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Thomas Dehaeze
2021-04-23 17:37:19 +02:00
parent f94effc9f4
commit 6b225a90ea
5 changed files with 218 additions and 174 deletions
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2
org/index.org
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@@ -82,6 +82,8 @@ Active damping techniques are applied to the full Simscape model.
In this file are gathered all studies about the control the Nano-Active-Stabilization-System.
* Nano-Hexapod Simscape Model ([[file:nano_hexapod.org][link]])
The nano-hexapod simscape model is described and used for simulations.
* Useful Matlab Functions ([[./functions.org][link]])
Many matlab functions are shared among all the files of the projects.

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org/nano_hexapod.org
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@@ -264,9 +264,10 @@ exportFig('figs/nano_hexapod_effect_encoder.pdf', 'width', 'full', 'height', 'ta
#+RESULTS:
[[file:figs/nano_hexapod_effect_encoder.png]]
#+begin_question
Why do we have zeros at 400Hz and 800Hz when the encoders are fixed on the struts?
#+end_question
#+begin_important
The zeros at 400Hz and 800Hz should corresponds to resonances of the system when one of the APA is blocked.
It is linked to the axial stiffness of the flexible joints: increasing the axial stiffness of the joints will increase the frequency of the zeros.
#+end_important
** Effect of APA flexibility
<<sec:effect_apa_flexibility>>
@@ -2446,6 +2447,46 @@ exportFig('figs/nano_hexapod_dvf_compare_compliance_plates.pdf', 'width', 'wide'
[[file:figs/nano_hexapod_dvf_compare_compliance_plates.png]]
* To-order :noexport:
** Why Zero when encoder on the struts
#+begin_src matlab
n_hexapod = initializeNanoHexapodFinal('flex_bot_type', '4dof', ...
'flex_top_type', '4dof', ...
'motion_sensor_type', 'struts', ...
'actuator_type', '2dof');
#+end_src
The transfer function from actuator inputs to force sensors outputs is identified.
#+begin_src matlab
%% Options for Linearized
options = linearizeOptions;
options.SampleTime = 0;
%% Name of the Simulink File
mdl = 'test_apa300ml';
%% Input/Output definition
clear io; io_i = 1;
io(io_i) = linio([mdl, '/F'], 1, 'openinput'); io_i = io_i + 1; % Actuator Inputs
io(io_i) = linio([mdl, '/dLs'], 1, 'openoutput'); io_i = io_i + 1; % Force Sensors
io(io_i) = linio([mdl, '/dLp'], 1, 'openoutput'); io_i = io_i + 1; % Force Sensors
G = linearize(mdl, io, 0.0, options);
G.InputName = {'F'};
G.OutputName = {'dLs', 'dLp'};
bodeFig({G(1), G(2)}, logspace(1,4,1000))
#+end_src
The zero seems to be linked to the axial flexibility of the top joint.
In this mode, the APA does not experience any motion (hence the zero).
The resonance frequency then corresponds to the top mass on top of the axial stiffness of the two joints in series.
For the nano-hexapod, it corresponds to the resonance of the top mass when all (or *just one*?) of the APA is blocked.
#+begin_src matlab
sqrt((n_hexapod.flex_bot.kz(1)/2)/(55/3))/2/pi
#+end_src
** Verify why unstable strut
#+begin_src matlab :results value replace