Identifieringsmöjligheter av feljusterad bussdörr : - Studie av möjliga signalanalyser av dörrpositioner för att finna dörrar som kan orsaka problem

Sammanfattning: In the bus industry, it is well-known that bus doors often cause buses to stand at a stop after either a door could not be opened or closed. This causes huge costs for the bus owner. Therefore, it is desirable to be able to predict whether a door's behaviour begins to become too close to causing such an event. Based on this background, this study has been completed at Scania CV AB in Södertälje in order to find out which signals from a door system that can be used to determine if a door is at risk of failing. The main problems that this study is based on are: - Which existing sensors can be used to measure the most common errors before causing a bus that cannot drive? - Is it possible to find a model that can indicate how to adjust speed and attenuation to get a "perfect" adjusted door? These questions were studied by making measurements on a Scania City Wide bus with double inswing door leafs where measurements were made only on the rear door leaf and for its closing behaviour. To make measurements on the door an oscilloscope was used which measured the voltage across a potentiometer with a voltage that varied depending on how open the door was. Another measurement was made on the embedded control system in the bus body. The noise-corrupted measurement data was filtered with a simple type of filter, called moving average filter. In order to find different methods that predict if there were any errors on the door's settings or components, curves were examined over the doors' position during a closing event. One thing that was studied was which position value that was present when the door couldn’t get closed more. Another thing was the curve's slope in different segments of the closing. The slope of the curve was calculated by using the least squares method, which is a mathematical method in linear algebra. Based on the slope in some curve segments of a closing event, a model was created that could guess the door closing time as well as the damping. This model functioned in a convincing way for measurements from the test bus that was used when developing the model. Other models that the study resulted in was one that could warn if the potentiometer values began to approach a limit when the door could no longer be closed, as well as a model that calculated the closing and opening times of the door. Through these models, the idea was that a warning signal could be sent to a system that warned that the door should be adjusted. When some measurements for the guess model were made on another bus, it gave indications that the model did not work as well as the test bus. But one conclusion that could be drawn was that there was an indication that the door was misaligned, even though the model guessed wrong for the present settings. Another conclusion was that it is likely possible to proceed further with some research on this model to find a new model that is somewhat more general for all individual bus doors.