Abstract:

In order to improve the motion characteristics of the variable lead screw weft insertion mechanism, the displacement curve of weft insertion mechanism was designed based on the transformed trapezoidal acceleration curve. Firstly, an equation set was built according to the actual working conditions of weft insertion and the boundary conditions of the cut-off points in the acceleration curve. Parts of the variables were determined based on the empirical data and the vwriables were limited in a reasonable range. Then the equation set could be solved by MatLab. The optimal objective solution was selected from the solution space under comprehensive consideration of the peak acceleration, the peak velocity and the velocity of the critical point in the weft transition area. Subsiqently, a comparison between the designed optimal motion law with the one based on the classic trapezoidal acceleration curve was carried out. The result shows that when the rapier moves into the weft transition area, the velocity and the acceleration of the designed optimal motion law are significantly smaller than the ones based on the classic trapezoidal acceleration curve, so that the rapier operates more stably when in the weft transition area.

Key words: weft insertion mechanism, trapezoidal acceleration curve, optimal obfective solution, rapier, displacement curve