An adaptive fuzzy sliding-mode controller for servomechanism disturbance rejection

A two-level spring-lumped mass servomechanism system was constructed for di sturbance rejection control investigation. This dynamic absorber is similar to a model of the serial-type vehicle suspension system. The lower level i s actuated by two dc servo motors, to provide the specified internal and ex ternal disturbances to the vibration control system. The upper level has an other dc servo motor to control the main body balancing position. In order to tackle the system's nonlinear and time-varying characteristics, an adapt ive fuzzy sliding-mode controller is proposed to suppress the main mass pos ition variation due to external disturbance. This intelligent control strat egy combines an adaptive rule with fuzzy and sliding-mode control technolog ies. It has online learning ability for responding to the system's time-var ying and nonlinear uncertainty behaviors, and for adjusting the control rul es and parameters. Only seven rules are required for this control system, a nd its control rules can be established and modified continuously by online learning. The experimental results show that this intelligent control appr oach effectively suppresses the vibration amplitude of the body, with respe ct to the external disturbance.