在PID中，只使用比例增益（P）控制的局限性：

cn_young

PEN 发表于 2016-3-11 04:55
对于第4和第5点，我把整个证明推断的步骤做成了一个Mathcad - T1C1 P Only Daplace.pdf文件，作为附件粘 ...

Pen

I learned a lot from the attachment, but have 2 questions:
1.in the page 3 of file "Mathcad - T1C1 P Only Laplace", and the time constant τ=1/α=3/2ξω
in the page 5 of file "Mathcad - Kv", and the time constant τ=1/Kv. So which is correct?

2.what's relationship between Kv or K(velocity gain) and gain(=amplifier*valve*cylinder*transducer) of OLTF?

Thanks

PEN

我明白为什么会有混乱
这两份文件是在两个不同的时间编写的，以显示两种不同的想法。

注意T1C1 P Only Laplace.pdf。
我写这篇文档是为了展示使用仅比例控制的局限性。
在 T1C1 P 中只有 Laplace.pdf ( τ=1/α=3/2ξω ) τ 是时间常数。 α 是频率或时间常数的倒数。

忽略 Mathcad Kv.pdf
我写这篇文档是为了说明使用 Kv 或速度常数存在问题。

但是，有多种计算时间常数的方法。 在这两个文档中，Kv 和 α 是频率，但计算方式不同。

I can see why there is confusion
The two documents were written at two different times to show two different ideas.

Pay attention to T1C1 P Only Laplace.pdf.
I wrote this document to show the limitations of using proportional only control.
In         T1C1 P Only Laplace.pdf ( τ=1/α=3/2ξω ) τ is a time constant.  α is a frequency or the inverse of time constant.

Ignore Mathcad Kv.pdf
I wrote this document to show that there are problems using Kv or velocity constant.

However, there are multiple ways of calculating time constants. In these two documents, Kv and α are frequencies but calculated in different ways.

zhtok_fy

        积分消除偏差。纯比例控制不能消除偏差