Fusion of brake pedal sensors in by-wire cars: A fuzzy logic approach

By-wire braking is one of the important parts in a by-wire car from safety point of view. Because of safety critical issues, brake pedal is equipped with multiple sensors and their data must be properly fused. In addition to accuracy and robustness, mathematical complexity and computational load of the fusion method are also considered in this application. In this paper, a soft voting method is presented that uses fuzzy rule-base decision making. The fusion output is a weighted average of three sensory signals where the weights are calculated from a set of fuzzy rules. While there are only some piece-wise linear calculations in the proposed method, our experimental results show that the performance of the proposed voting method is desirable in presence of short circuits to ground or supply voltage, considerable SNR and sensor drifts. Voting error (in terms of MSE) is reduced by 82% by soft voting method, compared to simple majority (hard) voting.