关于开环传递函数的更好测试。

mayseven

VCCM方程中只考虑了动力学系统中的质量项，而忽略了阻尼因素的影响，在系统达到最大稳态速度时加速度为零，但阻尼项依然会产生阻尼力，在阻尼系数较小的情况下对计算结果影响不大，但若系统存在较大的阻尼，VCCM方程计算的最大稳态速度会偏大，不知道我的理解是否正确？

PEN

VCCM方程用于计算最大稳态速度。 不考虑质量，因为质量没有加速或减速，因此没有因加速或减速而产生的力。 可以增加由于摩擦或阻尼产生的力，但通常会忽略它。 解决这个问题更复杂。 这是一个更完整的例子，但它仍然没有考虑油的体积模量。 更精确的公式需要微分方程。 使用微分方程系统解决了最佳解决方案，但这非常复杂。

有9个微分方程必须同时求解。 这个模拟是旧的，是英文的。 Amesim仿真可能类似。
https://deltamotion.com/peter/Mathcad/Mathcad%20-%20Hydraulic%20Cylinder.pdf

模拟可以像您希望的那样详细。 问题是为所有组件获取正确的参数。

The VCCM equation is for calculating the maximum steady state speed.  The mass is not considered because the mass is not being accelerated or decelerated so there is no force due to acceleration or deceleration.  The force due to friction or damping can be added but normally it is ignored.  Solving this problem is more complex.  Here is a more complete example but it still does not consider the bulk modulus of oil.  Differential equations are required for more exact formulas.   The best solution is solved using a system of differential equations, but this is very complex.

There are 9 differential equations that must be solved simultaneously.  This simulation is old and is in English.   The Amesim simulation are probably similar.
https://deltamotion.com/peter/Mathcad/Mathcad%20-%20Hydraulic%20Cylinder.pdf

Simulations can be as detailed as you want them to be.  The problem is getting the right parameters for all the components.

danielsong

PEN 发表于 2019-7-23 12:54
VCCM方程用于计算最大稳态速度。 不考虑质量，因为质量没有加速或减速，因此没有因加速或减速而产生的力。  ...

Hello Peter,

   I have read many articles which you published on the forum. expecially how to place close-loop pole position. But I found the gain calculator result is a little bit different with what you said in your articles. for example, the transfer function is 40.49779*201.4008/(s+201.4008),
close -loop transfer function with PI controller is :(8156.2Kp*s+8156.2Ki)/(s^2+(201.4008+8156.2kp)*s+8156.2Ki), if kp=0.2475,ki=0.6367, then s1=-2.34,s2=-2216.73. major pole is 2.34 and tranfer to frequency 2.34/2*3.14=0.3726. but the result from gain calculator is 0.42Hz. what am I doing wrong?