Date of Award
Master of Science in Mechanical Engineering and Applied Mechanics
Mechanical Engineering and Applied Mechanics
The modeling and compensation of hysteresis in piezoelectrically driven systems is very important for positioning and vibration compensation applications. A vacuum clamping system for a stationary wood machining center is integrated with a piezoelectric actuator for the purpose of vibration control. This actuator is used to reduce workpiece vibrations through an X-filtered LMS algorithm. The clamping system has an inherent hysteresis effect between input voltage and the output position of the vacuum plate. This hysteresis effect is modeled with two main techniques: the Bouc-Wen and the Classical Preisach models.
The parameters for the Bouc-Wen model were identified using the Optimization Toolbox in Matlab. The parameters were identified from hysteresis curves from the unloaded actuator as well as the loaded actuator. The unloaded actuator parameters were more suitable for feed-forward compensation. Compensation based on these parameters was implemented experimentally, and an average outer loop hysteresis reduction of 30% was observed for input rates of 10, 100, 500, 1000 and 1500 V /s.
The Classical Preisach technique was used to model descending hysteresis curves in the 0 to 10 V input range. The compensation of this model was split into parallel and series inverse implementations. The parallel inverse could reduce outer loop hysteresis by 66% and the series inverse could reduce by 80%. The Classical Preisach model was used to model hysteresis in the offset 4 to 8 V range. The series inverse control used for this case could achieve a reduction in outer loop hysteresis of 77%.
The offset inverse series compensation was used in conjunction with the X-filtered LMS algorithm to test its effectiveness. The hysteresis compensated system could reduce acceleration output amplitude to 10% its original value twice as quickly as the uncompensated system. However, the compensated system could not reduce the amplitude any further, while the uncompensated system could reduce the amplitude down to 3% of its original value.
Anderson, Erik Allen, "Feed-Forwad Hypertensis Compensation for Active Clamping Systems on Wood Machining Centers" (2009). Open Access Master's Theses. Paper 1171.