Precision repositioning of the balancing ball in an auto-balancer system via a fuzzy speed regulator equipped with a sliding-mode observer

An intelligent fuzzy rotor speed-regulator is developed to reposition the balancing ball inside an automatic balancer system (ABS) to its desired location. This repositioning is designed and activated to remedy the commonly-seen mis-positionings of the rolling ball inside ABS, which is caused by an inevitable rolling friction moment of the rolling ball in contact with its race, leading to large, undesired radial vibrations. The repositioning is accomplished by essentially generating required circumferential inertial force on the ball to suppress the rolling friction. For preliminary feasibility, the case of a single ball is considered. The first step is to establish the dynamic model of the system, which is followed by the analysis to ensure stability of the desired ball equilibrium position. The second step is to forge a sliding-mode observer for estimating online position and velocity of the ball, which are offered to the fuzzy speed-regulator as inputs. The fuzzy speed regulator is then synthesized by three parts: fuzzification of inputs/output, the rule table, and a reference engine accompanied by defuzzification. Finally, an incremental speed-adjustment scheme is designed in order for the spindle to reach target operating speed, while retaining the ball at the desired position. Simulations and experiments are conducted to demonstrate the effectiveness of the proposed fuzzy ball-repositioning scheme.