Research And Development Of ESC Inertial Measurement Unit

The control principle of ESC is to find out the difference between actualtrajectory and the desired trajectory, then apply brake force on the correspondingwheel, or control the output torque of engine, so that we can adjust the yawingmoment of car, making the car go back to the desired trajectory.Inertial Measurement Unit is an important part of automotive Electronic StabilityControl System, it is used to measure the yawing angular velocity, lateral accelerationand the longitudinal acceleration of a car in driving. The control targets of ESC aremeasured by Inertial Measurement Unit directly or indirectly.The IMU is designed in this paper. The hardware circuit of IMU includs powerregulating circuit, microprocessor peripheral circuit, inertial sensor peripheral circuitand CAN communication module. IMU includs three parts: signal acquisition, signalprocessing and signal transmission. Signal acquisition part selects a digital inertialsensor, which transmite signal through SPI. Signal processing part is used to collecteoriginal signal of inertial sensor and then processing it by wavelet filter. Selecting theparameters suitable for the wavelet transform of inertial units by simulation analysis inMATLAB, and then designing wavelet filter for the inertial measurement unit signal.Signal transmission part is used to transmite signal by CAN communication. Thesoftware program of IMU includes Bootloader and user application program.Test results show that the IMU designed in this paper, can accurately measure theyawing angular velocity, lateral acceleration and the longitudinal acceleration signalof a car in driving, satisfies the requirement of ESC system on the accuracy of theinertial signal.