A mathematical representation of hydraulic servomechanisms

This paper gives a basic representation of a high performance hydraulic servo actuator. The discussion gives a means of calculating the servo gain and rate limit characteristics as functions of the design parameters. Assumptions are discussed that would allow simplification of the equations for their application with computing equipment. Representation of the supply accumulator and pump is included. The effects of equipment nonlinearities can be incorporated into the basic model with appropriate modification of the computer program. The work of this paper has been applied to the design and analysis of missile flight control systems where the rate limit characteristic of the actuator is significant to dynamic performance.