Design Initial PI Controller

Load a Simulink^®包含PID控制器块的模型。

open_system（“单次窃听”)

此示例中的植物是：

The model also includes a reference signal and a step disturbance at the plant input. Reference tracking is the response atyto the reference signal,r. Disturbance rejection is a measure of the suppression atyof the injected disturbance,d. When you usePID调谐器to tune the controller, you can adjust the design to favor reference tracking or disturbance rejection as your application requires.

为工厂设计初始控制器。为此，请双击PID控制器块以打开块参数对话框，然后单击Tune.PID调谐器打开并自动计算初始控制器设计。

The controller in the Simulink model is configured as a PI-type controller. Therefore, the initial controller designed byPID调谐器is also of PI-type.

添加输入干扰拒绝的步骤响应图。选择添加图>Input Disturbance Rejection.

PID调谐器tiles the disturbance-rejection plot in a new tab.

默认情况下，对于给定的带宽和相位边距，PID调谐器调谐控制器以在参考跟踪和干扰拒绝之间达到平衡。在这种情况下，控制器在参考跟踪响应中产生一些过冲。在初始峰后，控制器还以比参考跟踪更长的沉降时间抑制输入干扰。

Clickto update the Simulink model with this initial controller design. Doing so also updates the Block Response plots inPID调谐器, so that as you change the controller design, you can compare the results with the initial design.

Adjust Transient Behavior

Depending on your application, you might want to alter the balance between reference tracking and disturbance rejection to favor one or the other. For a PI controller, you can alter this balance using theTransient Behavior滑块。移动Transient behavior向左滑动以改善干扰拒绝。现在，使用初始控制器设计的响应显示为块响应（虚线）。

将瞬态行为系数降低到0.45速度加快了干扰排斥反应，但也增加了参考跟踪响应中的过冲。

移动Transient behavior在右边，直到参考跟踪响应中的过冲。

将瞬态行为系数增加到0.70几乎消除了过冲，但导致干扰抑制缓慢。您可以尝试移动Transient behavior滑块,直到你找到一个合适的平衡元素een reference tracking and disturbance rejection for your application. How much the slider affects the balance depends on the plant model. For some plant models, the effect is not as large as shown in this example.

Change PID Tuning Design Focus

So far, the response time of the control system has remained fixed while you have changed the transient-behavior coefficient. These operations are equivalent to fixing the bandwidth and varying the target minimum phase margin of the system. If you want to fix both the bandwidth and target phase margin, you can still change the balance between reference tracking and disturbance rejection. To tune a controller that favors either disturbance rejection or reference tracking, you change thedesign focusof the PID tuning algorithm.

更改PID调谐器设计焦点更有效，在控制系统中存在更可调的参数。因此，与PI控制器一起使用时，它没有太大影响。要查看其效果，请将控制器类型更改为PID。在Simuli万博1manbetxnk模型中，双击PID控制器块。在“块参数”对话框中，在控制器drop-down menu, selectpid.

ClickApply. Then, clickTune. This action updatesPID调谐器with a new controller design, this time for a PID controller. Clickto the Simulink model with this initial PID controller design, so that you can compare the results when you change design focus.

As in the PI case, the initial PID design balances reference tracking and disturbance rejection. In this case as well, the controller yields some overshoot in the reference-tracking response, and suppresses the input disturbance with a longer settling time.

更改PID调谐器design focus to favor reference tracking without changing the response time or the transient-behavior coefficient. To do so, clickOptions，在Focusmenu, select参考跟踪.

PID调谐器automatically retunes the controller coefficients with a focus on reference-tracking performance.

现在，使用平衡控制器的响应显示为块响应，以及用焦点参考跟踪调整的控制器是Tuned response. The plots show that the resulting controller tracks the reference input with considerably less overshoot and a faster settling time than the balanced controller design. However, the design yields much poorer disturbance rejection.

Finally, change the design focus to favor disturbance rejection. In theOptionsdialog box, in theFocusmenu, select输入干扰拒绝.

This controller design yields improved disturbance rejection, but results in some increased overshoot in the reference-tracking response.

当您使用设计焦点选项时，您仍然可以调整Transient Behavior滑块以进一步微调这两种绩效指标之间的平衡。使用设计焦点和滑块一起实现最能满足您设计要求的性能平衡。这种微调对系统性能的影响很大程度上取决于植物的特性。对于某些植物，移动Transient Behaviorslider or changing theFocus选项几乎没有效果。

To obtain independent control over reference tracking and disturbance rejection, you can use a two-degree-of-freedom controller,pid控制器(2DOF), instead of a single degree-of-freedom controller.