| Magnetorheological (MR) dampers, based on MR fluids, have attractedconsiderable interests and are expected as one of the most prospective semi-activeactuators, as they can provide fast response, controllable damping force, simplestructure, long durability, and low power consumption. MR dampers have been widelyused or studied as shock absorbers and vibration isolation dampers in vehiclesuspensions, medical equipments, civil structures, aircrafts and space vehicles, andweaponry, to guarantee the durability, comfortability, and safety. However, to make fulluse of the adjustable damping characteristics of MR dampers by altering the externalcurrent, the premise lies in that MR dampers integrated into the plant should besemi-actively controlled through accessing the dynamic responses of the plant andfeeding back to the system controller. For the current semi-active systems, the extradynamic sensors are needed to access the dynamic responses of the plant integrated withMR dampers, so that the extra dynamic sensors will not only increase the cost but alsocomplicate the structure, occupy too much installation space, as well as increase theweight. In addition, the reliability of the semi-active systems will be decreased due tothe added dynamic sensors, which may be disturbed or even damaged due to theirexposure to the circumstance. Moreover, the MR dampers, the dynamic sensors, and thesemi-active controllers, as the key elements of the semi-active systems based on MRdampers, should be supplied with extra power source, which will restrict theapplications of the MR dampers based semi-active systems. Therefore, how to simplifythe structure, save the installation space, decrease the application cost, guarantee thereliability of semi-active MR systems is the key factor to determine whether or not MRdampers can be massively applied in industry. To solve these issues has academicsignificance and prospect of engineering applications.Aiming at solving aforementioned problems, this study develops a prototype ofintegrated relative displacement self-sensing magnetorheological damper (IRDSMRD)based on the principle proposed by Wang and Wang (2009) and its electronic system.Sequently, the principle of a self-powered self-sensing magnetorheological damper(SPSSMRD) is proposed and its prototype is developed. Experimental setup based onMTS849shock absorber test system and the real-time simulation system (type: DS1103from the dSPACE GmbH) is established to test the performance of the prototype of the SPSSMRD/IRDSMRD. Based on the experimental results, on one hand, aprinciple based on the Pareto optimization to optimize the performances of the dampingforce and the linearity of the integrated relative displacement sensor (IRDS) is proposed.On the other hand, a single-degree-of-freedom (SDOF) semi-active vibration and shockcontrol system is proposed, established, and investigated.The major research and innovations in this dissertation are summarized as follows:1. The prototypes of the IRDSMRD and the corresponding electronic system toachieve the integrated relative displacement sensing and controllable damping force,including the relative displacement modulator/demodulator, circuit for superposing thecarrier signal for the IRDS on the current from the controllable current driver for thecontrollable damping, and controllable current driver are developed and tested. Thecharacteristics of the developed IRDSMRD, including the linearity, sensitivity, andhysteresis error of the IRDS and the controllable damping force are tested on theestablished experimental setup based on the MTS849shock absorber test system andthe real time simulation system.2. Aiming at self-powering the IRDS and the corresponding electronic system ofthe IRDSMRD based semi-active systems, the principle of a SPSSMRD is proposed andrealized. The characteristics of the developed SPSSMRD, including the energyharvested by the pick-up coil, the relative displacement sensed by the IRDS, and thecontrollable damping force, are modeled and analyzed.3. The established experimental setup based on the MTS849shock absorber testsystem and the real time simulation system is established and the prototype of theSPSSMRD and its electronic system are developed. The characteristics of the developedSPSSMRD, including the energy harvested by the pick-up coil, the relativedisplacement sensed by the IRDS, and the controllable damping force, are tested andanalyzed.4. In order to make the best compromise between the damping force and thelinearity of the IRDS of an SPSSMRD/IRDSMRD, a Pareto optimization based method,which optimizes the key structural parameters by taking the damping force and thelinearity of the IRDS of the SPSSMRD/IRDSMRD as the objective functions, isproposed and realized. The Pareto front, representing the best tradeoff between thedamping force and the linearity of the IRDS of the SPSSMRD/IRDSMRD, is obtainedby considering that the maximum magnetomotive force applied to the exciting coil ofthe SPSSMRD/IRDSMRD is constant. Three SPSSMRDs/IRDSMRDs with different piston modules, which are determined according to the Pareto optimal solutions, aredeveloped and tested.5. According to the experimental results of the SPSSMRD/IRDSMRD, thecharacteristics of the damping force and the IRDS influence each other. In order tostudy whether the SPSSMRD/IRDSMRD can be used for applications to replace the“MR damper plus additional sensor”, a SDOF semi-active systems based on theSPSSMRD/IRDSMRD for vibration and shock control is established. The controleffectiveness of the SDOF systems based on the SPSSMRD/IRDSMRD and the “MRdamper plus additional sensor” for vibration and shock control are investigated,compared and the discussed.The research results in the dissertation have established the theoretical foundationfor simplifying the structure, decreasing the application cost, guaranteeing the reliability,and saving the installation space of semi-active MR systems. Meanwhile, the realizedSPSSMRD/IRDSMRD and its semi-active control system have apparent engineeringprospect. |
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