دانلود رایگان مقاله انگلیسی طراحی و کنترل یک دمپر الکترومغناطیسی هیبریدی خودتنظیم - الزویر 2018

abstract

In this paper, the characteristics of a hybrid regenerative electromagnetic (EM) damper are first determined and experimentally examined. The main idea is to have two modes of operation for the EM damper, namely passive energy harvesting and semi-active modes. In the passive mode, the vibrational energy of an underlying structure is harvested and stored in a rechargeable battery. The harvested energy can then be employed in the semi-active control mode to supply the power demand for the required sensors and microcontroller. This hybrid damper would thus be capable of realizing the characteristics of a selfpowered EM damper. A prototype of the damper was designed and tested under different harmonic excitations. The mechanical and electrical characteristics of both passive and semi-active modes were investigated and verified. The average harvested power and current were measured, and the efficiency of the different elements of the damper is determined. Next, for tuning the semi-active mode, a sliding mode control algorithm was proposed which considers the inherent nonlinear parasitic force of the EM damper. The proposed algorithm aims to track the response of an optimally controlled structure, by having knowledge of the bound of the nonlinear parasitic force. Finally, the effects of the proposed damper and sliding mode controller for vibration mitigation of a small-scale structure is demonstrated through a series of shake table tests, under harmonic and random excitations.

 Conclusions

Prototyping and experimental characterization were performed for a novel hybrid EM damper. This damper was designed to switch between a passive energy harvesting mode and a semi-active control mode depending on the amount of energy harvested and stored in the battery. Under harmonic excitation, the passive energy harvesting mode exhibited an actual average resistance close to the theoretical value. It is shown that the average efficiency of the passive energy harvesting mode is around 30%. In the semi-active case, a detailed explanation of the operation of the circuit was given, and the tuning range of the semi-active mode was experimentally verified. A sliding mode based controller was developed to address the effect of the nonlinear parasitic force appearing in addition to the electromagnetic force. Finally, the prototype of the damper along with the control algorithm were examined in a laboratory setting, for vibration control of a small-scale shear frame structure. It is shown that the passive energy harvesting mode was able to increase the equivalent structural damping ratio of the model up to 6%. For the semi-active mode, the displacement response of the model under random band-limited Gaussian noise is presented. It is demonstrated that the sliding mode based controller could track the response of a closed-loop optimal system despite the effect of the nonlinear parasitic force. In order to have a full picture of the damper's performance, both modes were compared with the uncontrolled and open-circuit cases. Using a sine sweep excitation, the advantage of the semi-active mode over the other cases was displayed in terms of displacement mitigation. Further studies are needed to investigate the full-scale application of the damper. To scale-up the damper, a larger EM motor with a larger motor constant is necessary. In that case, rotary motors might be more suitable options as they tend to have a smaller coil resistance and are able to generate a larger back-emf.