Hydraulic metering mode transitioning technique for a velocity based control system

摘要

The flow of fluid to a hydraulic actuator is controlled by a valve assembly which operates in different metering modes at various points in time for energy conservation. The metering mode to use is selected in response to the hydraulic load acting on the hydraulic actuator. Specifically, the present magnitude of hydraulic load is determined and compared to first and second thresholds. Below the first threshold only a first metering mode is activated, and only a second metering mode is activated above the second threshold. A combination of the first and second metering modes is utilized when the hydraulic load is between those thresholds, wherein the metering modes are used in proportion to a proportional relationship of the hydraulic load to the first and second thresholds. Using a metering mode combination in this manner smoothes transitions between the first and second metering modes.