create a code for plotting dc motor efficiency map, y axis is torque, x axis is speed rpm in matlab

Assuming you have the necessary data to create an efficiency map of the DC motor, you can follow these steps:

1. Create a matrix of torque values (y-axis) and speed rpm values (x-axis).
2. Calculate the efficiency value for each combination of torque and speed values. Store these values in another matrix.
3. Use the surf() function in MATLAB to plot the efficiency map, with torque on the y-axis, speed rpm on the x-axis, and efficiency as the z-axis.

Here's some example code:

main.m
% Create a matrix of torque and speed values
torque = linspace(0, 10, 100); % Nm
speed_rpm = linspace(0, 5000, 100); % RPM
[T, S] = meshgrid(torque, speed_rpm);

% Calculate efficiency for each combination of torque and speed
eff = zeros(size(T));
for i = 1:numel(T)
    eff(i) = calculate_efficiency(T(i), S(i));
end

% Plot the efficiency map
surf(S, T, eff)
xlabel('Speed (rpm)')
ylabel('Torque (N-m)')
zlabel('Efficiency')
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Replace calculate_efficiency() with your actual function that calculates the efficiency value. The code above assumes that the function takes two arguments: torque and speed, and returns the corresponding efficiency value.