Dynamic Simulation And Experimental Research On Silk Knot Robot

The silk cloth industry is a traditional industry in China.Silk industry,as the foundation and important part of the silk cloth industry,is the treasure of China.At present,domestic and international silk reeling machine adopts the mechanism of Japan's early automatic silk reeling machine.This structure leads to the breaking silk due to the stop mechanism in the process of reeling raw silk,if the impurities in silk,which could not meet the requirements,is detected by porcelain hole.It is artificial to make a knot to rough treatment if the phenomenon appears which leads to time consuming,high labor cost,and low efficiency of silk production and so on.Therefore,a silk knot robot for knot and remove impurities to silk automatically is proposed.The detailed optimization design of silk knot robot is carried out,and the experimental verification is proposed.The results shows silk knot robot could knot and remove impurities automatically smoothly.The main contents of this paper are as follows:(1)Aiming at the complex structure and high processing cost of mechanical automatic knotter,a separate and four driven silk knot robot is proposed.Separate means there are four mechanisms of silk knot robot,which are silk-extract mechanism,silk-press mechanism,silk-knot mechanism and silk-remove mechanism.The four driven means the four mechanisms have their own drivers.This kind of structure makes a simple silk knot robot,and the four mechanisms are independent,coordinate to knot,and remove impurities automatically.(2)In view of the large size of knotter with the form of external contact cam,the silk knot robot adopts an inner contact silk-knot mechanism to finish the knot of silk.The inner contact silk-knot mechanism realizes the function of "?" ring through the matching of the knot knife arm and the eccentric cylinder,which could greatly reduce the size of the silk knot robot.According to the principle of inner contact silk-knot mechanism,a method for projecting the connection of the top of the knot knife arm to the cross section of the eccentric cylinder is proposed.The method uses the kinematic model of the jaw mechanism and the main geometric dimensions of the knot knife arm to solve the key geometric dimensions of the eccentric cylinder.(3)Aiming at the high acceleration fluctuation during the dynamic simulation on silkknot mechanism,which leads to a low stability of silk-knot mechanism,the sequential quadratic programming method is used to optimize the silk-knot mechanism.The optimization model takes the minimum acceleration fluctuation of the silk-knot mechanism as the objective function,taking the geometric size of the knot knife arm as the design variable,taking the sheath retention,structural interference and silkworm force as constrains.The optimal solution of the geometric size of the knot knife arm are found out as the acceleration fluctuation reaches the minimum.(4)The optimized silk knot robot is verified by experiments and its knotting performance is analyzed.The experimental verification includes two parts,which are experimental verification of a single roughening experiment and experimental verification of continuous roughening experiment.Single roughening experiment is used to analysis the effect of the influence of jitter of motor driven by electric wire on the knotting performance of silk knot robot,and continuous roughening experiment is used to analysis the influence of different velocity of the four mechanisms on the knotting performance of silk knot robot.Experimental result shows that the silk knot robot could finish the knot of silk successfully,and it has a good knotting performance.