Research On Magnetic Analysis And Circuit Design Of The Automotive Shitf

With the development of Automatic Transmission (AT) and the automotiveelectronic technology, Automotive Shift of electromagnetic induction is replacing thetraditional mechanical lever Shift gradually. Compare with the way of traditionalmechanical shift, the Automotive Shift determines its gear by the outputs of Hallsensors which are depended on position of permanent magnet, so it can avoid theserious consequence due to mechanical wear. The Automotive Shift has manyadvantages such as easy operation, safe and comfortable, strong security etc. Also, itcan prevent the damage of automatic transmission caused by the driver’s misoperationand correct the driver’s bad habit of gearing shift so as to protect the transmissionbetter.The basic principle of electromagnetic induction Automotive Shift is that apermanent magnet is installed under the shift lever. Meanwhile, a circuit board withseveral Hall components is designed to induct of permanent magnet magnetic fluxdensity. When driver shifts gears, the position of magnet will be changed, anddifferent Hall components on the circuit will be induced; then the circuit willautomatically send a signal to the Transmission Control Module of the automobile tochange the gears according to the operation intention of the driver. So during thedesign process, the layout of Hall sensor is of great importance. The key to designAutomotive Shift is how to calculate the magnetic fields in the space of any pointcreated by permanent magnet.The most common magnetic which is an axial magnetized cylindrical permanentmagnet of electromagnetic induction Automotive Shift is taken into account in thispaper. The magnetic flux density distribution model is established using numericalanalysis method which is based on Colombian’s model. This method can calculate themagnetic fields of any point created by magnet of different position. A kind ofAutomotive Shift magnetic fields simulation software is designed combined with thefeatures of Hall switch sensor. This software is to draw the trigger area on the circuitboard due to different position of permanent intuitively and provide the decisionsupport to determine the distribution of Hall Sensors. So it can save a lot of time andmoney. Finally, an Automotive Shift System of manual/automotive is designed in thispaper. The Shift contains a total of six gears, and the microcontroller PIC16F677isselected to collect the different Hall sensors’ output to be encoded with the communication protocol. The sensor A1121of Allegro is used to realize the signalcollection function. At the same time, the magnetic fields simulation software is usedto analyze the trigger area in order to get the effective layout of Hall sensors whichcan be the guarantee of shifting gears accurately. The software testing and physicaltesting can verify the correctness of the magnetic fields model, the effectiveness ofthe magnetic fields simulation software and the reliability of the system in this paper.