The invention discloses a 
coupling self-adaptive 
robot finger device characterized in that the 
tail end moves along a straight line, and belongs to the technical field of 
robot hands. The 
coupling self-adaptive 
robot finger device comprises a base, a pedestal, a first finger section, a 
second finger section, a near joint shaft, a far joint shaft, a motor, three transmission mechanisms, two springparts, a 
cam, a push rod, a rolling wheel, a 
stroke increasing mechanism and a poking block. The 
coupling self-adaptive 
robot finger device can achieve coupling movement, achieves the effect of pinching an object, can also achieve self-adaptive movement, and achieves the effect of covering and holding objects with different shapes and different sizes. In the stage of coupling movement, the 
tail end of the 
second finger section moves along the straight line relative to the pedestal, the coupling self-adaptive 
robot finger device is suitable for pinching the object on a 
workbench in a coupling mode, the whole height of a 
robot hand does not need to be adjusted, the control difficulty of a mechanical arm is reduced, and the working efficiency is improved. The coupling self-adaptive 
robot finger device adopts an under-actuated move, two joints are driven by one driving device, and no complex sensing and 
control system is required. The coupling self-adaptive robot finger device is compact in structure, small in size and low in cost, and is suitable for the 
robot hand.