The invention provides a double-arm 
robot cooperative vibration reduction method for 
grinding a large thin-walled workpiece in the technical field of 
machining. The method comprises the following steps that (1) a steady-state 
response model of forced vibration of the thin-walled workpiece is analyzed and established; (2) 
modal testing is carried out on the thin-walled workpiece with two fixed sides and two free sides; (3) an initial value of i is set, and i is equal to 1; (4) the position of a 
grinding end is input, whether the position of the 
grinding end is the end point of the grinding track or not is judged, if yes, grinding is finished, and if not, operation turns to the step (5); (5) a target 
modal is selected, and a vibration absorber is controlled to move to the 
maximum amplitude position {xi, yi} under the selected target 
modal; and (6) the position of the next grinding end is input, the maximum modal amplitude position under the target modal at the next grinding position is predicted, if the maximum modal amplitude position of this time is the same as the last 
maximum amplitude position, a transfer 
robot does not move, and if the maximum modal amplitude position of this time is different from the last 
maximum amplitude position, a transfer task is established, and the transfer 
robot acts. By means of the method, vibration generated when the thin-walled workpiece is ground is reduced.