Design And Control Of Underwater Cable-driven Multi-joint Manipulator

With the increasing demand for marine resources exploration and mining,underwater sampling,underwater biological detection,and underwater equipment maintenance are often completed by underwater manipulators.Although the traditional underwater rigid manipulator has the advantages of strong operation ability and high efficiency,its degree of freedom is limited and cannot effectively meet the requirements of underwater narrow space operations.The cable-driven multi-joint manipulator,due to its high degree of freedom,has good obstacle avoidance and load grasping capabilities.Therefore,this paper designs a cable-driven multijoint manipulator,it can be used for underwater work.Structural optimization and modular design of the manipulator drive-system,manipulator arm and mechanical gripper,and the count and selection of the major units are finished.Then,kinematic analysis of the manipulator arm,and the correspondence rapport of the spatial location,joint angle and cable-length variation in the workspace is deduced.The off-line planning of the joint angle and cable length variation of the manipulator was carried out,and the discrete sequence of the joint angle and cable length variation was obtained.Finally,the manipulator control system was integrated,and the prototype assembly of the underwater cable-driven multi-joint manipulator was completed.Plane swing experiment.The main study details of this dissertation are as follows:Firstly,the research background and significance of the underwater cable-driven multijoint manipulator are expounded,and the research status of the underwater rigid manipulator and the cable-driven high-redundancy manipulator are compared and introduced.Difficulties in structural design,driving mode and controlling method are discussed,and the primary study details of the dissertation are summarized,and the process of obtaining the design of the cabledriven multi-joint manipulator is summarized.Secondly,an underwater cable-driven multi-joint manipulator is proposed based on the load capacity of the manipulator,lightweight modular design,airtightness and material factors.The structural optimization and modular design of its drive-system,manipulator arm and mechanical gripper have been finished,part engineering drawings are drawn,and the master devices including the motor,ball screw,guide rail and slider have been computed and chosen.Then,the idea of kinematics dissecting of the cable-driven multi-joint manipulator is put forward.,the kinematic model is established,four D-H variables are obtained,the working space range of the manipulator is solved,and the movement simulation of the manipulator is performed by Adams..Then,an inverse kinematics method based on space spherical coordinates is put forward to get the connection between the spatial location and the articulation angle,and the variation of the cable-length and the articulation angle of the manipulator are dissected,and the variation of the cable-length and the articulation angle are acquired.The correspondence rapport of the articulation angle,and the analytic between the spatial location,articulation angle and cable-length variation of the manipulator is gained.Thirdly,off-line planning of joint angle,cable length variation and manipulator motion control research are carried out.Using the method from single joint to multi-joint,the discrete time series of joint angle is obtained,and then the corresponding change of cable length is get from the rapport between joint angle and cable-length variation.Cable-length variation is used as the motor controlling instructions.Then,the hardware subsystem of the control system is work up,the functions of the major hardware are described,and the relevant manipulator motion control program is written to accomplish the design of the manipulator control layer.Finally,the assembly of the manipulator prototype is completed,and the plane swing experiment is opened.The study content and completion acquired in this paper are summarized,and the following study work of the underwater cable-driven multi-joint manipulator is prospected.