| With the rapid development of major equipment manufacturing industries such as China’s ship transportation,rail transportation,petrochemicals,etc.,the demand for large-scale forgings are increasing day by day,and double-forging manipulators forge collaboratively on the world stage.The dual-machine collaborative forging has extremely high requirements on motion control.The asynchronous movement will produce a coupling force on the clamped high-temperature forgings,affecting the quality of the forgings.Therefore,it is necessary to introduce force control in the dualmachine motion control to achieve the effective compliance of the coupling force of the forging.In the harsh working environment of the forging manipulator,the difficulty of force control is to achieve effective force sensing.Thus,it is urgent to propose a method for sensing the internal force of forgings under high temperature and complex working conditions.In view of the symmetrical characteristics of the two machines,this paper takes the 20 k N single forging manipulator of "5 MN fast forging hydraulic unit pilot platform" as the research object.The deformation resistance of the forgings under the forging condition is equivalent to replace the coupling force of the forgings of the twomachine movement,and then the research of the force sensing method is carried out,aiming to lay the foundation for the subsequent two-machine cooperative movement.The main contents are shown in the following sections:(1)An indirect force sensing method based on the force of the hinge point of the clamping mechanism to realize the internal force of the forging was proposed.The mapping relationship between the position and posture of each member of the clamping mechanism and the displacement of the hydraulic clamping cylinder and the diameter of the clamping forging was established by using forward and inverse kinematics analysis.Based on the inverse kinematics analysis,the Newton-Euler method was used to establish the force sensing model of the clamping mechanism in different clamping states,and the force transmission law of the clamping mechanism was obtained.(2)Analyzed the force sensitivity of each hinge point of the clamping mechanism based on the force-sensing model and obtained the force-sensing characteristic hinge point of the clamping mechanism based on the selection principle of different clamping mechanism structural characteristics and the arrangement requirements of the hinge point force measurement equipment.By improving the design of the pin axis of the force sensing point,the requirements for the collection of force in the orthogonal direction of the hinge point under high temperature conditions were realized.The ADAMS virtual prototype model of the clamping mechanism was established,and the simulation results and theoretical calculation results of the force-sensing hinge point were compared and analyzed to verify the correctness and reliability of the forcesensing model.(3)Aiming at the problem of coupling of force sensing feature points when the deformation resistance of forgings in different directions and sizes work together,a decoupling study was conducted using BP neural network algorithm,and an indirect force sensing decoupling model of clamping mechanism based on neural network algorithm was built.Using the force model training data to determine the number of hidden layer nodes when the decoupling effect was optimal,the mapping relationship between the hinge point force information and the forging deformation resistance under different clamping conditions was obtained.Finally,the test data of the ADAMS simulation model of the clamping mechanism was used for decoupling analysis to prove the decoupling and perception effect of the neural network on the direction and value of the internal force of the forging. |
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