Research On Constant Tension Control System For Paying-off Process In Steel Cord Bunching Machine

As tire's frame material,steel cord is the most widely developed product.In the process of twisting and bunching,tension control is very important to the quality of steel cord products.Compared with the foreign industries,domestic steel cord industries developed relatively late.The tension control system applied in the steel cord industry generally has low control accuracy and poor stability.In order to solve the problem,tension control methods and strategies of the external paying-off bunching machine are researched,and in this paper,a constant tension control system for the bunching machine is designed.By means of simulation and experiments,the paper verifies that the processed tension control method is effective and the designed system is useful.Firstly,the overall scheme of the outside paying-off strander's constant tension control system is designed,the important parts which include the execution unit,the detecting unit,and the control unit are emphatically researched.The paper optimizes the actuator's brake mode by applying the new-type electromagnetic induced brake,and proposes the detecting unit which takes the tension sensor?the proximity switch and the actuator's three phase pulse signal as the core.The paper also establishes a mathematical model,analyzing the change of tension during paying-off process from two aspects:static rotation and dynamic rotation,and points out that unwinding spools' common problem in wire wrapping would influence the tension control stability seriously.Secondly,for the reason that the unwinding tension control system of the bunching machine is non-linear,time-varying and with strong disturbance,the paper pays much attention on the control strategies and analyzes a variety of PID control algorithms.Considering the two problems,the first problem is the traditional PID control strategies' deficiency in self-optimization on PID parameters,the second problem is the serious effects on tension control cause by the deviation of the winding radius prediction value.In the paper,a radius-adaptively-feedforward-fuzzy-PID constant tension control strategy is designed.Through simulation,it is verified that compared with the traditional PID control strategy,the radius-adaptively-feedforward-fuzzy-PID constant tension control strategy has better control stability on tension.In addition,it always cost a long time that the tension output would be stable.Directing at the problem,algorithm is further adjusted and improved,a tension set-value adjustable and radius-adaptively-feedforward-fuzzy-PID constant tension control strategy is designed,and the effectiveness is verified through simulation.Finally,the relative circuits based on the ARM embedded platform is designed,and the improved tension control strategy is verified on the experimental bunching machine.Carrying out experiments in the tension set-value adjustable and radius-adaptively-feedforward-fuzzy-PID constant tension control system,the experimental results show that the improved strategy has high stability and strong anti-interference ability,and it can meet the constant tension requirements of steel cord paying-off system better.