Anti-Windup Methods for Integrators of Integral Controllers for Robotic Applications

This article categorises three straightforward integral anti-windup methods - Saturating integral accumulator output, Clamping integral accumulator, and a combination of them - to enhance the performance of the integral term of controllers and avoid overshoots caused by integral windups, particularly in robotic applications. These methods decrease overshoots without decreasing the integral gains which result in higher robustness against uncertainties and disturbances. Additionally, a peripheral method for resetting integral accumulators when the error crosses zero is introduced, and its advantages and disadvantages are discussed. Simulations are executed for all these methods for various integral controllers, widely used in industrial and research applications, in different conditions with diverse levels of uncertainty. Their performances are analysed and compared to each other, as well as with situations where these methods are not applied. In various situations with different uncertainties, the Clamping and Hybrid methods demonstrate the best performance with only slight differences between them. Furthermore, when the Reset method is optionally integrated with other methods, enhances the performance in some cases but causes sudden changes in others. Moreover, the implementation of these methods in Simulink Matlab and programming scripts is presented.