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<meta http-equiv="Content-Type" content="text/html;charset=utf-8" /> <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<title>Delta Robot</title> <title>Delta Robot</title>
<meta name="author" content="Dehaeze Thomas" /> <meta name="author" content="Dehaeze Thomas" />
@@ -11,19 +11,19 @@
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@@ -39,43 +39,43 @@
<h2>Table of Contents</h2> <h2>Table of Contents</h2>
<div id="text-table-of-contents" role="doc-toc"> <div id="text-table-of-contents" role="doc-toc">
<ul> <ul>
<li><a href="#org9dbd6be">1. Geometry</a></li> <li><a href="#orgbb3e49b">1. Geometry</a></li>
<li><a href="#org8130b11">2. Kinematics: Jacobian Matrix and Mobility</a></li> <li><a href="#org91b49ae">2. Kinematics: Jacobian Matrix and Mobility</a></li>
<li><a href="#org4dd69f9">3. Kinematics: Degrees of Freedom</a></li> <li><a href="#orgbb025c8">3. Kinematics: Degrees of Freedom</a></li>
<li><a href="#org25e6eb0">4. Kinematics: Number of modes</a></li> <li><a href="#org1176a21">4. Kinematics: Number of modes</a></li>
<li><a href="#org494f6d0">5. Flexible Joint Design</a> <li><a href="#orgc5910ca">5. Flexible Joint Design</a>
<ul> <ul>
<li><a href="#org4834fcb">5.1. Studied Geometry</a></li> <li><a href="#org5239597">5.1. Studied Geometry</a></li>
<li><a href="#orgcf04565">5.2. Stiffness seen by the actuator</a></li> <li><a href="#org40e3596">5.2. Stiffness seen by the actuator</a></li>
<li><a href="#org8e8af24">5.3. Bending Stiffness</a></li> <li><a href="#orga0e7fd0">5.3. Bending Stiffness</a></li>
<li><a href="#org6d455b1">5.4. Axial Stiffness</a></li> <li><a href="#orgc0a9e90">5.4. Axial Stiffness</a></li>
<li><a href="#orgd75f092">5.5. Torsional Stiffness</a></li> <li><a href="#org6acb2ad">5.5. Torsional Stiffness</a></li>
<li><a href="#org9700eaf">5.6. Shear Stiffness</a></li> <li><a href="#org2e164b4">5.6. Shear Stiffness</a></li>
<li><a href="#orgbed5ca4">5.7. Effect of cube&rsquo;s size</a> <li><a href="#org6f2c076">5.7. Effect of cube&rsquo;s size</a>
<ul> <ul>
<li><a href="#org531ae45">5.7.1. Effect on the plant dynamics</a></li> <li><a href="#org934b7b1">5.7.1. Effect on the plant dynamics</a></li>
<li><a href="#org9a49c2b">5.7.2. Effect on the compliance</a></li> <li><a href="#org91b34ef">5.7.2. Effect on the compliance</a></li>
</ul> </ul>
</li> </li>
<li><a href="#org14884a8">5.8. Effect of the strut length ?</a> <li><a href="#org75891de">5.8. Effect of the strut length ?</a>
<ul> <ul>
<li><a href="#orgea1bcc5">5.8.1. Effect on the plant dynamics</a></li> <li><a href="#orgda43225">5.8.1. Effect on the plant dynamics</a></li>
<li><a href="#orga760c24">5.8.2. Effect on the compliance</a></li> <li><a href="#orgd0abd06">5.8.2. Effect on the compliance</a></li>
</ul> </ul>
</li> </li>
<li><a href="#org1693b06">5.9. Having the Center of Mass at the cube&rsquo;s center</a></li> <li><a href="#org0105411">5.9. Having the Center of Mass at the cube&rsquo;s center</a></li>
<li><a href="#org9065437">5.10. Conclusion</a></li> <li><a href="#orgcac595f">5.10. Conclusion</a></li>
</ul> </ul>
</li> </li>
<li><a href="#org41e56de">6. Conclusion</a></li> <li><a href="#org0f914f1">6. Conclusion</a></li>
</ul> </ul>
</div> </div>
</div> </div>
<p> <p>
<a id="org2b67556"></a> <a id="orgf136f49"></a>
</p> </p>
<div id="outline-container-org9dbd6be" class="outline-2"> <div id="outline-container-orgbb3e49b" class="outline-2">
<h2 id="org9dbd6be"><span class="section-number-2">1.</span> Geometry</h2> <h2 id="orgbb3e49b"><span class="section-number-2">1.</span> Geometry</h2>
<div class="outline-text-2" id="text-1"> <div class="outline-text-2" id="text-1">
<p> <p>
The Delta Robot geometry is defined as shown in Figure <a href="ref:fig:delta_robot_schematic">ref:fig:delta_robot_schematic</a>. The Delta Robot geometry is defined as shown in Figure <a href="ref:fig:delta_robot_schematic">ref:fig:delta_robot_schematic</a>.
@@ -91,7 +91,7 @@ The geometry is fully defined by three parameters:
</ul> </ul>
<div id="orgf0c5783" class="figure"> <div id="org1393dba" class="figure">
<p><img src="figs/delta_robot_schematic.png" alt="delta_robot_schematic.png" /> <p><img src="figs/delta_robot_schematic.png" alt="delta_robot_schematic.png" />
</p> </p>
<p><span class="figure-number">Figure 1: </span>Schematic of the Delta Robot</p> <p><span class="figure-number">Figure 1: </span>Schematic of the Delta Robot</p>
@@ -149,22 +149,22 @@ Let&rsquo;s initialize a Delta Robot architecture, and plot the obtained geometr
</p> </p>
<div id="org31ec0d3" class="figure"> <div id="org54b1a70" class="figure">
<p><img src="figs/delta_robot_architecture.png" alt="delta_robot_architecture.png" /> <p><img src="figs/delta_robot_architecture.png" alt="delta_robot_architecture.png" />
</p> </p>
<p><span class="figure-number">Figure 2: </span>Delta Robot Architecture</p> <p><span class="figure-number">Figure 2: </span>Delta Robot Architecture</p>
</div> </div>
<div id="org80c1e20" class="figure"> <div id="orgbfb2618" class="figure">
<p><img src="figs/delta_robot_architecture_top.png" alt="delta_robot_architecture_top.png" /> <p><img src="figs/delta_robot_architecture_top.png" alt="delta_robot_architecture_top.png" />
</p> </p>
<p><span class="figure-number">Figure 3: </span>Delta Robot Architecture - Top View</p> <p><span class="figure-number">Figure 3: </span>Delta Robot Architecture - Top View</p>
</div> </div>
</div> </div>
</div> </div>
<div id="outline-container-org8130b11" class="outline-2"> <div id="outline-container-org91b49ae" class="outline-2">
<h2 id="org8130b11"><span class="section-number-2">2.</span> Kinematics: Jacobian Matrix and Mobility</h2> <h2 id="org91b49ae"><span class="section-number-2">2.</span> Kinematics: Jacobian Matrix and Mobility</h2>
<div class="outline-text-2" id="text-2"> <div class="outline-text-2" id="text-2">
<p> <p>
Jacobian matrix between actuator displacement and top platform displacement. Jacobian matrix between actuator displacement and top platform displacement.
@@ -199,7 +199,7 @@ The achievable workspace is a cube whose edge length is equal to the actuator st
</p> </p>
<div id="org7052783" class="figure"> <div id="org19bbc82" class="figure">
<p><img src="figs/delta_robot_3d_workspace.png" alt="delta_robot_3d_workspace.png" /> <p><img src="figs/delta_robot_3d_workspace.png" alt="delta_robot_3d_workspace.png" />
</p> </p>
<p><span class="figure-number">Figure 4: </span>3D workspace</p> <p><span class="figure-number">Figure 4: </span>3D workspace</p>
@@ -214,7 +214,7 @@ Depending on how the YZ plane is oriented (i.e., depending on the Rz angle of th
</p> </p>
<div id="org40b9c06" class="figure"> <div id="org524d43a" class="figure">
<p><img src="figs/delta_robot_2d_workspace.png" alt="delta_robot_2d_workspace.png" /> <p><img src="figs/delta_robot_2d_workspace.png" alt="delta_robot_2d_workspace.png" />
</p> </p>
<p><span class="figure-number">Figure 5: </span>2D mobility for different orientations</p> <p><span class="figure-number">Figure 5: </span>2D mobility for different orientations</p>
@@ -226,15 +226,15 @@ Maximum YZ mobility for an angle of 270 degrees, square with edge size of 117 um
<div id="org02a87d6" class="figure"> <div id="orgdabe3d4" class="figure">
<p><img src="figs/delta_robot_2d_workspace_optimal.png" alt="delta_robot_2d_workspace_optimal.png" /> <p><img src="figs/delta_robot_2d_workspace_optimal.png" alt="delta_robot_2d_workspace_optimal.png" />
</p> </p>
<p><span class="figure-number">Figure 6: </span>2D mobility for the optimal Rz angle</p> <p><span class="figure-number">Figure 6: </span>2D mobility for the optimal Rz angle</p>
</div> </div>
</div> </div>
</div> </div>
<div id="outline-container-org4dd69f9" class="outline-2"> <div id="outline-container-orgbb025c8" class="outline-2">
<h2 id="org4dd69f9"><span class="section-number-2">3.</span> Kinematics: Degrees of Freedom</h2> <h2 id="orgbb025c8"><span class="section-number-2">3.</span> Kinematics: Degrees of Freedom</h2>
<div class="outline-text-2" id="text-3"> <div class="outline-text-2" id="text-3">
<p> <p>
In the perfect case (flexible joints having no stiffness in bending, and infinite stiffness in torsion and in the axial direction), the top platform is allowed to move only in the X, Y and Z directions while the three rotations are fixed. In the perfect case (flexible joints having no stiffness in bending, and infinite stiffness in torsion and in the axial direction), the top platform is allowed to move only in the X, Y and Z directions while the three rotations are fixed.
@@ -524,8 +524,8 @@ Therefore, to model some compliance of the top platform in rotation, both the ax
</p> </p>
</div> </div>
</div> </div>
<div id="outline-container-org25e6eb0" class="outline-2"> <div id="outline-container-org1176a21" class="outline-2">
<h2 id="org25e6eb0"><span class="section-number-2">4.</span> Kinematics: Number of modes</h2> <h2 id="org1176a21"><span class="section-number-2">4.</span> Kinematics: Number of modes</h2>
<div class="outline-text-2" id="text-4"> <div class="outline-text-2" id="text-4">
<p> <p>
In the perfect condition (i.e. infinite stiffness in torsion and in compression of the flexible joints), the system has 6 states (i.e. 3 modes, one for each DoF: X, Y and Z). In the perfect condition (i.e. infinite stiffness in torsion and in compression of the flexible joints), the system has 6 states (i.e. 3 modes, one for each DoF: X, Y and Z).
@@ -541,11 +541,11 @@ State-space model with 3 outputs, 3 inputs, and 6 states.
</pre> </pre>
</div> </div>
</div> </div>
<div id="outline-container-org494f6d0" class="outline-2"> <div id="outline-container-orgc5910ca" class="outline-2">
<h2 id="org494f6d0"><span class="section-number-2">5.</span> Flexible Joint Design</h2> <h2 id="orgc5910ca"><span class="section-number-2">5.</span> Flexible Joint Design</h2>
<div class="outline-text-2" id="text-5"> <div class="outline-text-2" id="text-5">
<p> <p>
<a id="org1d3485b"></a> <a id="orga126d5e"></a>
</p> </p>
<p> <p>
The goal is to extract specifications for the flexible joints of the six struts. The goal is to extract specifications for the flexible joints of the six struts.
@@ -571,8 +571,8 @@ First, the dynamics of a &ldquo;perfect&rdquo; Delta-Robot is identified (i.e. w
Then, the impact of the flexible joint&rsquo;s imperfections will be studied. Then, the impact of the flexible joint&rsquo;s imperfections will be studied.
</p> </p>
</div> </div>
<div id="outline-container-org4834fcb" class="outline-3"> <div id="outline-container-org5239597" class="outline-3">
<h3 id="org4834fcb"><span class="section-number-3">5.1.</span> Studied Geometry</h3> <h3 id="org5239597"><span class="section-number-3">5.1.</span> Studied Geometry</h3>
<div class="outline-text-3" id="text-5-1"> <div class="outline-text-3" id="text-5-1">
<p> <p>
The cube&rsquo;s edge length is equal to 50mm, the distance between cube&rsquo;s vertices and top joints is 20mm and the length of the struts (i.e. the distance between the two flexible joints of the same strut) is 50mm. The cube&rsquo;s edge length is equal to 50mm, the distance between cube&rsquo;s vertices and top joints is 20mm and the length of the struts (i.e. the distance between the two flexible joints of the same strut) is 50mm.
@@ -584,7 +584,7 @@ The obtained geometry is shown in Figure <a href="ref:fig:delta_robot_studied_ge
</p> </p>
<div id="org0edf7cb" class="figure"> <div id="orgac9fd7a" class="figure">
<p><img src="figs/delta_robot_studied_geometry.png" alt="delta_robot_studied_geometry.png" /> <p><img src="figs/delta_robot_studied_geometry.png" alt="delta_robot_studied_geometry.png" />
</p> </p>
<p><span class="figure-number">Figure 7: </span>Geometry of the studied Delta Robot</p> <p><span class="figure-number">Figure 7: </span>Geometry of the studied Delta Robot</p>
@@ -598,15 +598,15 @@ The dynamics is shown in Figure <a href="ref:fig:delta_robot_dynamics_perfect">r
</p> </p>
<div id="org0ef4cae" class="figure"> <div id="org280fddc" class="figure">
<p><img src="figs/delta_robot_dynamics_perfect.png" alt="delta_robot_dynamics_perfect.png" /> <p><img src="figs/delta_robot_dynamics_perfect.png" alt="delta_robot_dynamics_perfect.png" />
</p> </p>
<p><span class="figure-number">Figure 8: </span>Dynamics of the delta robot with perfect joints</p> <p><span class="figure-number">Figure 8: </span>Dynamics of the delta robot with perfect joints</p>
</div> </div>
</div> </div>
</div> </div>
<div id="outline-container-orgcf04565" class="outline-3"> <div id="outline-container-org40e3596" class="outline-3">
<h3 id="orgcf04565"><span class="section-number-3">5.2.</span> Stiffness seen by the actuator</h3> <h3 id="org40e3596"><span class="section-number-3">5.2.</span> Stiffness seen by the actuator</h3>
<div class="outline-text-3" id="text-5-2"> <div class="outline-text-3" id="text-5-2">
<p> <p>
Because the flexible joints will have some bending stiffness, the actuator in one direction will &ldquo;see&rdquo; some stiffness due to the struts in the other directions. Because the flexible joints will have some bending stiffness, the actuator in one direction will &ldquo;see&rdquo; some stiffness due to the struts in the other directions.
@@ -619,7 +619,7 @@ The parallel stiffness seen by the actuator as a function of the bending stiffne
</p> </p>
<div id="orgef85bd9" class="figure"> <div id="org1a31cf8" class="figure">
<p><img src="figs/delta_robot_bending_stiffness_parallel_k.png" alt="delta_robot_bending_stiffness_parallel_k.png" /> <p><img src="figs/delta_robot_bending_stiffness_parallel_k.png" alt="delta_robot_bending_stiffness_parallel_k.png" />
</p> </p>
<p><span class="figure-number">Figure 9: </span>Effect of the bending stiffness of the flexible joints on the stiffness seen by the actuators</p> <p><span class="figure-number">Figure 9: </span>Effect of the bending stiffness of the flexible joints on the stiffness seen by the actuators</p>
@@ -640,8 +640,8 @@ This should be validated with the final geometry.
</p> </p>
</div> </div>
</div> </div>
<div id="outline-container-org8e8af24" class="outline-3"> <div id="outline-container-orga0e7fd0" class="outline-3">
<h3 id="org8e8af24"><span class="section-number-3">5.3.</span> Bending Stiffness</h3> <h3 id="orga0e7fd0"><span class="section-number-3">5.3.</span> Bending Stiffness</h3>
<div class="outline-text-3" id="text-5-3"> <div class="outline-text-3" id="text-5-3">
<p> <p>
Then, the dynamics is identified for a bending Stiffness of \(50\,Nm/\text{rad}\) and compared with a Delta robot with no bending stiffness in Figure <a href="ref:fig:delta_robot_bending_stiffness_dynamics">ref:fig:delta_robot_bending_stiffness_dynamics</a>. Then, the dynamics is identified for a bending Stiffness of \(50\,Nm/\text{rad}\) and compared with a Delta robot with no bending stiffness in Figure <a href="ref:fig:delta_robot_bending_stiffness_dynamics">ref:fig:delta_robot_bending_stiffness_dynamics</a>.
@@ -654,15 +654,15 @@ It is not critical from a dynamical point of view, it just decreases the achieva
</p> </p>
<div id="org3b5ebdd" class="figure"> <div id="orgc78914f" class="figure">
<p><img src="figs/delta_robot_bending_stiffness_dynamics.png" alt="delta_robot_bending_stiffness_dynamics.png" /> <p><img src="figs/delta_robot_bending_stiffness_dynamics.png" alt="delta_robot_bending_stiffness_dynamics.png" />
</p> </p>
<p><span class="figure-number">Figure 10: </span>Effect of the bending stiffness on the dynamics</p> <p><span class="figure-number">Figure 10: </span>Effect of the bending stiffness on the dynamics</p>
</div> </div>
</div> </div>
</div> </div>
<div id="outline-container-org6d455b1" class="outline-3"> <div id="outline-container-orgc0a9e90" class="outline-3">
<h3 id="org6d455b1"><span class="section-number-3">5.4.</span> Axial Stiffness</h3> <h3 id="orgc0a9e90"><span class="section-number-3">5.4.</span> Axial Stiffness</h3>
<div class="outline-text-3" id="text-5-4"> <div class="outline-text-3" id="text-5-4">
<p> <p>
Now, the effect of the axial stiffness on the dynamics is studied (Figure <a href="ref:fig:delta_robot_axial_stiffness_dynamics">ref:fig:delta_robot_axial_stiffness_dynamics</a>). Now, the effect of the axial stiffness on the dynamics is studied (Figure <a href="ref:fig:delta_robot_axial_stiffness_dynamics">ref:fig:delta_robot_axial_stiffness_dynamics</a>).
@@ -673,15 +673,15 @@ Therefore, we should aim at \(k_a > 100\,N/\mu m\).
</p> </p>
<div id="org1f7d588" class="figure"> <div id="org650666d" class="figure">
<p><img src="figs/delta_robot_axial_stiffness_dynamics.png" alt="delta_robot_axial_stiffness_dynamics.png" /> <p><img src="figs/delta_robot_axial_stiffness_dynamics.png" alt="delta_robot_axial_stiffness_dynamics.png" />
</p> </p>
<p><span class="figure-number">Figure 11: </span>Effect of the joint&rsquo;s axial stiffness on the plant dynamics</p> <p><span class="figure-number">Figure 11: </span>Effect of the joint&rsquo;s axial stiffness on the plant dynamics</p>
</div> </div>
</div> </div>
</div> </div>
<div id="outline-container-orgd75f092" class="outline-3"> <div id="outline-container-org6acb2ad" class="outline-3">
<h3 id="orgd75f092"><span class="section-number-3">5.5.</span> Torsional Stiffness</h3> <h3 id="org6acb2ad"><span class="section-number-3">5.5.</span> Torsional Stiffness</h3>
<div class="outline-text-3" id="text-5-5"> <div class="outline-text-3" id="text-5-5">
<p> <p>
Now the compliance in torsion of the flexible joints is considered. Now the compliance in torsion of the flexible joints is considered.
@@ -692,7 +692,7 @@ If we look at the compliance of the delta robot in rotation as a function of the
</p> </p>
<div id="orgfec2a22" class="figure"> <div id="orgc2d0c2a" class="figure">
<p><img src="figs/delta_robot_kt_compliance.png" alt="delta_robot_kt_compliance.png" /> <p><img src="figs/delta_robot_kt_compliance.png" alt="delta_robot_kt_compliance.png" />
</p> </p>
<p><span class="figure-number">Figure 12: </span>Effect of the joint&rsquo;s torsional stiffness on the Delta Robot compliance</p> <p><span class="figure-number">Figure 12: </span>Effect of the joint&rsquo;s torsional stiffness on the Delta Robot compliance</p>
@@ -703,7 +703,7 @@ If we have a look at the effect of the torsional stiffness on the plant dynamics
</p> </p>
<div id="org919b485" class="figure"> <div id="org8a91569" class="figure">
<p><img src="figs/delta_robot_kt_dynamics.png" alt="delta_robot_kt_dynamics.png" /> <p><img src="figs/delta_robot_kt_dynamics.png" alt="delta_robot_kt_dynamics.png" />
</p> </p>
<p><span class="figure-number">Figure 13: </span>Effect of the joint&rsquo;s torsional stiffness on the Delta Robot plant dynamics</p> <p><span class="figure-number">Figure 13: </span>Effect of the joint&rsquo;s torsional stiffness on the Delta Robot plant dynamics</p>
@@ -714,8 +714,8 @@ Therefore, the torsional stiffness is not a super important metric for the desig
</p> </p>
</div> </div>
</div> </div>
<div id="outline-container-org9700eaf" class="outline-3"> <div id="outline-container-org2e164b4" class="outline-3">
<h3 id="org9700eaf"><span class="section-number-3">5.6.</span> Shear Stiffness</h3> <h3 id="org2e164b4"><span class="section-number-3">5.6.</span> Shear Stiffness</h3>
<div class="outline-text-3" id="text-5-6"> <div class="outline-text-3" id="text-5-6">
<p> <p>
As shown in Figure <a href="ref:fig:delta_robot_shear_stiffness_compliance">ref:fig:delta_robot_shear_stiffness_compliance</a>, the shear stiffness of the flexible joints has some effect on the compliance in translation and almost no effect on the compliance in rotation. As shown in Figure <a href="ref:fig:delta_robot_shear_stiffness_compliance">ref:fig:delta_robot_shear_stiffness_compliance</a>, the shear stiffness of the flexible joints has some effect on the compliance in translation and almost no effect on the compliance in rotation.
@@ -727,15 +727,15 @@ A value of \(100\,N/\mu m\) seems reasonable.
</p> </p>
<div id="org47b9f27" class="figure"> <div id="org3922cac" class="figure">
<p><img src="figs/delta_robot_shear_stiffness_compliance.png" alt="delta_robot_shear_stiffness_compliance.png" /> <p><img src="figs/delta_robot_shear_stiffness_compliance.png" alt="delta_robot_shear_stiffness_compliance.png" />
</p> </p>
<p><span class="figure-number">Figure 14: </span>Effect of the shear stiffness of the flexible joints on the Delta Robot compliance</p> <p><span class="figure-number">Figure 14: </span>Effect of the shear stiffness of the flexible joints on the Delta Robot compliance</p>
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<div id="outline-container-orgbed5ca4" class="outline-3"> <div id="outline-container-org6f2c076" class="outline-3">
<h3 id="orgbed5ca4"><span class="section-number-3">5.7.</span> Effect of cube&rsquo;s size</h3> <h3 id="org6f2c076"><span class="section-number-3">5.7.</span> Effect of cube&rsquo;s size</h3>
<div class="outline-text-3" id="text-5-7"> <div class="outline-text-3" id="text-5-7">
<p> <p>
Let&rsquo;s choose reasonable values for the flexible joints: Let&rsquo;s choose reasonable values for the flexible joints:
@@ -751,8 +751,8 @@ Let&rsquo;s choose reasonable values for the flexible joints:
And we see the effect of changing the cube&rsquo;s size. And we see the effect of changing the cube&rsquo;s size.
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<div id="outline-container-org531ae45" class="outline-4"> <div id="outline-container-org934b7b1" class="outline-4">
<h4 id="org531ae45"><span class="section-number-4">5.7.1.</span> Effect on the plant dynamics</h4> <h4 id="org934b7b1"><span class="section-number-4">5.7.1.</span> Effect on the plant dynamics</h4>
<div class="outline-text-4" id="text-5-7-1"> <div class="outline-text-4" id="text-5-7-1">
<ul class="org-ul"> <ul class="org-ul">
<li class="off"><code>[&#xa0;]</code> <b>Understand why such different dynamics between 3dof_a joints and 6dof joints with very high shear stiffnesses</b></li> <li class="off"><code>[&#xa0;]</code> <b>Understand why such different dynamics between 3dof_a joints and 6dof joints with very high shear stiffnesses</b></li>
@@ -768,22 +768,22 @@ The effect of the cube&rsquo;s size on the plant dynamics is shown in Figure <a
</ul> </ul>
<div id="org55507e2" class="figure"> <div id="org53bd331" class="figure">
<p><img src="figs/delta_robot_cube_size_plant_dynamics.png" alt="delta_robot_cube_size_plant_dynamics.png" /> <p><img src="figs/delta_robot_cube_size_plant_dynamics.png" alt="delta_robot_cube_size_plant_dynamics.png" />
</p> </p>
<p><span class="figure-number">Figure 15: </span>Effect of the cube&rsquo;s size on the plant dynamics</p> <p><span class="figure-number">Figure 15: </span>Effect of the cube&rsquo;s size on the plant dynamics</p>
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<div id="outline-container-org9a49c2b" class="outline-4"> <div id="outline-container-org91b34ef" class="outline-4">
<h4 id="org9a49c2b"><span class="section-number-4">5.7.2.</span> Effect on the compliance</h4> <h4 id="org91b34ef"><span class="section-number-4">5.7.2.</span> Effect on the compliance</h4>
<div class="outline-text-4" id="text-5-7-2"> <div class="outline-text-4" id="text-5-7-2">
<p> <p>
As shown in Figure <a href="ref:fig:delta_robot_cube_size_compliance_rotation">ref:fig:delta_robot_cube_size_compliance_rotation</a>, the stiffness of the delta robot in rotation increases with the cube&rsquo;s size. As shown in Figure <a href="ref:fig:delta_robot_cube_size_compliance_rotation">ref:fig:delta_robot_cube_size_compliance_rotation</a>, the stiffness of the delta robot in rotation increases with the cube&rsquo;s size.
</p> </p>
<div id="org6c387e6" class="figure"> <div id="org23696c7" class="figure">
<p><img src="figs/delta_robot_cube_size_compliance_rotation.png" alt="delta_robot_cube_size_compliance_rotation.png" /> <p><img src="figs/delta_robot_cube_size_compliance_rotation.png" alt="delta_robot_cube_size_compliance_rotation.png" />
</p> </p>
<p><span class="figure-number">Figure 16: </span>Effect of the cube&rsquo;s size on the rotational compliance of the top platform</p> <p><span class="figure-number">Figure 16: </span>Effect of the cube&rsquo;s size on the rotational compliance of the top platform</p>
@@ -795,8 +795,8 @@ With a cube size of 50mm, the resonance frequency is already above 1kHz with see
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<div id="outline-container-org14884a8" class="outline-3"> <div id="outline-container-org75891de" class="outline-3">
<h3 id="org14884a8"><span class="section-number-3">5.8.</span> Effect of the strut length ?</h3> <h3 id="org75891de"><span class="section-number-3">5.8.</span> Effect of the strut length ?</h3>
<div class="outline-text-3" id="text-5-8"> <div class="outline-text-3" id="text-5-8">
<p> <p>
Let&rsquo;s choose reasonable values for the flexible joints: Let&rsquo;s choose reasonable values for the flexible joints:
@@ -811,8 +811,8 @@ Let&rsquo;s choose reasonable values for the flexible joints:
And we see the effect of changing the strut length. And we see the effect of changing the strut length.
</p> </p>
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<div id="outline-container-orgea1bcc5" class="outline-4"> <div id="outline-container-orgda43225" class="outline-4">
<h4 id="orgea1bcc5"><span class="section-number-4">5.8.1.</span> Effect on the plant dynamics</h4> <h4 id="orgda43225"><span class="section-number-4">5.8.1.</span> Effect on the plant dynamics</h4>
<div class="outline-text-4" id="text-5-8-1"> <div class="outline-text-4" id="text-5-8-1">
<p> <p>
As shown in Figure <a href="ref:fig:delta_robot_strut_length_plant_dynamics">ref:fig:delta_robot_strut_length_plant_dynamics</a>, having longer struts: As shown in Figure <a href="ref:fig:delta_robot_strut_length_plant_dynamics">ref:fig:delta_robot_strut_length_plant_dynamics</a>, having longer struts:
@@ -829,22 +829,22 @@ So, the struts length can be optimized to not decrease too much the stiffness of
</p> </p>
<div id="org52ddd53" class="figure"> <div id="org7c04cf7" class="figure">
<p><img src="figs/delta_robot_strut_length_plant_dynamics.png" alt="delta_robot_strut_length_plant_dynamics.png" /> <p><img src="figs/delta_robot_strut_length_plant_dynamics.png" alt="delta_robot_strut_length_plant_dynamics.png" />
</p> </p>
<p><span class="figure-number">Figure 17: </span>Effect of the cube&rsquo;s size on the plant dynamics</p> <p><span class="figure-number">Figure 17: </span>Effect of the cube&rsquo;s size on the plant dynamics</p>
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<div id="outline-container-orga760c24" class="outline-4"> <div id="outline-container-orgd0abd06" class="outline-4">
<h4 id="orga760c24"><span class="section-number-4">5.8.2.</span> Effect on the compliance</h4> <h4 id="orgd0abd06"><span class="section-number-4">5.8.2.</span> Effect on the compliance</h4>
<div class="outline-text-4" id="text-5-8-2"> <div class="outline-text-4" id="text-5-8-2">
<p> <p>
As shown in Figure <a href="ref:fig:delta_robot_strut_length_compliance_rotation">ref:fig:delta_robot_strut_length_compliance_rotation</a>, the strut length has an effect on the system stiffness in translation (left plot) but almost not in rotation (right plot). As shown in Figure <a href="ref:fig:delta_robot_strut_length_compliance_rotation">ref:fig:delta_robot_strut_length_compliance_rotation</a>, the strut length has an effect on the system stiffness in translation (left plot) but almost not in rotation (right plot).
</p> </p>
<div id="org170bf64" class="figure"> <div id="org3d8b133" class="figure">
<p><img src="figs/delta_robot_strut_length_compliance_rotation.png" alt="delta_robot_strut_length_compliance_rotation.png" /> <p><img src="figs/delta_robot_strut_length_compliance_rotation.png" alt="delta_robot_strut_length_compliance_rotation.png" />
</p> </p>
<p><span class="figure-number">Figure 18: </span>Effect of the cube&rsquo;s size on the rotational compliance of the top platform</p> <p><span class="figure-number">Figure 18: </span>Effect of the cube&rsquo;s size on the rotational compliance of the top platform</p>
@@ -852,8 +852,8 @@ As shown in Figure <a href="ref:fig:delta_robot_strut_length_compliance_rotation
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<div id="outline-container-org1693b06" class="outline-3"> <div id="outline-container-org0105411" class="outline-3">
<h3 id="org1693b06"><span class="section-number-3">5.9.</span> Having the Center of Mass at the cube&rsquo;s center</h3> <h3 id="org0105411"><span class="section-number-3">5.9.</span> Having the Center of Mass at the cube&rsquo;s center</h3>
<div class="outline-text-3" id="text-5-9"> <div class="outline-text-3" id="text-5-9">
<p> <p>
To make things easier, we take a top platform with no mass, mass-less struts, and we put a payload on top of the platform. To make things easier, we take a top platform with no mass, mass-less struts, and we put a payload on top of the platform.
@@ -866,24 +866,24 @@ But how sensitive this decoupling is to the exact position of the CoM still need
</p> </p>
<div id="orgab013d8" class="figure"> <div id="orge91c166" class="figure">
<p><img src="figs/delta_robot_CoM_pos_effect_plant.png" alt="delta_robot_CoM_pos_effect_plant.png" /> <p><img src="figs/delta_robot_CoM_pos_effect_plant.png" alt="delta_robot_CoM_pos_effect_plant.png" />
</p> </p>
<p><span class="figure-number">Figure 19: </span>Effect of the payload&rsquo;s Center of Mass position with respect to the cube&rsquo;s size on the plant dynamics</p> <p><span class="figure-number">Figure 19: </span>Effect of the payload&rsquo;s Center of Mass position with respect to the cube&rsquo;s size on the plant dynamics</p>
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<div id="outline-container-org9065437" class="outline-3"> <div id="outline-container-orgcac595f" class="outline-3">
<h3 id="org9065437"><span class="section-number-3">5.10.</span> Conclusion</h3> <h3 id="orgcac595f"><span class="section-number-3">5.10.</span> Conclusion</h3>
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<div id="outline-container-org41e56de" class="outline-2"> <div id="outline-container-org0f914f1" class="outline-2">
<h2 id="org41e56de"><span class="section-number-2">6.</span> Conclusion</h2> <h2 id="org0f914f1"><span class="section-number-2">6.</span> Conclusion</h2>
</div> </div>
</div> </div>
<div id="postamble" class="status"> <div id="postamble" class="status">
<p class="author">Author: Dehaeze Thomas</p> <p class="author">Author: Dehaeze Thomas</p>
<p class="date">Created: 2025-12-02 Tue 14:32</p> <p class="date">Created: 2025-12-02 Tue 14:41</p>
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