SingleAxisLinearDrive:

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   Model a single axis drive with the motor dynamics modeled by a lag.
   Typing SingleAxisLinearDrive is the same as
   SingleAxisLinearDrive('initialize')
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   Inputs
   -------
   action      (1,:)     'initialize' 'get power consumption'
                         'set torque'  'get torque'
                         'get state derivative' 'update'
                         'set failure' 'get default datastructure'
   d           (1,1)     Depends on the action

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   Outputs
   -------
   y           (1,1)     Depends on the action

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