Increasing the Accuracy of Digital Force Control Process Using the Act-and-Wait Concept

Proportional gains are to be increased in force control processes in order to reduce the force error. However, the control process may become unstable for large gains due to the digital and delay effects. In this paper, the act-and-wait control concept is compared with the traditional, continuous control concept for a digital force control model with proportional feedback subject to a short, one sample unit feedback delay. Both concepts are implemented in an experimental setup. It is shown that the proportional gain can be increased significantly without losing stability when the act-and-wait controller is used; thus, the force error can effectively be decreased this way. The results are confirmed by experiments.