Patent attributes
A method for adapting a closing boundary for a proportional spool valve includes generating or detecting a pressure command signal. Next a pressure error is obtained by subtracting an actual wheel brake pressure from its pressure command. Then a modified pressure error is calculated a modified pressure error is calculated in such a way that steady state pressure errors resulting from mismatched feedforward term, control deadzone and other factors are subtracted from measured pressure error to leave the only error to be that due to boundary deviation. An estimator is then used to estimate an apply boundary deviation or a release boundary deviation of the spool valve, as appropriate. A boundary table is updated using the resultant boundary deviation estimate.
