Structure Design And Key Technical Research Of The Automatical Yarn Piecing Machine For Ring Spinning

Yarn breakage is an inevitable malfunction which is always found in the process of ring spinning. In current textile enterprise, the quality of the jointing yarn and the efficiency of yarn piecing depends on the manual skill of the workers. It results in unstable yarn quality and low yarn production which directly affects production efficiency of the spinning equipment. With the development and application of robot technology, the use of robotic technology for automatic yarn piecing has become one of the hotspots of textile machinery. According to the problem of automatic piecing for broken yarn in ring spinning, an automatic yarn piecing system based on robotic technology is developed and the research of key technology which is robot-related is carried out. The main contents of this paper are as follows:1. According to the functional requirements of piecing system for broken yarn in ring spinning, the structural scheme of each functional unit is designed and the mechanical model of the whole system is determined.2. The detailed mechanical structure of the robot which is the key implementation component of the automatic yarn piecing system is designed. Based on the work space and movement characteristics of the robot, the work of structural parameters calculation of the boom and arm, mechanical structure design of the arms, type selection of motors for joints is carried out. Topological optimization method is adopted to analyze the key components. According to the analysis results, mechanical structure of arms are optimized to achieve the goal of lightweight design.3. The dynamics equations of yarn piecing robot are established by using the Newton-Euler recursive method and the driving torque of each joint is obtained with Matlab. By contrast with the dynamic simulation results, the correctness of theoretical analysis is verified. Furthermore, the dynamics simulation with non-trajectory searching method is taken to obtain the peak torque. Based on the simulation results, the motors of each joints are confirmed to be the reasonable choice.4. Established the terminal position and posture error model of the robot based on a modified D-H kinematic model.Then, the numerous simulation and statistical analyses of the end position error are carried out with Monte Carlo method and an intuitive simulated image of the end positioning accuracy is obtained. By sensitivity analysis, the main error which influence the terminal positioning accuracy are acquired, which can provide reference for the error compensation during debugging process for the prototype. Followed by, the parts of the automatical yarn piecing system are manufactured and the assembly is finished.In summary, the research results of this paper lays a foundation to some extent for the application and industrialization of the automatic yarn piecing robot in textile industry.