The Development Of Automotive Smart Step Controller

Automotive Smart Step Controller was designed for the personalizationfeatures of the high chassis SUV in the car market. The controller was used toachieve the auto movement of the step which was installed under the car’s door, forthe convenience of passengers climbing on and off. The controller was designed as amass production, so that the stability, user experience and fabrication cost were keyconsiderations.Decorative lamp, remote switch were set to improve the user experience.Controller’s hardware was consisted of signal input unit, control unit, execution unitand power unit. PIC18F series with CAN controller was used, supporting for thecompatibility with many cars and product upgrade.The main problems were the car’s door signal detecting and step motiondetecting, and both solved with hardware and software. The fore problem was solvedwith hardware while the back one was solved by measuring the current of DC-motorwhich was used for driving the steps.For the current of DC-motor changes with the resistance on the step, EWMAalgorithm was used to predict the current so that the state of reaching the right placeand the state of meeting obstacles of the step were detected in the shortest time,avoiding the DC-motor’s long time locked-rotor and the possibly injure to bodies.The controller’s safety performance was improved.Then the stability was considered with ISO/TS16949. Necessary experimentswas carried out, such as temperature experiment, voltage experiment, etc. Workingperformance was guaranteed with poor environment.