Design Of Control System For Locomotive Mechanical Arm And The Research Of Coping Strategy For Fault Joint

The robot can finish the essential rescuing task flexibly and efficiently instead of people during the rescuing of the nuclear accident,which make people realize that the robot plays an important role in delaying the progress,controlling the diffusion of nuclear radiation and other aspects.However,it is unavoidable that the fault happen in the accident while the locomotive mechanical arm often execute the task under severe environment,the fault can come into being in one or more joints.In order to ensure the adaptive capacity of the rescue robot in the accident,how to enhance the performance reliability of robot becomes an urgent problem.Control system for locomotive mechanical arm used for rescuing is designed in the paper to satisfy the active demand of the nuclear accident for rescue robot.The fault-tolerant design is operated in the locomotive mechanical arm based on the way of model reconstruction to solve the fault of robot joints.The control system of locomotive rescuing robot is based on flushbonading industrial personal computer called Advantech ARK5260.Two drivers are harmonically controlled by multiple spindle motion controllers named Googol GTS-400-PV(S)-PCI,which realizes high precision control of locomotive robot.The task is finished by the controlling of the mechanical arm called LWA 4D of SCHUNK.The information of visual feedback is attained by clear net camera.The operating lever of multi-degree of freedom named Extreme 3D Pro of Logitech is applied to control and to operate robot distantly.The robot can be moved to the scene of action under the way of remote control according to the information of visual feedback.The robot also can change kinds of ends to execute corresponding task in face of different work objects and generate motion trail automatically.Besides,the robot can finishthe rescuing task such as opening the door,turning the valve and so on.While fault appears in one or more joints of the mechanical arm,all joints will be detected according feedback of the mechanical arm.After the fault joint is found,the D-H dynamitic model of the mechanical arm is reconstruction according to the actual fault condition.Then the fault condition of low DOF after reconstructing is used for continuing finishing corresponding taskIn the paper,the experiment of “opening the door” is operated using designed robot.The result shows that the robot can finish given task efficiently and accurately.In order to verify the feasibility of coping strategy,the fault of the third joint and the forth joint of mechanical arm are simulated.The movement trail of the mechanical arm is also replanned based on the way of model reconstruction.Besides,the feedback data of six DOF mechanical arm and four DOF mechanical arm after reconstructing are contrasted.The experiment data shows that the error of kinds of axis is less than 1mm,which proves that the fault mechanical arm has certain operational capability and can finish the given task.