Towards modelling of washing machines with semi-active vibration damping

Abstract

Minimizing vibrations is very much about understanding why and when damping is needed. Important is also to know just how much damping a system needs. Damping excessively or not enough will produce either massive vibrations or big machine breaking movements. This knowledge is put into practice in this thesis. A washing machine is the biggest source of vibrations in almost every household. The struts of a Cylinda washing machine have been investigated extensively and the machine as a whole have been experimentally analyzed and implemented in a computer model using MSC.ADAMS and Matlab/Simulink. Although it was not easy to implement a washing machine's full behaviour in a computerized model some possible improvements have indeed been found using optimization techniques. Smart damping using magnetorheological technology has been shown in this thesis as one possible solution. Smart damping in this case means to damp at the right time with just the right amount of force. Using this technology the vibrations were reduced with about 66% during a 30 second spin up. Furthermore the mounting angles of the struts, springs and rubber bushings have been shown to be future subjects for optimization.