I have a control model in Simulink which consists of two blocks. One which takes some inputs and generates three signals, x,y,z as arrays (trajectory) and feeds them to the second block as reference for the control.
I would like to be able to run this using a recorded trajectory. I have simulated the trajectory (by running the simulation once) and written the data to a mat file (signals plus timestamp). I can remove the first block and feed the mat file to the second control block and it works fine.
The trajectory is a loop. My question is, I would like to be able to start the simulation at any point in the file and I am not familiar with how Simulink manages time. If I want to start from a different point what do I need to do and can I make it continuous so that if I start from point N-1 in the file it will proceed through N and back to 1,2,3 etc.
Thanks,
Bryan
If you want to start at a different time point you won't be able to directly use the .mat file that you have created. You'll need to load the data into MATLAB and change the time vector so that t=0 corresponds to the data that you do want to start with.
Since you want to repeat the sequence, you most likely want to use the Repeating Sequence block. This would require you to load the data into MATLAB (and do the time alignment) anyway.
Related
What I'm doing is a real-time application for visual servoing that needs to read an X and Y values of a coordinate during running time. As the simulation runs, these values are changed in time by a Python Script and then, I need to read every n milliseconds (say 20ms) this changing values in Simulink to move some DC motors based on the said (X,Y) coordinates.
To sum up, what I need is how to read in run-time values from an external file in Simulink. I could be a .txt, or any other kind of file but it has to read the changing values in real-time.
I'd totally appreciate your help!
I've tried to read a .txt file from a user-defined simulink block, but the functions I used are not supported in simulink, like fscanf.
I am a new user of Matlab Simulink and currently i am working with Fuzzy Logic Controller with Simulation. In the Simulink, i want to input the values(i highlighted in the picture below), that changes with time.
Here, i am using Uniform Random Number Block which sends four values(which i feed) at same time but i want one value must input first, then another and so on. My target is to use Scope block(the one which is highlighted in the right side) and check the output that varies with time. But with current configuration, i just input ONLY one value. Please help?
I have written a matlab program for a simulink model and taking control through it programmatically, but I am facing one problem while using set_param('testmodel11', 'SimulationCommand', 'start');.
It gives all the values at once, that is gives the entire scope and workplace values all at the same time, but I don't want this. I would like to run the program and execute at that point, seeing only rest of the values should be zero. How can I stop the simulation at that point and fetch plots and values from that point only, the rest should be zero. And ideally have this same behavior for the next break points too?
There is a way to pause the simulation at certain breakpoints (simulation points), plot the output or do whatever is desired of it, and then continue the simulation until the next breakpoint.
However, at any breakpoint, you will get output data from all the time samples till the breakpoint is reached. To isolate data from a certain timestamp, you can calculate its index based on the sample time and extract it from the workspace (output data is stored as an array)
Here is the link to my answer which will be helpful, pls go through it:
https://stackoverflow.com/a/38348315/6580313
Now, in the m-file which you will run when the simulation is paused, you can change the value of the constant block which specifies the next simulation time at which simulation needs to be paused. In the m-file, you can also write a code snippet to access the output data.
Once the simulation continues, it will be paused at the new simulation time specified in the constant block.
Let me know in case you have any queries.
It sounds like you want to use the Simulink Debugger. Check out the documentation for more details on how to use it. The main command-line interface to it is sldebug.
I have a data store block (let's say 20x5000 array), it is used for generating a schedule.
The simulation uses SimEvents blocks.
Every time step it's being updated.
The problem is that it generates a 3-D array (the third one is the time steps), and I only want a 2-D array. I don't need the evolution of it.
How do I prevent Simulink from keeping the history of all the steps?
Apparently, it was more simple that I thought.
In the block "To Workspace", I have set the value of "limit data points to last" to 1.
I'm using the simulink block From Workspace to read in some audio data provided by a script. I have formatted the data in a matrix with 2 columns, the first is the timestamp and the second is the data.
In the configuration paramaters, I have specified Fixed-Step and Discrete solver. The Start time and Stop also need to be configured manually and don't seem to come from the data.
Also, in the From Workspace block configuration, I need to specify the sample time (1/44100) or I get a warning if I specify -1, to inherit from the data and then get strange sample times.
So, how can I get simulink to use only the sample times in the matrix and use the first and last timestamps as the start and stop time of the simulation?
You should be able to do what you want by doing the following:
Firstly note that your problem is by definition not fixed step, hence you cannot use a fixed-step solver, which by definition is ... fixed-step.
You must use a variable step solver.
Assuming your (2 column) input data is called simin then set the start and stop times to be simin(1,1) and simin(end,1) respectively.
In your From Workspace block set the sample time to be 0 (which should have been the default).
Also de-select the Interpolate data option; and set "Form the output after final data value by:" to zero (you won't be using anything past the end of your data set so this should be OK.
Then you need to tell the solver to take additional steps to those that it would naturally want to take.
Do this on the Data Import/Export pane of the Model Configuration Parameters.
Near the bottom of the pane there is a selection box and an edit box for doing this.
Note however that this does not prevent the solver from taking steps at other time points, it just forces it to take additional steps at the times you specify.
But because you have your From WOrkspace block to not interpolate this shouldn't be a problem either. You should put simin(:,1) in here so that the solver is guaranteed to take steps at the time points in your input data.
Note that if you want an input block that only samples at the time points in the simin time vector then the only way to do this is to write an S-function that uses the mdlGetTimeOfNextVarHit method to tell the solver what the next sample time (for this block) should be.