On the basis of analyzing the work principle of feeding hopper cover door mechanism

a planar four-bar linkage math model is built based on the parameters error sensitivity theory.Combined with changing characteristics of the parameters sensitivity in different positions

the errors disturbance effects and variation trend on door open angle are analyzed in the door open and close position.The changing extent of the rotating angle of the cover door in the different parameters error cases

and change rule of the door open angle is revealed.This can provide the guidance for the tolerance design

also can provide the theory basis for rational selection opening angle of feeding hopper cover door

and then improve the motion accuracy of mechanism.