Inverse-Kinematics and Forward Kinematics

In this topic we explain inverse and forward kinematics when applied to cam mechanisms.

We explain why we use Inverse-Kinematics to design multi-axis, multi-link mechanisms for the packaging machine industry.

hmtoggle_plus1        Terminology Alert

Tool-Part: the Part that interacts with the product or packaging. You might call it the end-effector.
Cam-Follower: the Part moved by the Cam. It 'carries' the Cam-Follower shape.
Motion-Part: the Part to which you give the motion - it is the Cam-Follower or the Tool-Part.
Transforming-Dyad(s): Dyad, or Dyads, that transforms the motion:
ofrom the Cam-Follower to the Tool-Part

- or, inversely -

ofrom the Tool-Part to the Cam-Follower

Forward-Kinematics and Inverse-Kinematics - a comparison.

In general, the Cam and the Follower Parts can be any Part in a kinematically-defined chain. However, it is easiest to explain inverse and forward-kinematics when there is one Dyad and one Motion-Part.

When there is a dyad 'between' the Cam-Follower and the Tool, then you can use Forward or Inverse-Kinematics.

If you give the motion to the Tool-Part, and let MechDesigner find the motion of the Cam-Follower, we would say that we are using 'Inverse-Kinematics'.
If you give the motion to the Cam-Follower, and let MechDesigner find the motion of the Tool-Part, we would say that we are using 'Forward-Kinematics'.

We strongly recommend Inverse-Kinematics. It is much easier to edit and find a design solution.

 

Motion-Part

Motion found by MechDesigner.

Forward-Kinematics

Follower

Tool-Part

Inverse-Kinematics

Tool-Part

Follower

Forward and Inverse Kinematics Examples

 

Forward Kineamatics

 

Forward Kinematics

If you design and add the motion-dimension to the Power-Part, and use a Dyad to transfer the motion to the Tool-Part, then the design approach is 'Forward-Kinematics'.

In the image:

The Motion is given to the Power-Part
An RRP Dyad transforms the motion to the Tool-Part.

 

Inverse Kineamatics

 

Inverse-Kinematics

If you design and apply the motion to the Tool-Part, and use a Dyad to transfer the motion to the Power-Part, then the design uses 'Inverse-Kinematics'.

In the image:

The Motion is given to the Tool-Part.
An RRR Dyad transforms the motion to the Power-Part.

Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd