How do I create a 2D lookup table from efficiency map?

Hi,

I have created a efficiency plot using [speed,torque] points (see figure). Efficiency inside the red curve is 96% and between the red and the green line, the efficiency is 94%. How do I create a 2D lookup table that gives out efficiency value for a given torque and speed?

Regards,

Bidhan

Answer 1

[Chunru]

% Combine all the points for red and green curves to form the three vectors
% speed, torque, efficiency.  Then use the scatteredUbterpolant
F = scatteredInterpolant(speed, torque, efficiency)

% now you can look up
e = F(speed0, torque0)

% doc scatteredInterpolant

[bidhan pandey]

Thanks for the answer. I did use your answer in a Matlab funtion block in Simulink to get back an efficiency value. But that made my model too slow. Actually I want to create a 2D lookup table (in the 2-D Lookup Table block) that I can use inside Simulink. Any help on that?

[Chunru]

If you want to improve the speed, one way is to interpolate the data into a 2-D regular grid, for example

[x, y] = meshgrid(0:.1:1, 0:.1:1);
z = F(x, y);

Once these are evaluated offline, you can use a 2D-lookup table in simulink with x, y, z the lookup table.