Robot automatic step-by-step bolt assembly method and system and double-arm robot

The invention relates to the technical field of robot automatic assembly, and provides a robot automatic step-by-step bolt assembly method and system and a double-arm robot. The method comprises the following steps of driving a first mechanical arm to clamp a pin to a first preassembly point located in a first mechanical arm base coordinate system; driving a second mechanical arm to clamp a pin seat with an inlet into a second preassembly point located in a second mechanical arm base coordinate system; obtaining inlet three-dimensional information of the inlet in the second machine arm base coordinate system when the pin seat is positioned at the second preassembly point; continuously detecting multi-dimensional force information of a pin wall on the pin seat in the second mechanical arm base coordinate system; and driving a first preassembly point of the first mechanical arm to start to assemble the pin into the pin seat step by step according to the three-dimensional information of the inlet and the multi-d