Synchronization control of hydraulic horizontal regulation system

This paper presents a control algorithm to address the leveling issue for lifting vehicle. The leveling system is achieved by electro-hydraulic system because of its advantages, such as small size-to-power ratios and so on. As four cylinders used to achieve synchronization, the issue of cylinder redundancy appears. In order to address this issue, the approach that two cylinders are only allowed to move in the same time is used. The two moving cylinders both are at the front of vehicle or at the back of vehicle. So the leveling issue is converted to motion synchronization of dual-cylinder. The design of controller to achieve motion synchronization of dual-cylinder is presented. The synchronization controller is a double loop controller. Inner-loop controller is a PID controller that is used to achieve the tracking performance of individual cylinder. Outer-loop controller is a compensation controller that is used to compensate the synchronization error of the cylinder the displacement of which is smaller. Simulation results on a dual-cylinder system verified the effectiveness of the proposed approach.