滚筒洗衣机瞬态脱水振动的分析与控制

为控制滚筒洗衣机瞬态脱水振动,建立了带有磁流变阻尼器的滚筒洗衣机平面振动模型;通过数值求解,分析了脱水过程按指数规律启动时,系统最大振幅随加速时间常数的变化;讨论了不同稳态转速下,系统最大振幅平均值随衣物负载质量和阻尼器控制电流的变化,结果表明:磁流变阻尼器控制电流对系统最佳加速时间常数的影响不大,对于1～9 kg的衣物而言,采用0.7的加速时间常数可取得较好的综合控制效果。此外,为综合考虑悬挂系统的瞬态抑振与稳态隔振,提出一种简单的磁流变阻尼器控制策略:采用短时傅里叶变换追踪盛水桶振动频率,当该频率大于预设的基准频率后,将阻尼器控制电流从最大降为最小以取得较好的隔振效果,最后,通过仿真验证了该策略的有效性。

Vibration Analysis and Control of the Spin-Drying Process of a Horizontal Axis Washing Machine during the Transient Stage

To control vibrations of the spin-drying process of a horizontal axis washing machine during the transient stage, a planner model is built for a horizontal axis washing machine with MR dampers; Numerical simulations considering an acceleration process following an exponential curve is considered, the relation between the maximum vibration amplitude and the time constant of the exponential curve is studied; The average value of the maximum vibration amplitude under several different rotation speeds is calculated, and variations of the average value along with the increase of the mass of the clothes and control current of the MR damper are analyzed, the result shows that the control current of the MR damper has little influence on the optimal time constant, and for clothes with mass between 1 to 9 kilograms, the time constant can be set at 0.7 to achieve a good comprehensive control result. Besides, a simple control strategy of the MR damper considering vibration suppression at the transient stage and vibration isolation at the steady stage is proposed, the short time frontier transform is employed for tracing the vibration frequency of tub, once the frequency grows bigger than a preset value, the control current of the MR turns from the maximum value to the minimum one for vibration isolation, at last, the control effect is proved by numerical simulations.