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Model Based Controller Design for Position Control of Servo Controlled Hydraulic Actuator against Air Entrainment

Shilpesh M. Gupte, S M. Kulkarni, Mukesh Prasad


Position control is important for numerous industrial and aircraft applications. Electro-hydraulic actuators are used for position control for advantages they provide over other actuation systems. The hydraulic fluid used for actuation, though desired to be incompressible, has some compressibility in practice. Entrainment of air in the fluid increases compressibility effect by reducing the effective bulk modulus. Reduced bulk modulus makes position control difficult. The paper studies the effect of effective bulk modulus on system stability using the root locus approach. Thereafter, a model based controller has been designed to ensure stability and meet design requirements, even in case of practically high values of air entrainment


Position control, air entrainment, effective bulk modulus, model based controller design; stability analysis

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