Improved Tracking Control of Hydraulic Systems

Abstract

Tracking control for hydraulic systems is a key system requirement, as these devices must often follow prescribed motions. Tracking control of hydraulic systems has been approached using both linear and nonlinear control laws. The latter provides improved performance, but at the expense of additional sensors. Further, the control laws often employ hydraulic fluid bulk modulus—a difficult-to-characterize quantity—as a parameter. To overcome these difficulties, we have developed a control design procedure that requires no additional sensors and is robust to variations in the bulk modulus. A dual approach of singular perturbation theory and Lyapunov techniques form the basis for the procedure. For the cases of a small-amplitude sinusoidal input and large-amplitude polynomial input, a candidate system achieved good tracking performance and exhibited outstanding robustness. The ability to accomplish good tracking in a robust manner with no additional sensors provides advantages over other nonlinear tracking algorithms.

Flatness based control with adaptive load torque compensation for position tracking of electro hydraulic actuators

“…Variable structure control (VSC) strategies have been studied for the control of EHA in [2], [3], [4]. Input-output (IO) linearization has also been used to develop EHA without consideration of the servo valve dynamics [5], [6], [7], [8].…”

Review on Inlet/Outlet Oil Coordinated Control for Electro-Hydraulic Power Mechanism under Sustained Negative Load

“…In order to solve the issue that fluid bulk elastic modulus is difficult to quantify, Bora [41] developed a control design process, where additional sensors are not needed. Moreover, the design process makes the variables in bulk modulus have robustness.…”

Experimental Control of Variable Cam Timing Actuators

“…We desire to achieve fast and, very importantly, accurate transients. We propose an alternative model reduction obtained thanks to a singular perturbation approach (as used in (Eryilmaz and Wilson, 2001) and (Manhartsgruber, 2000)). …”

“…It determines the displacement x, which alters the valve timing. The piston is connected to one of the walls through a spring and a viscous damping (this is a classic modeling assumption see (Eryilmaz and Wilson, 2001)). Classically, the physical equations governing the system can be written under the form (deSilva, 1989) …”