusoidal test signals at the frequencies 1/10,1/3, 1, 3, 10ω c. Mar 09, 2020 PID Control System Design and Automatic Tuning using MATLAB/Simulink is intended for undergraduate electrical, chemical, mechanical, and aerospace engineering students, and will greatly benefit postgraduate students, researchers, and industrial personnel who work with control systems and their applications.
PID controller tuning appears easy, but finding the set of gains that ensures the best performance of your control system is a complex task. Traditionally, PID controllers are tuned either manually or using rule-based methods. Manual tuning methods are iterative and time-consuming, and if used on hardware, they can cause damage. Rule-based methods also have serious limitations: they do not support certain types of plant models, such as unstable plants, high-order plants, or plants with little or no time delay.
You can automatically tune PID controllers to achieve the optimal system design and to meet design requirements, even for plant models that traditional rule-based methods cannot handle well.
Feb 09, 2018 Published on Feb 9, 2018 in this video, PID controller and PID tuning is shown. In this work a boost converter pid controller is taken and manual pid tuning is done with the help of Ziegler Nichols. What algorithm is applied in the auto-tuning of PID block in Simulink? Is it Zeigler-Nicholson or Cohen-Coon tuning method or other one?
For more information, see Control System Toolbox™ for use with MATLAB® and Simulink®.
An automated PID tuning workflow involves:
- Identifying plant model from input-output test data
- Modeling PID controllers in MATLAB using PID objects or in Simulink using PID Controller blocks
- Automatically tuning PID controller gains and fine-tuning your design interactively
- Tuning multiple controllers in batch mode
- Tuning single-input single-output PID controllers as well as multiloop PID controller architectures
How PID Autotuning Works
To use PID autotuning, configure and deploy one of the PID autotuner blocks, Closed-Loop PID Autotuner or Open-Loop PID Autotuner.
Autotuning Process
Pid Tuning Simulink
The PID autotuner blocks work by performing a frequency-response estimation experiment. The blocks inject test signals into your plant and tune PID gains based on an estimated frequency response.
The following schematic diagram illustrates generally how a PID autotuner block fits into a control system.
Until the autotuning process begins, the autotuner block relays the control signal directly from u to the plant input at u+Δu. In that state, the module has no effect on the performance of your system.
When the autotuning process begins, the block injects a test signal at u out to collect plant input-output data and estimate frequency response in real time.
If you use the Open-Loop PID Autotuner block, the block opens the feedback loop between u and u+Δu for the duration of the estimation experiment. It injects into u+Δu a superposition of sinusoidal signals at frequencies [1/3, 1, 3, 10]ωc, where ωc is your specified target bandwidth for tuning. For nonintegrating plants, the block can also inject a step signal to estimate the plant DC gain. All test signals are injected on top of the nominal plant input, which is the value of the signal at u when the experiment begins.
If you use the Closed-Loop PID Autotuner block, the plant remains under control of the PID controller with its current gains during the experiment. Closed-loop tuning uses sinusoidal test signals at the frequencies [1/10,1/3, 1, 3, 10]ωc.
When the experiment ends, the block uses the estimated frequency response to compute PID gains. The tuning algorithm aims to balance performance and robustness while achieving the control bandwidth and phase margin that you specify. You can configure logic to transfer the tuned gains from the block to your PID controller, allowing you to validate closed-loop performance in real time.
Workflow for PID Autotuning
The following steps provide a general overview of the workflow for PID autotuning.
Auto Tuning Shop Cz
Incorporate a PID autotuner block into your system, as shown in the schematic diagram.
Configure the start/stop signal that controls when the tuning experiment begins and ends. You can use this signal to initiate the PID autotuning process at any time. When you stop the experiment, the block returns tuned PID gains.
Specify controller parameters such as controller type and the target bandwidth for tuning.
Configure experiment parameters such as the amplitudes of the perturbations injected during the frequency-response experiment.
Start the autotuning process using the start/stop signal, and allow it to run long enough to complete the frequency-response estimation experiment.
Stop the autotuning process. When the experiment stops, the autotuner computes and returns tuned PID gains.
Transfer the tuned gains from the block to your PID controller. You can then validate the performance of the tuned controller in Simulink® or in real time.
For detailed information on performing each of these steps, see:
See Also
Closed-Loop PID Autotuner | Open-Loop PID Autotuner