Deriving an Empirical Model of an Electrohydraulic Actuator System from Frequency Response Data

摘要

This report, prepared by the Analytical and Physical Simulation Branch of the Tank-Automotive Technology Directorate, describes an empirical approach to modeling the hydraulic/actuator portion of a physical simulation system. A frequency response curve fit technique is applied to measure actuator responses. The curve fit technique will not produce a general analytical model but will provide an empirical model which should incorporate the system's performance characteristics for many types of analyses. The objective of this study is to define a means of predicting the validity and fidelity of physical simulation testing before actual laboratory test runs are made. In the past, the hydraulic/actuator system was assumed to be ideal where the actuator responds perfectly to the desired command signal. Motions were directly predicted from the command signals or the source from which the command signals were derived, but these prediction techniques did not account for the performance capabilities of the hydraulic/actuator system. The process used in the past gave inaccurate predictions of accelerations for simulation tests which contained high-frequency components (i.e., frequencies beyond the system's bandwidth). Keywords: Trucks, 5-Ton truck. (aw)