High performance nonlinear motion/force controller design for redundant hydraulic construction crane automation

• State-of-the-art control performance is achieved for the studied system.
• Results are achieved with the low-tech hydraulic construction crane.
• Stability of the highly nonlinear articulated hydraulic crane is guaranteed.
• The proposed method can be easily retrofitted into existing systems.

In this paper, a stability-guaranteed Cartesian free-space motion control for the redundant articulated hydraulic construction crane is addressed in order to increase system safety and productivity. To cope with the nonlinearities of coupled mechanical linkage dynamics of articulated systems and the inherently strong nonlinearities of hydraulic actuator dynamics, the proposed controller is designed based on the recently introduced Virtual Decomposition Control (VDC) approach. The VDC approach, which was developed especially for the control of complex robotic systems, allows the conversion of the control problem of the entire system to a control problem of individual subsystems, while rigorously guaranteeing the stability of the entire hydraulic system. In the experiments it is demonstrated that, the proposed controller is able to extensively cope with the highly nonlinear nature of the articulated hydraulic system, and an improved control performance is achieved compared to the current state-of-the-art studies in the category of the hydraulic robot manipulators.