1. network of physical objects (things)
2. embedded with sensors, software
3. is used for connecting and exchanging data
4. with other devices and systems over the Internet

1. an interconnection of physical components
2. connected
3. direct or regulate itself or another system.

• The control of dynamical systems in engineered processes and machines.
• develop a model or algorithm governing the application of system
• minimizing any delay, overshoot, or steady-state error
• ensuring a level of control stability
• achieve a degree of optimality

1. Additivity propertyx1(t) x2(t) → y1(t) y2(t)
2. Homogeneity or Scaling property ax(t) → ay(t)
3. ax1(t) bx2(t) → ay1(t) by2(t)

Disadvantages:

• Costly
• Complex
• 又贵又复杂

Advantages:

• Decreased sensitivity of the system to variations提升系统对抗变化的能力
• Improved rejection of the disturbances提升系统对抗扰动的能力
• Improved measurement noise attenuation提升了测量噪声的衰减，抗噪声
• Improved reduction of the steady-state error of the system提升了对于稳态误差的减少
• Easy control and adjustment of the transient response of the system

找到合适的零点和极点步骤：

1. Evaluate the sum of angles

   • 首先，振动不变，因此阻尼比不变，根仍在直线上（阻尼比表示根与原点连接cos）
   • 然后，由settle time求出横坐标
   • 计算出让这一点成为根轨迹上所需的角度补偿

   Evaluate the sum of angles from the open-loop to a designed point，which yields the desired transient response.

2. The difference between 180° are the compensator

   180° 补偿器所需的角度贡献必须是计算角度角度

3. Arbitrarily select either a lead compensator pole or zero, then find another one by 180° principle

   通过和为180°另一个零点或极点的位置

• By variable that is， the type of quantity being measured

  根据变量，即测量的类型

  • Temperature
  • Pressure
  • Displacement
  • Flow
  • Humidity
  • Velocity
  • Acceleration

• By type that is, the operating principle of the transducer being
  used

  根据类型，即传感器的工作原理

  • Resistive电阻式
  • Inductive电感式
  • Capacitive电容式

  accordingly电阻率、介电常数和磁导率三个属性。

Some types of transducer can be used for measuring different
variables.可用于测量不同变量的传感器。

影响因素：

• strain (拉伸材料是否改变应力)
• temperature

R=ρL/A L:导体长度 A:横截面面积

𝑅t=𝑅(1+𝛼𝑇)

L=(μN^2 A)/L

c=eA/d

1. Negative Temperature Coefficient (NTC) thermistors

   负温度系数 (NTC) 热敏电阻

2. Positive Temperature Coefficient (PTC)thermistors

   正温度系数 (PTC) 热敏电阻

is required for two reasons:

• Characteristics of the input variable输入变量的特征
  • Range (范围max and min)
  • Overload protection过载保护
  • Frequency response频率响应
  • Transient response瞬态响应
  • Resonant frequency共振频率
• Transducer input/output relation传感器输入/输出关系
  • Accuracy即输出是否准确
  • Precision ：the apparent degree of accuracy是准确度的度量
  • Repeatability： 重复实验给出相似结果的能力
  • Linearity
  • Sensitivity输入端的改变在输出端的反应
  • Resolution：清晰度
  • Stability：稳态
  • Slew rate：压摆率the highest possible rate of change at the output
  • Hysteresis：滞后
• Overall System整体系统
  • Output characteristics：输出特性
  • Size and weight：尺寸和重量
  • Power requirements：能源需求
  • Accessories needed：需要的配件
  • Mounting requirements：增长需要
  • Environment of transducer location：传感器所在地的环境
  • Crosstalk串扰
• Measurement Reliability测量可靠性
  • Ease of speed of calibration and testing易于校准和测试
  • Time available for calibration and testing可用于校准和测试的时间
  • Stability against drift抗漂移稳定性
  • Vulnerability to sudden failure突发故障的脆弱性
  • Fail safety故障安全
  • Failure recognition故障识别
• Purchase购买是否便利
  • Availability and delivery
  • Price
  • Previous experience以往的经验

• yields a staircase approximation to the analog
  signal.
  产生模拟信号的阶梯近似值。
• 它在 𝑡∈[𝑘𝑇, (𝑘+1)𝑇] 期间保持一个常数 𝑓(𝑘𝑇) 的输出