State-of-the-Art control strategies for robotic PiH assembly

Nowadays, industrial robots have been widely applied for performing position-controlled tasks with minimum contact such as spot welding, spray painting, packing, and material handling; however, performing high-tolerance assembly tasks still poses a great challenge for robots because of various uncertainties of the parts to be assembled such as fixtures, end effector tools, or axes. From this perspective, the advancement of research and development has led to cutting-edge robotic technologies for industrial applications. To understand the technological trend of industrial robots, investigated the state-of-the-art robotic assembly technologies to identify the limitations of existing works and clarify future research directions in the field. This paper especially interested on typical peg-in-hole (PiH) assemblies, as PiH methods provide insights for further development of robot assemblies. The assembly control strategies for PiH operations is classified by based on the types and features of the assemblies, and the literature in terms of the contributions of these studies is compared to PiH assembly. Finally, the control strategies for robotic PiH assemblies are discussed in detail, and the limitations of the current robotic assembly technologies are discussed to identify the future direction of research for the control of robotic assembly.