Automation of excavation tasks requires real-time trajectory planning satisfying various constraints. To guarantee both constraint feasibility and real-time trajectory re-plannability, we present an integrated framework for real-time optimization-based trajectory planning of a hydraulic excavator. The proposed framework is composed of two main modules: a global planner and a real-time local planner. The global planner computes the entire global trajectory considering excavation volume and energy minimization while the local counterpart tracks the global trajectory in a receding horizon manner, satisfying dynamic feasibility, physical constraints, and disturbance-awareness. We validate the proposed planning algorithm in a simulation environment where two types of operations are conducted in the presence of emulated disturbance from hydraulic friction and soil-bucket interaction: shallow and deep excavation. The optimized global trajectories are obtained in an order of a second, which is tracked by the local planner at faster than 30 Hz. To the best of our knowledge, this work presents the first real-time motion planning framework that satisfies constraints of a hydraulic excavator, such as force/torque, power, cylinder displacement, and flow rate limits.
翻译:挖掘任务的自动化需要实时轨迹规划,以满足各种限制。为了保证限制可行性和实时轨迹重新规划,我们为液压挖土机实时优化轨迹规划提出了一个综合框架。拟议框架由两个主要模块组成:全球规划员和实时当地规划员。全球规划员计算了整个全球轨迹,考虑挖掘量和能源最小化,而当地对应人员则以退缩地平线的方式跟踪全球轨迹,满足动态可行性、物理制约和扰动意识。我们验证了在模拟环境中拟议的规划算法,在模拟环境中,在模拟环境中,在水压摩擦和土壤桶相互作用的模拟干扰下,进行两种类型的作业:浅层和深层挖掘。最佳全球轨迹以第二位顺序获得,由当地规划员在30赫兹以内跟踪。根据我们的最佳了解,这项工作提出了第一个实时运动规划框架,满足了液压挖掘机的制约,如力/压力、电力、气瓶流流流和流速限制。