Hi, Could anyone tell me how to extract transfer function from a non linear differential equation?

Question

Sumukh Surya 2019-5-26

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/464105-hi-could-anyone-tell-me-how-to-extract-transfer-function-from-a-non-linear-differential-equation

评论： Marwan Adel 2020-5-19

Dear Sir/ Madam,

I need to extract a transfer function from a non linear equation stated below. I have solved the equation by modelling it in simulink. I also understood that I need to use lonear analysis tool to extract transfer function. The problem which I am facing is that I am unable to configure my output port as output port is time. Could you please help me on this?

Equation is dp/dt = -(n*c*sqrt(r*t*gamma)/vs)*((ps^(2*n-1)/n)*av)/(pso^((n-1)/n)) where ps is a variable quatity and rest all values are constants

5 个评论
显示 3更早的评论隐藏 3更早的评论

Star Strider 2019-5-26

System Identification Toolbox

Integrate your differential equation, then use the time variable and integrated function to estimate the transfer function.

Sumukh Surya 2019-5-29

编辑：Sumukh Surya 2019-5-29

Transfer function.pdf

Could you please elaborate on this?

I have solved for the equation which means I have the variation of ps with respect to time. I now need to calculate Ps(s)/T(s) . Please find attached document using which I have solved the non linear differential equation

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Grufff 2019-5-29

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/464105-hi-could-anyone-tell-me-how-to-extract-transfer-function-from-a-non-linear-differential-equation#answer_377019

Sorry, my memory of control engineering is VERY hazy... but I think you need to apply the Laplace transform.

The transfer function of a system is the system output over the system input, all represented in the complex s domain. Your function/s are currently in the time domain, so apply the Laplace transform to system input and output and express as a ratio, that's your transfer function.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Sumukh Surya 2019-5-31

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/464105-hi-could-anyone-tell-me-how-to-extract-transfer-function-from-a-non-linear-differential-equation#answer_377341

编辑：Sumukh Surya 2019-5-31

Hi, I understand that I need to take Laplace transform for obtaining the transfer function. But to find the transfer function for the equation shown above, manual effort might take more time. Hence I prefer doing it in MATLAB