Import Tire Measurement Data for Analysis

This example shows how to use the Tire Manager app to analyze tire measurement data. Analyzing tire data helps you to understand tire behavior, identify potential issues, and prepare the data for modeling.

Alternatively, you can directly import tire measurement data for analysis using the tireData functions.

Download Example Tire Data File

The example-data.tdx file contains the tire data to import to the Tire Manager app.

Launch Tire Manager

Open the Tire Manager app in MATLAB^®. On the Apps tab, under Automotive, click the Tire Manager icon. Alternatively, enter this command in the MATLAB Command Window.

tireManager

The app opens with an empty tire object in the Workspace tree.

Import Tire Data

Import the tire data.

1. Navigate to the Main tab in the Tire Manager toolstrip and click Import.

2. To import tire data from a file, click Import Data Files.

3. Select the example-data.tdx file to import.

View Tire Data

Visually examine the distribution of data across different data channels using the violin plot feature.

1. Select the Data folder in the Workspace tree.

   

2. Click New Plot.

3. Click Violin Plot. The app automatically selects the check boxes next to the relevant data files in the Workspace tree and displays the data in the plot.

   

   By default, violin plots are displayed for these channels:

   • Normal force [N]

   • Inflation pressure [Pa]

   • Slip angle [rad]

   • Inclination angle [rad]

   • Total velocity [m/s]

   

   The plots indicate that the data was collected from slip angle sweep testing performed at five different normal loads and at three different inclination angles, using a single inflation pressure at a constant speed.

Crop Tire Data

Visually inspect the tire data to determine whether any data needs to be excluded.

1. Plot the normal force versus elapsed time. Keeping the data boxes selected in the tree from the previous step, click New Plot and, in the Line Plots section, select New Plot.

2. From the X-Axis list, select Elapsed time [s]. From the Y-Axis list, select Normal Force [N].

   

   The plot shows repeated conditions at the start of the test. Use the crop function to remove this section of data.

3. Keeping the data boxes selected in the tree from the previous step, click Edit Data.

4. Click Crop. The Crop Tire Data document opens. Here, you can plot a preview of the selected data and specify the crop criteria.

5. Preview the normal force versus elapsed time on the plot. From the Y-Axis list select, Normal force [N]. From the X-Axis list, select Elapsed time[s].

   

6. Select the repeated conditions to crop from the data. You can specify the range of data to crop by manually entering values in the Crop Range (start) and the Crop Range (end) edit boxes, or by clicking the graph and dragging to define the region of the data to crop.

   

7. Click Apply Crop.

   

Split Tire Data

Sometimes a single tire data file contains multiple test conditions or test types. In these cases, you can split a single tire data object into multiple tire data objects, each corresponding to a specific condition or test. For this example, use the split function to split the single tire data object based on the normal force applied during testing. This split prepares the data so that filtering or averaging a data channel is performed within each test condition, rather than across multiple test conditions. Splitting the data also gives you more control over what data is used when fitting tire models.

1. Keeping the data boxes selected in the tree from the previous step, click Edit Data.

2. Click Split. The Split Tire Data document opens. Here, you can plot a preview of the selected data and specify the split criteria.

3. To preview the normal force versus elapsed time on the plot, from the Y-Axis list, select Normal force [N].

   

4. From the Method list, select Split by Data.

   

5. To split the data, from the Select Split Criteria Channel(s) list, select Normal force [N].

   

   

   The plot displays where the data will be split.

6. Click Apply Split. The selected data in the workspace tree is split into multiple tire data objects.

Filter Tire Data

To use this data for model fitting, first inspect it for noise. Since this data comes from slip angle sweep testing, it will be used to fit the aligning torque response Mz pure, the overturning moment response Mx, and the lateral force response Fy pure. Check these data channels for noise before fitting. For more information, see fitType.

1. To select all the data, select the check box next to the Data node in the Workspace tree and click New Plot.

2. In the Slip Angle Sweep: Common 2-D Plot Templates section, select the Fy vs Alpha template.

3. From the Color-By list, select Normal force [N}.

4. To enable the colorbar, click the button next to the drop-down list.

   

   This plot shows that the lateral force data channel contains noise.

   Repeat these plots for the Mx vs Alpha and Mz vs Alpha templates. Noise is also present in the overturning moment and self-aligning moment data channels.

5. Keeping the data boxes selected in the Workspace tree from the previous step, click Edit Data.

6. Click Filter. The Filter Tire Data document opens. Here, you can specify plots to preview and specify the filter criteria.

7. From the Data Set list, select a data set to preview in the plot.

   

8. To select data to filter, press and hold the Ctrl key, and in the Channels list, click Lateral force [N], Overturning moment, and Self-aligning moment [Nm].

   

9. From the Method list, select Low-pass Cutoff Frequency, and in the Cutoff Frequency (F) [Hz] edit box, enter 3.

   

   

   View the plots to preview the filtered data.

10. Click Apply Filter. The filter is applied to all data selected in the Workspace tree.

    

Apply Mean

Plot the normal force to visually inspect the channel for noise. Since the normal force is a steady-state input to the slip angle sweep testing, ideally, it should not be noisy for fitting tire data. Refer back to the normal force versus elapsed time plot created in, Crop Tire Data. Noise can be seen in the normal force data channel. Edit the data to apply the mean to the normal force.

1. Keeping the data boxes selected in the Workspace tree from the previous step, click Edit Data.

2. Click Mean.

3. From the Data Set list, select a data set to preview in the plot.

   

4. From the Method list, select Mean.

   

5. From the Channels list, select Normal force [N].

   

   

6. Click Apply Mean. The mean is applied to all data selected in the Workspace tree.

   

Export Edited Tire Data

Export the edited tire data.

1. Select the data object to export in the Workspace tree.

   

2. Click Export, and then select Export to TYDEX File(s). All the data objects under the selected data object are exported to individual files.