Research On Tension Control System Of Multi-Layer Stranded-Wire Helical Springs In The Winding Process

The stranded-wire helical springs made by steel cable are cylindrical helical springs.Compared with single spring,the stranded-wire helical springs have better damping effect,variable stiffness.which are widely used in weapon launch system,submarine aerospace engine and other national defense equipment.The quality of The stranded-wire helical springs must be strictly required for the high reliability and performances of the national defense equipment.There are few researches on the control of steel wire tension,but the fluctuation of steel wire tension causes the different elongation and different stress of each strand of steel wire,which leads to the increase of friction between the inner and outer layers of steel wire of stranded-wire helical spring,and it is difficult to form on the theoretical cylinder surface which reduces the fatigue life and mechanical properties of stranded-wire helical spring.Therefore,it is necessary to study the cause and control algorithm of tension fluctuation of steel wire to ensure the consistency of steel wire tension and improve the forming quality of multi strand spring.The main research contents of this paper include:(1)Based on the analysis of tension demand of stranded-wire helical spring,the hardware and software structure of tension control of stranded-wire helical spring CNC machine tool is put forward,and the main factors influencing tension fluctuation are explored.The influence rule of the winding diameter change on the tension fluctuation at the unwinding end is studied.By comparing the sensitivity experiment of the sensor,the angle between the detection direction of the sensor and the line tension direction is determined to be 45 degrees,and the sensor is calibrated,which provides the basis for the subsequent experiment.The characteristic curve of the moment transmission of the magnetic powder clutch is studied.Within the working range,the working current of the magnetic powder clutch is determined It has a linear relationship with the transfer torque,but there are return error and hysteresis phenomenon,which provides a theoretical basis for the follow-up study of tension system.(2)The 3+5 type tension system of multi-layer stranded-wire helical spring is established by studying the dynamic moment balance model of unwinding end,the mechanism of steel wire tension and the model of steel wire interaction between layers.The simulation results show that the sudden change of the tension of one steel wire in the outer layer will lead to the corresponding change of the twist angle of the rest steel wires,which will cause the change of the traction speed and the unwinding speed at the forming point,and then lead to the tension fluctuation and affect the forming quality of the stranded-wire helical spring.It is worth mentioning that the mathematical model of stranded-wire helical spring tension can not be obtained by analytical method and can not be directly applied to the tension control of stranded-wire helical spring in the production and processing.(3)In view of the fact that the tension model of multi-layer stranded-wire helical spring can not be directly applied to the actual control,an adaptive control method based on the tension-free control model is proposed.The parameters of the model-free adaptive tension controller are determined by using the quantum particle swarm optimization method.The effectiveness of the method is verified by the simulation of the model-free adaptive tension controller based on quantum particle swarm in the tension control of 3 + 5 multi-layer stranded-wire helical spring.The disturbance suppression time of the proposed controller is 35% shorter than that of PID control,which proves the superiority of the method.It provides a good foundation of tension controller for the following practical experiments.(4)According to the demand of stranded-wire helical tension control and the structural characteristics of stranded-wire helical spring CNC machine tool,the tension control desktop program of upper computer is designed.Through the tension control software of the upper computer,the communication between the upper computer and the lower computer,the real-time control of the tension of each strand of steel wire,the monitoring alarm and the online adjustment of the control algorithm parameters can be realized.