Method for performing tool change with robot arm

A method for performing a tool change with a robot arm, comprising the following steps of:

• providing a first coupling unit connected to a robot arm end shaft;
• providing a plurality of tool changer grippers and second coupling units detachably connected to the respective tool changer grippers;
• the robot arm end shaft driving the first coupling unit to perform a coupling operation for the first coupling unit to be coupled with a selected one of the second coupling units and take the selected second coupling unit away from the corresponding tool changer gripper;
• the robot arm end shaft driving the first coupling unit coupled with the selected second coupling unit back to the corresponding tool changer gripper and performing a decoupling operation for the first coupling unit to be decoupled from the selected second coupling unit;
• enabling the corresponding tool changer gripper to have a degree of freedom;
• the corresponding tool changer gripper being self-displaced by the degree of freedom in the coupling operation and in the decoupling operation to overcome a position error of the first coupling unit so that the first coupling unit can be coupled with or decoupled from the second coupling unit.