Dynamic Analysis And Optimization Of Rotating Dobby Opening Mechanism

Rotary dobby is a shedding mechanism which is widely used in the looms,it has some advantages in terms of high speed,compact structure and strong stability.In comparision with foreign countries,the rotary dobby made at home has some drawbacks,including poor reliability,low rotating speed and so on,as a consequence,the domestic dobby enterprises and textile enterprises have been suffering from the falling global competitiveness.Aiming at the lifting comprehensive mechanism and the election comprehensive mechanism,which are the core mechanisms of rotary dobby,the following studies are mainly conducted in this paper:Based upon the kinematic analysis of the lifting comprehensive mechanism,dynamic model of the mechanism is developed by the Lagrange equation,and its virtual prototype is developed based on ADAMS.The consistency of the drive torque for large disk obtained by numerical simulation and virtual simulation is compared and analyzed to validate the correctness and validity of the established dynamic model.Based upon the established dynamic model,the influence of rotating speed of the big disk,the material and the movement distance of the heald frame,the theoretical profile of the heald cam on the drive torque of the large disk are simulated and optimized respectively.In terms of the dynamic model,it is inferred to build the dynamic model for the rotary dobby with multiple heald frames from a set of heald frame.The finite element method is employed to discretize the bending arm effectively,which is the key component of the rotary dobby.Combining with the modal synthesis techniques,the rigid-flexible coupling dynamic model of the bending arm is developed by Kane's equation,which can be calculated numerically.On this basis,modal truncation is studied while the dynamic performance of the system is derived.The influence of different modal truncation order number on the dynamic response of heald frame is investigated,and the influence of different structure parameters and motion parameters on the motion law of the heald frame is analyzed.The virtual prototype model of lifting comprehensive mechanism for rotary dobby is developed by means of ADAMS software.The effect of the collision for cam and roller on the motion law of heald frame is studied.Combined with ANSYS software,the rigid-flexible coupling dynamics of the lifting comprehensive mechanism is analyzed,which lays the foundation for the optimization design of the loom.The kinematics analysis is carried out for the election comprehensive mechanism,and the influence of flexible deformation of the cam follower for the election comprehensive cam on the heald frame precision is studied by virtue of ADAMS and ANSYS.The research provides theoretical support for the optimization design of the election comprehensive mechanism.