Hybrid adaptive control of intelligent structures with simultaneous precision positioning and vibration suppression

Author(s):  
Kougen Ma ◽  
Saeid Pourjalali ◽  
Mehrdad N. Ghasemi-Nejhad
2003 ◽  
Vol 9 (11) ◽  
pp. 1285-1302
Author(s):  
Kougen Ma ◽  
J Melcher

In this paper we focus on the adaptive control of structural acoustics using intelligent structures with embedded piezoelectric (PZT) patches and low cost digital signal processor systems. After a discussion on the adaptive feedforward control scheme, a hybrid adaptive control scheme is proposed, which takes advantage of both feedback control and adaptive feedforward control. The two schemes are realized on a low-cost, small volume, convenient and universal digital signal processing (DSP) board. A carbon fiber reinforced polymer plate with two embedded PZT patches is developed and used in two experiments. The first experiment is adaptive interior noise control using the intelligent plate, in which the adaptive feedforward control scheme is employed. Obvious noise reduction is obtained for constant frequency, swept frequency and varying amplitude harmonic disturbances. The second experiment is adaptive control of sound-induced vibration of the plate, where two embedded PZT patches are used as an actuator and a sensor, respectively, and the hybrid adaptive controller is applied. The full vibration reduction for various harmonic excitations is obtained, verifying the advantage of the hybrid adaptive control. It is demonstrated that active control of structural acoustics can be efficiently achieved by employing intelligent structures, advanced adaptive control schemes and the low-cost DSP board.


1999 ◽  
Author(s):  
Hans Kurt Tönshoff ◽  
Stephan Scherger ◽  
Helmut Hinkenhuis

Abstract Conventional process control in noncircular grinding requires high efforts concerning adjustment and optimization. The increasing demands on multi-product-ability as well as small lot sizes or single piece production do no longer allow these efforts. Furthermore, process relevant information like normal or tangential forces is not monitored, consequently there is no possibility for process quality control to support a constant workpiece quality. This article introduces a hybrid adaptive control which consists of three components: The contour pre-filtering unit converts the contour data into a nominal value curve that is twice differentiable. Limited dynamic ranges of the drives, especially at high rates of workpiece rotations, are considered in the predictive feeddrive position control unit. The normal force control unit keeps the swelling of the machine at a constant value and therefore improves the dimensional accuracy of noncircular workpieces like e.g. cams. The hybrid adaptive control dramatically reduces the setup time of the process and results in improved workpiece quality.


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