i need help with plotting a phase diagram for the TVMS of a planetary gear set.

i have the formula, ksp1=kr(theta_p). i have formulas with which i derived values for the parameters. i also have my phi_sp value, but i need to plot a phase diagram which looks like this. how do i write the code for me to be able to get such results (with the same initial and final values). the mesh cycle is 15.5

Answer 1

[praguna manvi]

Hi @Adilah Ahmed,

As I understand it, you are looking to plot the phase diagram using the available stiffness data while highlighting point P. You can use the "plot" function along with the "linspace" function to generate theta. Here is a sample code for random "ksp" periodic values, which can be used as a template:

% Define the angular displacement
theta_p = linspace(0, 180, 1000);

% Define the mesh stiffness function
k_sp1 = 1.5e9 + 1e9 * square(2 * pi * theta_p / 20);

% Plotting
figure;
plot(theta_p, k_sp1, 'b', 'LineWidth', 1.5);
hold on;

% Highlight a specific point (P) on the plot
theta_p_P = 8.96;
k_sp1_P = 2e9;
plot(theta_p_P, k_sp1_P, 'ro', 'MarkerSize', 8, 'MarkerFaceColor', 'r');

% Add text annotations
text(theta_p_P + 2, k_sp1_P, 'P', 'FontSize', 12, 'VerticalAlignment', 'bottom');
text(0, 3e9, 'B', 'FontSize', 12, 'HorizontalAlignment', 'right');

% Labels and title
xlabel('Angular displacement of the planet gear \theta_p (°)', 'FontSize', 12);
ylabel('Mesh stiffness k_{sp1} (N/m)', 'FontSize', 12);
title('Mesh Stiffness vs. Angular Displacement', 'FontSize', 14);

% Set limits and ticks
ylim([1.5e9, 3.5e9]);
yticks(1.5e9:0.5e9:3.5e9);
yticklabels({'1.5', '2.0', '2.5', '3.0', '3.5'});
xlim([0, 180]);

% Add grid
grid on;
box on;

% Adjust figure properties
set(gca, 'FontSize', 12);

% Show the plot
hold off;

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For more examples on using the "plot" function refer to the following link:

https://www.mathworks.com/help/matlab/ref/plot.html

Hope this helps!