Research On Self-adaptive Fuzzy Force/Posture Control Strategy For Flexible Cable Insertion

In the manufacturing of electrical devices,it is a basic process to insert the metal end of the flexible cable into the corresponding connector hole,and the workload is enormous.As the cable becomes thinner and the shape of the metal end of the cable becomes more complicated,higher requirements are placed on both the accuracy and reliability of the inserting process.And the success or failure of the inserting plays a key role in the function realization of the product.Traditional wire-inserting process are accomplished by trained workers,taking the manual method of inserting(inserting the metal end into the connector hole),listening(listening to the squeak of the buckle)and pulling(pulling the cable to make sure it is tight).The method has poor reliability,low efficiency and high labor intensity,and has been unable to meet the production requirements of industrial automation for enterprises development.This paper starts from the actual needs of enterprises,applies industrial robot to design and complete the automation of the cable inserting process.The contact force model and the self-adaptive fuzzy force/posture control strategy of the inserting process are mainly studied,and the industrial robot and CCD camera are integrated in building the robot automatic cable inserting prototype system.The main contents of the research include:(1)According to the analysis of the process in which the robot manipulating the flexible cable and inserting it into the corresponding connector hole,the assembly operation is divided into four stages: pre-insertion proximity,search hole positioning,in-hole constraint,and inserting completion.The contact force model is separately established for the three possible contact states of the cable and the hole according to the actual stress situation.(2)According to the established contact force models,the method for judging each contact state and the force judgment criterion for the completion of the insertion are proposed.The attitude adjustment strategy of the inserting process is studied and a self-adaptive fuzzy force/posture control strategy is proposed.(3)The conducting relevant performance indicators and requirements for wiring terminal are analyzed.The industrial robot and CCD camera are integrated in building the robot automatic cable inserting prototype system.The modules of the system are designed and the prototype system software is developed based on Visual Studio 2017 platform.(4)Two types of typical flexible cables and connectors in HITACHI elevators controller are used to verify the versatility of the prototype system.And Several comparative case studies are designed to evaluate the contact force model and the proposed self-adaptive force/posture strategy.The results show that the proposed contact force model can correctly judge different contact state of wires and holes.In the process of automatic cable insertion,the proposed self-adaptive fuzzy force/posture control strategy can correct the robot altitude in real time,smoothly insert the cable into the connector hole and successfully complete the task.