Research On Spatial Trajectory Tracking Control Of Low-speed Maneuver Target For UUV

Achieving tracking the spatial trajectory of low-speed underwater maneuvering target accurately plays a decisive role in many underwater operations that UUV needs to finish.Preprocessing the noise of UUV's sensor measurement data,such as denoising and smooth-fitting,can provide more accurate input for the trajectory tracking controller;Designing a controller,which can not only realize trajectory tracking of target accurately for UUV,but also has a strong robustness to the uncertainty of UUV's system model parameters and external disturbance,is crucial for UUV to complete various tasks in the complex underwater environment.Therefore,several key problems existed in spatial trajectory tracking of low-speed underwater maneuvering target for UUV have been researched in this paper as follows:Firstly,through analyzing motion characteristic of the simulation object and tracked target,as well as the relevant knowledge of underwater robot,establish the spatial kinematics and dynamics models for UUV.Deeply analyzing the movement features of low-speed underwater maneuvering target,several mathematical models that can describe the typical movement of tracked target is established.Secondly,considering the system error caused by the craftsmanship of sensors and all kinds of disturbances from the outside,which can result in the measurement data(the information including position,posture,speed et al.)on UUV and tracked target through sensors always containing a mass of noise,wavelet threshold de-noising method is adopted to preprocess the sensor measurement data for the first time,that can filter the noise whose frequency is more different from the frequency of real signal to a large extent;then reprocess the sensor data by using particle filter method,which can further remove the noise whose frequency is relatively close to the frequency of real signal.as for the data preprocessing methods aforementioned,the simulation tests are designed respectively to verify the feasibility.Thirdly,considering the uncertainty of systems model parameter,the current disturbance existed in external environment and the high overshoot of the position and posture controlling existed in target trajectory tracking process,a double closed-loop non-singular terminal sliding mode(NTSM)controller is designed.The reference velocities are designed based on tracking error of position and posture between UUV and low-speed underwater maneuvering target in the outer loop,which are regarded as the outer loop controller;At the same time,a non-singular terminal sliding mode controller is designed in the inner loop,and the reference velocities generated by the outer loop are treated as the virtual tracking targets for inner loop controller.The stability of the controllers is verified by the theory of Lyapunov and other relevant theorem in the end.Finally,taking into account the motion state information of tracking target measured by UUV's sensor,the data preprocessing methods and the target trajectory tracking controller,a complete simulation experiment is designed based on the Matlab/Simulink,which can further verify the feasibility and effectiveness of the proposed methods in this paper in achieving the spatial trajectory tracking of low-speed underwater maneuvering target for UUV.