What is the mistake in the simulation, if the transient initialization at time x, solving for consistent states and modes, failed to converge?

12 次查看（过去 30 天）
Emefun
Emefun 2024-2-7
评论： Emefun 2024-2-15
Hey, I am using a 4-Way Directional Valve to controll a double-acting Actuator. To switch the valve I am using a valve actuator.
Error:An error occurred while running the simulation and the simulation was terminated
Caused by:
['test_dumm/Solver Configuration']: Transient initialization at time 0.06666666666666732, solving for consistent states and modes, failed to converge.
Nonlinear solver: Linear Algebra error. Failed to solve using iteration matrix.
all components and nodal across variables involved
Cannot solve for one or more variables, including dynamic variable derivatives:
Time derivative of 'Double_Acting_Actuator_IL.chamber_A.p_I' (Pressure of liquid volume)
Time derivative of 'Double_Acting_Actuator_IL.chamber_A.interface_displacement' (Interface displacement)
Time derivative of 'Double_Acting_Actuator_IL.chamber_B.p_I' (Pressure of liquid volume)
Time derivative of 'Double_Acting_Actuator_IL.chamber_B.interface_displacement' (Interface displacement)
Time derivative of 'Double_Acting_Actuator_IL.hard_stop.x' (Position)
Time derivative of 'Double_Acting_Actuator_IL.sensor.x' (Position)
Time derivative of 'Ideal_Translational_Motion_Sensor.x' (Position)
'Double_Acting_Actuator_IL.R.v' (Velocity)
'Double_Acting_Actuator_IL.chamber_A.R.v' (Velocity)
'Double_Acting_Actuator_IL.chamber_B.R.v' (Velocity)
'Double_Acting_Actuator_IL.hard_stop.R.v' (Velocity)
'Double_Acting_Actuator_IL.hard_stop.v' (Velocity)
'Double_Acting_Actuator_IL.sensor.R.v' (Velocity)
'Double_Acting_Actuator_IL.sensor.V' (V)
'Ideal_Translational_Motion_Sensor.R.v' (Velocity)
'Ideal_Translational_Motion_Sensor.V' (V)
'Translational_Free_End1.V.v' (Velocity)
'Translational_Free_End1.v' (Velocity)
The controlling structure for the valve actuator is correct
Can you tell me where I made mistakes?
Thank you
  2 个评论
Yifeng Tang
Yifeng Tang 2024-2-12
The error message seems to suggest that there is something wrong with the way the model is assembled. Possibly overconstrained. But it's impossible to tell without seeing the modeling. If you can share the model here, I can help take a quick look. Or at least, a snapshot of the model (but I can do way less with only a picture).

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Yifeng Tang
Yifeng Tang 2024-2-14
Hi Emefun,
It looks like the piston side of your hydraulic cylinder doesn't have any mass. Adding a mass block to the rod allow the model to simulate to completion. See below:
And now I understand what the error message is trying to say about time derivative: when you try to divide the force by the mass to get acceleration (derivative of velocity) but the mass is zero, the derivative goes crazy :p
With that fixed, I also believe the valve parameter needs some further work. As the input S varies between -5mm and 5mm, all the flow paths in this valves are open, so the piston isn't moving anywhere. You can right click on the valve -> Fluids -> Plot Valve Characteristics, and view the opening curves. I saw the following, and I'm not sure if it's the intended behavior.
Hope this helps.
Yifeng
  4 个评论
显示 2更早的评论
Yifeng Tang
Yifeng Tang 2024-2-15
You can add another double-acting cylinder, but you probably also need to keep the mass. The rod side of the added cylinder has no mass either, so if there is ANY difference in the cylinder forces, the acceleration becomes inf. So, keep the mass, and set it as the same (or best guess) as the actual piston+rod mass.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Upgrading Hydraulic Models to Use Isothermal Liquid Blocks 的更多信息

标签

产品


版本

R2023b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by