tireData object fails to plot custom .tdx file - "Unrecognized tire test type"

Hi,

I am trying to load a custom .tdx file using tireData in MATLAB, but I am running into issues when calling plot(td).

After loading the file, I receive several warnings regarding missing parameters and unrecognized keywords, such as:

• Warning: MEASURCHANNELS parameter(s) ... missing 'a', 'b', and/or 'c' factors
• Warning: Keywords 'MODELPARAMETERS' are unsupported.
• Warning: Unrecognized tire test type for index '1'.
• Warning: Data channel 'Fz' must be steady-state for automatic plotting.

Eventually, the plot(td) function throws an error: "Error using autoplot: All data sets removed due to unrecognized tire test type."

I checked the td object and found that many properties are empty or default. My questions are:

1. Does the tireData class require the .tdx file to strictly follow a specific template (e.g., specific header keys or channel names) for the plot() function to work?
2. Must all properties in the tireData object be populated for the automatic plotting to function?
3. Is there a way to manually map my custom channel names (e.g., 'FZH', 'SLIPANGL') to the ones expected by the tireData object so that it can recognize the test type?

Any guidance on how to fix these parsing/plotting issues would be greatly appreciated.

Thank you!

Answer 1

[Matthew]

Hello!

For context on the first two warnings, you may consult the Tydex data format standard: TYDEX-Format

The first warning indicates that your Tydex file does not have the 'a', 'b', and 'c' values in the '**MEASURCHANNELS' section, refer to section 2.2.4 in the linked document. Since they are missing, the import assumes no scaling or offsets are required. As the standard says, they can be omitted so the warning is precautionary.

The second warning indicates that the "MODELPARAMETERS" section of the Tydex is not yet supported. If it contains tire model parameters, then you will have to write an importer for those. Tydex is predominantly used for tire measurement data, and "TIR" files for tire model parameters, so that's been the implementation in the tire support package.

The next two warnings indicate that the measurement data does not represent a recognized tire test type (such as a slip angle sweep, longitudinal slip sweep, etc). Therefore, additional input arguments are necessary to create a plot, to explicitly tell the plot function what to plot.

Refer to the plot documentation: tireModel.plot - Plot response of tire models - MATLAB

To create the plot, provide additional input arguments. For example:

td = tireData.import("yourData.tdx");
plot(td,"DataVariableNames",["alpha","Fy"],"ColorBy","Fz")

[윤상]

I am currently analyzing the logic behind the tireData object and the associated plot functions. However, I noticed that these are provided as .p (P-code) files, which prevents me from reading the source code.

Could you provide the readable .m source files or a detailed technical specification of the logic? Specifically, I am looking to understand:

1. The Parsing Logic: How the .tdx file (text/data format) is parsed and mapped into the properties of the tireData object.
2. The Visualization Logic: How the plot function processes the tireData object to generate specific tire characteristic curves (e.g., Magic Formula/Pacejka coefficients).

If the source files cannot be shared, a breakdown of the mathematical models used during the loading process would be greatly appreciated.

[Matthew]

Hello,

The source files cannot be shared. However, I'm happy to address your specific questions:

(1) The Parsing Logic: How the .tdx file (text/data format) is parsed and mapped into the properties of the tireData object.

The tireData imports the data as expected and defined in the Tydex standard (linked previously). The import logic knows which Tydex variables to map to which tireData properties, but this is not explicitly documented. It's fairly straightforward, as they are both well documented on their own. For example, the Tydex "SLIPANGL" variable maps to the tireData "alpha" variable. The import function also carefully handles units conversions and coordinate transforms, where necessary.

I recommend to use the import function without any need for edit. If you've found a bug or critically missing feature, I'd be eager to learn about it.

(2) The Visualization Logic

For plotting data in the tireData object, the plot does not need to evaluate a tire model to create the characteristic curves. It simply plots the data contained in the tireData object properties. However, the tireModel.plot method (or using the "Model" input argument in the tireData.plot method) does evaluate the tire model.

For tireModel.plot, it internally utilizes the tireData.generate method for creating the requested operating conditions, and then uses the tireModel.compute method to evaluate the model and return the compute data. You may consider using these methods to write your custom plotting functions. The plot method is an extremely convenient way to plot desired data at specific operating conditions without much coding. If you have suggestions for further enhancements, please let me know!

I hope this helps!

Matt

[윤상]

Thank you for your detailed explanation. If I have further questions, I will reach out again.

[Matthew]

Sounds good! May I ask you to mark this question answered? Thanks!

[윤상]

Sure!