A Method of the Real-Time Damage Mitigating Control for Manual Operation of Hydraulic Cranes

Abstract

In hydraulically actuated mobile cranes, actuator-induced force variations directly affect internal stress levels. The motion under dynamic loading can lead to progressive stress build-up over time, increasing the risk of material degradation and structural failure. Conventional control approaches typically omit structural stress feedback, focusing on performance objectives and overlooking internal force effects. This study introduces a stress-responsive valve control framework for the hydraulic crane systems. The proposed method uses simulation data to create a stress profile that follows the same pattern as the applied loads. A control coefficient K is computed in real time based on normalized stress and stress rate, using a polynomial formulation. This coefficient adjusts the actuator valve signals to reduce control intensity when stress levels increase or fluctuate. The implementation is carried out in a rigid multibody simulation environment with integrated sensor emulation and actuator logic. At each simulation step, valve signals are updated according to the stress levels therefore adjusting the dynamics of crane, adaptively. Comparative analysis between the stress-aware control system and an uncontrolled baseline is performed under identical actuation conditions. Results indicate a reduction in stress peaks while maintaining smooth and desired movements of crane. The analysis showed a 62.71 % reduction in the effective damping ratio. These results demonstrate that the proposed method reduces actuator aggressiveness in high-stress regions and limits structural loading without compromising actuation objectives.