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n-th order Systems

LT
by Lukas T.

What is a zero order System? Formular, behaviour, example!

In control systems theory, a zero-order system is a type of dynamic system that can be described by a zero-order differential equation. This means that the output variable is proportional to the input variable, with no time derivative involved.

Mathematically, a zero-order system can be represented by the following equation:

y = k*u

where y is the output variable, u is the input variable, and k is a constant that represents the gain of the system.

The term "zero-order" refers to the fact that there is no differentiation of the output variable with respect to time. This means that the system has no inherent time delay, and its response is instantaneous.

Examples of zero-order systems include simple electrical resistors, which obey Ohm's law and have a linear relationship between voltage and current. In this case, the output variable (current) is proportional to the input variable (voltage), with the proportionality constant being the resistance of the resistor.

Another example of a zero-order system is a fixed-gain amplifier, which amplifies an input signal by a fixed amount. In this case, the output voltage is proportional to the input voltage, with the proportionality constant being the gain of the amplifier.

In summary, a zero-order system is a dynamic system in which the output variable is proportional to the input variable, with no differentiation involved. The system has no inherent time delay, and its response is instantaneous.

What is a second order system?

In summary, a second-order system is a dynamic system that can be described by a second-order differential equation. Its behavior depends on its natural frequency and damping ratio, and can be classified as overdamped, critically damped, or underdamped. Examples of second-order systems include mass-spring-damper systems, which are widely used in engineering and physics applications.

described by a second-order differential equation

This equation relates the rate of change of the output variable and its acceleration to the input variable and the current value of the output variable.

Mathematically, a second-order system can be represented by the following differential equation:

d²y/dt² + 2ζωn dy/dt + ωn²y = Kp u

where y is the output variable, u is the input variable, Kp is the proportional gain of the system, ωn is the natural frequency of the system, and ζ is the damping ratio of the system.

The natural frequency is a measure of how quickly the system oscillates in the absence of any damping, and is defined as ωn = sqrt(K/m), where K is the stiffness of the system and m is its mass. The damping ratio is a measure of how quickly the system returns to equilibrium after being disturbed, and is defined as ζ = c/(2sqrt(Km)), where c is the damping coefficient.

The behavior of a second-order system depends on the values of its parameters, including its natural frequency and damping ratio. The system response can be classified into three types: overdamped, critically damped, and underdamped.

  • Overdamped: In an overdamped system, the damping ratio is greater than 1. This means that the system returns to equilibrium slowly and without oscillation.

  • Critically damped: In a critically damped system, the damping ratio is exactly 1. This means that the system returns to equilibrium as quickly as possible without oscillation.

  • Underdamped: In an underdamped system, the damping ratio is less than 1. This means that the system oscillates with a frequency close to its natural frequency, and takes some time to return to equilibrium.


Author

Lukas T.

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