Velocity control of a washing machine: a mechatronic approach

A mechatronic analysis of the velocity control loop of a washing machine is presented in this paper. The aim is to characterise how the control performance is influenced by each mechanical, electrical and control components. A model of the machine including a description of the electrical aspects involved in the torque generation, as well as the transmission chain, the load, the spring–damper system connecting the tub to the cabinet, and the velocity estimator, is discussed. Simple experimental procedures to identify the main mechanical parameters of the machine are presented and the accuracy of the model is demonstrated through validation experiments. The model is then exploited to analyse the behaviour of the machine at the stability limit and to propose a modification in the mechanical design, in order to simplify the tuning procedure