The Design And Test On Six Degree Of Freedom Underwater Robotic Arm System

The oceans are the origin of life on earth,with the diversity of life and the rich mineral resources.It is the living environment of life on earth and how to better utilize and protect Marine resources is an important issue for mankind.Due to the extreme Marine environment,the oceans is explored and developed by humans through Marine equipment and instruments,and underwater manipulator is a very important tool,The underwater extreme environment operation can be carried out by the operator's instructions,Therefore,the study of underwater manipulator has important scientific value and practical significance.Firstly,combining task requirements,to carry out the six degrees of freedom of the underwater manipulator system structure design,select the mechanical arm material,use the anti-corrosive aluminum alloy?6061?and the anode oxidation treatment,use O-type sealing ring and a pan-plug seal with high performance sealing characteristics,The design of six joints and claw structure of underwater manipulator was carried out in detail,and determine the structure parameters of each joint on this basis,calculating the required driving torque and power for each joint to determine the motor power,drive moment and reducer model of each joint.Secondly,according to the underwater manipulator mechanical structure parameters,position posture and the way of coordinate transformation on kinematics are introduced,and using D-H method to perform the overall kinematics modeling of the manipulator arm,and deriving the forward kinematics equation of underwater manipulator through the transformation matrix between the various links.So it is obtained to the position matrix of the arm end of the reference frame he mechanical arm relative to the reference frame at the end of the pose matrix.This paper analyzes the forward kinematics and inverse kinematics of underwater manipulator,and deduces the analytical expression of positive inverse kinematics of underwater manipulator.Thirdly,using the method of Lagrange to derive dynamics model of underwater manipulator,which is simplified by differential transformation in the inertia termD_ij,centripetal force itemC_ijj ,elder brother's force item C_ijk and gravity item _iG of the equation.And it is helpful to control calculation.Through a single connecting rod by mechanical arm hydrodynamic analysis,based on Fluent simulation software and Morison formula to set up underwater water dynamics equation of mechanical arm,to get a hydrodynamic effect on the mechanical arm,and lays the foundation for the underwater manipulator control.Fourthly,the control system design of underwater manipulator is carried out.The mechanical arm control system based on TMS320F2812 was designed.Using DSP chip to send PWM wave to the IR2136S drive module to generate the three-phase alternating current and drive motor.and the control system of each joint control system be controlled by CAN bus.With double closed loop negative feedback,the motor speed and current can be detected to achieve stable control.The fuzzy PI controller is designed to guarantee the robustness of the control system while ensuring the control precision of the motor.Finally,an underwater robotic arm test platform is built to control the joint motion control test of underwater robotic arm,and verify the rationality and effectiveness of the design of underwater robotic arm structure and control system.