Adaptive positive-position feedback controller design for the vibration suppression of smart structures

Author(s):  
Moon K. Kwak ◽  
Seok Heo ◽  
Gil-Joo Jin
2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Ehsan Omidi ◽  
S. Nima Mahmoodi

This paper develops H2 modified positive position feedback (H2-MPPF) and H∞-MPPF controllers for spatial vibration suppression of flexible structures in multimode condition. Resonant vibrations in a clamped–clamped (c–c) and a cantilever beam are aimed to be spatially suppressed using minimum number of piezoelectric patches. These two types of beams are selected since they are more frequently used in macro- and microscale structures. The shape functions of the beams are extracted using the assumed-modes approach. Then, they are implemented in the controller design via spatial H2 and H∞ norms. The controllers are then evaluated experimentally. Vibrations of multiple points on the beams are concurrently measured using a laser vibrometer. According to the results of the c–c beam, vibration amplitude is reduced to less than half for the entire beam using both H2- and H∞-MPPF controllers. For the cantilever beam, vibration amplitude is suppressed to a higher level using the H2-MPPF controller compared to the H∞-MPPF method. Results show that the designed controllers can effectively use one piezoelectric actuator to efficiently perform spatial vibration control on the entire length of the beams with different boundary conditions.


Author(s):  
H. Gu ◽  
G. Song

Positive position feedback (PPF) control is widely used in active vibration control of flexible structures. To ensure the vibration is quickly suppressed, a large PPF scalar gain is often applied in a PPF controller. However, PPF control with a large scalar gain causes initial overshoot, which is undesirable in many situations. In this paper, a fuzzy gain tuner is proposed to tune the gain in the positive position feedback control to reduce the initial overshoot while still maintaining a quick vibration suppression. The fuzzy system is trained by the desired input-output data sets by batch least squares algorithm so that the trained fuzzy system can behave like the training data. A 3.35 meter long I-beam with piezoceramic patch sensors and actuators is used as the experimental object. The experiments include the standard PPF control, standard PPF control with traditional fuzzy gain tuning, and PPF control with batch least squares fuzzy gain tuning. Experimental results clearly demonstrate that PPF control with batch least squares fuzzy gain tuner behaves much better than the other two in terms of successfully reducing the initial overshoot and quickly suppressing vibration.


Author(s):  
Mehmet R. Simsek ◽  
Onur Bilgen

A control strategy called hybrid position feedback control is applied to a bistable system to prevent multiple crossovers during actuation from one stable equilibrium to the other. The hybrid controller is based on a conventional positive position feedback controller. The controller uses the inertial properties of the structure around the stable positions to achieve large displacements by destabilizing a positive position feedback controller. Once the unstable equilibrium is reached, the controller is stabilized to converge to the target stable equilibrium. The bistable system under harmonic excitation and hybrid controller are investigated for its behavior. In addition, energy analysis of the system controlled by the hybrid controller is investigated using numerical time domain methods. The energy variance by parameters and the comparison between the open-loop system with harmonic excitation and the controlled system is investigated.


Author(s):  
Ehsan Omidi ◽  
S. Nima Mahmoodi

One of the predominant difficulties in the theory of distributed structure control systems comes from the fact that these resonant structures have a large number of active modes in the working band-width. Among the different methods for vibration control, Positive Position Feedback (PPF) is of interest, which uses piezoelectric actuation to overcome the vibration as a collocated controller. Modified Positive Position Feedback (MPPF) is later presented by adding a first-order damping compensator to the conventional second-order compensator, to have a better performance for steady-state and transient disturbances. In this paper, Multivariable Modified Positive Position Feedback (MMPPF) is presented to suppress the unwanted resonant vibrations in the structure. This approach benefits the advantages of MPPF, while it controls larger number vibration modes. An optimization method is introduced, consisting of a cost function that is minimized in the area of the stability of the system. LQR problem is also used to optimize the controller performance by optimized gain selection. It is shown that the LQR-optimized MMPPF controller provides vibration suppression in more efficiently manner.


2020 ◽  
Vol 26 (15-16) ◽  
pp. 1155-1164 ◽  
Author(s):  
Ahmad Paknejad ◽  
Gouying Zhao ◽  
Michel Osée ◽  
Arnaud Deraemaeker ◽  
Frédéric Robert ◽  
...  

Positive position feedback is an attractive control law for the control of plants having no high frequency roll-off. The tuning of the parameters of the positive position feedback to obtain the desired closed-loop performance is quite challenging. This paper presents a technique to design the positive position feedback controller with the optimal damping. The technique is demonstrated on a single degree-of-freedom system. The poles of the positive position feedback are tuned using the method of maximum damping, which states that the maximum damping is achieved when both closed-loop poles of the system are merged. The parameters of the positive position feedback are dependent on the desired target damping in the closed-loop system. However, arbitrary choice of target damping results in high response at the frequencies lower than the tuning frequency. The optimal value of the target damping is obtained by minimizing the [Formula: see text] norm of the closed-loop transfer function of the system. The influence of the various parameters of the positive position feedback on the closed-loop response of the system is also studied. Finally, the experiments are conducted to verify the effectiveness of the proposed technique.


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