Research On Kinematics Accuracy And Reliability Of Beating-up Mechanism In High-speed Rapier Loom

Rapier loom is one main type of weaving machine. It is widely used in modern looms with its advantages such as wide variety adaptability of its products, fast changing variety, better overall mechanical properties, etc. The beating-up mechanism is a key component of the rapier loom. Its structural form and movement performance determine directly the quality and efficiency of rapier loom. With the progress and rapid development of modern technology, the rapier loom has been put forward higher demand. The high speed, high precision and high efficiency have become an irresistible trend. Compared with foreign advanced rapier loom, domestic rapier loom has still large gap in operating speed, kinematics accuracy and reliability. The issue that how to deal with the contradiction between working velocity and weaving performance in high-speed rapier loom and produce high-stability, high-speed and high-precision textiles become an urgent research topic in design and manufacture of our high-speed rapier loom.The beating-up mechanism in rapier loom is the research object. Based on creating three-dimensional parametric model, multi-body system dynamics analysis, kinematics accuracy analysis, kinematics accuracy reliability and optimization research, the issue of kinematics accuracy affected by motion performance and various error factors of beating-up mechanism and improving kinematics accuracy reliability have been studied systematically. The main works are as follows.Firstly, using analytical method to deduce the profile curve equation of conjugate cam, three-dimensional parameterized design of beating-up mechanism in rapier loom is carried out based on development tool modules in Pro/E. This method could overcome the defect of the previous design method of conjugate cams beating-up mechanism such as design is cumbersome, the observability is not strong, is difficult to form a simulation animation and inconvenient for subsequent analysis.Secondly, using virtual prototyping technology, multi-rigid body dynamics theory and flexible multi-body dynamics theory, the multi-rigid body dynamics model and multi-flexible body dynamics model with the flexible beating rocker of beating-up mechanism in rapier loom are established based on ADAMS software. And multi-body dynamics simulation for the above two dynamics models is conducted respectively. The research on influence of multi-rigid body model and multi-flexible body model to the dynamic characteristics of beating-up mechanism is carried out. Thirdly, using the inversion principle of cam mechanism, the theory of effective length, the method of conversion mechanism and kinematics, the mathematical models of the follower position errors of beating rocker in beating-up mechanism with swing rollers are established respectively considering the three errors including dimension errors, clearances of hinged joints and the surface wear caused by conjugate cam in beating-up mechanism. The relationship between position errors of the follower and cam angle was established. The kinematics accuracy simulation of beating-up mechanism is carried out by MAPLE software. Based on the analysis of the kinematics accuracy of beating-up mechanism influenced by the basic dimension errors, clearances of hinged joints and the surface wear, the effective techniques of improving kinematics accuracy in design of beating-up mechanism in rapier loom are put forward.Fourthly, based on the above three mathematical models of the follower position errors of beating rocker, the precise analytic equation for the solution of kinematics accuracy reliability of beating-up mechanism is deduced by using the method of Taylor series expansion, and the solution on kinematics accuracy reliability of beating-up mechanism is put forth. The simulation analysis is carried on by using MAPLE software and the influence relationship between the three errors including dimension errors, clearances of hinged joints, the surface wear and kinematics accuracy reliability of conjugate cam in beating-up mechanism is obtained.According to the geometrical principle of reliability index, the mathematical solution model and index of kinematics accuracy reliability are established. Using improved particle swarm optimization, the kinematics accuracy reliability of beating-up mechanism is optimized. It can provide a new effective way to the design and manufacture of high-speed rapier loom.In this study, the major error factors are found to have an impact on kinematics accuracy and reliability of beating-up mechanism in rapier loom. The technical direction of improving the accuracy of beating-up mechanism has been found. The analytical theory and research methods are provided to the analysis, design and manufacture of beating-up mechanism in high-speed rapier loom. It has important theoretical significance and practical value to high speed and high precision of the domestic rapier loom.