Trajectory Optimization and Adaptive Control of Multi-DOF Hydraulic Manipulator for Tunnel Drilling
Abstract
High-performance positioning of multi-degree-of-freedom (multi-DOF) hydraulic manipulators in tunnel environments remains challenging. A major reason is the need to reconcile operational efficiency with motion smoothness in the presence of highly nonlinear hydraulic dynamics and lumped disturbances. To address these challenges, this paper proposes a synergistic optimization framework that integrates multi-objective trajectory optimization with high-precision hydraulic control. Within this framework, we construct a time-jerk multi-objective trajectory optimization model and propose a dynamic adaptive multi-objective whale optimization algorithm (DA-MOWOA). This approach achieves a favorable trade-off between operational efficiency and joint jerk, yielding an optimized trajectory that balances motion efficiency and dynamic smoothness. For accurate tracking of the optimized trajectory, an extended state observer-based backstepping sliding mode control strategy (ESO-BSMC) is designed to estimate and compensate for lumped disturbances. The observer-based disturbance compensation combined with the backstepping sliding mode structure effectively suppresses control chattering and improves trajectory tracking accuracy. Comprehensive mechanical-electrical-hydraulic co-simulations and continuous physical inter-hole positioning experiments validate the effectiveness of the proposed framework in achieving efficient and accurate positioning. Note to Practitioners—This paper provides a practical framework for the automated positioning of heavy-duty hydraulic manipulators in tunnel excavation. To address the trade-off between motion efficiency and mechanical shock, a synergistic trajectory planning and control framework is proposed. In practical applications, the optimization algorithm can be used to generate smooth motion trajectories that improve motion efficiency while reducing excessive joint jerk and mechanical shock. Meanwhile, the robust controller compensates for hydraulic transient disturbances and system uncertainties, thereby improving end-effector positioning accuracy while alleviating high-frequency chattering. The proposed framework is applicable to continuous multi-hole positioning operations. Future work will extend the framework to accommodate complex time-varying loads during actual rock drilling.