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parallel_flexure_guide_transfer [2018/05/16 13:51]
marijn.nijenhuis
parallel_flexure_guide_transfer [2020/06/04 12:26] (current)
marijn.nijenhuis
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 ===== Example: Compute transfer function of a parallel flexure guide ===== ===== Example: Compute transfer function of a parallel flexure guide =====
  
-This example shows the computation of the transfer function from input actuator force (force in x-direction on the end-effector) to output stage displacement (motion in x-direction of the end-effector) of a parallel flexure guide. +This example shows the computation of the transfer function from input actuator force (force in x-direction on the end-effector) to output stage displacement and velocity (motion in x-direction of the end-effector) of a parallel flexure guide. 
 {{::parallel flexure guide.png?direct|}} {{::parallel flexure guide.png?direct|}}
  
-The state-space equations (from which the transfer function follows) can be computed by specifying the input and output for the transfer function. For this example, actuation force in x-direction on node 3 (a node on the end-effector) is used for input, and displacement in x-direction of node 3 is used for the outputThis can be specified with the ''nprops(i).transfer_in'' and ''nprops(i).transfer_out'' arguments. Furthermore, to enable the computation of the state-space equations, the optional field ''opt.transfer'' has to be set to ''true''. For details, see the [[full_syntax|SPACAR Light full syntax]]. For this case, the MATLAB file that defines the flexure mechanism is supplemented with+The state-space equations (from which the transfer function follows) can be computed by specifying the input and output for the transfer function. For this example, actuation force in x-direction on node 3 (a node on the end-effector) is used for input. Two desired outputs are specified: the first is the displacement in x-direction of node 3; the second is the velocity in x-direction of node 5These can be specified with the ''nprops(i).transfer_in'' and ''nprops(i).transfer_out'' arguments. Furthermore, to enable the computation of the state-space equations, the optional field ''opt.transfer'' has to be set to ''true''. For details, see the [[full_syntax|SPACAR Light full syntax]]. For this case, the MATLAB file that defines the flexure mechanism is supplemented with
 <code matlab> <code matlab>
-nprops(3).transfer_in  = {'force_x'};       %Input for state-space equations +nprops(3).transfer_in  = {'force_x'};       %Input for state-space equations 
-nprops(3).transfer_out = {'displ_x'};       %Output for state-space equations+nprops(3).transfer_out = {'displ_x'};       %Output 1 for state-space equations 
 +nprops(5).transfer_out = {'veloc_x'};       %Output 2 for state-space equations
 ... ...
 opt.transfer = {true 0.01};       %Calculation of state-space equations (with relative damping 0.01) opt.transfer = {true 0.01};       %Calculation of state-space equations (with relative damping 0.01)
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 For details, see the [[full_syntax|SPACAR Light full syntax]]. For details, see the [[full_syntax|SPACAR Light full syntax]].
  
-The resulting transfer function is plotted in the figure below. The first eigenfrequency is approximately 10 rad/s;  the first parasitic eigenfrequency appears at 360 rad/s.+The resulting transfer function between the input and the first output is plotted in the figure below. The first eigenfrequency is approximately 10 rad/s;  the first parasitic eigenfrequency appears at 360 rad/s.
  
 {{::transfer pfg.png?direct|}} {{::transfer pfg.png?direct|}}
 +
 +Note that in case of multiple inputs and/or outputs, the resulting state-space structure in MATLAB will also indicate with named labels what these inputs and outputs are (i.e. node number and displacement, velocity or force).
  
 An example file for providing the input for SPACAR Light and plotting the transfer function is provided below. An example file for providing the input for SPACAR Light and plotting the transfer function is provided below.
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 %node 3 %node 3
 nprops(3).transfer_in  = {'force_x'};       %Input for state-space equations nprops(3).transfer_in  = {'force_x'};       %Input for state-space equations
-nprops(3).transfer_out = {'displ_x'};       %Output for state-space equations+nprops(3).transfer_out = {'displ_x'};       %Output nr 1 (displ. in x-direction on node 3) for state-space equations 
 +nprops(5).transfer_out = {'veloc_x'};       %Output nr 2 (veloc. in x-direction on node 5) for state-space equations
  
 %node 4 %node 4
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 %% OPTIONAL ARGUMENTS %% OPTIONAL ARGUMENTS
 opt.transfer = {true 0.01};       %Calculation of state-space equations (with relative damping 0.01) opt.transfer = {true 0.01};       %Calculation of state-space equations (with relative damping 0.01)
 +opt.filename = 'file';
  
 %% CALL SPACAR_LIGHT %% CALL SPACAR_LIGHT
parallel_flexure_guide_transfer.1526471496.txt.gz · Last modified: 2018/05/16 13:51 by marijn.nijenhuis