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Performance Characteristics of Sensors and Actuators

The performance characteristics of the device or system are the most important issues the engineer is faced with.
The properties of sensors and actuators are usually given by the manufacturer and engineers can usually rely on these data.
We can describe both types of devices by a transfer function that relates input and output regardless of what these quantities are.

The transfer function

The input/output characteristic function or response of a device is a relationship between the output and input of the device, usually defined by some kind of mathematical equation and a descriptive curve or graphical representation in a given range of inputs and outputs.
With the exception of linear transfer functions, it is usually difficult to describe the transfer function mathematically.



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import matplotlib.pyplot as plt
import numpy as np
%matplotlib inline

x = np.array([226, 248, 278, 369, 532, 718])
y = np.array([154, 155, 166, 219, 289, 314])
y = np.abs(y-350)

a,b,c,d,e = np.polyfit(x,y,4)

y2 = a*x**4+b*x**3+c*x**2+d*x+e

plt.xkcd()  # Yes...
plt.plot(x,y2)
plt.axis([200,800,20,220])
plt.xlabel('T')
plt.ylabel('R')
plt.show()



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