Method and device of dynamically configuring linear density and blending ratio of yarn by two-ingredient asynchronous/synchronous drafted

A method of dynamically configuring linear density and a blending ratio of a yarn by two-ingredient asynchronous/synchronous drafted, the method comprising:

• 1) providing an actuating mechanism, wherein the actuating mechanism includes a two-ingredient asynchronous/synchronous two-stage drafting mechanism, a twisting mechanism and a winding mechanism wherein the two-ingredient asynchronous/synchronous two-stage drafting mechanism includes a first stage asynchronous drafting unit and a successive second stage synchronous drafting unit;
• 2) providing a combination of a plurality of back roller and a middle roller included by the first stage asynchronous drafting unit;
• the combination of back rollers has two rotational degrees of freedom and includes a first back roller, a second back roller, which are set abreast on a same back roller shaft;
• the first back roller, the second back roller move at the speeds Vh1, Vh2 respectively, the middle roller rotates at the speed Vz the second stage synchronous drafting unit includes a front roller and the middle roller;
• the front roller rotates at the surface linear speed Vq;
• assuming the linear densities of a first roving yarn ingredient, a second roving yarn ingredient, drafted by the first back roller, the second back roller are respectively ρ1, ρ2, the linear density of the yarn Y drafted and twisted by the front roller is ρy;
• ρ
• y
• =
• 1
• V
• q
• 
• (
• V
• h
• 
• 
• 1
• *
• ρ
• 1
• +
• V
• h
• 
• 
• 2
• *
• ρ
• 2
• )
• (
• 1
• )
• the blending ratios of the first roving yarn ingredient, the second roving yarn ingredient are respectively k1, k2;
• K
• =
• k
• 1
• k
• 2
• =
• ρ
• 1
• 
• V
• h
• 
• 
• 1
• ρ
• 2
• 
• V
• h
• 
• 
• 2
• 3) keeping the ratio of linear speeds of the front roller and the middle roller Vq/Vz constant, the speeds of the front roller and the middle roller depend on reference linear density of the yarn;
• 4) adjusting the rotation rates of the first back roller, the second back roller, so as to adjusting the linear density of yarn Y or/and blending ratio, according to the changes of the blending ratio K of the yarn Y with a time t, and the changes of the linear density ρy of the yarn Y with the time t, the changes of the surface linear speeds of the first back roller, the second back roller, are derived;
• wherein surface linear speeds of the first back roller Vh1:
• V
• h
• 
• 
• 1
• =
• ρ
• y
• 
• K
• ρ
• 1
• 
• V
• q
• 
• (
• 1
• +
• K
• )
• surface linear speeds of the second back roller Vh2:
• V
• h
• 
• 
• 2
• =
• ρ
• y
• ρ
• 2
• 
• V
• q
• 
• (
• 1
• +
• K
• )
• .