Using Feedback Linearization to Improve the Tracking Performance of a Linear Hydraulic-Actuator

Abstract

In this paper, a simple feedback linearization method is used to improve the tracking performance of a linear hydraulic-actuator. This research uses an open-centered four-way valve to control the displacement of the hydraulic actuator, based upon an input command from the operator. In this research, the operator is modeled as a first-order system with a bandwidth frequency of 2 Hz. The feedback linearization method is used to adjust the operator input based on the measurement of fluid pressure on only one side of the actuator and the pump pressure that supplies the valve. No other sensing is needed. Using this approach, the R-squared value for tracking a sinusoidal displacement of the actuator and the bandwidth frequency of the actuator are increased. Furthermore, it is shown that the feedback linearization method reduces and nearly eliminates the load dependence of the tracking response, which means that operators should have less difficulty learning how to operate the machine over a wide range of conditions, and the overall productivity of the machine should go up. In summary, the elegance of this model is found in the fact that it is very simple to implement and that the alterations in output performance are greatly enhanced.