The Design Of Direct Tire Pressure Monitoring System With Auto-Localization Feature

Nowadays, vehicle has become one of the most important parts in people's daily life and the safety is becoming more focus. Tire is one of the key components through all whose safety is also the main focus. How to make sure the tire is under normal working conditions, how to let the driver know everything about tire. With the rapid development of automotive electronics, TMPS helps us solve the above problems. TPMS is used to monitor the status of tire, when NG, it will inform drive to repair or stop using. It's very important for us to design a real time and accurate TMPS.This article did an investigation on the background of TPMS, get to know the regulation and function requirement of different country.By analyzing the two different TPMS(direct and indirect), points out the advantages and disadvantages.Taking direct TPMS as the design topic,design the whole system conforming to the requirement of regulation.Direct TMPS is using the tire sensor which attached on the tire to gather the info including pressure, temperature, tire speed, by sending the data through the RF channel to the receiver in car.After analyzing the date, judge whether it's under normal status or not.The tire sensor is designed basing on freescale MPXY8300, data collecting is performaed by IC, software is in charge of data transfer, IC work mode switch. The main focus is on how to balance the data collecting, real time sending and lower the power consumption. The sensor also has low frequency wake up function.The receiver is mainly desined base on micro-controller with RF and LF communication interface, also with CAN communiation. Accord to the upper application protocol, pick up the tire information on real time, analize receiving data and judge tire work status. Receiver also implements data transfering between RF and CAN network. LF uses to wake-up and configurate tire sensors, schedules every sensor when it starts running, creates the association for every sensor and receiver with different IDs. So the location on car of sensor can be recognized by receiver.After testing, this direct TPMS can measure the tire pressure with high accuracy, fast data analysis and alert to driver within short time while abnormal case happens. The sensor consumption is satisfied with regulation strictly and receiver can recognize the four tires automatically. So this design can fulfill system requirement.