This paper deals with an analysis of dynamic mechanism for the industrial two-step folding automatic door. A nonlinear equation of motion was derived in terms of folding angle to estimate driving forces. Based on this dynamic behavior, time taken during the door’s opening well as their velocities were controlled so that the operating conditions can be obtained for the purpose of design. The stiffness of twisting spring was also investigated when the automatic door closed, because a dangerous accident takes place from the door’s free falling. The current research will be a very useful tool in the near future for the dynamic analysis for the multi-step folding automatic door.
