Motion controlled cleaning of large tanks

Sammanfattning: Reduction of the cleaning time is an important issue for companies using large tanks. A common solution is a stationary pipe going into the tank with a cleaning nozzle mounted on the end. Today the spray pattern of most cleaning systems is fixed. It would be beneficial to adjust the cleaning cycles so that the most soiled places of the tank get extra attention without increasing the total cleaning time of the tank. This thesis develops and implements an algorithm for an arbitrary cleaning pattern for a tank with the shape of a cylinder. By using two asynchronous motors, one connected to each axis, the cleaning nozzle can move independently both horizontally and vertically. Feedback is obtained from two incremental encoders, for positioning and speed, and two inductive sensors used to identify the position of the nozzle at start (homing). A Human Machine Interface (HMI) is used for basic control and monitoring of the process. The main focus has been on developing the algorithm but major time has also been spent on getting the hardware to function together to enable testing. By introducing a coordinate system and converting the coordinates, given by the user, to motor positions it is possible to create a pattern of cleaning points. Varying the output signals to the motors it is possible for both motors to reach the point simultaneously and keep a constant peripheral velocity of the jet beam. Tests were carried out on a test stand without cleaning fluid.