diff --git a/figs/identification_comp_bot_stages.png b/figs/identification_comp_bot_stages.png index e230dd7..720237d 100644 Binary files a/figs/identification_comp_bot_stages.png and b/figs/identification_comp_bot_stages.png differ diff --git a/figs/identification_comp_mid_stages.png b/figs/identification_comp_mid_stages.png index e2c8e59..9d2225f 100644 Binary files a/figs/identification_comp_mid_stages.png and b/figs/identification_comp_mid_stages.png differ diff --git a/figs/identification_comp_top_stages.png b/figs/identification_comp_top_stages.png index 7cfc2d5..5b4f884 100644 Binary files a/figs/identification_comp_top_stages.png and b/figs/identification_comp_top_stages.png differ diff --git a/identification/index.html b/identification/index.html index 6fe712b..b5e14b9 100644 --- a/identification/index.html +++ b/identification/index.html @@ -3,7 +3,7 @@ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
- +-The goal here is to make an identification of the micro-station in order to compare the model with the measurements on the real micro-station. +The goal here is to tune the Simscape model of the station in order to have a good dynamical representation of the real system.
-In order to do so: +In order to do so, we reproduce the Modal Analysis done on the station using the Simscape model. +
+ ++We can then compare the measured Frequency Response Functions with the identified dynamics of the model. +
+ ++Finally, this should help to tune the parameters of the model such that the dynamics is closer to the measured FRF. +
+ ++The Simscape Model of the micro-station consists of several solid bodies:
-For the excitation, we can choose the same excitation points as the one used for the modal test. -For the measurement points, we can choose the Center of Mass of each solid body. -The center of mass of each solid body is not easily defined using Simscape. -Indeed, we can define the center of mass of any solid body but not of multiple solid bodies. However, one solid body is composed of multiple STEP files. -One solution could be to use one STEP file for one solid body. -However, the position of the center of mass can be exported using simulink and then defined on Simscape. +Each solid body has some characteristics: Center of Mass, mass, moment of inertia, etc… +These parameters are automatically computed from the geometry and from the density of the materials.
-
-We first define some parameters for the identification.
-The simulink file for the identification is sim_micro_station_id.slx
.
+Then, the solid bodies are connected with springs and dampers.
+Some of the springs and dampers values can be estimated from the joints/stages specifications, however, we here prefer to tune these values based on the measurements.
open('identification/matlab/sim_micro_station_id.slx') --
%% Options for Linearized -options = linearizeOptions; -options.SampleTime = 0; - -%% Name of the Simulink File -mdl = 'sim_micro_station_id'; --
%% Micro-Hexapod -% Input/Output definition -io(1) = linio([mdl, '/Micro-Station/Fm_ext'],1,'openinput'); -io(2) = linio([mdl, '/Micro-Station/Fg_ext'],1,'openinput'); -io(3) = linio([mdl, '/Micro-Station/Dm_inertial'],1,'output'); -io(4) = linio([mdl, '/Micro-Station/Ty_inertial'],1,'output'); -io(5) = linio([mdl, '/Micro-Station/Ry_inertial'],1,'output'); -io(6) = linio([mdl, '/Micro-Station/Dg_inertial'],1,'output'); --
% Run the linearization -G_ms = linearize(mdl, io, 0); - -% Input/Output names -G_ms.InputName = {'Fmx', 'Fmy', 'Fmz',... - 'Fgx', 'Fgy', 'Fgz'}; -G_ms.OutputName = {'Dmx', 'Dmy', 'Dmz', ... - 'Tyx', 'Tyy', 'Tyz', ... - 'Ryx', 'Ryy', 'Ryz', ... - 'Dgx', 'Dgy', 'Dgz'}; --
%% Save the obtained transfer functions -save('./mat/id_micro_station.mat', 'G_ms'); --
+here +
+We load the configuration. +
open('identification/matlab/sim_micro_station_modal_analysis.slx') +load('mat/conf_simscape.mat');
+We set a small StopTime
.
+
%% Options for Linearized -options = linearizeOptions; -options.SampleTime = 0; - -%% Name of the Simulink File -mdl = 'sim_micro_station_modal_analysis'; +set_param(conf_simscape, 'StopTime', '0.5');
%% Micro-Hexapod -% Input/Output definition -io(1) = linio([mdl, '/Micro-Station/F_hammer'],1,'openinput'); -io(2) = linio([mdl, '/Micro-Station/acc9'],1,'output'); -io(3) = linio([mdl, '/Micro-Station/acc10'],1,'output'); -io(4) = linio([mdl, '/Micro-Station/acc11'],1,'output'); -io(5) = linio([mdl, '/Micro-Station/acc12'],1,'output'); --
% Run the linearization -G_ms = linearize(mdl, io, 0); - -% Input/Output names -G_ms.InputName = {'Fx', 'Fy', 'Fz'}; -G_ms.OutputName = {'x9', 'y9', 'z9', ... - 'x10', 'y10', 'z10', ... - 'x11', 'y11', 'z11', ... - 'x12', 'y12', 'z12'}; --
figure; -hold on; -plot(freqs, abs(squeeze(freqresp(G_ms('x9', 'Fx'), freqs, 'Hz')))); -set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); -ylabel('Amplitude [m/N]'); -hold off; --
load('../meas/modal-analysis/mat/frf_coh_matrices.mat', 'FRFs', 'COHs', 'freqs'); --
dirs = {'x', 'y', 'z'}; - -n_acc = 9; -n_dir = 1; % x, y, z -n_exc = 1; % x, y, z - -figure; -hold on; -plot(freqs, abs(squeeze(FRFs(3*(n_acc-1) + n_dir, n_exc, :)))./((2*pi*freqs).^2)'); -plot(freqs, abs(squeeze(freqresp(G_ms([dirs{n_dir}, num2str(n_acc)], ['F', dirs{n_dir}]), freqs, 'Hz')))); -set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); -ylabel('Amplitude [m/N]'); -hold off; --
+We initialize all the stages. +
initializeGround(); initializeGranite(); @@ -491,21 +379,103 @@ initializeRy(); initializeRz(); initializeMicroHexapod(); initializeAxisc(); +initializeMirror(); +initializeNanoHexapod(struct('actuator', 'piezo')); +initializeSample(struct('mass', 50));
[ ]
Verify that this is coherent with the simscape and with the measurementsopen('identification/matlab/sim_micro_station_com.slx') ++
+Thanks to the Inertia Sensor simscape block, it is possible to estimate the position of the Center of Mass of a solid body with respect to a defined frame. +
-+ | granite bot | +granite top | +ty | +ry | +rz | +hexa | +
---|---|---|---|---|---|---|
X [mm] | +52.4 | +51.7 | +0.9 | +-0.1 | +0.0 | +-0.0 | +
Y [mm] | +190.4 | +263.2 | +0.7 | +5.2 | +-0.0 | +0.1 | +
Z [mm] | +-1200.0 | +-777.1 | +-598.9 | +-627.7 | +-643.2 | +-317.1 | +
+We can compare the obtained center of mass (table 1) with the one used for the Modal Analysis shown in table 2. +
+ ++The results are quite similar. +The differences can be explained by some differences in the chosen density of the materials or by the fact that not exactly all the same elements have been chosen for each stage. +
+ ++For instance, on simscape, the fixed part of the translation stage counts for the top granite solid body. +However, in SolidWorks, this has probably not be included with the top granite. +
+ + + +
+Now we use one inertiasensor
block connected on each solid body that measured the center of mass of this solid with respect to the same connected frame.
+
+We do that in order to position an accelerometer on the Simscape model at this particular point. +
+ +open('identification/matlab/sim_micro_station_com_estimation.slx') ++
sim('sim_micro_station_com_estimation') ++
+ | granite bot | +granite top | +ty | +ry | +rz | +hexa | +
---|---|---|---|---|---|---|
X [mm] | +0.0 | +51.7 | +0.9 | +-0.1 | +0.0 | +-0.0 | +
Y [mm] | +0.0 | +753.2 | +0.7 | +5.2 | +-0.0 | +0.1 | +
Z [mm] | +-250.0 | +22.9 | +-17.1 | +-146.5 | +-23.2 | +-47.1 | +
+We now same this for further use: +
+granite_bot_com = granite_bot_com.Data(end, :)'; +granite_top_com = granite_top_com.Data(end, :)'; +ty_com = ty_com.Data(end, :)'; +ry_com = ry_com.Data(end, :)'; +rz_com = rz_com.Data(end, :)'; +hexa_com = hexa_com.Data(end, :)'; + +save('mat/solids_com.mat', 'granite_bot_com', 'granite_top_com', 'ty_com', 'ry_com', 'rz_com', 'hexa_com'); ++
+Then, we use the obtained results to add a rigidTransform
block in order to create a new frame at the center of mass of each solid body.
+
+We now use a new Simscape Model where 6DoF inertial sensors are located at the Center of Mass of each solid body. +
+ +load('mat/solids_com.mat', 'granite_bot_com', 'granite_top_com', 'ty_com', 'ry_com', 'rz_com', 'hexa_com'); ++
open('identification/matlab/sim_micro_station_modal_analysis_com.slx')
+We use the linearize
function in order to estimate the dynamics from forces applied on the Translation stage at the same position used for the real modal analysis to the inertial sensors.
+
%% Options for Linearized options = linearizeOptions; @@ -589,12 +686,12 @@ mdl = 'sim_micro_station_modal_analysis_com';@@ -611,138 +708,53 @@ G_ms.OutputName = {'hexa_x', 'hexa_y', 'hexa_z', 'hexa_rx', 'hexa_ry', 'hexa_rz'};%% Micro-Hexapod % Input/Output definition -io(1) = linio([mdl, '/Micro-Station/F_hammer'],1,'openinput'); -io(2) = linio([mdl, '/Micro-Station/acc_gtop'],1,'output'); -io(3) = linio([mdl, '/Micro-Station/acc_ty'],1,'output'); -io(4) = linio([mdl, '/Micro-Station/acc_ry'],1,'output'); -io(5) = linio([mdl, '/Micro-Station/acc_rz'],1,'output'); -io(6) = linio([mdl, '/Micro-Station/acc_hexa'],1,'output'); +io(1) = linio([mdl, '/F_hammer'],1,'openinput'); +io(2) = linio([mdl, '/acc_gtop'],1,'output'); +io(3) = linio([mdl, '/acc_ty'],1,'output'); +io(4) = linio([mdl, '/acc_ry'],1,'output'); +io(5) = linio([mdl, '/acc_rz'],1,'output'); +io(6) = linio([mdl, '/acc_hexa'],1,'output');
+The output of G_ms
is the acceleration of each solid body.
+In order to obtain a displacement, we divide the obtained transfer function by \(1/s^{2}\);
+
G_ms = G_ms/s^2; ++
+We now load the Frequency Response Functions measurements during the Modal Analysis (accessible here). +
+load('../meas/modal-analysis/mat/frf_coh_matrices.mat', 'freqs'); load('../meas/modal-analysis/mat/frf_com.mat', 'FRFs_CoM');
dirs = {'x', 'y', 'z', 'rx', 'ry', 'rz'}; -stages = {'gbot', 'gtop', 'ty', 'ry', 'rz', 'hexa'} - -n_stg = 2; -n_dir = 5; % x, y, z, Rx, Ry, Rz -n_exc = 2; % x, y, z - -f = logspace(0, 3, 1000); - -figure; -hold on; -plot(freqs, abs(squeeze(FRFs_CoM(6*(n_stg-1) + n_dir, n_exc, :)))./((2*pi*freqs).^2)'); -plot(f, abs(squeeze(freqresp(G_ms([stages{n_stg}, '_', dirs{n_dir}], ['F', dirs{n_exc}]), f, 'Hz')))); -set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); -ylabel('Amplitude [m/N]'); -hold off; -xlim([1, 200]); --
dirs = {'x', 'y', 'z', 'rx', 'ry', 'rz'}; -stages = {'gtop', 'ty', 'ry', 'rz', 'hexa'} - -f = logspace(1, 3, 1000); - -figure; -for n_stg = 1:2 - for n_dir = 1:3 - subplot(3, 2, (n_dir-1)*2 + n_stg); - title(['F ', dirs{n_dir}, ' to ', stages{n_stg}, ' ', dirs{n_dir}]); - hold on; - plot(freqs, abs(squeeze(FRFs_CoM(6*(n_stg) + n_dir, n_dir, :)))./((2*pi*freqs).^2)'); - plot(f, abs(squeeze(freqresp(G_ms([stages{n_stg}, '_', dirs{n_dir}], ['F', dirs{n_dir}]), f, 'Hz')))); - set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); - ylabel('Amplitude [m/N]'); - if n_dir == 3 - xlabel('Frequency [Hz]'); - end - hold off; - xlim([10, 1000]); - ylim([1e-12, 1e-6]); - end -end --
+We then compare the measurements with the identified transfer functions using the Simscape Model. +
-dirs = {'x', 'y', 'z', 'rx', 'ry', 'rz'}; -stages = {'ry', 'rz', 'hexa'} -f = logspace(1, 3, 1000); - -figure; -for n_stg = 1:2 - for n_dir = 1:3 - subplot(3, 2, (n_dir-1)*2 + n_stg); - title(['F ', dirs{n_dir}, ' to ', stages{n_stg}, ' ', dirs{n_dir}]); - hold on; - plot(freqs, abs(squeeze(FRFs_CoM(6*(n_stg+2) + n_dir, n_dir, :)))./((2*pi*freqs).^2)'); - plot(f, abs(squeeze(freqresp(G_ms([stages{n_stg}, '_', dirs{n_dir}], ['F', dirs{n_dir}]), f, 'Hz')))); - set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); - ylabel('Amplitude [m/N]'); - if n_dir == 3 - xlabel('Frequency [Hz]'); - end - hold off; - xlim([10, 1000]); - ylim([1e-12, 1e-6]); - end -end --
dirs = {'x', 'y', 'z', 'rx', 'ry', 'rz'}; -stages = {'hexa'} -f = logspace(1, 3, 1000); - -figure; -for n_stg = 1 - for n_dir = 1:3 - subplot(3, 1, (n_dir-1)*2 + n_stg); - title(['F ', dirs{n_dir}, ' to ', stages{n_stg}, ' ', dirs{n_dir}]); - hold on; - plot(freqs, abs(squeeze(FRFs_CoM(6*(n_stg+4) + n_dir, n_dir, :)))./((2*pi*freqs).^2)'); - plot(f, abs(squeeze(freqresp(G_ms([stages{n_stg}, '_', dirs{n_dir}], ['F', dirs{n_dir}]), f, 'Hz')))); - set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log'); - ylabel('Amplitude [m/N]'); - if n_dir == 3 - xlabel('Frequency [Hz]'); - end - hold off; - xlim([10, 1000]); - ylim([1e-12, 1e-6]); - end -end --
@@ -751,24 +763,22 @@ f = logspace( -
+For such a complex system, we believe that the Simscape Model represents the dynamics of the system with enough fidelity. +
+