With the development trend of intelligent manufacturing

the production process of products is becoming more and more flexible. Human-robot collaboration with high flexibility and automation level has become a research hotspot of manufacturing industry. In product assembly

the assembly operation with high flexibility and complex operation still needs to be finished by human

while the robot has the advantages of good repeatability

high load and high accuracy. In time and/or space sharing environment

robots are used to assist workers in assembly

which will reduce ergonomic pressure and workload

and achieve complementary advantages. Based on these understandings

this paper summarizes the research of human-robot collaborative assembly with time-space sharing. This paper reviews the current research status of the four hot spots developed around by scholars in recent years

namely

task allocation for human-robot collaboration

intention recognition for human-robot collaboration

path planning for human-robot collaboration

and safety design for human-robot collaboration collaborative assembly system. The development trend of these four aspects is discussed and prospected.