Model Drivetrain Noise

R2026b

This example shows how to inject a fault into a drivetrain using a Torque Noise Source block. Injecting noise into your model allows you to predict how your actual physical system responds when it experiences environmental or internal disturbances. It also allows you to test the robustness and responsiveness of your control system.

In the example, the noise is injected into one of the sprockets on a metal sheet feeder that is moving a piece of stock. Although you can perform most of the steps in this example using tools that the Simulink® and Simscape™ Driveline™ user interfaces provide, programmatic commands are supplied. You can combine the programmatic commands to create a script for parameter sweeps.

  1. Open the model. At the MATLAB® command prompt, enter:

    openExample('sdl/SheetMetalFeederExample')
model = 'SheetMetalFeeder';

  2. Simulate the model and plot the results.

    %% Simulate
sim(model)

%% Define the data
simlog1 = simlog_SheetMetalFeeder;
time = simlog1.Sensor_Stock.Motion_Sensor.x.series.time;
sheetPosition = simlog1.Sensor_Stock.Motion_Sensor.x.series.values;
sprocketTorque = simlog1.Sprocket_to_Belt_R.t.series.values;

%% Create figure
figure1 = figure('NumberTitle','off',...
    'Name','Simscape Results: SheetMetalFeeder_noise',...
    'OuterPosition',[565 52 733 822]);

%% Create subplot 1: Sprocket to Belt L Tourque versus Time
% Create axes for 
axes1 = axes('Parent',figure1,...
    'Position',[0.13 0.709 0.775 0.216]);
hold(axes1,'on')
box(axes1,'on')
grid(axes1,'on')
% Create title & axis labels
title('Stock Position versus Time')
% xlabel('Time (s)')
ylabel('m')
% Create plot 
plot(time,sheetPosition,'Parent',axes1) 

%% Create subplot 2: Sprocket to Belt R Tourque versus Time
% Create axes
axes2 = axes('Parent',figure1,...
    'Position',[0.13 0.409 0.775 0.2156]);
hold(axes2,'on')
box(axes2,'on')
grid(axes2,'on')
% Create title & axis labels
title('Sprocket-to-Right-Belt Torque versus Time')
xlabel('Time (s)')
ylabel('N*m')
% Create plot with linked axes
plot(time,sprocketTorque,'Parent',axes2)
linkaxes([axes1,axes2],'x')

  3. Add, configure, connect, and arrange these blocks as shown:

    • Step block — Specify 7.5 for the Step time parameter and 300 for the Final value parameter.

    • Simulink-PS Converter block

    • Mechanical Rotational Reference block

    • Torque Noise Source block — For the Sample time, specify 1e-1, for Repeatability, select Specify seed, and for Seed specify 0.

    %% Expand the model window to make room for new blocks
set_param(model,'Location',[108    73   881   682])

%% Add and configure Step block
% Define block
stepPath = [model,'/Step'];
stepLib = 'simulink/Sources/Step';
stepPosition = [-195   205  -165   235];
stepTime = '7.5';
stepValue = '300';
% Add block
add_block(stepLib,stepPath,'Position',stepPosition)
% Configure Step block
set_param(stepPath,'Time',stepTime,...
    'After',stepValue)
% Check block configuration
open_system(stepPath)
pause(3);
close_system(stepPath)
% Get output port
stepPortHandle = get_param(stepPath,'PortHandles');
stepOutport = stepPortHandle.Outport;

%% Add and configure S-PS Converter block
% Define block
sPSConvPath = [model,'/Simulink-PS Converter'];
sPSConvLib = ...
   'nesl_utility/Simulink-PS Converter';
sPSConvPathPosition = [-115   205   -85   235];
% Add block
add_block(sPSConvLib,sPSConvPath,'Position',sPSConvPathPosition)
% Get output port
sPSConvPortHandle = get_param(sPSConvPath,'PortHandles');
sPSConvInport = sPSConvPortHandle.Inport;
sPSConvConPort = sPSConvPortHandle.RConn(1,1);


%% Add Mechanical Rotational Reference block
% Define block
mechRotRefPath = [model,'/Mechanical Rotational Reference'];
mechRotRefLib = ...
   'fl_lib/Mechanical/Rotational Elements/Mechanical Rotational Reference';
mechRotRefPosition = [-40   255   -20   275];
% Add block
add_block(mechRotRefLib,mechRotRefPath,'Position',mechRotRefPosition)
%% Get output port
mechRotRefPortHandle = get_param(mechRotRefPath,'PortHandles');
mechRotRefConPort = mechRotRefPortHandle.LConn(1,1);

%% Add and configure Torque Noise Source block
% Define block
torqueNoisePath = [model,'/Torque Noise Source'];
torqueNoiseLib = 'sdl_lib/Sources/Torque Noise Source';
torqueNoisePosition = [25   210    65   250];
%% Add block
add_block(torqueNoiseLib,torqueNoisePath,'Position',torqueNoisePosition)
%% Get output port
torqueNoisePortHandle = get_param(torqueNoisePath,'PortHandles');
torqueNoiseConPort1 = torqueNoisePortHandle.LConn(1,1);
torqueNoiseConPort2 = torqueNoisePortHandle.LConn(1,2);
torqueNoiseConPort3 = torqueNoisePortHandle.RConn(1,1);
%% Configure  block
set_param(torqueNoisePath, 'sample_time','1e-1',...
    'repeatability','3')
%% Check block configuration
open_system(torqueNoisePath)
pause(3);
close_system(torqueNoisePath)

%% Get block points for connecting as a branched line
torqueNoisePortPoints = get_param(torqueNoisePath,'PortConnectivity');
[torqueNoiseLConnPoints1,torqueNoiseLConnPoints2,torqueNoiseRConnPoints]...
    = torqueNoisePortPoints.Position;
sprocketPath = [model,'/Sprocket to Belt R'];
sprocketPortHandle = get_param(sprocketPath,'PortHandles');
sprocketConPort1 = sprocketPortHandle.RConn(1,1);
sproketPortPoints = get_param(sprocketPath,'PortConnectivity');
[sproketLConnPoints,sproketRConnPoints] = sproketPortPoints.Position;

%% Connect blocks
add_line(model,stepOutport,sPSConvInport)
add_line(model,sPSConvConPort,torqueNoiseConPort1)
add_line(model,mechRotRefConPort,torqueNoiseConPort2)
add_line(model,[sproketLConnPoints;torqueNoiseRConnPoints])

%% Hold to check connections
pause(5);

  4. Simulate the model and plot the results.

    %% Simulate model
sim(model)

%% Define the datalog variable
simlog2 = simlog_SheetMetalFeeder;
time = simlog2.Sensor_Stock.Motion_Sensor.x.series.time;
sheetPosition = ...
    simlog2.Sensor_Stock.Motion_Sensor.x.series.values;
sprocketTorque = simlog2.Sprocket_to_Belt_R.t.series.values;
noiseTorque = simlog2.Torque_Noise_Source.t.series.values;

%% Update plots 1 & 2
figure1;
hold on
axes1;
hold on
plot(time, sheetPosition,'Parent',axes1,'Linestyle','--','Color','r')
axes2;
hold on 
plot(time,sprocketTorque,'Parent',axes2','Linestyle','--','Color','r')


%% Create subplot 3: Sprocket to Belt R Tourque versus Time
% Create axes
axes3 = axes('Parent',figure1,...
    'Position',[0.13 0.11 0.775 0.200]);
hold(axes3,'on')
box(axes3,'on')
grid(axes3,'on')

% Create title and axis labels
title('Noise Source Torque versus Time')
xlabel('Time (s)') 
ylabel('N*m')
linkaxes([axes1,axes2,axes3],'x')

% Create plot
plot(time,noiseTorque,'Parent',axes3,'Color','r')
legend(axes1,'No Noise','Noise','Location','southeast');
ylim(axes3,[-120 120]);

    The noise injected at simulation time, t = 7.5 seconds introduces torque disturbances.

  5. Zoom in to see the effects of the disturbance.

    %% Zoom to examine data at peak noise
xlim(axes3,[12.0 14.50]);
ylim(axes3,[-120 120]);

    When the noise source torque exceeds ±50 N*m, it most significantly effects the torque applied by the sprocket and, therefore, the position of the stock.

See Also

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