Abstract
A position control system with a small velocity input often shows a jerky output response, which is usually called a “jerking motion” or a “stick-slip motion”. This phenomenon has been studied by several authors, and has been explained that it is induced by the negative slope characteristic of the friction in a lower speed range. But the friction characteristic in such a speed has not been well defined, and it seems that a quantitative investigation for this phenomenon has not been made.
On the other hand, the position control system, which has the torque varying with angular position, often shows a jerky output response with respect to a small velocity input, too. In this paper, such a phenomenon is regarded as the jerking motion, and the limiting conditions of the jerking motion are investigated by computer simulation.
As a result, it becomes clear that the limiting conditions of the jerking motion are shown with complicated curves of the system parameters, and that, with respect to the magnitude of the velocity inputs, there may be a number of ranges where the jerking motion is induced. These results are remarkably different from the usual results. In order to confirm these results, a position control servo model is experimented. The experimental results agreee very well with the simulation results.
