Very briefly I will introduce the topic and then take a look at the dynamic equations for feedback controlled robots. We will look at some of the simulation results and then some analytical criteria and conclusions. Chaos means that it is a deterministic, physical and mathematical system whose time history has sensitive dependence on the initial conditions. This occurs in many non-linear systems, a very common example is the so-called Duffing's equation. In the Duffing's equation you can see that the spring has a cubic dependence - it is not a linear spring.

---