Novel method for hexapod robots performing human-robot collaborative locomotion and bolt assembly based on screw theory

In the field of automatic assembly, legged robots, with excellent mobility, can expand the scope of assembly work. When legged robots are engaged in assembly, two key issues need to be addressed, namely approaching target objects and executing manipulations. The paper proposes a novel method for the hexapod robot to accomplish bolt assembly based on screw theory. Firstly, given the limitations of the visual system caused by lighting conditions, a human-robot collaborative locomotion method is innovatively introduced for the hexapod robot performing bolt assembly, aiming to overcome visual limitations. The robot formulates the motion planning strategy by analyzing the force applied by the operator, thus following human guidance to approach the target and align the bolt with the hole. Moreover, the screw theory is utilized to determine the pose of the bolt and execute the assembly manipulation, which efficiently solves the motion planning problem of bolt assembly. In addition, admittance control is incorporated in practical operations to guarantee compliant assembly. Based on the above initiatives, experiments were conducted to verify the effectiveness of the method.