Feedforward controlof electrical drives - rulesand limits

Abstract

Nowadays, there are several application in the field of position controlled electric drives, such as high speed cutting, where traditional cascade control structures provide insufficient accuracy. Therefore, it is necessary either to completely change the control structure (e.g. sliding mode control) or to modify and extend the basic cascade structure. One of those modifications can be feedforward direct branches. Feedforward increase order of astatism without stability influencing but on the other hand it brings other problems regarding to the feedforward technique implementation, system parameters changing or neglecting particular system behavior. This paper describes basic control structures, their features and several mentioned problems related to feedforward control of electric drives.