# 二阶系统 PD 校正后在阶跃响应下时域指标的计算

## 一般形式的计算

### 基础公式

$$G (s) = \frac {C (s)}{E (s)} = \frac {K\left (T_{d} s+1\right)}{s\left [s /\left (2 \zeta \omega_{n}\right)+1\right]} \tag {1.1}$$

$$\Phi (s)=\frac {\omega_{n}^{2}}{z} \cdot \frac {s+z}{s^{2}+2 \zeta_{d} \omega_{n} s+\omega_{n}^{2}} \tag {1.2}$$

$$\zeta_{d}=\zeta+\frac {\omega_{n}}{2z} \tag {1.2.1}$$

# To：Cheems of the future…

To: cheems of the future…

Hello, long time no see.

I am the past you.

When you think of this letter…

Have you fulfiled our dream?

Or, not done by life?

I don’t know.

But, cheems…

Never stop chasing.

I know it may be difficult…

Even if I tried hard, the flame of hope can’t be lit.

But, cheems…

If one day…

I give up.

Bury our dreams..

Well, no matter how many times.

Pick up your shovel again and dig out the dream again!

Our stories should not be buried deep in the ground…

But should store in the sky!

No matter how many times we’ve been knocked down,

don’t forget the power of dreams.

Go to the end of the Earth.

But it’s not just the end of the Earth…

To see the endless wilderness,

go and see the mountains stretching thousands of miles,

go and see the waterfall flowing straight down,

go and see the clear and clean lake,

no why, just because I wanted to go.

Isn’t that the best life?