Sensitivity Analysis and Characteristics Study of Area-Pressure-Difference Composite Regulated Flow Control Systems

Industrial automation demands increasingly high performance from hydraulic control systems. However, the key nonlinear factors within these systems significantly affect their control characteristics throughout the operating cycle. Traditional bond graph analysis focuses on the system’s dynamic response, but lacks efficient and systematic methods to evaluate how parameter variations influence performance. Although sensitivity analysis can assess these influences, it relies heavily on state-space equations, which involve complex modeling, offer limited physical intuition, and are prone to derivation errors that are difficult to verify. Therefore, this study focuses on an area-pressure difference composite flow control system and proposes a novel integration of power bond graph-based state-space modeling with first-order trajectory sensitivity analysis. A comprehensive sensitivity equation system with 21 parameters was established, and a dual-sensitivity evaluation metric was introduced for quantitative analysis. Quantitative analysis confirmed that the flow force dominated the fluctuations in the main valve pressure difference, with negligible effects from the spring force. The hydraulic resistance of the non-spring chamber orifice, spool equivalent mass, and throttle equivalent flow area significantly affected the compensator spool momentum. Further research indicates that increasing the hydraulic resistance of the damping orifice effectively suppresses spool momentum fluctuations, although hysteresis effects must be considered. Experimentally, flow-force compensation reduced the flow error by 4%, validating its role as the primary cause of the pressure difference variations. This research holds significant engineering application value for optimizing control strategies and improving dynamic response performance to enhance the flow control accuracy of the system.