# Commits

committed 3fb8c91

robot.dh: fixed and improved docstrings.

# ars/model/robot/dh.py

-"""Denavit-Hartenberg related code
+r"""This module contains Denavit-Hartenberg related code.
+
+For a serial chain of links (defined by D-H parameters), matrix T defines the
+pose (position and orientation) of the end effector with respect to the base,
+based in the joints' n coordinates.
+
+.. math::
+
+	T = \operatorname{}^{0}A_1 \cdot \operatorname{}^{1}A_2 \cdots \operatorname{}^{n - 1}A_n

 """
 from ars.utils.mathematical import sin, cos
 	* :attr:angle: a.k.a. :math:\theta

 	On the other hand, :attr:convention stores which convention for the
-	parameters is used. There are two: standard ('s') and Craig's modified
-	('m'). By default the former is used.
+	parameters is used. There are two: standard ('s', default) and Craig's
+	modified ('m').

 	>>> (length, offset, twist, angle) = (0.0, 0.0, 0.0, 0.0)
 	>>> DHLink(*(length, offset, twist, angle))
 	###########################################################################

 	def calc_transform(self):
-		r"""Calculate the corresponding transformation matrix.
+		r"""Calculate link homogeneous transformation matrix.

-		This matrix, designated by :math:\operatorname{}^{n - 1}T_n, is useful
+		This matrix, designated as :math:\operatorname{}^{n - 1}T_n, is useful
 		to transform points from frame n to n-1. For the standard
 		convention:

 		source:
 		http://en.wikipedia.org/wiki/Denavit%E2%80%93Hartenberg_parameters#Denavit-Hartenberg_matrix

+		:return: 4x4 matrix
 		:rtype: tuple of tuples

 		"""