Tall buildings lose a big part of their expensive space to elevator shafts. A ropeless elevator reduces the amount of shafts, because multiple cabins are able to move in the same shaft. Currently an elevator using a row of linear motors along the shaft is in the end phase of development. Tests on a full scale prototype 5 have proven the concept. However vibrations in the current concept are over ten times higher than those in traditional elevators, resulting in an uncomfortable ride. Actuators are placed over the length of the shaft, each one of them operating independently from its neighbors. Every single actuator contains its own position sensor, which was specifically designed for this application. With the measured position every actuator can apply a feedback force on top of 10 the feed forward force. In theory a smooth vibration free ride is possible, but yet for unknown reasons vibrations exist. The first objective of this research is to investigate the sources of vibration. With the knowledge obtained in this investigation, improvements are proposed and worked out. The final goal is to improve the comfort to an internationally accepted level.
15 Causes of vibrations are found. The dominant factors are the position sensor, the magnet yoke and the control algorithm. All position sensors will be calibrated, the tolerances of the magnet yoke can be compensated using a correction model and the controller is improved to fit the needs of the distributed actuation. The comfort is increased by a more than a factor ten, which brings it to a level equal to that of traditional elevators.