Global import export freight indexes

List of the contents of this article:

• 1,Global import export freight indexes The stability of the system is determined by?
• 2. How to improve the stability of the system, reduce and eliminate steady-state errors
• 3, How to judge system stability< /Li>
• 4,Definition of system stability
• 5. What is system stability?

The stability of the system is determined by?

Biodiversity can determine the self-regulation ability of ecosystems. Generally speaking, the richer the biodiversity, the more complex the food chain and food web it forms, so the stronger its automatic adjustment ability, that is to say, the stronger the stability of the ecosystem.

Stability is the primary condition for the normal operation of the system. The stability of the system is completely determined by the structure and parameters of the system itself, and has nothing to do with the input of the system. The steady-state error of the system is the steady-state performance index of the system, which marks the control accuracy of the system. The time-domain response of the system can be qualitatively or quantitatively analyzed. The dynamic performance of the system.

Resilience stability (resilience stability) Resilience stability refers to the ability to restore the original state in place after the ecosystem has been destroyed.

Please be more specific. Conceptually, the closed-loop poles determine which motion modes are included in the system response, and the closed-loop zero points will affect the proportion of each motion mode (that is, the coefficients of each). Therefore, the closed-loop zero point will not affect the stability of the system, but it will affect the shape of the response curve.

How to improve the stability of the system, reduce and eliminate steady-state errors

1. Discuss the way to reduce or eliminate the steady-state error: the way to reduce the steady-state error: increase the open-loop amplification coefficient of the system; improve the order N of the series integral link in the open-loop transfer function;Adopt the compensation method for one-by-one composite control or feedforward control.

2. Increase the open-loop gain of the system or the forward channel gain of the system before the disturbance point. However, this method is limited. We cannot infinitely increase the open-loop gain of the system, because when the open-loop gain increases to a certain extent, it will inevitably affect the stability of the system, which is not what we want to see.

3. Set up a series points link in the forward channel or main feedback channel of the system. Among them, in the feedback system, the measures of setting up a series integral link or increasing the open-loop gain to eliminate or reduce the steady-state error will inevitably reduce the stability of the system, and even cause system instability, thus worsening the dynamic performance of the system.

4. Increase the gain and add the integral controller. Lead toIncrease the open-loop gain of the system or the gain of the forward channel of the system before the disturbance of the point to increase the response speed of the system, so as to reduce the steady-state error. The integral controller can accumulate errors and continuously reduce errors, thus reducing steady-state errors.

The method of judging the stability of the system

1. The stability of a linear system is the main performance indicator of the system. The methods for judging the stability of a linear system include algebraic method, root trajectory method and Nyquist judgment method.

2. Nyquist's judgment: Use the geometric characteristics of the open-loop frequency to judge the stability and stability of the closed-loop system, which is more convenient to analyze the impact of open-loop parameters and structural changes on the transient performance of the closed-loop system.

3, the system is affected by some kind ofInterference and deviation from the normal state, when the interference is eliminated and its normal state can be restored, then the system is stable; on the contrary, if once the system deviates from its normal state, it cannot be restored to the normal state, and the deviation is getting bigger and bigger, the system is unstable.

4. The stability of the amplitude margin and phase angle margin judgment system is aimed at the minimum phaseless system. When the system is stable: the amplitude margin is 1 and the phase angle margin is 0; the larger the amplitude margin and the phase angle margin, the more stable the system is. When the criticality of the system is stable: amplitude margin = 1, phase angle margin = 0. When the system is unstable: amplitude margin 1, phase angle margin 0.

5. According to the definition, f(t) produces y(t), and f(t-t0) produces y1(t). Let's see if y1(t) is equal to y(t-t0). If they are equal, they remain unchanged.

6. Stability discrimination method: Rolls stability judgment, Helwitz stability judgment, Nyquist stability judgment, the stability of the system judged by Bird diagram, root trajectory method, Lyapunov stability method, there are two types of algebic stability judgment, Rolls stability judgment and Helwitz stability Qualitative judgment.

Definition of system stability

The so-called system stability refers to the performance of the system restored from the initial deviation state to the original equilibrium state after the disturbance disappears. In classical control theory, the sufficient necessary condition for system stability is that when time tends to infinity, the unit pulse of the system is correspondingly equal to zero.

System Stability Definition 1 System stability refers to a certain stable state shown by system elements under external influence.Its meanings are roughly divided into the following three categories: (1) External temperature, mechanical and other changes do not have a significant impact on the state of the system.

Equip stability can be understood as: the whole process of the program from installation to loading, start-up and operation to the completion of the program is as without abnormalities, errors and other problems as possible, which is called the equipment stability index.

What is system stability?

The so-called system stability refers to the performance of the system restored from the initial deviation state to the original equilibrium state after the disturbance disappears. In classical control theory, the sufficient necessary condition for system stability is that when time tends to infinity, the unit pulse of the system is correspondingly equal to zero.

Refers to when the system is disturbed,It deviates from the original equilibrium state, and when the disturbance disappears, the system can gradually return to the original equilibrium state, it is said that the system is stable.

The stability of the system usually refers to the ability of measuring instruments to have the measurement characteristics unchanged over time. If stability is not for time, but for other quantities, it should be clearly explained.

The stability of a linear system is the main performance indicator of the system. The methods for judging the stability of a linear system include algebraic method, root trajectory method and Nyquist judgment method.

System stability refers to a certain stable state shown by system elements under external influence. Its meanings are roughly divided into the following three categories: (1), external temperature, mechanical and other various changes, which do not have a significant impact on the state of the system.