Control strategy for reducing boom oscillation

Abstract

A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic cylinder (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic cylinder, and a second chamber (118, 116) of the hydraulic cylinder may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The method may include measuring first pressure ripples at the second chamber and reducing a magnitude of second pressure ripples at the first chamber. The pressure ripples may be transformed into a flow command by multiplying the pressure ripples by a gain and/or phase shifting. The gain and/or the phase shifting may be adjusted by feedback. The feedback may include the second pressure ripples at the load holding chamber, a position of the hydraulic actuator, and/or an operator input. A reference signal may be filtered with a moving average filter.

Dependencies are inferred from the claim text.