How to acces a simscape.logging.Node

I have a simulink/Simscape model, the results are logged in a variable called 'simlog'. I am struggeling to get the rotational speed from the Motor to plot it in a matlab skript.

I started to extract the informationm to a separate varibale called temp:

>> temp=(simlog.Motor_And_Load.PMSM.Permanent_Magnet_Synchronous_Motor.angular_velocity);
>> whos temp
  Name      Size            Bytes  Class                    Attributes

  temp      1x1                 8  simscape.logging.Node        

>> temp

temp = 

  Node with properties:

            id: 'angular_velocity'
       savable: 1
    exportable: 0
        series: [1×1 simscape.logging.Series]    

With plot(temp) a new figure opens every time. My goal is to have an array with time and velocity values that I can use in subplots and for further calculations. I tried it with a get but that doesn't work. Can someone please help?

        >> test = get(temp, 'angular_velocity');
        Path 'angular_velocity' is not a valid path for this node.

[madhan ravi]

I don"t have the toolbox but this should work.

 plot(simlog.Motor_And_Load.PMSM.Permanent_Magnet_Synchronous_Motor.angular_velocity.series) % first column is the time and second is the angular velocity

[Kai]

Thanks for your reply. This is what the plot returns:

ans =

1×1 cell array

{1×1 Figure}

I attached the temp and the 'ans' return from the plot command. It looks like just the figure but not the datapoints are logged. Is that correct?

[madhan ravi]

Unfortunately I can’t test MAT file either since I don’t have access to computer. But you are right it’s already a figure.

Answer 1

[Githin George]

Hello,

My understanding is that you would like to store the velocity and time values of a simulation output, for a model containing Simscape blocks.

I’m assuming that the variable “simlog” is the simulation output variable exported to workspace. You can use the following code to obtain the values of ‘angular_velocity’ and store them in an array.

data = simlog.Motor_And_Load.PMSM.Permanent_Magnet_Synchronous_Motor.angular_velocity.series 
angular_velocity = values(data) 
% the time variable is already stored in workspace as ‘tout’ 

You can verify these values by doing a plot of tout vs angular_velocity.

I hope this helps.

[Kai]

Hello,

many thanks for your support. It works almost a I expected it!

But with one exception: The values of 'tout' are from the simulink solver and the data comes from the simscape solver. 'angular_velocity' has a different length than 'tout' But a workaround can be to use for one variable a 'to Workspace' block and extract the time vector for all variables from it.