Cam Discussion

One of the first things that needs to be done in order to analyze this mechanism is to characterize the cam. The radius of the cam varies with the change in angle. The Karakuri book shows a qualitative graph of what the cam radius should look like. This can be found in the figure below.

Figure 1. Cam model from Karakuri book

As can be seen the radius changes nonlinearly for part of the cam, and then drops and remains constant for the rest of the cam. In order to figure out the relationship I measured 8 radii at varying angles and created an excel plot to find the trend line of best fit. The trend that produced the best results is shown in the graph below.

Figure 2. Trinomial Fit of the Cam

After finding the radius as a function of theta, I went on to perform the rest of my kinematic analysis.