Coordinated Synchronization and Attitude Control for the Dual-Motor-Driven Lifting Beam via Online Eccentric-Load Estimation and Dynamic Differential Allocation

To address the problems of increased bilateral synchronization error, accumulated beam attitude deviation, and degraded operating stability of a dual-motor-driven lifting beam under eccentric loading, this paper proposes a coordinated synchronization–attitude control method based on online eccentric-load estimation and dynamic differential allocation. First, a two-dimensional dynamic model incorporating overall vertical translation and small-angle beam rotation is established. On this basis, the control task is decomposed into trajectory tracking in the common channel and synchronization–attitude regulation in the differential channel. Second, an online equivalent eccentric-load moment estimator is introduced to extract the dominant eccentric-load effect through differential-channel residuals and first-order low-pass filtering. Then, a dynamic differential allocation mechanism jointly driven by the estimated moment and beam attitude is constructed to adaptively adjust the left–right driving-force difference while maintaining the total lifting force. Furthermore, synchronization-error feedback, attitude feedback, and eccentric-load compensation are unified in the differential control law. Finally, comparative simulations and experiments under step and preset eccentric-loading conditions show that, for an additional mass of 10 kg placed 0.45 m from the nominal beam center, the proposed method reduces the experimental tracking RMSE to 4.31 mm, limits the peak tilt angle to 0.64°, and reduces the steady-state synchronization error to 1.48 mm. These results demonstrate improved tracking accuracy, synchronization consistency, attitude stability, and adaptability to persistent eccentric loading.