www.gusucode.com > signal 案例源码程序 matlab代码 > signal/OrderMapOfHelicopterVibrationDataExample.m
%% Order-RPM Map of Helicopter Vibration Data % Analyze simulated data from an accelerometer placed in the cockpit of a % helicopter. %% % Load the helicopter data. The vibrational measurements, |vib|, are % sampled at a rate of 500 Hz for 10 seconds. Inspection of the data % reveals that it has a linear trend. Remove the trend to prevent it from % degrading the quality of the order estimation. load('helidata.mat') vib = detrend(vib); %% % Plot the nonlinear RPM profile. The rotor runs up until it reaches a % maximum rotational speed of about 27,600 revolutions per minute and then % coasts down. plot(t,rpm) xlabel('Time (s)') ylabel('RPM') %% % Compute the order-RPM map. Specify an order resolution of 0.015. [map,order,rpmOut,time] = rpmordermap(vib,fs,rpm,0.015); %% % Visualize the map. imagesc(time,order,map) ax = gca; ax.YDir = 'normal'; xlabel('Time (s)') ylabel('Order') %% % Repeat the computation using a finer order resolution. Plot the map using % the built-in functionality of |rpmordermap|. The lower orders are % resolved more clearly. rpmordermap(vib,fs,rpm,0.005)