Research On The Motion Planning And Control For Underwater Vehicle-Manipulator System

With the steady decline of non-renewable resources on the land, themankind plays a more and more good view on the development and utilizationof marine resources. The underwater vehicle-manipulator system (UVMS)containing operating manipulator will become an important tool in thedevelopment process of marine resources and it is currently the only high-techequipment executed task in the deepwater. Since UVMS is a highly kinematicredundancy dynamics non-linear and multi-degree-of-freedom mechanicalsystem, research the motion planning and control technology for a givenunderwater task is helpful to improve its control performance, reliability,intelligence and speed up its application in practice, and has important researchsignificance and practical value.In order to research motion planning and control technology of the UVMS,this paper developed an underwater electric manipulator and integrated with asmall autonomous underwater vehicle (AUV) constituted a UVMS experimentplatform, developed the kinematics and dynamics model and simulationplatform of UVMS, researched the motion planning and control technology of UVMS.According to the demand of subject, developed an underwater electricmanipulator and integrated with a small AUV constituted a UVMS experimentplatform. According to the design specifications, designed the whole scheme ofthe manipulator. Considering the expansion of function and shorten the cycle ofdevelopment, developed a modular swing joint for the manipulator and used themodular swing joint do the multi-degree of freedom arm assembly experiments.According to the manipulate object of manipulator, designed an introductoryend-effector that can shear cable. In order to improve the reliability ofmanipulator, analyzed the important parts’ strength and stability in the joint.This paper established kinematics model, dynamics model and simulationplatform of UVMS. On the modeling of UVMS side, developed forwardkinematics model, and according to the established kinematics model derivedthe Jacobian matrix of UVMS. In order to solve the problem that speed isnon-integrable in the moving coordinate system, introduced Quasi-Lagrangeequations to establish the dynamics model of UVMS. In order to study themotion planning and control methods of UVMS, established a simulation platform of UVMS, given the mathematical model of simulation platform,containing UVMS, DC motor and propeller.This paper studied control scheme of UVMS. In order to control the motionof UVMS, designed velocity control with PI and position control with PD twoclosed-loop PID motion controllers, expected to shorten the response time ofvelocity and inhibit or reduce the overshoot of position. To solve the problemthat the steady-state response time of AUV is too long when used the PDcontroller, proposed a slide fuzzy motion controller switched smoothly withcubic root function. Computer simulations were performed to verify theproposed schemes on the simulation platform of UVMS in the static water andcurrents environment and compared the control performance under differentcontrol schemes.This paper studied motion planning scheme of UVMS. In order to avoid thecollision between manipulator and AUV, and joints move beyond its limits whenUVMS executed task, developed joints limit motion planning scheme. In thetraditional joint limit algorithm, the movement has been restricted when the jointmoved from middle to its limits. To solve the above problem, proposed an improved weighted least norm (WLN) joint limit motion planning scheme byredefined the joint potential function. Computer simulations were performed toverify the proposed improvement scheme on the simulation platform of UVMSin the static water environment. In order to study the threshold values of joints’potential function impact on UVMS’s motion, computer simulations wereperformed under five different threshold values. To take full advantage of theredundancy DOFs of UVMS to execute the second task, a task priority schemewas proposed to solve multi-task integration motion planning of UVMS andused fuzzy logic to determine the priority of multiple secondary tasks. Computersimulations were performed to verify the proposed multi-task integration motionplanning scheme on the simulation platform of UVMS in the static waterenvironment.