A new adaptive vibration control of magnetorheological damper system and its application to washing machine

Abstract

Some undamped vibrations may cause undesirable behavior such as noise, overloads, excessive displacements, and early fatigue failures in the mechanical systems. Active vibration control is crucial for some of the mechanical systems such as washing machines. This article proposes a new vibration control strategy (VCS) for reduction of vibrations in washing machine. VCS utilizes adaptive nonlinear terminal sliding mode control (NTSMC) of double coil shear mode magnetorheological (MR) dampers and DC-DC buck converter. To achieve this goal, a control mechanism was designed that consists of two loops.The first loop implemented a force feedback control using proportional integral (PI) control and load cells. The second loop consists of adaptive NTSMC that was applied on buck converter to control current flow in MR dampers.The control law and finite convergence time to the equilibrium point were guaranteed for the current error using NTSMC. Moreover, an adaptive law was incorporated in NTSMC for the dynamic current control of MR dampers. The stability analysis of adaptive NTSMC was carried out using Lyapunov stability theory. An experimental setup was established for VCS that helps to study the performance of washing machine. A comparative analysis is presented for VCS with the passive dampers and other vibration control techniques that are reported in literature for washing machines.

Bidisperse magnetorheological fluids with strong magnetorheological response, long-term stability and excellent in-use performance

“…Two MR dampers were manufactured and further tested in the washing machine at the Manufacturing and Automation Research Center, Koç University. The vibration patterns and noise levels of the washing machine were demonstrated in our previous work [67,68], however, the details of damping force at different values of electric current for various synthesized MRF samples are provided here.…”

“…In addition to that, the hysteresis curves of force versus velocity and force versus displacement of one of MRF samples (MRF-5) are shown in the figures 14(a) and (b) which are the part of a previously published article by our research group [67]. It is important to mention that the characteristics of MR damper were analyzed by using one of our best MRF sample (MRF-5) and the experimental setup given in figure 13.…”

“…The linear actuator was given a sinusoidal signal of amplitude of 5 mm and frequency of 1 Hz. The hysteresis behavior of of MR damper was recorded at 0.6 A due to the high area value of hysteresis loop [67]. Keeping in view the aforementioned characteristics of MRF 5 sample, it has comparable MR properties to the commercial one with significantly lower content of the micronsized particles, and with better shelf-life and, equally important, a lifetime in use due to the improved sedimentation resistance thanks to SPION-PAA.…”