The fixed joint applet has 4 constraints: the coordinate of its pivot,
its radius (the length of the line) and its maximum and minimum angles.
The angle of the joint varies in time between the maximum and minimum angle.
Here we have used a sine wave to demonstrate smooth cyclic behaviour of the
moving joint.
The double joint is no more than an extension of the fixed joint. As
the above fixed joint model, we supply the first (fixed) joint with the same
constraints. The second joint extends the first joint at its location and
angle are dependent on the first joint's angle (and position) at any point
in time. The double joint inherits the fixed joint.
The buttons in both applets are used to switch on and off the cyclic motion
in the respective joint. This is particularly useful in the double joint
model in demonstrating the second joint's dependency on the first joint's
angle and position.
[James Michel - 20th June 1998 - email:
michel@clara.net ]