How To Auto Tune Pid Controller Toms

Since the board is set up from the factory for bang-bang control for the heatbed and not PWM/PID control, I don't think there is any tuning you can do for the bed without reflashing the firmware with settings for PID/PWM. PWM/PID cannot be used with an external mechanical relay, only a FET or some solid-state relays. If using the on-board FET, it should be possible to use PWM/PID but only with reflashed firmware.

After the bed reaches temperature, is it stable within a few degrees C?

If while heating up, there is massive temperature overshoot and/or a bad oscillation of temperature above and below the target temp, then yes, there is a problem that will need some tuning or redesign ( the bed thermistor may not be thermally connected to the bed well enough). Otherwise, don't worry about it.

Aug 15, 2016 A Control Design reader wrote to us: I often have difficulty tuning PID loops, especially for temperature control applications and servo-motor motion applications. If I use a temperature controller, the auto-tune built into the device often works well if I follow the manufacturer’s recommendations. Feb 15, 2017 A basic tutorial on how to perform a 'PID Tuning' on the Prusa Mk2 using Pronterface. Advanced Tuning: ESTEPS calibration and PID Control for your Tevo Tornado 3D Printer. Auto PID Tuning. In this paper, the simulation environment is proposed that enables accurate full-scale investigation of the pressure adjustment for a centrifugal pump. Amazon.com: Dell G7 17 Gaming Laptop (Windows 10 Home, 9th Gen Intel Core i7-9750H, NVIDIA GTX 1660 Ti 6G, 17.3' FHD LCD Screen, 512GB SSD, 16 GB RAM) G7790-7662GRY-PUS: Computers & Accessories.

I haven't had any issues with wild temperature swings. I have my bed set up so I can use it with 12v through the FET for lower temperatures or with a flip of a switch, powered by a 20V power supply through a relay.

How To Tune Pid Parameters

This example shows how to automatically tune a PID Controller block using PID Tuner.

Introduction of the PID Tuner

PID Tuner provides a fast and widely applicable single-loop PID tuning method for the Simulink® PID Controller blocks. With this method, you can tune PID controller parameters to achieve a robust design with the desired response time.

A typical design workflow with the PID Tuner involves the following tasks:

(1) Launch the PID Tuner. When launching, the software automatically computes a linear plant model from the Simulink model and designs an initial controller.

(2) Tune the controller in the PID Tuner by manually adjusting design criteria in two design modes. The tuner computes PID parameters that robustly stabilize the system.

(3) Export the parameters of the designed controller back to the PID Controller block and verify controller performance in Simulink.

Open the Model

Open the engine speed control model with PID Controller block and take a few moments to explore it.

Design Overview

In this example, you design a PI controller in an engine speed control loop. The goal of the design is to track the reference signal from a Simulink step block scdspeedctrlpidblock/Speed Reference. The design requirement are:

In this example, you stabilize the feedback loop and achieve good reference tracking performance by designing the PI controller scdspeedctrl/PID Controller in the PID Tuner.

Open PID Tuner

To launch the PID Tuner, double-click the PID Controller block to open its block dialog. In the Main tab, click Tune.

Initial PID Design

When the PID Tuner launches, the software computes a linearized plant model seen by the controller. The software automatically identifies the plant input and output, and uses the current operating point for the linearization. The plant can have any order and can have time delays.

The PID Tuner computes an initial PI controller to achieve a reasonable tradeoff between performance and robustness. By default, step reference tracking performance displays in the plot.

The following figure shows the PID Tuner dialog with the initial design:

Display PID Parameters

Click Show parameters to view controller parameters P and I, and a set of performance and robustness measurements. In this example, the initial PI controller design gives a settling time of 2 seconds, which meets the requirement.

How

How To Tune A Pid Controller

Adjust PID Design in PID Tuner

The overshoot of the reference tracking response is about 7.5 percent. Since we still have some room before reaching the settling time limit, you could reduce the overshoot by increasing the response time. Move the response time slider to the left to increase the closed loop response time. Notice that when you adjust response time, the response plot and the controller parameters and performance measurements update.

The following figure shows an adjusted PID design with an overshoot of zero and a settling time of 4 seconds. The designed controller effectively becomes an integral-only controller.

Complete PID Design with Performance Trade-Off

In order to achieve zero overshoot while reducing the settling time below 2 seconds, you need to take advantage of both sliders. You need to make control response faster to reduce the settling time and increase the robustness to reduce the overshoot. For example, you can reduce the response time from 3.4 to 1.5 seconds and increase robustness from 0.6 to 0.72.

The following figure shows the closed-loop response with these settings:

Write Tuned Parameters to PID Controller Block

After you are happy with the controller performance on the linear plant model, you can test the design on the nonlinear model. To do this, click Update Block in the PID Tuner. This action writes the parameters back to the PID Controller block in the Simulink model.

The following figure shows the updated PID Controller block dialog:

Completed Design

Gsnap

The following figure shows the response of the closed-loop system:

The response shows that the new controller meets all the design requirements.

You can also use the Control System Designer to design the PID Controller block, when the PID Controller block belongs to a multi-loop design task. See the example Single Loop Feedback/Prefilter Compensator Design.

See Also

Related Topics