Finite Element-Based Control of a Single-Link Flexible Hydraulic Manipulator

In this study, a stability-guaranteed, nonlinear, finite element-based control is presented for a single-link flexible manipulator with hydraulic actuation, subject to experimental validation. The strong, inherent nonlinearities of the hydraulic cylinder and fluid dynamics, coupled with flexible link dynamics, cause remarkable challenges in controlling the system effectively. In an attempt to cope with these challenges, a controller based on the Virtual Decomposition Control (VDC) approach is introduced. The VDC approach takes advantage of subsystem-dynamics-based control, enabling the handling of the dynamics and control of the hydraulic actuator and the flexible link separately, thus keeping the controller design relatively simple. The rigorous stability theory of the VDC approach guarantees the stability of the entire system. The experiments demonstrate the VDC controller’s performance in end-point control with built-in vibration dampening.