Model-based Wheel Speed acquistion by interrupt capture method for integrated stability control

A key technological feature of automotive active safety systems is the accurate and instantaneous calculation of the Wheel Speed and Wheel angular Acceleration or Deceleration. Accurate and fast measurements are critical for the functionality of the active safety systems, irrespective of the control logic used to realize the control function. The accurate estimation of critical vehicle dynamic states such as Vehicle Speed, Vehicle Acceleration or Deceleration, Vehicle Longitudinal Force, Wheel Load, Road Friction Coefficient and Vehicle Yaw Rate depend on the accurate acquisition of the Wheel Speed This paper presents a novel model-based method for Wheel Speed acquisition based on interrupt capture. This method assures accuracy at high and low speed and the real-time performance at low speed. The hardware interrupts are generated for every rising and falling edges of Hall effect Wheel Speed Sensor, and are used to trigger an Interrupt Service Routine that implements a time capture algorithm. This method ensures that Hall effect sensor pulses are not missed hence provides accurate measured values compared to conventional Input capture methods based on either rising or falling edges. The paper also provides the results of above strategy from MIL and Vehicle tests.