534 A. Vemuri et al. Comparison of Assigned Tach Vs. Baysian Estimate Difference between Processed Tach Estimate and Baysian Estimate Percentage Difference between Processed Tach Estimate and Baysian Estimate Instantaneous speed estimate (rpm) Instantaneous speed estimate (rpm) Instantaneous speed estimate (rpm) Time(sec) Time(sec) Time(sec) Time(sec) Assigned Tach Bayesian a c d b 2.5 2 1.5 0.15 0.05 -0.05 0.5 0.1 -0.5 -1.5 -1 -2 0 50 100 150 200 250 0 50 100 150 200 250 0 2000 Raw RPM estimate from Tach signal 1900 1800 1700 1600 1500 1400 2000 1900 1800 1700 1600 1500 1400 1300 50 100 150 200 250 0 50 100 150 200 250 0 0 -0.1 -0.15 -0.2 Percentage difference in RPM (%) 1 Fig. 46.16 6 cylinder engine powertrain—(a) raw estimate, (b) Bayesian estimate vs nth pulse estimate, (c) absolute difference and (d) % difference The comparisons presented show that both the Adaptive nth Pulse and the Bayesian algorithms arrive at similar speed profiles although the processes are independent of each other. Also, the curves always lie within bounds of the raw tachometer estimate and seem to be a better fit to the data than the mathematical spline fit. It should be noted however that there is no way to know the true value of instantaneous speed. As such, no error analysis can be done with respect to the true value. These two methods support each other and provide results that are more physically reasonable than the spline fit approach. For a detailed description of the work presented in this paper, refer to the Master’s thesis from which this paper was extracted [8].
RkJQdWJsaXNoZXIy MTMzNzEzMQ==