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Update strut length

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Thomas Dehaeze
2025-12-02 16:32:26 +01:00
parent a938e958ac
commit aef2acdea0
6 changed files with 176 additions and 87 deletions
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@@ -1452,7 +1452,7 @@ exportFig('figs/delta_robot_cube_size_compliance_rotation.pdf', 'width', 'wide',
** Effect of the strut length
<<ssec:delta_robot_flexible_geometry_strut_length>>
*** Introduction :ignore:
*** Obtained geometries
Let's choose reasonable values for the flexible joints:
- Bending stiffness of 50Nm/rad
- Torsional stiffness of 500Nm/rad
@@ -1460,6 +1460,71 @@ Let's choose reasonable values for the flexible joints:
And we see the effect of changing the strut length.
The strut length is varied from 10mm (Figure [[fig:delta_robot_strut_small]]) to 100mm (Figure [[fig:delta_robot_strut_large]]) to study the effect on the system dynamics.
#+begin_src matlab
d = 50e-3; % Cube's edge length [m]
b = 20e-3; % Distance between cube's vertices and top joints [m]
L = 50e-3; % Length of the struts [m]
#+end_src
#+begin_src matlab
%% Effect of torsional stiffness on the plant dynamics
delta_robot = initializeStewartPlatform();
delta_robot = generateDeltaRobot(delta_robot, 'd', d, 'b', b, 'L', 10e-3);
delta_robot = computeJointsPose(delta_robot);
delta_robot = initializeActuatorDynamics(delta_robot);
delta_robot = initializeJointDynamics(delta_robot);
delta_robot = initializeCylindricalStruts(delta_robot);
delta_robot = computeJacobian(delta_robot);
delta_robot = initializeStewartPose(delta_robot);
#+end_src
#+begin_src matlab :exports none :results none
%% Delta Robot Architecture
displayArchitecture(delta_robot, 'labels', false, 'frames', false);
plotCube(delta_robot, 'Hc', d/sqrt(3), 'FOc', delta_robot.geometry.H+delta_robot.platform_M.MO_B(3), 'color', [0,0,0,0.2], 'link_to_struts', false);
view([70, 30]);
#+end_src
#+begin_src matlab :tangle no :exports results :results file replace
exportFig('figs/delta_robot_strut_small.pdf', 'width', 'wide', 'height', 'tall');
#+end_src
#+name: fig:delta_robot_strut_small
#+caption: Obtained Delta Robot for a cube's size of 10mm
#+RESULTS:
[[file:figs/delta_robot_strut_small.png]]
#+begin_src matlab
%% Effect of torsional stiffness on the plant dynamics
delta_robot = initializeStewartPlatform();
delta_robot = generateDeltaRobot(delta_robot, 'd', d, 'b', b, 'L', 100e-3);
delta_robot = computeJointsPose(delta_robot);
delta_robot = initializeActuatorDynamics(delta_robot);
delta_robot = initializeJointDynamics(delta_robot);
delta_robot = initializeCylindricalStruts(delta_robot);
delta_robot = computeJacobian(delta_robot);
delta_robot = initializeStewartPose(delta_robot);
#+end_src
#+begin_src matlab :exports none :results none
%% Delta Robot Architecture
displayArchitecture(delta_robot, 'labels', false, 'frames', false);
plotCube(delta_robot, 'Hc', d/sqrt(3), 'FOc', delta_robot.geometry.H+delta_robot.platform_M.MO_B(3), 'color', [0,0,0,0.2], 'link_to_struts', false);
view([70, 30]);
#+end_src
#+begin_src matlab :tangle no :exports results :results file replace
exportFig('figs/delta_robot_strut_large.pdf', 'width', 'wide', 'height', 'tall');
#+end_src
#+name: fig:delta_robot_strut_large
#+caption: Obtained Delta Robot for a cube's size of 100mm
#+RESULTS:
[[file:figs/delta_robot_strut_large.png]]
*** Effect on the compliance
As shown in Figure [[fig:delta_robot_strut_length_compliance_rotation]], the strut length has an effect on the system stiffness in translation (left plot) but almost not in rotation (right plot).