kamm circle

README.md

@@ -4,7 +4,7 @@
 [![GitHub release (latest by date)](https://img.shields.io/github/v/release/teasit/magic-formula-tyre-library)](https://github.com/teasit/magic-formula-tyre-library/releases/latest)
 [![MATLAB Latest Tests Status](https://github.com/teasit/magic-formula-tyre-library/actions/workflows/test-matlab-r2023b.yml/badge.svg?branch=main)](https://github.com/teasit/magic-formula-tyre-library/actions/workflows/test-matlab-r2023b.yml)
 
-![Fitting Example](doc/images/magic_formula_library_socialpreview.png)
+![Social-Preview](doc/images/magic_formula_library_socialpreview.png)
 
 ```matlab
 [FX,FY,MZ,MY,MX] = magicformula(params,__)
@@ -50,26 +50,27 @@ The data has been de-identified to conform with the FSAE TTC's
 [license agreement](https://www.millikenresearch.com/FSAE_TTC_agreement.pdf).
 
 ```matlab
-folder = 'doc/examples/fsae-ttc-data';
-file = fullfile(folder, 'fsaettc_obfuscated.tir');
-tyre = MagicFormulaTyre(file);
-
-file = fullfile(folder, 'fsaettc_obscured_testbench_drivebrake.mat');
 parser = tydex.parsers.FSAETTC_SI_ISO_Mat();
-measurements = parser.run(file);
-measurements = measurements([30 40 55 60 70 75]);
+measurements = parser.run('doc/examples/ttc/drivebrake.mat');
+tyre = MagicFormulaTyre('doc/examples/ttc/obfuscated.tir');
+figure(); grid on; hold on
+magicformula.plots.compareFxSX(tyre, measurements(2:5))
+```
+
+![Model vs. Data Plot](doc/images/magic_formula_library_socialpreview.png)
 
+### Example: Friction Ellipse
+
+Also known as the Kamm-Circle when approximating the tire friction limit as a circle when it actually is an ellipse.
+
+```matlab
+tyre = MagicFormulaTyre('doc/examples/ttc/obfuscated.tir');
 figure(); grid on; hold on
-c = colororder();
-for i = 1:numel(measurements)
-    [SX,SA,FZ,IP,IA,VX,FX] = unpack(measurements(i));
-    FX_mdl = magicformula(tyre,SX,SA,FZ,IP,IA,VX);
-    plot(SX, FX_mdl, 'Color', c(i,:), 'LineWidth', 2)
-    plot(SX, FX, '.', 'Color', c(i,:), 'MarkerSize', 4)
-end
-xlabel('SX / 1'); ylabel('FX / N')
+magicformula.plots.kamm(tyre)
 ```
 
+![Kamm Plot](doc/images/kamm.png)
+
 Further examples can be found in the  [`doc/examples`](./doc/examples) folder.
 
 ## Motivation

resources/project/KKwRZMM_uQtHUGS6av7oVuDcA3Y/i8GbdTSnXNO6sK9CIx8NUGawyBMd.xml

@@ -0,0 +1,6 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<Info>
+    <Category UUID="FileClassCategory">
+        <Label UUID="design"/>
+    </Category>
+</Info>

resources/project/p2B2kuKn-TR4inf0L2-zoGElvj0/X5-guf9UeAL81lUZlgeqld7t0ycd.xml → resources/project/KKwRZMM_uQtHUGS6av7oVuDcA3Y/i8GbdTSnXNO6sK9CIx8NUGawyBMp.xml

@@ -1,2 +1,2 @@
 <?xml version='1.0' encoding='UTF-8'?>
-<Info />
+<Info location="kamm.m" type="File"/>

resources/project/da3pseG73FWx727v-FXvG8DlK6w/AYKKPpYesS1DUoGdlY3P5BBQzegd.xml

@@ -0,0 +1,6 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<Info>
+    <Category UUID="FileClassCategory">
+        <Label UUID="design"/>
+    </Category>
+</Info>

resources/project/da3pseG73FWx727v-FXvG8DlK6w/AYKKPpYesS1DUoGdlY3P5BBQzegp.xml

@@ -0,0 +1,2 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<Info location="Example_PlotKamm.mlx" type="File"/>

resources/project/p2B2kuKn-TR4inf0L2-zoGElvj0/MNIcqQviTG7eMTwdizcHhYdwXt0d.xml → resources/project/p2B2kuKn-TR4inf0L2-zoGElvj0/Ws9pIQ8Ay0-QIc6SrvhwVnCT6xQd.xml

@@ -1,2 +1,2 @@
 <?xml version='1.0' encoding='UTF-8'?>
-<Info />
+<Info/>

resources/project/p2B2kuKn-TR4inf0L2-zoGElvj0/Ws9pIQ8Ay0-QIc6SrvhwVnCT6xQp.xml

@@ -0,0 +1,2 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<Info location="test-matlab-r2023b.yml" type="File"/>

src/+magicformula/+plots/kamm.m

@@ -0,0 +1,30 @@
+function kamm(tyre, options)
+arguments
+    tyre MagicFormulaTyre
+    options.LimitsSX (1,2) = [-0.1 0.1]
+    options.LimitsSA (1,2) = [-pi/8 pi/8]
+    options.SweepLength {mustBeInteger} = 100
+    options.NumConstant {mustBeInteger} = 25
+end
+
+limits = options.LimitsSX;
+stepsz = diff(limits)/options.NumConstant;
+SX_sweep = linspace(limits(1), limits(2));
+SX_const = limits(1):stepsz:limits(2);
+
+limits = options.LimitsSA;
+stepsz = diff(limits)/options.NumConstant;
+SA_sweep = linspace(limits(1), limits(2));
+SA_const = limits(1):stepsz:limits(2);
+
+for i = 1:numel(SA_const)
+    [FX,FY] = magicformula(tyre,SX_sweep,SA_const(i));
+    plot(FY, FX, 'k-')
+end
+for i = 1:numel(SX_const)
+    [FX,FY] = magicformula(tyre,SX_const(i),SA_sweep);
+    plot(FY, FX, 'k-')
+end
+axis equal
+xlabel('FY / N'); ylabel('FX / N')
+end

src/+tydex/+parsers/FSAETTC_SI_ISO_Mat.m

@@ -30,7 +30,7 @@
         % Steady-state (bin) values are rounded to be more readable.
         SteadyStateNumberOfDigits (1,1) double = 2
     end
-    methods (Static)
+    methods (Static, Access = private)
         function [newUnit,factor] = convertUnit(unit)
             mustBeA(unit, 'char')
             unit = strtrim(unit);
@@ -171,7 +171,7 @@
             end
         end
     end
-    methods
+    methods (Access = private)
         function [output,units,vars_SS] = preprocessInputData(obj, input)
             mapping = obj.Mapping;
             vars = fieldnames(mapping);