Transfer Function of an unknown device

In summary, the conversation discusses the topic of controls engineering and the process of finding transfer functions for devices and systems in the real world. The speaker is seeking help in finding the transfer function of a motor in their house in order to control its velocity. They also inquire about finding transfer functions for systems without knowing the matrices A, B, C, and D. The suggested method for finding transfer functions is through system identification and recording the impulse response.
  • #1
nebbione
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Hi everyone, in the last times, I'm really interested in controls engineering, and I wanted toknow how to find transfer functions of devices, or systems in the real world, let me explain better, for example, in my house i have various dc motors, and stepper motors, since i want to make an automatic control of the velocity, I'm blocked since i don't know the trasfer function of the motor... how can i proceed ? How can i find the transfer function of this motor ?
And in general how do i find a transfer function of a system, without knowing the matrixes A,B,C,D ?
 
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  • #2
What you're asking is non-trivial. The subfield associated with it is called "System Identification".

The easiest thing you can try if you have access to the input and output ports of the system is to input a fast pulse (approximating an impulse) and then record the impulse response. The transfer function would then be the Laplace transform of the impulse response.
 

1. What is a transfer function of an unknown device?

A transfer function of an unknown device is a mathematical representation that describes the relationship between the input and output signals of the device. It shows how the device responds to different input signals and can be used to analyze and predict the behavior of the device.

2. Why is it important to determine the transfer function of an unknown device?

Determining the transfer function of an unknown device is important because it allows us to understand and characterize the behavior of the device. This information can then be used to design and optimize systems that use the device, as well as troubleshoot any issues that may arise.

3. How is the transfer function of an unknown device determined?

The transfer function of an unknown device can be determined by applying known input signals to the device and measuring the corresponding output signals. This data can then be used to calculate the transfer function using mathematical techniques such as Fourier analysis or Laplace transforms.

4. Can the transfer function of an unknown device change over time?

Yes, the transfer function of an unknown device can change over time due to factors such as aging, wear and tear, or environmental conditions. It is important to regularly test and update the transfer function to ensure accurate predictions and performance of the device.

5. How is the transfer function of an unknown device used in control systems?

In control systems, the transfer function of an unknown device is used to design controllers that can manipulate the input signals to achieve a desired output. By understanding the transfer function, engineers can design control systems that are stable and can accurately control the behavior of the device.

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