Change gravimeter axis
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90
index.org
90
index.org
@@ -138,7 +138,7 @@ The parameters used for the simulation are the following:
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G = linearize(mdl, io);
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G.InputName = {'F1', 'F2', 'F3'};
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G.OutputName = {'Ax1', 'Az1', 'Ax2', 'Az2'};
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G.OutputName = {'Ax1', 'Ay1', 'Ax2', 'Ay2'};
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#+end_src
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The inputs and outputs of the plant are shown in Figure [[fig:gravimeter_plant_schematic]].
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@@ -149,7 +149,7 @@ More precisely there are three inputs (the three actuator forces):
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\end{equation}
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And 4 outputs (the two 2-DoF accelerometers):
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\begin{equation}
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\bm{a} = \begin{bmatrix} a_{1x} \\ a_{1z} \\ a_{2x} \\ a_{2z} \end{bmatrix}
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\bm{a} = \begin{bmatrix} a_{1x} \\ a_{1y} \\ a_{2x} \\ a_{2y} \end{bmatrix}
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\end{equation}
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#+begin_src latex :file gravimeter_plant_schematic.pdf :tangle no :exports results
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@@ -158,7 +158,7 @@ And 4 outputs (the two 2-DoF accelerometers):
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% Connections and labels
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\draw[<-] (G.west) -- ++(-2.0, 0) node[above right]{$\bm{\tau} = \begin{bmatrix}\tau_1 \\ \tau_2 \\ \tau_2 \end{bmatrix}$};
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\draw[->] (G.east) -- ++( 2.0, 0) node[above left]{$\bm{a} = \begin{bmatrix} a_{1x} \\ a_{1z} \\ a_{2x} \\ a_{2z} \end{bmatrix}$};
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\draw[->] (G.east) -- ++( 2.0, 0) node[above left]{$\bm{a} = \begin{bmatrix} a_{1x} \\ a_{1y} \\ a_{2x} \\ a_{2y} \end{bmatrix}$};
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\end{tikzpicture}
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#+end_src
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@@ -232,12 +232,12 @@ Consider the control architecture shown in Figure [[fig:gravimeter_decouple_jaco
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The Jacobian matrix $J_{\tau}$ is used to transform forces applied by the three actuators into forces/torques applied on the gravimeter at its center of mass:
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\begin{equation}
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\begin{bmatrix} \tau_1 \\ \tau_2 \\ \tau_3 \end{bmatrix} = J_{\tau}^{-T} \begin{bmatrix} F_x \\ F_z \\ M_y \end{bmatrix}
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\begin{bmatrix} \tau_1 \\ \tau_2 \\ \tau_3 \end{bmatrix} = J_{\tau}^{-T} \begin{bmatrix} F_x \\ F_y \\ M_z \end{bmatrix}
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\end{equation}
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The Jacobian matrix $J_{a}$ is used to compute the vertical acceleration, horizontal acceleration and rotational acceleration of the mass with respect to its center of mass:
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\begin{equation}
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\begin{bmatrix} a_x \\ a_z \\ a_{R_y} \end{bmatrix} = J_{a}^{-1} \begin{bmatrix} a_{x1} \\ a_{z1} \\ a_{x2} \\ a_{z2} \end{bmatrix}
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\begin{bmatrix} a_x \\ a_y \\ a_{R_z} \end{bmatrix} = J_{a}^{-1} \begin{bmatrix} a_{x1} \\ a_{y1} \\ a_{x2} \\ a_{y2} \end{bmatrix}
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\end{equation}
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We thus define a new plant as defined in Figure [[fig:gravimeter_decouple_jacobian]].
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@@ -252,10 +252,10 @@ $\bm{G}_x(s)$ correspond to the $3 \times 3$transfer function matrix from forces
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\node[block, right=0.6 of G] (Ja) {$J_{a}^{-1}$};
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% Connections and labels
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\draw[<-] (Jt.west) -- ++(-2.5, 0) node[above right]{$\bm{\mathcal{F}} = \begin{bmatrix}F_x \\ F_z \\ M_y \end{bmatrix}$};
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\draw[<-] (Jt.west) -- ++(-2.5, 0) node[above right]{$\bm{\mathcal{F}} = \begin{bmatrix}F_x \\ F_y \\ M_z \end{bmatrix}$};
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\draw[->] (Jt.east) -- (G.west) node[above left]{$\bm{\tau}$};
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\draw[->] (G.east) -- (Ja.west) node[above left]{$\bm{a}$};
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\draw[->] (Ja.east) -- ++( 2.6, 0) node[above left]{$\bm{\mathcal{A}} = \begin{bmatrix}a_x \\ a_z \\ a_{R_y} \end{bmatrix}$};
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\draw[->] (Ja.east) -- ++( 2.6, 0) node[above left]{$\bm{\mathcal{A}} = \begin{bmatrix}a_x \\ a_y \\ a_{R_z} \end{bmatrix}$};
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\begin{scope}[on background layer]
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\node[fit={(Jt.south west) (Ja.north east)}, fill=black!10!white, draw, dashed, inner sep=14pt] (Gx) {};
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@@ -284,8 +284,8 @@ The Jacobian corresponding to the sensors and actuators are defined below:
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And the plant $\bm{G}_x$ is computed:
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#+begin_src matlab
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Gx = pinv(Ja)*G*pinv(Jt');
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Gx.InputName = {'Fx', 'Fz', 'My'};
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Gx.OutputName = {'Dx', 'Dz', 'Ry'};
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Gx.InputName = {'Fx', 'Fy', 'Mz'};
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Gx.OutputName = {'Dx', 'Dy', 'Rz'};
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#+end_src
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#+begin_src matlab :results output replace :exports results
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@@ -736,7 +736,7 @@ Similarly, the bode plots of the diagonal elements and off-diagonal elements of
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set(gca,'ColorOrderIndex',1)
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plot(freqs, abs(squeeze(freqresp(Gx(1, 1), freqs, 'Hz'))), 'DisplayName', '$G_x(1,1) = A_x/F_x$');
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plot(freqs, abs(squeeze(freqresp(Gx(2, 2), freqs, 'Hz'))), 'DisplayName', '$G_x(2,2) = A_y/F_y$');
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plot(freqs, abs(squeeze(freqresp(Gx(3, 3), freqs, 'Hz'))), 'DisplayName', '$G_x(3,3) = R_y/M_y$');
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plot(freqs, abs(squeeze(freqresp(Gx(3, 3), freqs, 'Hz'))), 'DisplayName', '$G_x(3,3) = R_z/M_z$');
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
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ylabel('Magnitude'); set(gca, 'XTickLabel',[]);
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@@ -961,7 +961,7 @@ The obtained transmissibility in Open-loop, for the centralized control as well
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
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set(gca, 'YTickLabel',[]); xlabel('Frequency [Hz]');
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title('$D_z/D_{w,z}$');
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title('$D_y/D_{w,y}$');
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ax3 = nexttile;
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hold on;
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@@ -971,7 +971,7 @@ The obtained transmissibility in Open-loop, for the centralized control as well
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
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set(gca, 'YTickLabel',[]); xlabel('Frequency [Hz]');
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title('$R_y/R_{w,y}$');
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title('$R_z/R_{w,z}$');
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linkaxes([ax1,ax2,ax3],'xy');
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xlim([freqs(1), freqs(end)]);
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@@ -1040,7 +1040,7 @@ Let say we change the position of the actuators:
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G = linearize(mdl, io);
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G.InputName = {'F1', 'F2', 'F3'};
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G.OutputName = {'Ax1', 'Az1', 'Ax2', 'Az2'};
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G.OutputName = {'Ax1', 'Ay1', 'Ax2', 'Ay2'};
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#+end_src
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#+begin_src matlab :exports none
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@@ -1077,7 +1077,7 @@ The closed-loop system are still stable, and their
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
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set(gca, 'YTickLabel',[]); xlabel('Frequency [Hz]');
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title('$D_z/D_{w,z}$');
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title('$D_y/D_{w,y}$');
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ax3 = nexttile;
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hold on;
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@@ -1087,7 +1087,7 @@ The closed-loop system are still stable, and their
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hold off;
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set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
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set(gca, 'YTickLabel',[]); xlabel('Frequency [Hz]');
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title('$R_y/R_{w,y}$');
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title('$R_z/R_{w,z}$');
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linkaxes([ax1,ax2,ax3],'xy');
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xlim([freqs(1), freqs(end)]);
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@@ -1145,7 +1145,7 @@ To do so, the actuators (springs) should be positioned such that the stiffness m
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G = linearize(mdl, io);
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G.InputName = {'F1', 'F2', 'F3'};
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G.OutputName = {'Ax1', 'Az1', 'Ax2', 'Az2'};
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G.OutputName = {'Ax1', 'Ay1', 'Ax2', 'Ay2'};
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#+end_src
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Decoupling at the CoM (Mass decoupled)
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@@ -1162,8 +1162,8 @@ Decoupling at the CoM (Mass decoupled)
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#+begin_src matlab
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GM = pinv(JMa)*G*pinv(JMt');
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GM.InputName = {'Fx', 'Fz', 'My'};
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GM.OutputName = {'Dx', 'Dz', 'Ry'};
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GM.InputName = {'Fx', 'Fy', 'Mz'};
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GM.OutputName = {'Dx', 'Dy', 'Rz'};
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#+end_src
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#+begin_src matlab :exports none
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@@ -1195,7 +1195,7 @@ Decoupling at the CoM (Mass decoupled)
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#+end_src
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#+name: fig:jac_decoupling_M
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#+caption:
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#+caption: Diagonal and off-diagonal elements of the decoupled plant
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#+RESULTS:
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[[file:figs/jac_decoupling_M.png]]
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@@ -1220,8 +1220,8 @@ Decoupling at the point where K is diagonal (x = 0, y = -h/2 from the schematic
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And the plant $\bm{G}_x$ is computed:
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#+begin_src matlab
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GK = pinv(JKa)*G*pinv(JKt');
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GK.InputName = {'Fx', 'Fz', 'My'};
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GK.OutputName = {'Dx', 'Dz', 'Ry'};
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GK.InputName = {'Fx', 'Fy', 'Mz'};
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GK.OutputName = {'Dx', 'Dy', 'Rz'};
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#+end_src
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#+begin_src matlab :exports none
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@@ -1253,7 +1253,7 @@ And the plant $\bm{G}_x$ is computed:
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#+end_src
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#+name: fig:jac_decoupling_K
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#+caption:
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#+caption: Diagonal and off-diagonal elements of the decoupled plant
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#+RESULTS:
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[[file:figs/jac_decoupling_K.png]]
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@@ -1286,7 +1286,7 @@ To do so, the actuator position should be modified
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G = linearize(mdl, io);
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G.InputName = {'F1', 'F2', 'F3'};
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G.OutputName = {'Ax1', 'Az1', 'Ax2', 'Az2'};
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G.OutputName = {'Ax1', 'Ay1', 'Ax2', 'Ay2'};
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#+end_src
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#+begin_src matlab
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@@ -1302,8 +1302,8 @@ To do so, the actuator position should be modified
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#+begin_src matlab
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GKM = pinv(JMa)*G*pinv(JMt');
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GKM.InputName = {'Fx', 'Fz', 'My'};
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GKM.OutputName = {'Dx', 'Dz', 'Ry'};
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GKM.InputName = {'Fx', 'Fy', 'Mz'};
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GKM.OutputName = {'Dx', 'Dy', 'Rz'};
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#+end_src
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#+begin_src matlab :exports none
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@@ -1335,7 +1335,7 @@ To do so, the actuator position should be modified
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#+end_src
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#+name: fig:jac_decoupling_KM
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#+caption:
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#+caption: Diagonal and off-diagonal elements of the decoupled plant
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#+RESULTS:
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[[file:figs/jac_decoupling_KM.png]]
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@@ -1373,7 +1373,7 @@ Or it can be decoupled at high frequency if the Jacobians are evaluated at the C
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G = linearize(mdl, io);
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G.InputName = {'F1', 'F2', 'F3'};
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G.OutputName = {'Ax1', 'Az1', 'Ax2', 'Az2'};
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G.OutputName = {'Ax1', 'Ay1', 'Ax2', 'Ay2'};
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#+end_src
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#+begin_src matlab
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@@ -1405,7 +1405,7 @@ Or it can be decoupled at high frequency if the Jacobians are evaluated at the C
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G = linearize(mdl, io);
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G.InputName = {'F1', 'F2', 'F3'};
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G.OutputName = {'Ax1', 'Az1', 'Ax2', 'Az2'};
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G.OutputName = {'Ax1', 'Ay1', 'Ax2', 'Ay2'};
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#+end_src
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#+begin_src matlab
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@@ -1430,8 +1430,8 @@ Or it can be decoupled at high frequency if the Jacobians are evaluated at the C
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#+begin_src matlab
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GM = pinv(JMa)*G*pinv(JMt');
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GM.InputName = {'Fx', 'Fz', 'My'};
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GM.OutputName = {'Dx', 'Dz', 'Ry'};
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GM.InputName = {'Fx', 'Fy', 'Mz'};
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GM.OutputName = {'Dx', 'Dy', 'Rz'};
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#+end_src
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#+begin_src matlab :exports none
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@@ -1506,36 +1506,6 @@ Or it can be decoupled at high frequency if the Jacobians are evaluated at the C
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ylim([1e-8, 1e0]);
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#+end_src
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** SVD U and V matrices :noexport:
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#+begin_src matlab
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la = l/2; % Position of Act. [m]
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ha = 0; % Position of Act. [m]
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#+end_src
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#+begin_src matlab
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c = 2e1; % Actuator Damping [N/(m/s)]
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#+end_src
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#+begin_src matlab
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%% Name of the Simulink File
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mdl = 'gravimeter';
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%% Input/Output definition
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clear io; io_i = 1;
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io(io_i) = linio([mdl, '/F1'], 1, 'openinput'); io_i = io_i + 1;
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io(io_i) = linio([mdl, '/F2'], 1, 'openinput'); io_i = io_i + 1;
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io(io_i) = linio([mdl, '/F3'], 1, 'openinput'); io_i = io_i + 1;
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io(io_i) = linio([mdl, '/Acc_side'], 1, 'openoutput'); io_i = io_i + 1;
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io(io_i) = linio([mdl, '/Acc_side'], 2, 'openoutput'); io_i = io_i + 1;
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io(io_i) = linio([mdl, '/Acc_top'], 1, 'openoutput'); io_i = io_i + 1;
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io(io_i) = linio([mdl, '/Acc_top'], 2, 'openoutput'); io_i = io_i + 1;
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G = linearize(mdl, io);
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G.InputName = {'F1', 'F2', 'F3'};
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G.OutputName = {'Ax1', 'Az1', 'Ax2', 'Az2'};
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#+end_src
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* Stewart Platform - Simscape Model
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:PROPERTIES:
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:header-args:matlab+: :tangle stewart_platform/script.m
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