Study On Active Balancing Method Of A Vertical Axis Washing Machine

The passive balance technology is often used to suppress the vibration of the vertical axis washing machine,but it has no effect or even increases the vibration of the system near the critical speed and below.The improvement of people’s living standard and quality puts forward higher requirements for washing machine vibration,and the conventional passive balance technology is difficult to meet.With the development of active balance technology,the active balance technology of washing machine has become the latest development trend.Therefore,a new active balance structure of vertical axis washing machine is proposed.The mechanism of vibration suppression is deeply explored.A new physical prototype structure is processed and manufactured,and the vibration suppression effect is verified by experiments.The details include:Firstly,the main structure of washing machine is classified,the kinetic energy expression of rigid bodies of different types of structures is derived,the total potential energy and generalized suspension force model of the system are analyzed,and the vibration model of vertical axis washing machine is established by Lagrange equation.In order to determine the key parameters in the dynamic model,the actual physical prototype is tested,and its steady amplitude is measured.The reasonable model parameters are determined by comparing with the simulation results.Secondly,in order to detect the eccentric phase and amplitude information required by active balancing,the sensor scheme of phase zero and displacement detection is analyzed,and the hall switch and Hall displacement sensor are selected to detect the zero and vibration displacement respectively;the influence of magnet width and sensor height on the output signal amplitude of Hall displacement sensor is analyzed through the magnetic field simulation model established by COMSOL Finally,the peak method,FFT,cross-correlation and other phase and amplitude detection methods are analyzed,and the cross-correlation method is determined as the final phase and amplitude detection method through experimental comparison.Then,a new type of active balance structure of the vertical axis washing machine is designed,and the common water is used as the balance quality to suppress the active vibration.The structure of water inlet,water storage and drainage is designed,and its working principle is expounded.The paper analyzes the influence of the key parameters such as the axial damping coefficient,the damping coefficient of the suspender ball hinge,the spring stiffness,the eccentric height and the eccentric mass on the dynamic performance of the active balance structure of the washing machine.Then,based on the simulation analysis of washing machine active balance at different speeds,the active balance control algorithm is determined.The multi speed point balance strategy is adopted.The water spray quantity is decomposed by vibration displacement and phase,and the water spray correction angle and stop condition are determined at different speed points,and the process of active balancing is simulated under different working conditions.Finally,the active balance physical prototype of the vertical axis washing machine is made,and the active balance MCU control system is developed.The active balance algorithm is developed,including the detection of eccentricity and active balance control.The active balancing experiments were carried out in two cases: fixed eccentric block and wet clothes.