bam.trajectory
==============

.. py:module:: bam.trajectory


Attributes
----------

.. autoapisummary::

   bam.trajectory.trajectories
   bam.trajectory.trajectory


Classes
-------

.. autoapisummary::

   bam.trajectory.Trajectory
   bam.trajectory.LiftAndDrop
   bam.trajectory.SinusTimeSquare
   bam.trajectory.UpAndDown
   bam.trajectory.SinSin
   bam.trajectory.Nothing


Functions
---------

.. autoapisummary::

   bam.trajectory.cubic_interpolate


Module Contents
---------------

.. py:function:: cubic_interpolate(keyframes: list, t: float) -> float

   Interpolate a scalar signal through a list of keyframes with cubic splines.

   Each keyframe is a triplet ``(t, x, x')`` where ``t`` is the time, ``x``
   the value, and ``x'`` the desired first derivative at that point.

   :param keyframes: List of ``[t, x, dx/dt]`` triplets, sorted by time.
   :param t: Query time.
   :returns: Interpolated value at time ``t``.


.. py:class:: Trajectory

   Abstract base class for identification trajectories.

   A trajectory is a callable that maps a time ``t`` to a target angle and a
   torque-enable flag.  All built-in trajectories run for 6 seconds.


   .. py:attribute:: duration
      :type:  float
      :value: None



.. py:class:: LiftAndDrop

   Bases: :py:obj:`Trajectory`


   Cubic move to −π/2 over 2 s, then torque disabled (gravity drop).

   Useful for identifying backdrivability and Stribeck effects at very low
   speed, as the arm falls freely under gravity after the motor is released.


   .. py:attribute:: duration
      :value: 6.0



.. py:class:: SinusTimeSquare

   Bases: :py:obj:`Trajectory`


   Progressively faster sinusoidal trajectory: :math:`\sin(t^2)`.

   General-purpose trajectory that sweeps a wide velocity range in a single
   run.  Recommended as the primary identification trajectory.


   .. py:attribute:: duration
      :value: 6.0



.. py:class:: UpAndDown

   Bases: :py:obj:`Trajectory`


   Slow cubic path 0 → π/2 → 0.8·π/2.

   Emphasises static friction and load-dependent effects at low to medium
   speed.


   .. py:attribute:: duration
      :value: 6.0



.. py:class:: SinSin

   Bases: :py:obj:`Trajectory`


   Multi-frequency trajectory: :math:`\sin(t)\cdot\pi/2 + \sin(5t)\cdot 0.5\cdot\sin(2t)`.

   Rich spectral content covers a broad range of velocities and accelerations.


   .. py:attribute:: duration
      :value: 6.0



.. py:class:: Nothing

   Bases: :py:obj:`Trajectory`


   Zero torque for the full duration (pure gravity response).

   Useful to isolate backdrivability and measure passive dynamics.


   .. py:attribute:: duration
      :value: 6.0



.. py:data:: trajectories
   :type:  dict[str, Trajectory]

.. py:data:: trajectory