Cylindrical
===========

A cylindrical joint creates a point that is translated along an axis defined in the reference frame, and a frame that is rotated relative to an existing frame about the same axis. 
**Keyword Arguments**

:param str name: Name given to the joint, default is uppercase characters in alphabetical order (A, B, C, ...)

:param str ref_point_key: Start point from which the vector component of the joint is defined

:param str ref_frame_key: Reference frame in which the translational and rotational displacement components are defined

:param str motion_axis: '+X', '-X', '+Y', '-Y', '+Z', or '-Z', represents the axis in which rotation and translation are defined,

**Initial Values**

:param numeric initial_t: Initial value in the translational coordinate

:param numeric initial_r: Initial value for rotation

:param numeric rate_t: Initial speed in the translational coordinate

:param numeric rate_r: Initial speed for rotation

**Spring Parameters**

:param numeric kt: Stiffness in the translational coordinate

:param numeric kr: Stiffness for rotation

:param numeric ct: Damping in the translational coordinate

:param numeric cr: Rotational damping

:param numeric equilibrium_t: Equilibrium distance in the translational coordinate

:param numeric equilibrium_r: Equilibrium angle