Washing machine velocity control

Project abstract

The drum of a washing machine is actuated by an electrical motor, usually an induction one. Such a motor is usually equipped with position transducers characterized by a very low precision. The goal of the control system is to guarantee that the velocities required for washing, distribution, and spinning, are reached within a prescribed time frame, and kept with an acceptable error. The performance of the velocity control must be guaranteed independently of:

• amount and type of clothes contained in the drum;
• amount of water loaded and/or absorbed by the clothes;
• position of the clothes within the drum;
• temperature of the water during washing;
• ware of mechanical parts.

The project has been carried out in cooperation with Fondazione Politecnico and Indesit Company. It aimed at elaborating procedures for tuning the velocity controller that are both simple and rational, and allow to maximize performance independently of the operating conditions. In the Systems and Control Laboratory at DEI (now DEIB) some experimental test-beds have been setup, composed of suitably instrumented washing machines and induction motors.