面向复杂流场的欠驱动AUV路径跟踪控制研究

Path tracking control for underactuated AUVs is more difficult than full drive AUVs because there are not direct driving forces in some degrees of freedom, which reduces the control inputs. It is influenced seriously by ocean current disturbance. Therefore, motion of complex flow field and three-dimensional path tracking control for underactuated AUVs will be discussed deeply in this program. According to the measure data of current velocity, we prove the relationship between steady flow and singular flow, and identify the position of singular point and the form of singular flow, and reveal the motion rule of flow field. According to cascade system theory, we decompose the tracking control system into two cascade subsystems which are kinematic control system and dynamic control system and design control laws independently. The system can not only track the reference path quickly, but also be robust strongly to parametric modeling uncertainty. An current observer is also added to estimate unknown current velocity, which can supply more effective feedback valves for the control system. Experiments are carried out based on WL-2 underactuated AUV to verify the feasibility and validity. The work can provide the theoretical basis to path tracking control for underactuated AUVs aiming at ocean current disturbance, and provide the technical support to the research and application for intelligence and long-distance of AUVs.

欠驱动水下机器人(AUV)由于在某些自由度上没有直接驱动力，减少了控制输入量，其运动控制较全驱动AUV困难得多，且受海流扰动影响非常严重。本项目拟对复杂流场运动及欠驱动AUV三维空间下路径跟踪控制方法进行深入研究。根据海流速度测量数据，探明定常流和奇异流的关系，辨识海流奇点位置和奇异流形态，揭示复杂流场运动规律，获得复杂流场模型。依据级联系统理论将跟踪控制系统分解为运动学控制和动力学控制两个相互级联的子系统，独立设计控制率，能够快速跟踪参考路径的同时对海流扰动和模型不确定有强鲁棒性。建立海流观测器估计完全未知的海流速度，为控制系统提供更为有效的反馈参量。通过WL-2欠驱动AUV的试验研究验证方法的可行性和有效性，为解决海流扰动下欠驱动AUV三维空间路径跟踪控制问题提供理论依据，为智能化、远程化AUV的研究和应用提供技术支持。

欠驱动水下机器人(AUV)由于在某些自由度上没有直接驱动力，减少了控制输入量，其运动控制较全驱动AUV困难得多，且受海流扰动影响非常严重。因此，本项目研究欠驱动AUV在海流扰动下的路径跟踪控制问题。首先对复杂海流流场进行模型辨识。根据某流域海流速度测量数据，探明定常流和奇异流的关系，通过求取估计函数的最小值确定奇异流奇点的位置。采用平均散度法和垂直涡度法对奇异矩阵相关参量进行限制，辨识出整个奇异矩阵，确定奇异流形态，为欠驱动AUV路径跟踪控制提供更为有效的仿真验证平台。针对海流扰动下的欠驱动AUV路径跟踪控制问题，建立一种自适应模糊反演滑模控制系统。采用模糊逻辑系统逼近模型未知函数，将反演思想与滑模控制技术相结合，设计反演滑模控制器；对欠驱动AUV纵向速度进行控制，将航向角作为路径跟踪误差的虚拟输入，设计航向角镇定函数和路径参数变化率；使用李亚普诺夫稳定性定理，证明控制系统的稳定性。仿真结果表明，设计的控制系统能有效地处理欠驱动AUV模型不确定性和海流扰动，具有极强的鲁棒性，且避免了执行机构的抖振现象，降低了机械损耗，有效节约了系统能源。最后，通过WL-2欠驱动AUV的试验研究验证方法的可行性和有效性，为解决海流扰动下欠驱动AUV路径跟踪控制问题提供理论依据，为智能化、远程化AUV的研究和应用提供技术支持。