D-H convention – tutorial 3

Sometimes the links of a manipulator have got such a shape that it is difficult to get the final result because equations are becoming complicated. In this case, not many software are able to deal with the problem of designating the parameters of the manipulator. In this tutorial, such a problem is introduced and later the method is proposed how to simplified working with such manipulators.

The problem is to derive the transformation matrix of the following manipulator:

The manipulator with 2 parallel joints and a spatial link
Fig 1. The manipulator with 2 revolute degrees of freedom (\(l_2\) link points beyond the monitor in the 3D dimension).
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D-H convention – tutorial 2

This tutorial presents one interesting example of how to deal with specifically oriented joints. In this case, it is necessary to extend a little bit previous definition of DH parameters.

Let’s consider the manipulator which is presented in Fig. 1 below:

Fig 1. The manipulator with 3 revolute joints. The last joint is oriented like a driller.
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Denavit-Hartenberg convention – tutorial 1

Denavit-Hartenberg convention is a technique which allows deriving parameters and variables of a kinematic chain of a manipulator. These parameters and variables can be after that used to get kinematic and dynamic models of a manipulator. Using the D-H convention can simplify the whole process. The notation will be explained on a sample manipulator which is illustrated in Fig. 1.

Fig. 1. Manipulator consists of 1 revolute joint oriented perpendicular to a floor and 2 revolute joints parallel to the floor.

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